WO2025078777A1 - Device and method for controlling the torque of a hydraulic machine - Google Patents

Abstract

Disclosed is a device for controlling the torque of a hydraulic machine (1) comprising a first assembly and a second assembly which are mobile in rotation relative to each other and define a rotor and a stator, the first assembly comprising a casing (110, 120, 126), and the second assembly comprising a cylinder block (114) having a plurality of housings and a plurality of pistons (116) mounted slidably in said housings, such that, for each housing, a piston (116) defines a chamber (30) with said housing, the control device being characterized in that it comprises control means (60, 42, 44) suitable for individually controlling the flow rates of flows entering and exiting each chamber, and means suitable for determining the pressure in each chamber (30).

Description

HYDRAULIC MACHINE TORQUE CONTROL DEVICE AND METHOD

Description

Technical Field

[0001] The present invention relates to the field of rotating hydraulic machines, in particular hydraulic motors and pumps.

Prior art

[0002] Conventionally, on devices and machines equipped with hydraulic motors, a hydraulic pump generates a flow which is sent to the motors. This flow will cause a pressure to be established in the hydraulic circuit, depending on the opposing resistance, that is to say in particular depending on the structure of the hydraulic circuit, the conditions of use and in particular depending on the resistance linked to the terrain.

[0003] Conventionally, if the hydraulic motor exceeds a speed setpoint, the displacement of the hydraulic pump, and therefore the flow rate, is reduced to approach the speed setpoint.

[0004]This type of piloting does, however, have limitations, particularly in managing situations of loss of grip, leading to excess fuel consumption.

[0005] The present invention thus aims to respond at least partially to these problems.

Statement of the invention

[0006] To this end, the present invention provides a torque control device for a hydraulic machine comprising a first assembly and a second assembly movable in rotation relative to each other defining a rotor and a stator, the first assembly comprising a casing, and the second assembly comprising a cylinder block having a plurality of housings and a plurality of pistons mounted to slide in said housings, so that for each housing, a piston defines a chamber with said housing, pistons and cylinders which make it possible to rotate a shaft relative to a casing, the control device being characterized in that it comprises pilot means adapted to individually control the flow rates entering and leaving each chamber, and means adapted to determine the pressure in each chamber.

[0007] Indeed, the torque generated by the hydraulic machine has a direct link with the pressure in the piston chambers. For each piston, the pressure in the chamber in which it slides generates a force on the cam in proportionality with its section. The input-output law of the roller/cam contact makes it possible to establish the link with the elementary rotation torque generated by the piston of the hydraulic machine. The sum of the elementary torques being the torque generated by the hydraulic machine.

[0008] According to one example, the device comprises means for determining the position and/or the angular speed of the rotor relative to the stator.

[0009] According to one example, the device comprises means for measuring the pressure established in each chamber.

[0010] According to one example, said flow control means comprise electrically or hydraulically controlled valves, and a controller adapted to control said valves.

[0011] According to one example, said electrically or hydraulically controlled valves are valves actuated using a piezoelectric actuator.

[0012] According to one example, the controller is adapted to control said electrically or hydraulically controlled valves to enable the fluid supply and discharge flow rates of each chamber to be controlled by successive switching of said valves from on to off state at a frequency imposed by the controller. [0013] According to one example, a switching period for said valves is defined as corresponding to the duration of a cycle comprising a passing state and a non-passing state, and in which the controller is adapted to modulate a ratio between the duration of the passing state relative to the duration of the non-passing state in said period, in particular by pulse width modulation control.

[0014] The present invention also relates to a method for torque control of a hydraulic machine comprising a first assembly and a second assembly movable in rotation relative to each other defining a rotor and a stator, the first assembly comprising a casing, and the second assembly comprising a cylinder block having a plurality of housings and a plurality of pistons mounted sliding in said housings, so that for each housing, a piston defines a chamber with said housing, said method comprising the following steps:

- receiving a couple's instruction

- determination of the position and/or angular speed of the rotor relative to the stator;

- calculation of the flow rates to be provided in each chamber for the determined position and/or angular velocity;

- determination of the pressure established in each of the chambers;

- determination of the actual torque, as a function of the pressure determined in the chambers,

- determination of the difference between the torque setpoint and the actual torque,

- correction of the flow rates applied to each chamber so as to minimize the difference between the torque setpoint and the actual torque.

[0015] In this embodiment of the invention, the torque regulation is achieved by a torque control.

[0016] The present invention also relates to a method for torque control of a hydraulic machine comprising a first assembly and a second assembly movable in rotation relative to each other defining a rotor and a stator, the first assembly comprising a casing, and the second assembly comprising a cylinder block having a plurality of housings and a plurality of pistons slidably mounted in said housings, such that for each housing, a piston defines a chamber with said housing, said method comprising the following steps:

- receiving a couple's instruction

- determination of the angular position and speed of the rotor relative to the stator;

- calculation of the pressures to be obtained in each chamber in order to generate the desired torque;

- calculation of the flow rates to be supplied to each chamber, for the speed and angular position of the hydraulic machine, in order to obtain the desired pressures;

- determination of the pressures established in each of the chambers;

- determination of the difference between actual pressures and desired pressures,

- correction of the flow rates to be supplied to each chamber so as to minimize the difference between the actual pressures and the desired pressures.

[0017] In this embodiment of the invention, the torque regulation is achieved by pressure control of each of the chambers.

[0018] According to one example, the determination of the position and the angular speed of the rotor relative to the stator are carried out by measuring the position or the angular speed of the rotor relative to the stator by means of an angular position sensor or a sensor for measuring the rotational speed of the hydraulic machine.

[0019] The present invention also relates to a method for torque control of a hydraulic machine comprising a first assembly and a second assembly movable in rotation relative to each other defining a rotor and a stator, the first assembly comprising a casing, and the second assembly comprising a cylinder block having a plurality of housings and a plurality of pistons mounted to slide in said housings, so that for each housing, a piston defines a chamber with said housing, said method comprising the following steps:

- receiving a couple's instruction

- determination of the angular position of the rotor relative to the stator;

- calculation of the average pressures to be obtained in each chamber in order to generate the desired torque;

- calculation of pressure in the inlet and discharge lines;

- calculation of a cyclic ratio for each piston, making it possible to obtain, on average over the coming period, the desired pressures in each chamber;

- determination of the actual torque generated by the motor;

- correction of the duty cycles so as to minimize the difference between the torque setpoint and the actual torque.

[0020] In this embodiment of the invention, the torque regulation is achieved by controlling the average pressure of each chamber.

[0021] The invention is typically applied to a multi-lobe cam hydraulic machine. A multi-lobe cam is a cam formed to have undulations or lobes, such that a piston in a cylinder block housing shown centered relative to the cam and remaining in contact with the cam moves back and forth in its housing during rotation.

[0022] The multi-lobe cam is typically positioned radially outwardly relative to the cylinder block. Alternatively, the hydraulic machine may have an internal multi-lobe cam. The cylinder block then surrounds the multi-lobe cam, the chambers and pistons are radially outwardly relative to the multi-lobe cam.

Brief description of the drawings

[0023] The invention and its advantages will be better understood upon reading the detailed description given below of different embodiments of the invention given as non-limiting examples. [0024] [Fig. 1] Figure 1 shows an overview of an exemplary rotating machine according to one aspect of the invention.

[0025][Fig. 2] Figure 2 schematically represents a control device according to the invention applied to a piston.

[0026] [Fig. 3] Figure 3 schematically illustrates a control method according to the invention.

[0027] [Fig. 4] Figure 4 schematically illustrates another example of a control device according to the invention.

[0028] [Fig. 5] Figure 5 schematically illustrates a step of the piloting law according to the invention.

[0029] [Fig. 6] Figure 6 schematically illustrates a control method according to the invention.

[0030] [Fig. 7] Figure 7 schematically illustrates a control method according to the invention.

[0031]In all the figures, the elements in common are identified by identical numerical references.

Description of the embodiments

[0032]Figure 1 shows a sectional view of a rotating hydraulic machine 1, typically a hydraulic machine with radial pistons and a multi-lobe cam. By hydraulic machine, we typically mean a hydraulic motor or a hydraulic pump, these devices typically having a reversible operation.

[0033] The rotating machine 1 comprises a distributor cover 110, a supply distributor 112, an assembly which is commonly referred to as a hydrocouple comprising a cylinder block 114 having a plurality of housings, pistons 116 equipped with a rolling roller 118 mounted to slide in said housings of the cylinder block 114, a multi-lobe cam 120 secured to a casing, a shaft 122, a bearing 124 consisting of a set of bearings, and a bearing cover 126. The shaft 122 is mechanically connected to the cylinder block 114 to transmit a rotational movement resulting from a torque applied to the shaft 122 or from a sliding of the pistons 116 in contact with the multi-lobe cam 120. In the cylinder block 114, each piston 116 is arranged in a separate housing. Each pair formed by a housing of the cylinder block 114 and the piston 116 arranged in said housing defines a chamber connected to the distributor 112 which ensures a supply and discharge of fluid.

[0034]A first assembly and a second assembly are generally defined, each of which is movable in rotation relative to the other. The first assembly typically comprises the casing and the cam 120, while the second assembly typically comprises the cylinder block 114. Depending on the chosen application, the first assembly may constitute the rotor and the second assembly the stator, or vice versa.

[0035]It is understood that the rotating machine 1 is only illustrated by way of example, and that other structures are possible. The rotating machine may in particular have an internal multi-lobe cam, where appropriate, the piston housings are arranged radially outwards around an axis of rotation of the rotating machine. The rotating machine may also, for example, be a hydraulic machine with axial pistons.

[0036]Figure 2 shows a piston 116 sliding in a housing of the cylinder block 114, and the chamber 30 thus defined between the piston 116 and the housing. The piston 116 is provided with a roller adapted to be in contact with the cam, the geometry of the cam or the inclination of the plate defining the back and forth movements of the piston 116 in its housing.

[0037]A hydraulic pipe 40 is shown diagrammatically for the chamber 30 to supply and discharge fluid. The operation is well known and will not be described in detail; an admission of fluid into the chamber 30 causes the piston 116 to exit its housing, while a return of the piston into its housing causes the fluid to be discharged from the chamber 30. The expression "piston exit from its housing" means a movement of the piston in the direction of increasing the internal volume of the chamber.

The expression "return of the piston into its housing" means a movement of the piston in the direction of reducing the internal volume of the chamber.

[0038] The present invention proposes to achieve torque control of the hydraulic machine via control of the flow rates entering and exiting the chambers 30 of the cylinder block 114.

[0039] The invention thus proposes a control device 60, typically an electronic controller, a computer or an “ECU” (according to the usual acronym in English) configured so as to control means for regulating the flow rates entering and leaving the chambers 30.

[0040]0n thus represents in figure 2:

- a 60 controller,

- a pressure sensor 50, adapted to measure the pressure within the chamber 30,

- pilot valves 42 and 44, controlling the admission and discharge of fluid into chamber 30.

[0041] Although Figure 2 only shows a single piston 116, it is understood that the different chambers of the cylinder block are provided with similar means, i.e. a pressure sensor and pilot valves or any other equivalent means, all of these means being connected to a controller 60.

[0042] The pressure sensor 50 is adapted to measure the pressure within the chamber 30 and provide information relating to the pressure thus measured to the controller 60. It is understood that the pressure sensor 50, which allows a verification of the pressure in each chamber 30, is optional; this pressure can be estimated in particular as a function of the opening of the pilot valves 42 and 44, the supply pressure and the geometry of the hydraulic machine.

[0043] In the example illustrated, the pilot valves 42 and 44 are positioned respectively on a supply line 71 and a discharge line 72. perform a function of controlling the supply and discharge of fluid into the chamber 30 via a conduit 40. The connection of the chamber 30 to the lines 71 and 72 via the pilot valves 42 and 44 makes it possible to operate the hydraulic machine. It is understood that other suitable means for performing this function may be used, in particular servovalves, dedicated hydraulic circuits or electric pumps in the case of large-scale systems.

[0044] The pilot valves 42 and 44 control the admission and discharge of fluid into the chamber 30. They will be arbitrarily designated as being a first pilot valve 42 and a second pilot valve 44. In the illustrated example, each pilot valve is represented as being either open or performing a calibrated non-return valve function, that is to say as being blocking in one direction, and open when the pressure exceeds a threshold value in the other direction. However, in another embodiment it could be envisaged that each pilot valve is either open or non-open (regardless of the direction of the pressure gradient) without departing from the scope of the invention.

[0045] Considering an operating mode given as an example, the first pilot valve 42 can carry out an admission at a pressure PI qualified as high pressure, to cause a movement of the piston 116 in the direction of an exit from its housing; the second pilot valve 44 then being in the closed position.

[0046] The pressure within the chamber 30 is then measured by the pressure sensor 50, and the controller 60 controls the pilot valves 42 and 44 so as to obtain the desired pressure in the chamber 30.

[0047] When the piston 116 is withdrawn from its housing, the controller 60 controls the opening of the second pilot valve 44 so as to control the evacuation of the fluid from the chamber 30 and therefore the pressure within the chamber 30. [0048] More generally, the control device as proposed aims to achieve torque control by pressure control within the different chambers 30.

[0049] Indeed, the torque being a function in particular of the effective section of each piston 116, of the angular position of each piston 116 and of the pressure within each chamber 30, it is understood that the control of the pressure in the chambers 30 makes it possible to control the torque delivered by the hydraulic machine. The total torque delivered by the hydraulic machine is calculated by taking the sum of the torques resulting from the pressure in each chamber 30.

[0050] The hydraulic machine typically comprises means for determining the position and angular speed of the cylinder block 114, or more generally the position and angular speed of the rotor relative to the stator, which thus makes it possible to determine the angular position and speed of each piston 116, the geometry of the cylinder block 114 being known.

[0051] The pilot valves 42 and 44 are typically electrically or hydraulically actuated valves. The pilot valves 42 and 44 are typically actuated using a piezoelectric actuator.

[0052] The controller 60 is typically configured to control the pilot valves 42 and 44 to enable the fluid supply and discharge flow rates of each chamber 30 to be controlled by successive switching from the on to the off state of the pilot valves 42 and 44 at a frequency imposed by the controller 60.

[0053] The controller 60 is typically configured to define a switching period for the pilot valves 42 and 44. For each pilot valve, a switching period corresponds to the duration of a cycle comprising an on state and a off state. The controller 60 is typically adapted to modulate the switching period and/or to modulate a ratio between the duration of the on state and the duration of the off state during said switching period. This modulation can in particular be carried out by pulse width modulation control. [0054]This control is carried out as the relative rotation between the rotor and the stator progresses. The controller 60 thus carries out the torque control for the different relative angular positions between the rotor and the stator, and carries out an adjustment of the pressure in the chambers 30 as the rotation progresses to obtain the desired torque in each chamber 30, and therefore the total torque desired for the hydraulic machine, i.e. for all of the chambers 30.

[0055] Figure 3 schematically represents the operation of such a control.

[0056]In this figure, El represents a torque setpoint applied to the controller 60. The controller 60 then determines the flow rates to be supplied in each chamber 30 as a function of the position and angular speed of the rotor relative to the stator, which can typically be measured or calculated.

[0057] The controller 60 then controls the different pilot valves so as to supply the different chambers 30 with a flow passing through the pilot valves. These flow rates (which can be positive or negative flow rates) applied to the different chambers are symbolized by E2. The supply of fluid into the different chambers 30 establishes a pressure in these chambers 30 against the pistons 116. Note that in the illustrated example E2 is represented by 3 arrows corresponding to the three potentially different flow rates to be established in the three chambers (in the case of a hydraulic machine with 3 pistons also included in the other examples of the other figures).

[0058]These different pressures established in the different chambers 30 are here identified by E3. These pressures are typically measured or estimated and this information is transmitted to the controller 60 which can then typically modulate the control of the control valves. A feedback loop for the pressure control of each of the chambers can then be produced, as symbolized in FIG. 3.

[0059] As previously indicated, the pressures in the different chambers can be measured or determined as a function of the geometry of the hydraulic machine and operating conditions, including angular position and chamber feeds 30.

[0060] The pressure generated in the chambers 30 causes a torque generated by each piston in contact with a complementary member such as a cam or an inclined plate. The elementary torques generated by the different pistons are here identified by E4.

[0061] The sum of these torques corresponds to the total torque (here E5) generated by the hydraulic machine.

[0062]This total torque, determined by a direct measurement of the actual torque (figure 7) or from the pressures in the chambers (figure 3), is then typically compared to the torque setpoint, and the controller 60 performs a correction of the flow rates applied in the different chambers so as to reduce or minimize the difference between the torque setpoint and the total torque thus obtained, typically via a feedback loop.

[0063] The present invention thus makes it possible to achieve torque control of a hydraulic rotating machine, by controlling the flow rates and pressures in the different chambers of the cylinder block.

[0064] In another embodiment, the control of the engine torque is carried out by controlling the average pressures in the different chambers of the cylinder block.

[0065] Figure 4 schematically shows a device suitable for such a control mode. In this embodiment, the hydraulic machine comprises means for determining the pressures on the high pressure supply line 71 and the low pressure discharge line 72. These determination means are for example pressure sensors 81 and 82 respectively arranged on the high pressure supply line 71 and on the low pressure discharge line 72.

[0066] A control period T is defined in order to control the pilot valves 42 and 44 by pulse width modulation. The pressure in the chambers 30 is assumed to be equal to the pressure of the high pressure line 71. (PHP pressure) when the first pilot valve 42 (HP valve) is open or equal to the pressure of the low pressure line 72 (PBP pressure) when the second valve 44 (BP valve) is open.

[0067] The controller 60 receives a torque setpoint as well as the angular position of the rotor of the machine relative to the stator. It then calculates the average pressures to be applied in each chamber 30 of the cylinder block 114 in order to obtain the desired torque for the angular position considered. For each piston 116, the controller 60 then calculates a duty cycle defined by the ratio between the duration of activation of the valve on the high-pressure supply line and the duration of the period considered, making it possible to obtain the desired average pressure Pp in the chamber 30 of the piston 116 considered.

[0068] A representation of the pulse width modulation is shown diagrammatically in Figure 5. This figure shows the pressure variation in a chamber 30, and the control of the two valves 42 and 44, 0 indicating a non-passing state, and 1 indicating a passing state.

[0069] The duty cycle can then be adjusted according to the difference between the desired torque and the torque provided by the machine via a feedback loop, as suggested by Figure 6.

[0070] Such control makes it possible to adjust the pressure in the different chambers to obtain a torque as close as possible to the desired setpoint, with a higher level of precision than conventional control.

[0071] In addition, such control allows better management of the loss of grip and better optimization of the consumption of the hydraulic machine. Indeed, in the case of an application to a movement member such as a wheel, a loss of grip commonly leads to excess energy consumption. The torque control as proposed makes it possible to address these issues, unlike the usual control based on a speed setpoint.

[0072] The various embodiments proposed can be applied to a hydraulic motor, and also to a hydraulic pump. In such a case, the hydraulic pump is typically driven in rotation by a motor, for electrical example, whose torque is controlled. The device and the control method as proposed thus make it possible to control the pressure at the outlet of the hydraulic pump.

[0073] Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various illustrated/mentioned embodiments may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0074] It is also obvious that all the characteristics described with reference to a method are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a method.

Claims

Claims [Claim 1] Torque control device for a hydraulic machine (1) comprising a first assembly and a second assembly movable in rotation relative to each other defining a rotor and a stator, the first assembly comprising a casing (110, 120, 126), and the second assembly comprising a cylinder block (114) having a plurality of housings and a plurality of pistons (116) slidably mounted in said housings, so that for each housing, a piston (116) defines a chamber (30) with said housing, the control device being characterized in that it comprises control means (60, 42, 44) adapted to individually control the flow rates entering and leaving each chamber, and means adapted to determine the pressure in each chamber (30). [Claim 2] Device according to the preceding claim, comprising means for determining the position and/or the angular speed of the rotor relative to the stator. [Claim 3] Device according to one of claims 1 or 2, in which said flow control means comprise electrically or hydraulically controlled valves (42, 44), and a controller (60) adapted to control said valves (42, 44). [Claim 4] Device according to claim 3, characterized in that said electrically or hydraulically controlled valves (42, 44) are valves actuated using a piezoelectric actuator. [Claim 5] Device according to the preceding claim, in which the controller (50) is adapted to control said electrically or hydraulically controlled valves (42, 44) to enable the flow rates to be controlled. supplying and discharging fluid from each chamber (30) by successive switching from on to off state of said valves (42, 44) at a frequency imposed by the controller (60). [Claim 6] Device according to the preceding claim, in which a switching period for said valves (42, 44) is defined as corresponding to the duration of a cycle comprising a passing state and a non-passing state, and in which the controller (60) is adapted to modulate a ratio between the duration of the passing state relative to the duration of the non-passing state in said period, in particular by pulse width modulation control. [Claim 7] A method of torque control of a hydraulic machine comprising a first assembly and a second assembly rotatable relative to each other defining a rotor and a stator, the first assembly comprising a casing (120, 126), and the second assembly comprising a cylinder block (114) having a plurality of housings and a plurality of pistons (116) slidably mounted in said housings, so that for each housing, a piston (116) defines a chamber (30) with said housing, said method comprising the following steps: - receiving a couple's instruction - determination of the position and/or angular speed of the rotor relative to the stator; - calculation of the flow rates to be provided in each chamber for the determined position and/or angular velocity; - determination of the pressure established in each of the chambers; - determination of the actual torque, as a function of the pressure determined in the chambers or by a torque determination device, - determination of the difference between the torque setpoint and the actual torque, - correction of the flow rates applied to each room in order to minimize the difference between the torque setpoint and the actual torque. [Claim 8] A method of torque control of a hydraulic machine comprising a first assembly and a second assembly rotatable relative to each other defining a rotor and a stator, the first assembly comprising a casing (120, 126), and the second assembly comprising a cylinder block (114) having a plurality of housings and a plurality of pistons (116) slidably mounted in said housings, so that for each housing, a piston (116) defines a chamber (30) with said housing, said method comprising the following steps: - receiving a couple's instruction - determination of the angular position and speed of the rotor relative to the stator; - calculation of the pressures to be obtained in each chamber in order to generate the desired torque; - calculation of the flow rates to be supplied to each chamber, for the speed and angular position of the hydraulic machine, in order to obtain the desired pressures; - determination of the pressures established in each of the chambers; - determination of the difference between actual pressures and desired pressures, - correction of the flow rates to be supplied to each chamber so as to minimize the difference between the actual pressures and the desired pressures. [Claim 9] Method according to claim 8, wherein the determination of the position and the angular speed of the rotor relative to the stator are carried out by measuring the position or the angular speed of the rotor relative to the stator by means of an angular position sensor or a sensor for measuring the rotational speed of the hydraulic machine. [Claim 10] A method for torque control of a hydraulic machine comprising a first assembly and a second assembly rotatable relative to each other defining a rotor and a stator, the first assembly comprising a casing (120, 126), and the second assembly comprising a cylinder block (114) having a plurality of housings and a plurality of pistons (116) slidably mounted in said housings, so that for each housing, a piston (116) defines a chamber (30) with said housing, said method comprising the following steps: - receiving a torque setpoint - determination of the angular position of the rotor relative to the stator; - calculation of the average pressures to be obtained in each chamber in order to generate the desired torque; - determination of the pressure in the intake and discharge lines; - calculation of a duty cycle for each piston, making it possible to obtain, on average over the coming period, the desired pressures in each chamber; - determination of the actual torque generated by the motor; - correction of the duty cycles in order to minimize the difference between the torque setpoint and the actual torque.