FR2957012A1 - Parallel robot for use as e.g. wrist type serial robot, has passive articulation space connecting end of mast of sub assembly to platform and determined by combination of position of moving part of three actuators of sub assembly - Google Patents

Abstract

The robot has a platform (100) coupled with a base (1). An end of a mast (40) is connected to the platform by a passive articulation space (50). Another end of the mast is connected to a mobile structure (5) by passive connection (38). The mobile structure is connected to the platform by a kinematic chain formed by the mast. The passive articulation space connects the former end of the mast of a sub assembly to the platform, and is determined by combination of position of a moving part (3) of three actuators (2) of the sub assembly.

Description

TECHNICAL AREA

The present invention relates to a parallel robot with three to six degrees of freedom, three degrees of freedom in translation. This robot makes it possible to move and orient a platform, to make position measurements in space or can be used as a haptic device. The platform may be equipped with a tool, an instrument, a transmitting device, a receiving device, a measuring device and / or a gripping device.

PRIOR ART

Parallel robots are composed of a group of kinematic chains, composed of actuators and articulated bars, acting in parallel from a base on a platform. The parallel robots have no actuator whose fixed part is moved in translation by another actuator and have no subset, including actuators, moved by another subset comprising actuators. Parallel robots have the advantage of high rigidity and high positioning and orientation accuracy, and can achieve high movement speeds and accelerations. They have a fast computation time of the inverse geometrical model. In the following, the qualifier "passive" applied to an element, a link or an articulation means that this element, this link or this articulation does not include a motorized actuator The pivot, cardan, spherical and prismatic links detailed in the following are all passive links The kinematic chains of known parallel robots having simultaneously three degrees of freedom in translation and degrees of freedom in rotation, comprise an actuator and two passive connection elements provided with at least two degrees of freedom in rotation. and each having their own center of rotation.

In a first variant, the fixed part of the actuator is connected to the base by means of a first passive connection element and the movable part of the actuator is connected to the platform by means of a second passive connection element Thus the fixed part of the actuator is displaced in rotation, but is not displaced in translation. 1 In a second variant, the fixed part of the actuator is integral with the base and the movable part of the actuator is connected to the first end of a bar by means of a first passive connection element and the second end of the bar is linked to the platform by means of a second passive link element.

The second passive connection element is capable of taking any position on a sphere whose center is located at the center of rotation of the first passive connection element and of radius equal to the distance between the centers of rotation of the two connecting elements liabilities. The posture of the platform results from the simultaneous action of all the chains on the platform and corresponds to a state of equilibrium which is determined by the combination of position of the moving part of the actuators of all the cinematic chains. For each connecting element fixed on the platform, the orientation of the bar or actuator connecting a passive link element to the other passive link element of the same kinematic chain and the position in the space of said element passive link fixed on the platform result from the simultaneous action of all kinematic chains on the platform. Indeed, the bars or the actuators are completely free in rotation and their orientation changes result only from the transition from one equilibrium state to another corresponding to the transition from one posture to another, so each bar or each actuator , linking the base to the platform, can not move by itself / itself. The modification of the position of the moving part of even one actuator of a kinematic chain modifies the orientation of the fixed part and the moving part of the actuator or the bar of all the kinematic chains and modifies the position in the space of all the passive connecting elements fixed on the platform. The resolution of the direct geometric model, which is extremely expensive in terms of computation time, shows that for the same combination of position of the moving part of the kinematic chain actuators, several posture solutions for the platform exist.

In a first case, the postures are distant from each other, and the platform is not likely to pass from one to the other without intervention of the control means of the robot. But, in a second case, there exist within the workspace known parallel robots, singular configurations of parallel type which correspond to regions of the work space in which several postures close to each other have the same combination of position of the movable part of the actuators and the platform can then be found in any of these postures due to the inertia of the platform, the forces exerted by the mass transported by the platform, gravity or games in the joints. If the trajectory of the platform passes through one of these regions, the platform can be found in any one of the postures verifying the combination of position of the movable part of the actuators, without the robot's control means being able to discern the robot's current posture, or even force the robot's platform into a certain posture. Subsequently, the instructions applied to the control of the actuators are no longer adapted to the succession of postures forming the initially programmed trajectory, it results in a loss of control of the robot. The trajectory of the robot must therefore be calculated to avoid passing through these regions, which requires a significant computation time and reduces the work space actually usable for operations such as machining or assembly and makes the use of these problematic robots in medical uses. When these robots are provided with six degrees of freedom, they have a small angular range of orientation of the platform of the order of +/- 30 degrees for the rotations 20 around the X and Y axes and +/- 40 degrees for the rotation around the Z axis. A hybrid robot of parallel-serial type is also known which consists of at least two subassemblies connected in series and each comprising a base, three actuators whose fixed part is integral with their respective base and a movable structure set in motion by means of said actuators acting in parallel on said movable structure. The mobile structure of a subset forms the basis of the next subset. A first subassembly, whose base forms the overall base of the robot, moves according to a degree of freedom in translation and orients according to two degrees of freedom in rotation a second subassembly, thus making it possible to move in at least five degrees of rotation. freedom the mobile structure of the second subset, the orientation of the base of the second subset being determined by the orientation of the movable structure of the first subset. The orientation range of the mobile structure of a subset is determined by the orientation of the base of this subset.

Each subset does not have a singular configuration of parallel type and therefore this robot does not have a singular configuration of parallel type. However, this robot has the drawbacks of serial robots, since it does not have an architecture that is only parallel, namely a large inertia due to the mass of the actuators of the second subassembly displaced in translation and in rotation by the actuators of the first subassembly. together, less rigidity and less precision compared to parallel robots, all actuators of the moving means all act in parallel only from the base on the platform, the fixed part of all the actuators being integral with the overall base robot or articulated in rotation to the overall base of the robot and not being moved in translation, and the movable part of all the actuators being hinged to the platform possibly by means of an articulated bar. Moreover, when the moving structure of the first subset changes orientation in order to position the center of the moving structure of the second subset at a point in the working space, the orientation range of the moving structure of the second subset, dependent on the orientation of the base of the second subset which is identical to the orientation of the moving structure of the first subset, is modified relative to the overall base of the robot. The robot therefore does not benefit from an orientation range of the overall robot platform that is constant throughout the workspace, considerably reducing the range of possible movements / orientations within the workspace, the corresponding global platform to the mobile structure of the second subset for a robot comprising two subsets. An increase in the number of serially mounted subassemblies or the series addition of angular actuators between a mobile structure and the base of the next subassembly in an attempt to overcome this latter problem would only reinforce the serial aspect of the robot by making it lose even more rigidity, while having a large footprint and while requiring a growing number of actuators.

SUMMARY OF THE INVENTION The object of the invention is to propose a robot presenting the advantages of known parallel robots by eliminating their disadvantages. The main advantages of the robot of the present invention reside in the fact that its platform has a single posture for a given combination of position of the movable part of the actuators, does not present a singular configuration parallel type inside the space of work, benefits from a simple and fast calculation of the direct and inverse geometrical models allowing the piloting, the verification of the conformity of the trajectory and the modification of the trajectory of the platform in real time and benefits from a great rigidity thanks to the that the fixed part of all the actuators is integral with the base or is constrained to a displacement only in rotation being articulated to the base by means of a passive connection provided with at least three degrees of connection of which three degrees of connection in translation.

These objectives are achieved thanks to the invention having for object a parallel robot, provided with three to six degrees of freedom, including three degrees of freedom in translation, comprising a base and a platform coupled to the base by means of movement which comprise only subassemblies all acting only in parallel from the base on the platform and all having at least one actuator, all the actuators of said moving means having their moving part with a single degree of freedom relative to their part respective fixed actuators, all the actuators of said moving means acting in parallel only, the fixed part of all the actuators of said moving means being connected to the base by means of a passive link provided with at least three degrees of link with three degrees of connection in translation, the fixed part of at least four actuators of said moving means being linked the base by means of a passive connection with at least three degrees of connection including three degrees of binding in translation. Said moving means comprise at least two subassemblies, of which a first subassembly comprises a single mobile structure, three kinematic chains linking the mobile structure to the base, a single mast and a passive articulation, said mobile structure being rigid. and being provided with two degrees of freedom in rotation and being provided with a degree of freedom in translation, said mast being constituted by a bar, said passive articulation being provided with at least two degrees of freedom in rotation and with at least two degrees of translation linkage, said mobile structure being linked to the base only by means of the three said kinematic chains linking said mobile structure to the base, each kinematic chain linking said mobile structure to the base comprising an actuator, each kinematic linkage said movable structure at the base comprising two passive articulation elements equivalent in total to four pivots ot passive, the setting in motion according to two degrees of freedom in rotation and a degree of freedom in translation of said mobile structure being obtained by means of the three actuators, of the three said kinematic chains linking said mobile structure to the base, acting in parallel and whose fixed part is connected to the base by means of a passive connection provided with at least three degrees of connection of which three degrees of connection in translation, the mobile part of each of said actuators being connected to said mobile structure by means of at least one of the two passive articulation elements of said respective kinematic chain linking said mobile structure to the base, the first end of said mast being connected to the platform only by means of said passive articulation, the second end of said mast being connected to said mobile structure only by means of a passive link having at least five degrees of connection, of which three degrees of translation in translation, said mobile structure being connected to the platform only by means of the kinematic chain formed solely by said mast provided at its first end with said passive articulation and at its second end of said passive connection, the longitudinal axis of said mast forming a constant angle with said movable structure, said first subset moving in said three degrees of freedom in translation said passive articulation of the first subset through the action of said three actuators of the first subset, and of which at least a second subset together, acting on the orientation of the platform around the center of rotation of said passive joint of said first subassembly, comprises at least one actuator whose fixed part is linked to the base by means of a passive link provided with at least three degrees of binding including three degrees of translation linkage. The position in the space of the passive joint linking the first end of the mast of the first subassembly to the platform is determined solely by the combination of position of the movable part of the three actuators of the first subassembly, independently of the action exerted by any of the other subsets of the moving means on the platform.

The fixed part of any actuator means for moving the platform is moved in translation by another actuator. The mobile structure is of any shape. A kinematic chain linking the mobile structure to the base can be achieved either by means of an actuator whose fixed part is connected to the base by means of a first passive articulation element and whose movable part is linked to the structure movable by means of a second passive articulation element, or by means of an actuator whose fixed part is integral with the base and whose movable part is connected by means of a first passive articulation element to the first end of a bar whose second end is connected by means of a second passive articulation element to the mobile structure. The first passive articulation element may consist of either a pivot connection, a universal joint or a spherical connection and the second passive articulation element consists respectively of a spherical connection, a cardan , a pivot link. The sum of the number of equivalent pivot connections of the two passive articulation elements of the same kinematic chain being equal to four, this results in geometrical constraints in obtaining the posture of the moving structure which make it less than a limiting angle between the plane of the movable structure and the plane of the base, for each combination of position of the moving part of the actuators the moving structure has a single respective posture in space, the limiting angle determining the limits of the working envelope of the mobile structure. The second end of the mast is bonded to the moving structure either by means of a fixed link, having six degrees of bonding, or by means of a passive pivot link, having five degrees of bonding. The longitudinal axis of the mast is preferably perpendicular to the movable structure and passes through the center of the movable structure. The mast is placed above a horizontal plane passing through the center of the mobile structure and remains permanently above this plane. For each combination of position of the moving part of the actuators of the subassembly, the passive joint fixed to the first end of the mast has a single respective position in space.

Thus, the mast, mounted on said mobile structure, transforms the displacement of the mobile structure, provided with two degrees of freedom in rotation and of a degree of freedom in translation, in a displacement according to three degrees of freedom in translation of the passive articulation, while having a minimal footprint of the mast and using only three actuators.

The second subassembly comprises a deformable prism and a mobile structure, with a degree of freedom in translation and two degrees of freedom in rotation, set in motion only by means of three actuators of said subassembly acting in parallel on said mobile structure, said deformable prism being constituted by at least three bars of the same length each provided at their two ends with a respective passive angular connection provided with at least two degrees of freedom in rotation, all the passive angular links of a same end of said bars forming a respective base of said deformable prism. The platform is linked to said mobile structure only by means of said deformable prism.

In the following, the expression "passive angular connection" designates only a passive angular connection which is fixed at the end of a bar of the deformable prism. When all the passive angular links of the two bases of the deformable prism are gimbals, the deformable prism imposes the parallelism between the mobile structure on which one of the bases of the deformable prism is mounted and the platform on which the other base of the deformable prism is mounted, thereby changing the orientation of the platform, around the center of rotation of the passive joint of the first subset, through a change of orientation of the movable structure of the second subset.

The fixed part of the passive articulation is fixed at the center of the platform. The passive joint forms a point element in the space and allows an unhindered rotation of the platform around this element. The mast of the first subset determines the position in the space of the passive joint. Since the platform is set in motion by means of two subassemblies, the position of the moving part of the actuators moving the respective moving structures of the two subassemblies must verify the following constraint, namely that the altitude of the base of the deformable prism mounted on the movable structure of the second subassembly is such that the center of the base of the same deformable prism mounted on the platform coincides with the center of rotation of the passive joint. Above the horizontal plane passing through the center of the mobile structure of the first subassembly, this altitude is unique and the platform thus presents a unique posture in space for the corresponding combination of position of the movable part of all the actuators. As a result, the robot does not present a singular configuration of parallel type within its workspace.

The orientation range of the platform is independent of the position of this passive articulation in space since it depends solely on the orientation range of the mobile structure of the second subassembly, setting in motion the deformable prism, which is constant, so the platform has a constant orientation range relative to the base in its workspace.

In a variant, the second subassembly comprises at least one passive rotary device consisting of a passive pivot connection, a deformable prism and a mobile structure, with a degree of freedom in translation and two degrees of freedom in rotation. moving only by means of three actuators of said subassembly acting in parallel on said movable structure, said deformable prism being constituted by at least three bars of the same length each provided at their two ends with a respective passive angular link provided with at least two degrees of freedom in rotation, all the passive angular links of the same end of said bars forming a respective base of said deformable prism. The platform is linked to said mobile structure only by means of the kinematic chain constituted by said deformable prism, all of the passive angular links of at least one of the bases of said deformable prism are integral with the fixed part of at least one said device. respective passive rotary. So the platform can rotate around its normal. The control of this rotation is effected by means of an additional rotary actuator, belonging to the second subassembly, whose fixed part is integral with the base and whose movable part is integral with the first end of a double telescopic cardan whose the second end is integral with the second end of the mast of the first subassembly, the second end of the mast being also connected to the movable structure of the first subassembly by means of a passive pivot link.

Thus the mast can be rotated about its longitudinal axis, and transmit the rotational movement of the additional rotary actuator to the platform, which is guided in rotation by means of said passive rotary device or deformable prism guided in rotation by means of of said passive rotary device. The platform can realize an unlimited number of complete turns around its normal.

In another variant, the second subassembly comprises a deformable prism and a mobile structure, provided with a degree of freedom in translation, set in motion solely by means of at least one actuator of said subset, said deformable prism being consisting of at least three bars of the same length each provided at both ends with a respective passive angular connection provided with at least two rotational degrees of freedom, all the passive angular links of the same end of said bars forming a base respective of said deformable prism. The platform is linked to said mobile structure only by means of said deformable prism. Thus the platform benefits from a constantly parallel orientation to the base.

In another variant, the second subassembly comprises at least one passive rotary device consisting of a passive pivot connection, a deformable prism and a mobile structure, provided with a degree of freedom in translation, set in motion only by means of at least one actuator of said subassembly, said deformable prism consisting of at least three bars of the same length each provided at their two ends with a respective passive angular connection provided with at least two degrees of freedom in rotation, all the passive angular links of the same end of said bars forming a respective base of said deformable prism. The platform is linked to said mobile structure only by means of the kinematic chain constituted by said deformable prism, all of the passive angular links of at least one of the bases of said deformable prism are integral with the fixed part of at least one said device. respective passive rotary. So the platform can rotate around its normal. When all the passive angular links of at least one of the bases of the deformable prism linking the platform to the mobile structure of the second subset are passive spherical links, the deformable prism makes it possible to modify the orientation of the platform according to three degrees of freedom in rotation by modifying the altitude and the orientation of the base of said deformable prism which undergoes a twisting due to the constraint imposed by the passive articulation.

In all the variants of the robot, the moving of the mobile structure of the second subassembly can be carried out according to one of the following variants: According to a first variant, the mobile structure of the second subassembly, provided with two degrees of freedom in rotation and of a degree of freedom in translation, is set in motion, according to two degrees of freedom of rotation and a degree of freedom in translation, solely by means of three actuators, of said subassembly, acting in parallel on said mobile structure, said mobile structure of said subset being bonded to the base only by means of three kinematic chains each comprising a respective actuator, said three actuators of said subset, and two respective passive articulation elements equivalent to links passive pivots, the total of the number of equivalent passive pivot links included in said two passive articulation elements res pectives, of the same said kinematic chain, is equal to four, the mobile part of each of said actuators being linked to said mobile structure by means of a respective passive kinematic branch comprising at least one passive link element consisting of one of said two passive articulation elements of a said respective kinematic chain. Said mobile structure is linked to the platform by means of a passive kinematic chain comprising at least one deformable prism. According to a second variant, the mobile structure of the second subassembly, endowed with a degree of freedom in translation and two degrees of freedom in rotation, is set in motion, according to two degrees of freedom in rotation and a degree of freedom in translation, only by means of three actuators, of said subassembly, acting in parallel on said mobile structure, the fixed part of each of said actuators being integral with the base, the movable part of each of said actuators of said subset being connected to said mobile structure of said subassembly only by means of a respective passive link element equivalent to three passive pivot links and a passive link. Said mobile structure is linked to the platform by means of a passive kinematic chain comprising at least one deformable prism. According to a third variant, the mobile structure of the second subassembly, provided with a degree of freedom in translation and two degrees of freedom in rotation, is set in motion, according to two degrees of freedom in rotation and a degree of freedom in translation, only by means of three actuators, said subassembly, acting in parallel on said movable structure, the fixed part of each of said actuators being integral with the base, said movable structure being connected to the movable portion of the first actuator, said actuators of said subassembly, only by means of a passive link element equivalent to two passive links and a passive prismatic link. Said mobile structure is linked to the moving part of the second actuator, said actuators of said subset, only by means of a passive link element equivalent to three pivot links and a passive prismatic link. The mobile structure of said subassembly is linked to the moving part of the third actuator, said actuators of said subset, only by means of a passive link element equivalent only to an assembly of passive pivot links. Said mobile structure is linked to the platform by means of a passive kinematic chain comprising at least one deformable prism. In a fourth variant, the second subset is similar to the first subset of the moving means. Thus, the moving means comprise at least two subassemblies each comprising a single mobile structure, three kinematic chains linking the mobile structure to the base, a single mast and a passive articulation, said mobile structure being rigid and being provided with two degrees of freedom in rotation and being provided with a degree of freedom in translation, said mast being constituted by a bar, said passive articulation being provided with at least two degrees of freedom in rotation and at least two degrees of link in translation, said mobile structure being linked to the base only by means of the three said kinematic chains linking said mobile structure to the base, each kinematic chain linking said mobile structure to the base comprising an actuator, each kinematic chain linking said mobile structure to the base comprising two passive articulation elements equivalent in total to four passive pivot links, the setting in motion according to two degrees of freedom in rotation and a degree of freedom in translation of said mobile structure being obtained by means of the three actuators, of the three said kinematic chains linking said mobile structure to the base, acting in parallel and whose fixed part is connected to the base by means of a passive link having at least three degrees of connection, of which three degrees of connection in translation, the mobile part of each of said actuators being connected to said mobile structure by means of at least one of the two passive articulation elements of said respective kinematic chain linking said mobile structure to the base, the first end of said mast being connected to the platform only by means of said passive articulation, the second end of said mast being connected to said mobile structure only by means a passive link with at least five links, of which three degrees of translation link, said mobile structure being connected to the platform only by means of the kinematic chain formed solely by said mast provided at its first end with said passive articulation and at its second end of said passive link, the longitudinal axis of said mast forming a constant angle with said mobile structure, said subset moving in three degrees of freedom in translation said passive articulation of said subset through the action of said actuators of said subset.

The moving means further comprise at least a third subassembly. At least the third subassembly may comprise an actuator whose fixed part is hinged to the base and whose movable part is articulated to the platform and / or an actuator whose fixed part is integral with the base and whose moving part is articulated at the first end of a bar whose second end is hinged to the platform. The moving means may comprise at least three subsets whose setting in motion is similar to the setting in motion of the first subset of the robot, and the mobile structure of at least one subset , provided with two degrees of freedom in rotation and a degree of freedom in translation, is set in motion, according to two degrees of freedom of rotation and a degree of freedom in translation, solely by means of three actuators, of said subset acting in parallel on said movable structure, said movable structure of said subset being bonded to the base only by means of three kinematic chains each comprising a respective actuator, said three actuators of said subset, and two respective passive articulation elements equivalent to passive pivot links including the total number of equivalent passive pivot links included in said two passive link members of the same said kinematic chain, is equal to four, the moving part of each of said actuators being connected to said mobile structure by means of a respective passive kinematic branch comprising at least one passive link element consisting of one of said two passive articulation elements of a said respective kinematic chain. The single mast linking said mobile structure to the platform is constituted by a bar, the first end of said mast being connected to the platform only by means of a passive articulation, provided with at least two degrees of freedom of rotation and rotation. at least two degrees of translation linkage, and the second end of said mast being linked to said mobile structure only by means of a passive link having at least five degrees of connection, including three degrees of translation linkage. For each subassembly comprising a mast, the position in the space of the passive articulation linking the first end of said mast of said subassembly to the platform is determined solely by the combination of position of the moving part of the three actuators of said sub. together, independently of the action exerted by any one of the other subsets of the moving means on the platform. Thus, the platform has a unique posture for the combination of position of the moving part of all the actuators of all the subassemblies, therefore the working space does not have a singular configuration of parallel type. In addition, the platform has an angular range greater than +/- 90 degrees depending on the rotations around the X, Y and Z axes, allowing it to travel through the platform of the five faces of a substantially cubic object without changing the posture of the object. The number of masts being reduced to three, the risk of collision between them is limited. When the robot has several subassemblies comprising a mast, one of these subsets is considered to be the first subset and another of these subsets is considered to be the second subset acting on the subset. orientation of the platform around the center of rotation of the passive joint belonging to the first subset. The platform is linked to the mobile structure of at least one subset solely by means of the passive kinematic chain formed solely by a mast, consisting of a bar of fixed length, provided at its first end with a single passive articulation having three degrees of freedom in rotation and a single degree of freedom in translation, the second end of said mast being integral with the movable structure, said movable structure having two degrees of freedom in rotation and a degree of freedom in translation, being set in motion by means of three actuators acting in parallel.

The prismatic connection of the passive joints makes it possible to avoid a deformation of the robot when a slight defect of position of the passive joints in space occurs relative to each other due to a synchronization fault of the movements of the actuators of the subassemblies. In a fifth variant, the second subassembly comprises at least two actuators each arranged in one of the following two variants, namely a first variant in which the fixed part of the actuator is articulated to the base and its movable part is articulated. to the platform and a second variant in which the fixed portion of the actuator is integral with the base and the movable portion is articulated to the first end of a bar whose second end is hinged to the platform.

In the variants of the robot in which the fixed part of all the actuators of the moving means is integral with the base, the robot has high rigidity, high dynamics and reduced energy consumption. In addition, high-precision measuring devices can be easily installed to measure the position of the moving part of the actuators, in order to accurately determine the posture of the platform, thanks to the calculation of the direct geometric model. The moving part of the actuators can be moved by means of electric motor, pneumatic, hydraulic, linear, piezoelectric or variable magnetic fields. In all embodiments of the robot, the movements of the movable portion of the actuators can be rotatable or linear. In the case of rotary actuators, the expression "the position of the moving part of an actuator" designates the angle of rotation of the moving part of an actuator. Each actuator may consist of two actuators whose fixed part is integral with the base, namely a primary actuator and a secondary actuator, the movement of the movable portion of the primary actuator being copied by means of a device, allowing a similarity ratio, on the movable part of the secondary actuator, the movable structure being connected to the respective moving parts of the secondary actuators.

The robot is provided with control means for controlling the motors of the actuators so as to control the movements of the platform. The actuators may be passive, in the case of a robot serving as a haptic device, and consist of linear displacement sensor and / or rotary displacement. The robot can be provided with clamps, cameras and device for measuring the position and orientation in the space of the base and / or the platform.

DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment, given by way of illustrative and nonlimiting example, and the accompanying figures forming an integral part of the invention. said description and all of which are perspective views, among which: FIG. 1 shows a robot, equipped with six degrees of freedom, comprising two subassemblies, a first subassembly of which comprises a movable structure (5) provided with a mast (40) and a second subassembly, in its first variant, comprises a movable structure (25) provided with a deformable prism (30, 31, 32) connected to a passive rotary device (41), - the FIG. 2 shows a detailed view of the kinematic chains linking the mobile structure (5) to the base (1), - FIG. 3 shows a robot, equipped with five degrees of freedom, comprising two subsets, the second subset. and In its second variant, FIG. 4 shows a robot, equipped with six degrees of freedom, comprising a deformable prism 25 (30, 31, 32) undergoing torsion, the second subassembly being in its third variant, the FIG. 5 shows a robot with three degrees of freedom of translation, whose platform (100) is constantly parallel to the base (1); FIG. 6 shows a robot with six degrees of freedom using only six actuators (2, 22, 33), - Figure 7 shows a robot, with six degrees of freedom, comprising three subassemblies, - Figure 8 shows a variant of the previous robot, whose platform (100) is provided with three bars connected to the first end of their respective mast (40) by means of a passive joint (50) respectively, - Figure 9 shows a robot with six degrees of freedom, the second subassembly comprises minus two actuators (22) whose fixed part is articulated to the base (1), - Figure 10 shows a robot with six degrees of freedom, the second subassembly comprises at least two actuators (22) whose fixed part is integral with the base (1). In the figures, only the fixed part of the links constituting the articulation elements is shown, the movable part being integral with another element and thus merged with this other element. A link member or link member, consisting of several links, is globally numbered with an integer. An integral link in a link member or hinge member is numbered with an additional index consisting of a letter of the alphabet. Several lines starting from the same number are directed to the different links or group of links constituting the same element. The number designating an actuator is carried on its fixed part. When the second end of the mast is connected to the mobile structure by means of a passive connection consisting of a fixed link, it is not shown in the figure, since the mast and the mobile structure are then integral.

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 shows a robot in its first embodiment, provided with six degrees of freedom, whose means for moving the platform (100) are composed of a first subset and a second subset. The first subassembly comprises a rigid structure (5) of any shape. The mobile structure (5) is set in motion, according to two degrees of freedom of rotation and a degree of freedom in translation, by means of three kinematic chains each comprising an actuator (2) and two passive articulation elements (4). A kinematic chain linking the mobile structure (5) to the base (1), presented in detail in FIG. 2, can be realized either by means of an actuator (2) whose fixed part is articulated by means of a first passive articulation element (4) at the base (1) and whose movable part is articulated by means of a second passive articulation element (4) to the mobile structure (5), or by means of an actuator (2) whose fixed part is integral with the base (1) and whose movable part (3) is articulated by means of a first passive articulation element (4) to the first end of a bar, the second of which end is articulated by means of a second passive articulation element (4) to the movable structure (5). The first passive articulation element (4) can consist of either a pivot connection, a cardan joint or a spherical connection and the second passive articulation element (4) consists respectively of a link spherical, a cardan, a pivot connection. All variants of the robot can be realized by means of any of the kinematic chain variants described above. The kinematic chain shown in the figure consists of an actuator (2) whose fixed part is integral with the base (1) and whose movable part (3) is connected to the first end of a bar by means of a passive articulation element (4) equivalent to three passive pivot links, the second end of said bar being connected to the movable structure (5) by means of a passive articulation element (4) consisting of a pivot connection passive. The first end of the mast (40) consists of a bar is articulated to the platform (100) by means of a passive joint (50) consisting of a cardan. The second end of the mast (40) is connected to the movable structure (5) by means of a passive pivot link (38). The longitudinal axis of the mast (40) forms a constant angle with the movable structure (5) and passes through the center of the movable structure. The second subassembly comprises a movable structure (25) which is set in motion, in two degrees of freedom of rotation and a degree of freedom in translation, solely by means of three actuators (22), of said subassembly, acting as parallel to the mobile structure (25). In a first variant, the mobile structure (25) of the second subassembly is linked to the base (1) only by means of three kinematic chains each comprising a respective actuator (22) and two respective passive articulation elements (24). equivalent to passive pivot links whose total of the number of equivalent passive pivot links included in the two respective passive articulation elements (24) of the same kinematic chain is equal to four. The movable part (23) of each of the actuators (22) being connected to the movable structure (25) by means of a respective passive kinematic branch comprising at least one passive connection element (24) consisting of one of said two elements d respective passive joints (24). A deformable prism (30, 31, 32), consisting of at least three bars (30) of the same length, is mounted on the movable structure (25) of the second subassembly. At the first end of each bar (30) of the prism is fixed the fixed portion of a passive angular connection (31) cardan type whose movable portion is integral with the movable structure (25). At the second end of each bar (30) of the prism is fixed the fixed part of a passive angular connection (32) cardan type whose movable portion is integral with the fixed part of a passive rotary device (41), constituted a passive pivot link, the movable portion of which is integral with the platform (100). Thus, the platform (100) and the mobile structure (25) of the second subassembly have the same orientation, whatever the orientation of said mobile structure (25), since the platform (100) and said mobile structure (25) 25) are constantly parallel, thanks to the constraints imposed by the deformable prism (30, 31, 32). The control of the rotation of the platform (100) around its normal is carried out by means of an additional rotary actuator (33), belonging to the second subassembly, whose fixed part is integral with the base (1) and whose the moving part (34) is connected to the second end of the mast (40) by means of a double telescopic cardan (35). Thus, the rotational movement of the additional rotary actuator (33) is transmitted to the mast (40), which in turn transmits it to the platform (100) which can rotate around its normal being guided in rotation by means of the passive rotary device (41).

In a variant, the rotational movement of the additional rotary actuator (33) can be transmitted directly to the platform (100) or to a device, such as a gripping device rotatably mounted on the platform, by means of at least one double telescopic cardan eventually provided at its end with a device such as a set of gears. One of the movable structures (5, 25) of a subassembly may comprise in its center an orifice through which the mast (40) of another subassembly passes. In all the variants of the robot comprising a deformable prism (30, 31, 32), the mobile structure (5) of the first subassembly can be placed above or below the mobile structure (25) of the second sub-assembly. together.

Figure 3 shows a robot with five degrees of freedom, consisting of two subsets. The first subassembly differs from the first subset of the robot of FIG. 1 in that the mast (40) is integrally mounted on the mobile structure (5) and the passive joint (50) is fixed to the first end of the mast (40) is a spherical joint. In a second variant of setting in motion the mobile structure (25) of the second subassembly, the movable part (23) of each of the actuators (22) is connected to the mobile structure (25) only by means of an element passive link (24) respectively equivalent to three passive pivot connections and a prismatic link, the fixed part of each of the actuators (22) being integral with the base (1). The movable part of each angular connection (32), whose fixed part is secured to the second end of a respective bar (30) of the deformable prism (30, 31, 32) is integral with the platform (100). FIG. 4 shows a robot with six degrees of freedom, the first subassembly of which is similar to the first subset of the robot of FIG. 1. The mobile structure (25) of the second subassembly being set in motion according to its third variant, comprises a first bar of circular section whose first end is integral with the rest of said movable structure (25). A first passive link element (24.1) equivalent to two passive links and a prismatic link is obtained by assembling a first pivot link whose movable portion is integral with the fixed portion of a second pivot link. which furthermore allows a prismatic connection, the second pivot connection thus forming a sliding pivot type connection with the integrated bar in the mobile structure (25), the fixed part of the first pivot connection being integral with the movable part (23) of a first actuator (22). A second passive link element (24.2), equivalent to three pivot links and a passive prismatic link is obtained by assembling a first pivot link whose movable portion is integral with the fixed portion of a second pivot link which furthermore allows a prismatic connection, the second pivot connection thus forming a sliding pivot-type connection with a second bar of circular section, one end of which is integral with the fixed part of a third pivot connection, the moving part of which is secured to the movable structure (25), the fixed portion of the first pivot connection being secured to the movable portion (23) of a second actuator (22).

The movable structure (25) is preferably connected at its center to the movable part (23) of a third actuator (22) by means of a third passive connection element (24.3) consisting of two mounted passive pivot links in cardan. The longitudinal axes of the two bars, preferably moving in two respective planes orthogonal to each other, are concurrent at a point which corresponds to the center of rotation of the third passive connection element (24.3). The angular links (32) of one of the bases of the deformable prism (30, 31, 32) are passive spherical links, and the deformable prism makes it possible to modify the orientation of the platform (100) according to three degrees of freedom. rotation by a torsion of the deformable prism combined with the action of the optional additional rotary actuator (33) which makes it possible to eliminate the singularity characteristic of this variant, occurring when all the bars (30) of the prism (30, 31 , 32) are parallel. The rotary actuator (33) constrains the platform (100) to rotate about its normal in the desired direction to one of two postures that are solutions of the same positional combination of the movable portion (3) of the actuators (2). This type of singularity does not have the drawbacks of parallel-type singularities of known parallel robots since it is possible to cross it and obtain at any time the posture of the desired platform (100). FIG. 5 shows a robot with three degrees of freedom whose platform (100) has an orientation that is constantly parallel to the base (1). The first subassembly is similar to the first subassembly of the robot of FIG. 3. The second subassembly comprises a deformable prism (30, 31, 32) mounted on a mobile structure (25), having a degree of freedom in translation, secured to the movable portion (23) of at least one actuator (22), provided with a degree of freedom in translation, 25 whose fixed part is integral with the base (1). To rotate the platform (100) about its normal, an additional rotary actuator (33) and a passive rotary device (41) may be added. The movable structure (25) shown in the figure is guided in translation by means of several actuators (22), having a degree of freedom in translation, which can be passive or motorized with possibly a device for copying movement between them. actuators (22). FIG. 6 shows a robot with six degrees of freedom whose first subset is similar to the first subset of the robot of FIG. 1. The mobile structure (25) of the second subset is linked to the part mobile (23) of a first actuator (22), the fixed part of which is integral with the base (1), by means only of a first passive connection element (24.1) equivalent to three pivot links and a first link passive prismatic. The movable structure (25) is connected to the movable part (23) of a second actuator (22), whose fixed part is integral with the base (1), only by means of a second passive connection element (24.2 ) formed from the assembly of a single passive pivot link (24.a) coupled to a passive hinge member (24.b, 24.c, 24.d) equivalent to three pivot links and a second prismatic link passive, the axis of rotation of said single passive pivot link being orthogonal to the longitudinal axis of said second prismatic link.

The movable structure (25) of the second subassembly is bonded to the mast (40) of the first subassembly only by means of a passive angular joint (70) having three degrees of freedom in rotation. The robot uses only six actuators and each degree of rotational freedom of the platform (100) is decoupled by means of a single respective actuator (22, 33). FIG. 7 shows a robot, equipped with six degrees of freedom, whose means for setting the platform (100) in motion are composed of three subassemblies each comprising a mobile structure (5). The first end of the mast (40), consisting of a bar, is connected to the platform (100) by means of a passive joint (50) consisting of a passive spherical joint. The second end of the mast (40) is integral with the movable structure (5). The longitudinal axis of the mast (40) forms a constant angle with the movable structure (5) and passes through the center of the movable structure (5). At least two subsets being identical, one of the subsets is considered to be the first subset and the other subset is considered to be the second subset. The numbering of the elements of each subset includes the numbering of the constituent elements (2, 3, 4, 5) of the first subset. FIG. 8 shows a variant of the robot of FIG. 7 in which each passive articulation (50) linking a respective mast (40) to the platform (100) is a passive spherical joint (50) which also allows a prismatic connection. The platform (100) comprises three bars of circular section whose first end is integral with the rest of the platform Each passive joint (50) is obtained by means of the assembly formed of two pivot links connected in series with a third pivot connection which allows in addition a prismatic connection, the third pivot connection thus forming a sliding pivot-type connection with a respective bar integrated in the platform (100).

The prismatic connection of the passive joints (50) makes it possible to avoid a deformation of the robot when a slight defect in the position of the passive joints (50) in space occurs relative to one another due to a lack of synchronization of the movements of the actuators (2) subsets. A safety device may be added to determine the position of the passive joint (50) relative to the end of a respective bar and to prevent the passive joint from going beyond said bar. In the two previous robots, the number of subsets can be increased to move heavy loads or large loads. The platform (100) may consist of the object to be moved and the passive joints linking the respective poles to the object are fixed temporarily on the object. FIG. 9 shows a robot, equipped with six degrees of freedom, which differs from the robot of FIG. 4 in that the second subassembly consists of at least two actuators (22) whose fixed part is articulated to the base (1) by means of a gimbal (46) and whose movable part is hinged to the platform (100) by means of a spherical connection (45). FIG. 10 shows a robot, with six degrees of freedom, which differs from the robot of FIG. 4 in that the second subassembly consists of at least two actuators (22) whose fixed part is integral with the base (1) and whose movable part (23) is articulated by means of a gimbal (48) to the first end of a bar (47) whose second end is hinged to the platform by means of a link spherical (45). In the variants presented in FIGS. 9 and 10, the rotation of the platform (100) according to three degrees of freedom can be obtained by means of the actuators (22) of the second subset of which there are three with the presence of a singularity similar to that described in the robot of Figure 4, which can be removed by providing the second subset of at least two actuators (22) and an additional rotary actuator (33) hinged to the mast (40). The presence of a third actuator (22) increases the strength of the robot.

In all the variants of the robot, in order to increase the strength of the robot, the platform (100) can also be provided with additional bars, each of the bars being articulated by means of a passive spherical joint which also allows a prismatic connection. passive either to the movable part of an additional actuator whose fixed part is hinged to the base (1) or to the first end of a bar whose second end is articulated to the movable part of an additional actuator whose part fixed is integral with the base. The posture of the platform (100) being entirely determined by the combination of position of the movable part (3, 23, 34) of the actuators (2, 22, 33) of the first two subassemblies, the additional actuators make it possible to increase the force of the robot without risk of deformation thereof since their articulation with the platform (100) is effected by means of a passive spherical joint allowing further a passive prismatic connection. In certain variants of the robot, the passive articulation (50) may be provided with a degree of freedom in complementary translation that makes it possible to avoid deformation of the robot when a slight synchronization defect occurs between the movements of the actuators (2) of the first subassembly, which move the passive joint (50), and the movements of the actuators of the second subassembly (22), which move the deformable prism (30, 31, 32). The passive connection elements (24), equivalent in total to three pivotal links and to a passive prismatic connection, can be arranged according to several assemblies and according to various combinations of order of the assembly, by way of nonlimiting example: hollowed-out ball joint, solid ball joint coupled to a prismatic connection, gimbal coupled to a sliding pivot connection, gimbal coupled to a pivot connection coupled to a prismatic link. The passive connection elements or the passive articulation elements do not comprise a motorized actuator. A linear motion actuator can be realized by means of a rotary motion actuator coupled to a device transforming linear motion into rotary motion. This device can be realized by means of two plates, respectively fixed plate and movable plate, articulated by means of at least two identical passive kinematic chains each comprising a first pivot connection whose movable part is integral with the first end of a first bar whose second end is integral with the fixed portion of a second pivot connection whose movable portion is integral with the first end of a second bar whose second end is secured to the fixed portion of a third pivot connection. The fixed part of the first pivot link of each passive kinematic chain being coupled to the movable part of a single rotary actuator, whose fixed part is integral with the fixed plate, possibly by means of a motion copying device optionally supplemented with by means of a device for reversing the direction of rotation. The movable portion of the third pivot link of each passive kinematic chain being secured to the movable platen. This results in a translation movement according to a degree of freedom of the movable plate relative to the fixed plate. The fixed plate forming the fixed part of an actuator, and the movable plate forming the movable part of an actuator.

The deformable prism (30, 31, 32) may comprise additional bars (30) for increasing the rigidity of the robot and to enhance the parallelism between the bars of the prism. Another advantage of this robot lies in the fact that according to the ratio between the length of the mast (40) and the distance between the fixed parts of the actuators (2, 22), it is possible to obtain displacements of the platform (100 ) having an amplitude smaller than the amplitude of the movements of the actuators, and thus to obtain a resolution of the movements of the platform (100) better than the resolution of the movements of the actuators (2, 22). Conversely, it is possible to obtain an amplitude of the movements of the platform greater than the amplitude of the movements of the actuators.

Engines, tools, instruments or devices attached to the platform (100) are additional elements that are not part of the robot, therefore their actuators and / or their motors are not part of the robot and the moving element of these motors can not be likened to the platform (100) of the robot. The term "fixed part" and "movable part" of elements such as pivot links and prismatic links serve only to name one part of an element with respect to the other, since the two parts of the element are movable relative to each other. It would not be departing from the scope of the invention to add elements, such as, for example, pivot links or additional prismatic links, which are not absolutely necessary to obtain movements of the robot. It would not be departing from the scope of the invention by replacing passive elements by motorized elements, such as the passive articulation (38) linking the second end of the mast (40) to the mobile structure (5) by a motor or the device passive rotary drive (41) by a motor, or by replacing the bar constituting the mast (40) with an actuator.

POSSIBILITIES OF INDUSTRIAL APPLICATION

The robot can be used in a wide variety of application areas, including machine tools or assembly devices that require highly accurate movements and orientations of the tool or object to be machined or assembled. The robot is particularly interesting for optical machining thanks to its very high angular precision. The robot can be used to move and / or orient a large mass object or devices such as medical measuring device, surgical tool, theodolite, telescope, telecommunication wave transmitter / receiver, radiation emitter / receiver (laser, ray X). The robot can be used to constitute a three-dimensional measuring machine. The robot can be used to perform the movements of a locomotion simulator or an attraction machine.

The robot can serve as a wrist for a serial robot, bringing to it a very high precision of movement locally, without moving all the elements of the robot arm, the position of the base and / or the platform of the robot. parallel robot in the space being determined by a measuring device. The robot can be attached to the arm of a construction machine, a handling machine or an articulated crane.

The robot can be used in fast pick-and-place or palletizing operations, especially for large loads, with a large work area benefiting from large angular ranges of orientation of the platform, with a small footprint of chains kinematics between the mobile structure (s) and the platform.

The robot can serve as a haptic device for detecting the movement and orientation of the platform made by an operator relative to the base by the use of position sensors of the movable part of the actuators, and supplemented or not by a device back from strength. The robot can be used as a third hand to hold an object, when the actuators are passive and have a controlled locking device. The robot can be mounted on a linear, rotary, Cartesian or gantry type moving device. Several robots can collaborate in handling a large object or large mass.

The sectors of activity likely to use such robots are varied: automotive, naval and aeronautic construction, building construction, electronics, agro-food, manufacture, biotechnology, medical, metrology, mechanics, logistics, ...

Claims (11)

REVENDICATIONS1. Parallel robot, having three to six degrees of freedom, three degrees of freedom of translation, comprising a base (1) and a platform (100) coupled to the base by means of moving which comprise only subsets acting all only in parallel from the base (1) on the platform (100) and all comprising at least one actuator (2, 22), all the actuators (2, 22) of said moving means having their moving part (3, 23) provided with a single degree of freedom relative to their respective fixed part, all the actuators (2, 22) of said moving means acting in parallel only, the fixed part of all the actuators (2, 22) of said means for setting in motion being connected to the base (1) by means of a passive connection provided with at least three degrees of connection, of which three degrees of connection in translation, the fixed part of at least four actuators (2, 22) said moving means being connected at the base (1) by means of a passive connection provided with at least three degrees of connection, of which three degrees of connection in translation, characterized in that the said moving means comprise at least two subassemblies, of which a first subassembly comprises a single movable structure (5), three kinematic chains linking the movable structure (5) to the base (1), a single mast (40) and a passive joint (50), said movable structure (5) being rigid and having two degrees of freedom in rotation and being provided with a degree of freedom in translation, said mast (40) being constituted by a bar, said passive articulation (50) being provided with at least two degrees of freedom of rotation and at least two degrees of translation connection, said mobile structure (5) being connected to the base (1) only by means of the three said kinematic chains linking said mobile structure (5) to the base (1) , each kinematic chain linking said struct mobile ure (5) at the base (1) comprising an actuator (2), each kinematic chain linking said mobile structure (5) to the base (1) comprising two passive articulation elements (4) equivalent in total to four links passive pivot, the setting in motion according to two degrees of freedom in rotation and a degree of freedom in translation of said mobile structure (5) being obtained by means of the three actuators (2), of the three said kinematic chains linking said mobile structure (5). ) to the base (1), acting in parallel and whose fixed part is connected to the base (1) by means of a passive connection provided with at least three degrees of connection, of which three degrees of connection in translation, the moving part (3) each of said actuators (2) being bonded to said movable structure (5) by means of at least one of the two passive articulation members (4) of said respective kinematic chain linking said movable structure (5) to the base (1), the first end said mast (40) being connected to the platform (100) only by means of said passive joint (50), the second end of said mast (40) being connected to said movable structure (5) only by means of a passive link ( 38) having at least five degrees of connection of which three degrees of translation connection, said movable structure (5) being connected to the platform (100) only by means of the kinematic chain formed solely by said mast (40) provided with its first end of said passive joint (50) and at its second end of said passive connection (38), the longitudinal axis of said mast (40) forming a constant angle with said movable structure (5), said first subset moving according to three degrees of freedom in translation said passive articulation (50) of the first subset through the action of said three actuators (2) of the first subset, and of which at least a second subset, acting on the orientation d e the platform (100) around the center of rotation of said passive joint (50) of said first subassembly comprises at least one actuator (22) whose fixed part is connected to the base (1) by means of a link passive member having at least three degrees of connection including three degrees of translation connection, and in that the position in the space of the passive joint (50) connecting the first end of the mast (40) of the first subset to the platform (100) is determined solely by the combination of position of the movable part (3) of the three actuators (2) of the first subassembly, independently of the action exerted by any one of the other subsets of the means for moving on the platform (100). 2. Parallel robot according to claim 1 characterized in that the moving means comprise at least two subassemblies each comprisinga single mobile structure (5), three kinematic chains linking the mobile structure (5) to the base (1). , a single mast (40) and a passive articulation (50), said movable structure (5) being rigid and being provided with two degrees of freedom in rotation and being provided with a degree of freedom in translation, said mast (40) being constituted by a bar, said passive articulation (50) being provided with at least two degrees of freedom in rotation and at least two degrees of translation connection, said mobile structure (5) being connected to the base (1 ) only by means of the three said kinematic chains linking said mobile structure (5) to the base (1), each kinematic chain linking said movable structure (5) to the base (1) comprising an actuator (2), each kinematic linkage said mobile structure ( 5) at the base (1) comprising two passive articulation elements (4) equivalent in total to four passive pivot links, the setting in motion according to two degrees of freedom in rotation and a degree of freedom in translation of said mobile structure ( 5) being obtained by means of the three actuators (2), three said kinematic chains linking said movable structure (5) to the base (1), acting in parallel and whose fixed part is connected to the base (1) by means of a passive link having at least three linkage degrees including three degrees of translation linkage, the mobile part (3) of each of said actuators (2) being connected to said mobile structure (5) by means of at least one of the two passive articulation elements (4) of said respective kinematic chain linking said mobile structure (5) to the base (1), the first end of said mast (40) being connected to the platform (100) only by means of said passive articulation (50), the second the end of said mast (40) being connected to said mobile structure (5) only by means of a passive connection (38) provided with at least five degrees of connection, of which three degrees of translation connection, said mobile structure (5) being connected to the platform (100) only by means of the kinematic chain formed solely by said mast (40) provided at its first end with said passive joint (50) and at its second end of said passive link (38), longitudinal axis of said mast (40) forming a constant angle with said movable structure (5), said subset moving in three degrees of freedom in translation said passive articulation (50) of said subset through the action of said actuators (2 ) of said subset. 3. parallel robot according to any one of the preceding claims characterized in that the second subassembly comprises a deformable prism (30, 31, 32) and a movable structure (25), with a degree of freedom in translation and two degrees of freedom in rotation, set in motion only by means of three actuators (22) of said subassembly acting in parallel on said movable structure (25), said deformable prism (30, 31, 32) consisting of at least three bars (30) of the same length each provided at their two ends with a respective passive angular connection (31, 32) provided with at least two degrees of freedom of rotation, all the passive angular links (31, 32) d one end of said bars (30) forming a respective base of said deformable prism (30, 31, 32) and in that the platform (100) is connected to said movable structure (25) only by means of said deformable prism (30, 31, 32). 4. Parallel robot according to any one of the preceding claims, characterized in that the second subassembly comprises at least one passive rotary device (41) consisting of a passive pivot connection and a deformable prism (30, 31, 32). and a movable structure (25), provided with a degree of freedom in translation and two degrees of freedom in rotation, set in motion only by means of three actuators (22) of said subassembly acting in parallel on said movable structure ( 25), said deformable prism (30, 31, 32) consisting of at least three bars (30) of the same length each provided at both ends with a respective passive angular connection (31, 32) provided with at least two rotational degrees of freedom, all the passive angular links (31, 32) of the same end of said bars (30) forming a respective base of said deformable prism (30, 31, 32) and that the platform (100) is related to said mobile structure (25) only by means of the kinematic chain consisting of said deformable prism (30, 31, 32) including all the passive angular links (31, 32) of at least one of the bases of said deformable prism (30, 31, 32). ) are secured to the fixed part of at least one said passive rotary device (41) respectively. 5. parallel robot according to any one of the preceding claims characterized in that the second subassembly comprises a deformable prism (30, 31, 32) and a movable structure (25), with a degree of freedom in translation, set in motion only by means of at least one actuator (22) of said subassembly, said deformable prism (30, 31, 32) consisting of at least three bars (30) of the same length each provided with both the ends of a respective passive angular link (31, 32) provided with at least two rotational degrees of freedom, all the passive angular links (31, 32) of the same end of said bars (30) forming a respective base of said deformable prism (30, 31, 32) and in that the platform (100) is connected to said movable structure (25) only by means of said deformable prism (30, 31, 32). 6. parallel robot according to any one of the preceding claims characterized in that the second subset comprises at least one passive rotary device (41), consisting of a passive pivot connection, a deformable prism (30, 31, 32). and a movable structure (25), provided with a degree of freedom in translation, set in motion only by means of at least one actuator (22) of said subassembly, said deformable prism (30, 31, 32) being constituted at least three bars (30) of the same length each provided at both ends with a respective passive angular connection (31, 32) provided with at least two rotational degrees of freedom, all the passive angular links (31, 32) of one end of said bars (30) forming a respective base of said deformable prism (30, 31, 32) and in that the platform (100) is connected to said movable structure (25) only by means of the chain kinematics constituted by said deformable prism (30, 31, 32) in which all the passive angular links of at least one of the bases of said deformable prism (30, 31, 32) are integral with the fixed part of at least one said respective passive rotary device (41). 7. Parallel robot according to any one of the preceding claims, characterized in that the mobile structure (5) of at least one subassembly, provided with two degrees of freedom of rotation and with a degree of freedom in translation, is set in motion, according to two degrees of freedom in rotation and a degree of freedom in translation, only by means of three actuators (2), said subassembly, acting in parallel on said movable structure (5), said movable structure (5 ) of said subassembly being connected to the base (1) only by means of three kinematic chains each comprising a respective actuator (2), said three actuators of said subset, and two respective passive articulation elements (4) equivalent to passive pivot links whose total of the number of equivalent passive pivot links included in said two passive articulation elements (4), respectively, of the same said kinematic chain, is equal to four, the movable part of each of said actuators (2) being connected to said movable structure (5) by means of a respective passive kinematic branch comprising at least one passive connection element (4) consisting of one of said two passive articulation elements (4) of a respective kinematic chain and in that the single mast (40) linking said movable structure (5) to the platform (100) consists of a bar, the first end of said mast (40) being bonded at the platform (100) only by means of a passive articulation (50), provided with at least two degrees of freedom of rotation and at least two degrees of translation connection, and the second end of said mast (40) being connected to said movable structure (5) only by means of a passive connection (38) having at least five degrees of connection, of which three degrees of translation linkage. 8. parallel robot according to any one of the preceding claims characterized in that the movable structure (25) of the second subassembly, with a degree of freedom in translation and two degrees of freedom in rotation, is set in motion , according to two degrees of freedom of rotation and a degree of freedom in translation, solely by means of three actuators (22), of said subassembly, acting in parallel on said movable structure (25), the fixed part of each of said actuators ( 22) being integral with the base (1), the movable part (23) of each of said actuators (22) of said subassembly being connected to said mobile structure (25) of said subassembly only by means of a connecting element passive (24) equivalent to three pivotal links and a passive prismatic link, and in that said movable structure (25) is linked to the platform (100) by means of a passive kinematic chain comprising at least one deforced prism mable (30, 31, 32). 9. parallel robot according to any one of the preceding claims characterized in that the mobile structure (25) of the second subassembly, with a degree of freedom in translation and two degrees of freedom in rotation, is put in motion , according to two degrees of freedom in rotation and a degree of freedom in translation, solely by means of three actuators (22), of said subassembly, acting in parallel on said mobile structure (25), the fixed part (22) of each said actuators (22) being integral with the base (1), said movable structure (25) being connected to the movable part (23) of the first actuator (22), said actuators of said subset, only by means of an element passive link device (24) equivalent to two passive links and a passive prismatic link and in that said mobile structure (25) is linked to the mobile part (23) of the second actuator (22), said actuators of said subset, only by means of a passive link element (24) equivalent to three passive linkages and a passive link and that the mobile structure (25) of said subassembly is connected to the mobile part (23) of the third actuator (22), said actuators of said subassembly, only by means of a passive link element (24) equivalent only to an assembly of passive pivot links and in that said movable structure (25) is connected to the platform (100) by means of a passive kinematic chain comprising at least one deformable prism (30, 31, 32). 10. Parallel robot according to any one of the preceding claims, characterized in that the movable structure (25) of the second subassembly, provided with two degrees of freedom of rotation and with a degree of freedom in translation, is set in motion. , according to two degrees of freedom of rotation and a degree of freedom in translation, solely by means of three actuators (22), said subassembly, acting in parallel on said movable structure (25), said movable structure (25) of said sub together being connected to the base (1) only by means of three kinematic chains each comprising a respective actuator (22), said three actuators of said subassembly, and two respective passive articulation elements (24) equivalent to pivotal links passive whose total of the number of equivalent passive pivot links included in said two respective passive articulation elements (24), of the same said kinematic chain, is equal to four, the movable portion (23) of each of said actuators (22) being bonded to said movable structure (25) by means of a respective passive kinematic branch comprising at least one passive connecting element (24) consisting of one of said two passive articulation members (24) of a said respective kinematic chain and in that said movable structure (25) is connected to the platform (100) by means of a passive kinematic chain comprising at least one deformable prism (30, 31, 32). Parallel robot according to any one of the preceding claims, characterized in that the platform (100) is connected to the mobile structure (5) of at least one subassembly solely by means of the passive kinematic chain formed solely by a mast (40), consisting of a bar of fixed length, provided at its first end with a single passive articulation (50) provided with three degrees of freedom in rotation and with a single degree of freedom in translation, the second end said mast (40) being integral with the mobile structure (5), said mobile structure (5), provided with two degrees of freedom in rotation and with a degree of freedom in translation, being set in motion by means of three actuators ( 2) acting in parallel.