WO2017146404A1 - Vertical multi-joint robot manipulator including gravity compensation device - Google Patents

Abstract

A vertical multi-joint robot manipulator according to the present invention includes: a first link; a second link connected to the first link and a first joint so as to be able to rotate with respect to the first link; a third link connected to a second joint spaced apart from the second link and the first joint so as to be able to rotate with respect to the second link; an input link connected to the first link so as to be able to rotate with respect to the first link separately from the second link; a coupler link having one side rotatably connected to the third link and the other side rotatably connected to the input link; a first joint driving part installed on the first link and providing driving force to the second link so as to be able to rotate the second link around the first joint; a second joint driving part installed on the first link and rotating the input link so as to be able to rotate the third link around the second joint through the input link and the coupler link; and a gravity compensation device installed on the first link to apply elastic force to at least one of the second link and the input link.

Description

Vertical Articulated Robot Manipulator with Gravity Compensation System

The present invention relates to a robot manipulator, and more particularly, to provide a driving torque required for a joint by providing a spring-based gravity compensator capable of canceling the gravity torque applied to the joint by its own weight when maintaining and driving the robot manipulator. A vertical articulated robotic manipulator having a gravity compensator capable of minimizing drive power by reducing it.

Currently, process automation is actively performed to improve efficiency in various industrial sites, and the importance of robotic manipulators that can be flexibly used for various tasks is increasing. In particular, the vertical articulated robot manipulator is used for various tasks such as transporting, assembling, welding, and painting heavy materials, and has been developed and used in various sizes according to the target work.

Gravity torque due to its own weight is applied to the joint moving the link in the direction of gravity when the posture of the vertical articulated robot manipulator is maintained or driven. The larger the robot manipulator, the larger the size, and the greater the drive power required for the joint. To reduce this power and reduce the required motor and reducer capacity, some industrial robots install weights on opposite sides of the working point to reduce the center of gravity, or use a spring to compensate for the weight of the link and apply the torque to the joint. A method of reducing this is being used.

However, the use of weights increases the weight of the robot manipulator and increases the influence of inertia. In addition, various methods of applying gravity compensation to joints of a multiple degree of freedom robot based on mechanical elements, such as springs and wires, are limited to be applied to robot manipulators due to their complicated structure. Compensation device is required. In addition, in the case of the conventional coil spring based gravity compensation device, the gravity compensation performance is easily degraded due to the deformation of the spring according to the long-term operation, and in this case, the robot manipulator needs to be disassembled to replace the spring. not.

The present invention is to solve the above problems, by applying a reliable mechanical element-based multi-degree of freedom gravity compensation device is a vertical having a gravity compensation device that can implement an effective gravity compensation for the joint to which a lot of gravity torque is applied An object is to provide an articulated robotic manipulator.

It is another object of the present invention to provide a vertical articulated robot manipulator having a gravity compensation device that can reduce maintenance problems by facilitating disassembly or assembly of the gravity compensation device through a modular design.

Vertical articulated robot manipulator according to the present invention for solving the above object, the first link; A second link connected to the first link and a first joint so as to rotate relative to the first link; A third link connected to the second link and a second joint spaced apart from the first joint to rotate about the second link; An input link coupled with the first link to rotate relative to the first link separately from the second link; A coupler link having one side rotatably connected with the third link and the other side rotatably connected with the input link; A first joint driver installed in the first link to provide a driving force to the second link to rotate the second link about the first joint; A second joint driver installed in the first link to rotate the input link to rotate the third link about the second joint through the input link and the coupler link; And apply an elastic force to at least one of the second link and the input link to compensate for gravity torque caused by the weight of a link mechanism comprising the second link, the third link, the input link and the coupler link. And a gravity compensating device installed at the first link.

The gravity compensating device may include an elastic member supported on the first link and a rotation center of the first link of either the second link or the input link to transmit the elastic force of the elastic member to the link mechanism. A connecting rod rotatably connected to a portion spaced from the connecting rod, and the connecting rod is rotatably connected and movable with respect to the first link to elastically deform the elastic member in response to the movement of the connecting rod. It may include a movable member is installed.

The gravity compensating apparatus may further include a support frame that is prefabricated to the first link, the elastic member may be coupled to the support frame, and the movable member may be slidably coupled to the support frame.

The gravity compensation device further includes a guide bar coupled to the support frame to extend in the sliding direction of the movable member, wherein the elastic member has a spring structure wound around an outer circumference of the guide bar, and the movable member includes the guide bar. It can be slidably coupled to the guide bar to compress the elastic member.

The connecting rod of the gravity compensator includes a first rotating rod having a first head portion rotatably coupled to either the second link or the input link, and a first rod body extending from the first head portion. And a second rotating rod having a second head portion rotatably coupled to the movable member, and a second rod body extending from the second head portion to be assembled with the first rod body of the first rotating rod. It may include.

The gravity compensator includes a first elastic member supported by the first link and a rotational center spaced from the rotation center of the second link with respect to the first link to transmit the elastic force of the first elastic member to the second link. A first connecting rod rotatably connected to the first portion, and the first link so that the first connecting rod is rotatably connected and elastically deforms the first elastic member in response to the movement of the first connecting rod. A first counter balancer having a first movable member operatively mounted relative to the second counter, a second elastic member supported on the first link, and the input for transmitting an elastic force of the second elastic member to the input link. A second connecting rod rotatably connected to a portion spaced from a center of rotation of the link with respect to the first link, and the second connecting rod rotatably connected; And it may include a second counter balancer having a second movable member in association with the movement of the second connecting rod being able to be movable relative to the first link to install the second so that the elastic member can be elastically deformed.

The first counter balancer further includes a first support frame prefabricated to the first link, the first elastic member is coupled to the first support frame, and the first movable member is the first support frame. Slidably coupled to the second counterbalancer, the second counter balancer further includes a second support frame assembleably coupled to the first link, wherein the second elastic member is coupled to the second support frame, and the second movable frame is movable. The member may be slidably coupled to the second support frame.

The first connecting rod is rotatable to the first movable member having a first head portion rotatably coupled to the second link, a first rod body extending from the first head portion, and the first movable member. And a second rotating rod having a second head portion possibly coupled thereto and a second rod body extending from the second head portion and prefabricatedly coupled to the first rod body of the first rotating rod.

The second connecting rod is rotatable to the first movable portion having a first head portion rotatably coupled to the input link, a first rotating rod having a first rod body extending from the first head portion, and the second movable member. And a second rotating rod having a second head portion coupled to each other, and a second rod body extending from the second head portion to be assembled with the first rod body of the first rotating rod.

The first counter balancer and the second counter balancer may be disposed to face each other such that the movable direction of the first movable member and the movable direction of the second movable member are parallel to each other.

The vertical articulated robot manipulator according to the present invention may further include a multiple joint unit having a plurality of joints and coupled to the third link.

The vertical articulated robot manipulator according to the present invention may further include a base unit connected to the first link and the base joint to rotate the first link about the base joint.

A vertical articulated robot manipulator having a gravity compensating device according to the present invention provides a compensating torque to a link mechanism with a counter balancer including an elastic member for providing an elastic force, a movable member and a connecting rod for transmitting an elastic force of the elastic member. By doing so, it is possible to mechanically compensate the torque generated due to gravity in the part having a weight such as a link mechanism. Therefore, it is not necessary to receive torque for offsetting the gravity torque from the joint drive, thereby reducing the load generated in the joint drive, and by using the joint drive of the same output to bear a larger load, or Joint drives can be used.

In addition, the vertical articulated robot manipulator according to the present invention implements gravity compensation by using a gravity compensation device having a simple structure, thereby maximizing payload, and minimizing rotational force by reducing torque load in joints, thereby providing high power. Accurate operation is possible without using the driving unit.

In addition, the vertical articulated robot manipulator according to the present invention can significantly reduce the capacity of the joint drive part such as a motor and a reducer when applied to the actual multi-axis joint robot, it can significantly lower the manufacturing cost.

In addition, the vertical articulated robot manipulator according to the present invention, by enabling a compact structure in addition to stable gravity compensation through a simple balance of the counter balancer, it is possible to maximize the utility in a variety of fields by the compact structure.

In addition, the vertical articulated robot manipulator according to the present invention, by designing the gravity compensation device in a modular structure to facilitate the installation of the gravity compensation device and replacement according to the component life, it can significantly reduce the time and cost of maintenance.

1 is a side view showing a vertical articulated robot manipulator according to an embodiment of the present invention.

Figure 2 is a rear view showing a vertical articulated robot manipulator according to an embodiment of the present invention.

3 and 4 are perspective views showing the vertical articulated robotic manipulator according to an embodiment of the present invention from different angles.

5 is a conceptual diagram briefly shown to explain the four-section link structure of the vertical articulated robot manipulator according to an embodiment of the present invention.

FIG. 6 is a view illustrating a vertical articulated robot manipulator having a gravity compensator separately from a gravity compensator according to an embodiment of the present invention.

7 is for explaining the coupling structure of the first counter balancer of the vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention.

8 is for explaining the coupling structure of the second counter balancer of the vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention.

9 is an exploded view of a second counter balancer of a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention.

FIG. 10 is a simplified conceptual diagram to explain an operation principle of a gravity compensator of a vertical articulated robot manipulator having a gravity compensator according to an embodiment of the present invention.

11 is a graph showing the compensation torque according to the joint rotation angle when the design variable is properly selected to explain the effect of the gravity compensator of the vertical articulated robot manipulator having a gravity compensator according to an embodiment of the present invention. .

12 is a conceptual diagram briefly shown to explain the gravity torque applied to each pitch joint of the vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention.

Hereinafter, a vertical articulated robot manipulator having a gravity compensation device according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a side view showing a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention, Figure 2 is a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention 3 and 4 are perspective views showing a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention from different angles, and FIG. 5 is a view showing an embodiment of the present invention. 4 is a conceptual diagram briefly illustrated to describe a four-section link structure of a vertical articulated robot manipulator having a gravity compensating device, and FIG. 6 is a vertical articulated robotic manipulator having a gravity compensating device according to an embodiment of the present invention. The compensation device is shown separately.

1 to 6, a vertical articulated robot manipulator 100 having a gravity compensation device according to an embodiment of the present invention includes a first link 110, a first link 110, and a first link 110. Link mechanism 115 connected to the joint (J1), and the gravity compensation device 142 to compensate for the gravity torque caused by the weight of the link mechanism 115. The first link 110 is connected to the base unit 180 and the base joint Jb, and one end of the link mechanism 115 is connected to the multiple joint unit 182. An end effector (not shown), which may be implemented as a roll motor or a gripper, may be installed at an end of the multiple joint unit 182.

As shown in the drawing, the vertical articulated robot manipulator 100 according to the present invention includes an arm part (base unit 180, made of three joints of roll-pitch-pitch, which can determine the position of the robot distal end in space). It is possible to take a structure having one link 110, a link mechanism 115, and a wrist part (multiple joint unit 182) composed of three joints for determining the orientation of the robot distal end. A four-section link structure parallel between the first joint J1 and the second joint J2 to implement gravity compensation for the two pitch joints of the arm part (first joint J1 and second joint J2) It is composed of a link mechanism 115, the gravity compensation device 142 can be connected to the link mechanism 115 to offset the gravity torque applied to the first joint (J1) and the second joint (J2).

The first link 110 may be connected to the base unit 180 and the base joint Jb to rotate with respect to the base unit 180. That is, the first link 110 may rotate with the axis (Z axis) perpendicular to the ground as the rotation center axis. The base unit 180 may include a driving unit for providing a driving force to the first link 110. The first link 110 may include a bottom frame 111 connected to the base unit 180, a first sidewall frame 112 and a second sidewall frame 112 disposed to be spaced apart from each other on the top of the bottom frame 111. 113).

The link mechanism 115 is connected with the first link 110 to be movable relative to the first link 110. The link mechanism 115 includes a second link 120 connected to one side of the first link 110, a third link 127 connected to the second link 120, and another of the first link 110. An input link 130 connected to one side and a coupler link 136 connecting the third link 127 and the input link 130.

The second link 120 may be connected to the first link 110 and the first joint J1 to rotate about the first link 110. That is, the second link 120 may rotate within a predetermined angle range using an axis (X axis) horizontal to the ground as the rotation center axis. The second link 120 is spaced apart from the second link right body 121 and the second link right body 121 rotatably connected to the first side wall frame 112 of the first link 110 to face each other. Connecting the second link left body 122, the second link right body 121, and the second link left body 122 to be rotatably connected to the second side wall frame 113 of the first link 110. It includes a connecting body 123. One side of the second link right body 121 is provided with a second link pivot connecting portion 125 (see FIG. 7). The second link pivot connector 125 is for connecting the first connecting rod 158 provided in the first counter balancer 144 of the gravity compensator 142 which will be described later. It is disposed at a position eccentrically spaced from the center of rotation of the two links 120.

The third link 127 is connected to the second joint J2 spaced apart from the second link 120 and the first joint J1 so as to rotate about the second link 120. The third link 127 may rotate within a predetermined angle range using an axis (X axis) horizontal to the ground as the rotation center axis. The multi-joint unit 182 is coupled to the third link 127, and the multi-joint unit 182 moves along with the movement of the third link 127.

The input link 130 is connected to the first link 110 so as to rotate relative to the first link 110 separately from the second link 120. The input link 130 may rotate within a predetermined angle range using an axis horizontal to the ground (X axis) as a rotation center axis. The central axis of rotation of the input link 130 and the central axis of rotation of the second link 120 are the same. The input link 130 includes a rotating part 131 rotatably coupled to the second side wall frame 113 of the first link 110 and an eccentricity extending in the radial direction of the rotating part 131 on the outer circumferential surface of the rotating part 131. It includes a connector 132. One side of the rotating part 131 is provided with an input link pivot connection part 134 (see FIG. 8). The input link pivot connection unit 134 is for connection of the second connecting rod 177 provided in the second counter balancer 170 of the gravity compensator 142 which will be described later. 131 is disposed at a position eccentrically spaced apart from the central axis of rotation.

The coupler link 136 is rotatably connected to one side of the third link 127, and the other side is rotatably connected to the input link 130, thereby connecting the third link 127 and the input link 130. One end of the coupler link 136 is rotatably connected to a portion spaced from the second joint J2 of the third link 127, and the other end of the coupler link 136 is an eccentric connection 132 of the input link 130. Is rotatably connected.

As such, the link mechanism 115 forms a four-section link structure in which the second link 120, the third link 127, the input link 130, and the coupler link 136 are connected. As briefly shown in FIG. 5, the second link 120 and the input link 130 have respective ends rotatably connected to the first link 110, and the third link 127 is connected to the second link ( 120 is rotatably connected, and the coupler link 136 has both ends rotatably connected to each of the third link 127 and the input link 130. Connect it.

The link mechanism 115 of the four-section link structure is moved by the first joint driver 138 and the second joint driver 140 installed in the first link 110. The first joint driver 138 is installed on the first side wall frame 112 of the first link 110 to rotate the second link 120 of the link mechanism 115 about the first joint J1. The second joint driver 140 is installed on the second side wall frame 113 of the first link 110 to rotate the input link 130 of the link mechanism 115 with respect to the first link 110. The driving force of the second joint driver 140 is transmitted to the third link 127 through the input link 130 and the coupler link 136 in turn, and the third link 127 is the driving force of the second joint driver 140. Received may be rotated about the second joint (J2) with respect to the second link 120. That is, the second joint driver 140 may rotate the third link 127 about the second joint J2 through the input link 130 and the coupler link 136.

The link mechanism 115 may have various postures changed by the action of the first joint driver 138 and the second joint driver 140. In addition, the link mechanism 115 changes the angle of the second link 120 with respect to the first link 110 by the first joint driver 138, and the second link 120 by the second joint driver 140. By varying the angle of the third link 127 relative to the third link 127, the position of the multiple joint unit 182 coupled to the third link 127 may be variously adjusted.

In order for the link mechanism 115 to maintain a certain position and posture in space, the first joint drive 138 and the second joint drive 140 need to provide driving torque necessary for movement. If the posture changes, the required torque of the first joint drive unit 138 and the second joint drive unit 140 also changes due to the change of the gravity torque caused by its own weight. Conventionally, a method of compensating gravity torque by measuring the position and attitude of the robot manipulator through an encoder mounted on the joint of the robot manipulator and measuring the rotation angle, calculating the required gravity torque and generating the required torque through the control of the driving unit. Was used.

On the contrary, the present invention uses gravity compensation device 142 that can provide elastic force, thereby automatically gravity for all positions and postures of the vertical articulated robot manipulator 100 without the help of a separate sensor, controller, and drive unit. Torque can be mechanically generated to compensate the torque. Therefore, the required torque of the joint drives 138 and 140 for compensating gravity torque can be made close to zero.

2 to 4 and 6 to 9, the gravity compensating device 142 may include a first force to provide the link mechanism 115 with an elastic force for compensating gravity torque caused by the weight of the link mechanism 115. It is installed in the link 110. The gravity compensator 142 is a first counter balancer 144 for applying an elastic force for gravity compensation to the second link 120 of the link mechanism 115, and gravity to the input link 130 of the link mechanism 115 And a second counter balancer 170 for applying an elastic force for compensation. The first counter balancer 144 and the second counter balancer 170 differ only in the installation position or the position of the portion connected to the link mechanism 115, and the overall structure and function are the same.

The first counter balancer 144 includes a first support frame 145 fixed to the first link 110, a first elastic member 148 supported by the first support frame 145, and a first support frame ( A first movable member 152 installed movably on the 145 and a first connecting rod 158 connecting the first movable member 152 and the second link 120 of the link mechanism 115. . The second counter balancer 170 includes a second support frame 171 fixed to the first link 110, a second elastic member 173 supported by the second support frame 171, and a second support frame ( The second movable member 175 is installed in the movable type 171, and the second connecting rod 177 for connecting the second movable member 175 and the input link 130 of the link mechanism 115. Here, it is merely for convenience of explanation that the components constituting the gravity compensator 142 are classified by attaching the first and the second according to the first counter balancer 144 and the second counter balancer 170. The division of names does not indicate any difference in structure or function. In the following description of the first counter balancer 144, the components of the second counter balancer 170 shown in FIG. 9 will be referred to for some components.

The first support frame 145 of the first counter balancer 144 is coupled to the first side wall frame 112 of the first link 110. The first support frame 145 may be detachably coupled to the first side wall frame 112 through fixing members such as screws or bolts. The first support frame 145 is provided on the guide rail 146 for guiding the movement of the first movable member 152.

The pair of first elastic members 148 are spaced apart from each other on the first support frame 145. The guide bar 149 is coupled to the first support frame 145 to install the first elastic member 148. The guide bar 149 is disposed in parallel with the pair spaced apart from each other. These guide bars 149 are coupled to the holder 150, one end of which is fixed to the first support frame 145. The first elastic member 148 has a spring structure that is wound around the outer circumference of the guide bar 149.

The first movable member 152 is installed on the first support frame 145 so as to be slidable. The first movable member 152 may linearly reciprocate along the guide rail 146 of the first support frame 145. The first movable member 152 is coupled to the pair of guide bars 149 so as to be slidably movable, and connected to the pressurizing unit 153 to be slidably coupled to the guide rail 146. The connecting rod connector 154 is included. One side of the connecting rod connecting portion 154 is provided with a slider pivot connecting portion 156 for coupling the first connecting rod 158. The first movable member 152 may be moved by the first connecting rod 158 and may be elastically deformed by pressing the first elastic member 148 with the pressing unit 153.

The first connecting rod 158 connects the second link 120 and the first movable member 152 of the link mechanism 115. The first connecting rod 158 has a first head portion 159 connected to the second link 120 and a second head portion 160 connected to the slider pivot connecting portion 156 of the first movable member 152. And a body portion 161 connecting the first head portion 159 and the second head portion 160.

The first head portion 159 of the first connecting rod 158 is connected to the second link 120 through the second link pivot connecting portion 125 provided in the second link right body 121 of the second link 120. Is rotatably connected. Since the second link pivot connecting portion 125 is eccentric from the center of rotation of the second link 120, when the second link 120 rotates, the first head portion 159 of the first connecting rod 158 becomes second. It may move along the center of rotation of the link 120. The second head portion 160 of the first connecting rod 158 is rotatably connected to the first movable member 152 through the slider pivot connecting portion 156 of the first movable member 152.

When the second link 120 rotates, the first head portion 159 of the first connecting rod 158 moves around the center of rotation of the second link 120, whereby the first of the first connecting rod 158 is moved. The second head 160 may move the first movable member 152 along the guide bar 149. When the first elastic member 148 is elastically deformed by the movement of the first movable member 152, the elastic force of the first elastic member 148 may be reduced through the first movable member 152 and the first connecting rod 158. Two links 120. Therefore, when the second link 120 rotates, it is possible to provide the second link 120 with a compensating torque that can compensate for the gravity torque caused by the weight of the link mechanism 115, and to move the second link 120. It is possible to reduce the driving torque of the first joint driver 138.

The first connecting rod 158 may be separated into a first rotating rod 163 having a first head portion 159 and a second rotating rod 166 having a second head portion 160. The first rotating rod 163 has a first head portion 159 and a first rod body 164 extending from the first head portion 159. The second rotating rod 166 has a second head portion 160 and a second rod body 167 extending from the second head portion 160. The first rod body 164 of the first rotary rod 163 and the second rod body 167 of the second rotary rod 166 may be detachably coupled through a fixing member such as a screw or a bolt. Thus, the first connecting rod 158 of the first counter balancer 144 is formed by a detachable structure in which a portion coupled to the second link 120 and a portion coupled to the first movable member 152 can be separated. Easy assembly and disassembly

For example, when assembling the first counter balancer 144, the first rotating rod 163 and the second rotating rod 166 of the first connecting rod 158 may be connected to the second link 120 and the first movable member 152. ) And the first counter balancer by coupling the first support frame 145 to the first link 110 and then coupling the first rotary rod 163 and the second rotary rod 166. 144 can be assembled.

In addition, when the parts of the first counter balancer 144 need to be repaired or replaced, the first rotating rod 163 and the second rotating rod 166 of the first connecting rod 158 are first separated, and then the first support is performed. By separating the frame 145 from the first link 110, the first counter balancer 144 may be easily removed.

As such, when the first counter balancer 144 has a modular structure in which the first counter balancer 144 is assembled to the first link 110, the first counter balancer ( 144 is easily removable and easily assembled. This saves time and money for maintenance.

The second counter balancer 170 is installed in the first link 110 and the link mechanism 115 separates from the first counter balancer 144 a compensation torque that can compensate for the gravity torque caused by the weight of the link mechanism 115. The input link 130 may be provided. The second counter balancer 170 is mutually different from the first counter balancer 144 such that the movable direction of the second movable member 175 is parallel to the movable direction of the first movable member 152 of the first counter balancer 144. Are placed facing each other.

The second support frame 171 of the second counter balancer 170 is coupled to the bottom frame 111 of the first link 110. The second support frame 171 may be detachably coupled to the bottom frame 111 through fixing members such as screws or bolts. The second support frame 171 is provided on the guide rail 146 for guiding the movement of the second movable member 175. The second support frame 171 may be coupled to a portion other than the bottom frame 111 of the first link 110, such as the second sidewall frame 113.

The pair of second elastic members 173 are spaced apart from each other on the second support frame 171. The guide bar 149 is coupled to the second support frame 171 to install the second elastic member 173. The guide bar 149 is disposed in parallel with the pair spaced apart from each other. These guide bars 149 are coupled to the holder 150, each end of which is fixed to the second support frame 171. Like the first elastic member 148, the second elastic member 173 has a spring structure wound around the outer circumference of the guide bar 149.

The second movable member 175 is mounted to the second support frame 171 so as to be slidable. The second movable member 175 may linearly reciprocate along the guide rail 146 of the second support frame 171. The second movable member 175 is coupled to the pair of guide bars 149 to be slidably movable, and is connected to the pressing unit 153 to be slidably coupled to the guide rail 146. The connecting rod connector 154 is included. One side of the connecting rod connecting portion 154 is provided with a slider pivot connecting portion 156 for coupling the second connecting rod 177. The second movable member 175 is moved by the second connecting rod 177, and can be elastically deformed by pressing the second elastic member 173 with the pressing unit 153.

The second connecting rod 177 connects the input link 130 of the link mechanism 115 and the second movable member 175. The second connecting rod 177 may include a first head portion 159 connected to the input link 130 and a second head portion 160 connected to the slider pivot connection portion 156 of the second movable member 175. And a body portion 161 connecting the first head portion 159 and the second head portion 160.

The first head portion 159 of the second connecting rod 177 is rotatably connected to the input link 130 through an input link pivot connecting portion 134 provided in the rotating portion 131 of the input link 130. Since the input link pivot connection 134 is eccentric from the center of rotation of the input link 130, when the input link 130 rotates, the first head 159 of the second connecting rod 177 is connected to the input link 130. Can move around the center of rotation. The second head portion 160 of the second connecting rod 177 is rotatably connected to the second movable member 175 through the slider pivot connecting portion 156 of the second movable member 175.

When the input link 130 is rotated, the first head portion 159 of the second connecting rod 177 moves around the rotation center of the input link 130, whereby the second head of the second connecting rod 177 is rotated. The unit 160 may move the second movable member 175 along the guide bar 149. When the second elastic member 173 is elastically deformed by the movement of the second movable member 175, the elastic force of the second elastic member 173 is input through the second movable member 175 and the second connecting rod 177. May be communicated to link 130. Therefore, when the input link 130 rotates, it is possible to provide the input link 130 with a compensating torque for compensating the gravity torque caused by the weight of the link mechanism 115, and the second link for moving the input link 130. The driving torque of the joint driver 140 can be reduced.

The second connecting rod 177 may be separated into a first rotating rod 163 having a first head portion 159 and a second rotating rod 166 having a second head portion 160. The first rotating rod 163 has a first head portion 159 and a first rod body 164 extending from the first head portion 159. The second rotating rod 166 has a second head portion 160 and a second rod body 167 extending from the second head portion 160. The first rod body 164 of the first rotary rod 163 and the second rod body 167 of the second rotary rod 166 may be detachably coupled through a fixing member such as a screw or a bolt. As such, the second counterbalancer 170 is assembled by the second connecting rod 177 having a detachable structure in which a portion coupled to the input link 130 and a portion coupled to the second movable member 175 can be separated. But disassembly becomes easy.

In this way, when the second counter balancer 170 has a modular structure that is prefabricated to the first link 110, the second counter balancer (when repairing or replacing a part of the second counter balancer 170) 170) can be easily removed and assembled easily. This saves time and money for maintenance.

Hereinafter, the operation principle of the gravity compensation device 142 described above with reference to the drawings.

10 is a simplified conceptual diagram for explaining the operation principle of the gravity compensation device of the vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention, Figure 11 is a gravity according to an embodiment of the present invention In order to explain the effect of the gravity compensator of the vertical articulated robot manipulator having a compensation device, a graph showing the compensation torque according to the joint rotation angle when the design variable is appropriately selected, and FIG. 12 is according to an embodiment of the present invention. It is a conceptual diagram briefly shown to explain the gravity torque applied to each pitch joint of a vertical articulated robot manipulator having a gravity compensation device.

As shown in FIG. 10, the length of the connecting rods 158 and 177 of the gravity compensator 142 is the length of the rod between the points where the connecting rods 158 and 177 are connected from the rotation center of the link mechanism 115. R, the spring constant of the elastic members 148 and 173 are k, the rotation angle of the link mechanism 115 is θ, and the rotation angle of the connecting rods 158, 177 is φ. The moving distance s of the movable members 152 and 175 according to the rotation may be expressed by the following equation.

Here, the compression distance of the elastic members 148 and 173 due to the movement of the movable members 152 and 175 is the initial compression distance of the elastic members 148 and 173 to the moving distance of the movable members 152 and 175. Same as si plus Therefore, the restoring force Fr of the elastic members 148 and 173 according to the compression of the elastic members 148 and 173 is multiplied by the compression distance of the elastic members 148 and 173 by the stiffness of the elastic members 148 and 173. It can be expressed as an expression.

If the force applied to the connecting rods 158 and 177 is F, the following relationship is established between F and Fr.

In addition, the moment arm lm which is the distance between the force transmitted through the connecting rods 158 and 177 and the center O of the first joint J1 is as follows.

Finally, the first joint J1 generates a compensating torque Tc, which is expressed as the product of the moment arm and the force transmitted through the connecting rods 158 and 177 as follows.

On the other hand, the rotation angle φ of the connecting rods 158 and 177 and the rotation angle θ of the link mechanism 115 are constrained by the following equation.

Therefore, the compensation torque Tc generated by the gravity compensator 142 according to the rotation angle θ of the link mechanism 115 is determined by four design variables R, k, si, and lrod, and the link mechanism 115 is selected through appropriate parameter selection. ) As a result of rotation, the gravity torque Tg, which appears in the form of a sine wave, can be offset.

For example, when the graph shows the compensation torque generated when R is 25 mm, lrod is 100 mm, k is 2.9 N / mm, and si is 75 mm, the shape of the sine wave is shown in FIG. 11. In the case of the gravity compensator 142 developed in the present invention, since the formula of the compensation torque does not coincide mathematically with the formula mgsin θ of the gravity torque, the gravity compensator 142 completely cancels the gravity torque due to the weight of the manipulator. I can't. However, if the gravity compensator is designed by optimizing the design variables, the error between the gravity torque and the compensating torque is insignificant. Therefore, it is possible to compensate the gravity torque and lower the driving unit power of the manipulator.

As shown in Fig. 12, in the case of the robot manipulator having three links L1, L2, and L3, the pitch joint 2 Jp1 and the pitch joint 3 Jp2 are provided on the roll joint 1 Jr. Each of the pitch joints Jp1 and Jp2 may be represented by the following gravity torque.

Where m2, m3 is the mass of each link (L2) (L3), lc2, lc3 is the center of gravity distance of each link (L2) (L3), l2 is between pitch joint 2 (Jp1) and pitch joint 3 (Jp2) Distance, and θ2 and θ3 are rotation angles of the pitch joints Jp1 and Jp2. Looking at the gravitational torque equation of pitch joint 2 (Jp1), since the first component (m2glc2 + m3gl2) sinθ2 is a function of the angle θ2 only, it is possible to compensate by adjusting the design parameters of the gravity compensation device appropriately. However, since the second component m3glc3sin (θ2 + θ3) must reflect both the angles of the pitch joint 2 (Jp1) and the pitch joint 3 (Jp2), it is difficult to compensate by applying a simple gravity compensator. Looking at this term, it can be seen that the same as the formula of gravity torque applied to pitch joint 3 (Jp2), which means that a torque equal to the gravity torque applied to pitch joint 3 (Jp2) due to action-reaction is linked (L2). Is transmitted to the pitch joint 2 (Jp1). Therefore, if this action-reaction torque is transmitted to the base through a structure other than the link, the torque applied to the pitch joint 2 (Jp1) remains only a term that depends only on the rotation angle of the pitch joint 2 (Jp1). By applying it is possible to compensate for gravity torque.

In the case of the gravity torque Tg3 applied to the pitch joint 3 (Jp2), it is determined by (θ2 + θ3), which is the sum of the rotation angles of the pitch joint 2 (Jp1) and the pitch joint 3 (Jp2), as shown in FIG. As such, the rotation angle of the link 3 (L3) is based on the direction of gravity. Therefore, when the gravity compensation device is applied to the pitch joint 3 (Jp2) based on the gravity direction, it is possible to compensate the gravity torque caused by the link 3 (L3).

Summarizing the above, in order to compensate the gravity torque of the robot manipulator composed of two pitch joints Jp1 and Jp2, link 1 without applying the torque generated by the action-reaction of gravity torque to the other joint is used. There is a need for a mechanism that can deliver to (L1) and the implementation of a gravity compensation device that always operates relative to the direction of gravity, regardless of the rotation of other joints.

The present invention can solve this problem by constructing parallel four-section links between two pitch joints J1 and J2, as shown in FIG. The rotational reference of the input link 130 constituting the parallel four-section link is above the first link 110, as in the second link 120, and thus is not affected by the rotation of the second link 120. Therefore, when the gravity compensation device 142 is applied to the input link 130 of the parallel four-section link, it is possible to always operate the second joint J2 based on the gravity direction.

In addition, since the gravity torque applied to the second joint J2 is transmitted to the first link 110 through the coupler link 136 of the parallel four-section link, the first joint J1 is the gravity of the second joint J2. Since it is not affected by the torque, only the components according to the rotation angle of the first joint J1 remain in the first joint J1, and a simple gravity compensator 142 may be applied. As such, by configuring two pitch joints J1 and J2 in a parallel four-section link structure, it is possible to apply gravity compensation through elastic force to both joints J1 and J2.

In addition, the second joint drive 140 is positioned on the first link 110 like the first joint drive 138 so that the rotation of the second joint J2 does not affect the rotation of the first joint J1. . Since the torque of the second joint J2 is transmitted to the first link 110 through the coupler link 136 and the input link 130, the torque of the second joint J2 acts on the first joint J1. I never do that.

As described above, the vertical articulated robot manipulator 100 according to the present invention follows the structure of a general industrial articulated articulated robot and compensates gravity torque for two joints J1 and J2 most affected by gravity torque. can do. Therefore, the amount of torque required at each joint J1 and J2 during the posture maintenance and driving of the vertical articulated robot manipulator 100 can be drastically reduced to lower the power required at the joint driving units 138 and 140. The manufacturing cost of the articulated robot manipulator 100 can be lowered.

In addition, since the articulated robotic manipulator 100 according to the present invention can use much smaller power to perform the same work due to gravity compensation, it is possible to obtain an effect of saving energy when operating the robot. In addition, by designing the gravity compensator 142 in a modular manner to facilitate the installation and replacement of the gravity compensator 142 according to the life of the component, it is possible to solve the maintenance problem of the vertical articulated robot manipulator (100).

Although the present invention has been described with reference to preferred examples, the scope of the present invention is not limited to the forms described and illustrated above.

For example, although the vertical articulated robot manipulator 100 is shown as being implemented in the form of a robot arm having an arm part having a multi-joint structure and a wrist part having a multi-joint structure, the vertical articulated robot of the present invention The manipulator can be modified to a variety of different structures with varying numbers of links and number of joints.

In addition, although the link mechanism 115 is shown as having a four-section link structure, the link mechanism may be changed to another structure including links having various numbers of various shapes. As another example, the rotation center of the second link constituting the link mechanism and the rotation center of the input link may be disposed at positions displaced from each other.

Also shown in the figure is a gravity counter 142 a first counter balancer 144 providing compensation torque to the second link 120 of the link mechanism 115 and a second counter providing compensation torque to the input link 130. Although shown as including a balancer 170, the gravity compensation device can be changed to another structure having one counter balancer to provide a compensation torque to at least one of the second link 120 and the input link 130. have.

In addition, the structures of the first counter balancer 144 and the second counter balancer 170 constituting the gravity compensator 142 are not limited to those shown in the drawings and may be variously changed. As another example, the elastic member constituting the counter balancer may be changed to another structure capable of providing an elastic force to the link mechanism in addition to the coil spring structure as shown, and connecting with the movable member for transmitting the elastic force of the elastic member to the link mechanism. The structure of the rod can also be changed in various ways.

While the invention has been shown and described in connection with preferred embodiments for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described. Rather, it will be apparent to those skilled in the art that many changes and modifications to the present invention are possible without departing from the spirit and scope of the appended claims.

Claims (12)

A first link; A second link connected to the first link and a first joint so as to rotate relative to the first link; A third link connected to the second link and a second joint spaced apart from the first joint to rotate about the second link; An input link coupled with the first link to rotate relative to the first link separately from the second link; A coupler link having one side rotatably connected with the third link and the other side rotatably connected with the input link; A first joint driver installed in the first link to provide a driving force to the second link to rotate the second link about the first joint; A second joint driver installed in the first link to rotate the input link to rotate the third link about the second joint through the input link and the coupler link; And The elastic force is applied to at least one of the second link and the input link to compensate for the gravity torque caused by the weight of the link mechanism including the second link, the third link, the input link and the coupler link. And a gravity compensation device installed on the first link. The method of claim 1, The gravity compensation device, An elastic member supported by the first link, A connecting rod rotatably connected to a portion spaced apart from a center of rotation with respect to the first link of either the second link or the input link to transmit the elastic force of the elastic member to the link mechanism; And a movable member rotatably connected to the connecting rod and movable to the first link to elastically deform the elastic member in association with the movement of the connecting rod. Robot Manipulator. The method of claim 2, The gravity compensation device, Further comprising a support frame prefabricated to the first link, The elastic member is coupled to the support frame, the movable member is a vertical articulated robot manipulator, which is slidably coupled to the support frame. The method of claim 3, wherein The gravity compensation device, Further comprising a guide bar coupled to the support frame to extend in the sliding direction of the movable member, The elastic member is made of a spring structure wound around the outer periphery of the guide bar, the movable member is a vertical articulated robot manipulator, characterized in that it is slidably coupled to the guide bar to compress the elastic member. The method of claim 3, wherein The connecting rod of the gravity compensation device, A first rotating rod having a first head portion rotatably coupled to either the second link or the input link, a first rod body extending from the first head portion, And a second rotating rod having a second head portion rotatably coupled to the movable member, and a second rod body extending from the second head portion and prefabricatedly coupled to the first rod body of the first rotating rod. Vertical articulated robot manipulator, characterized in that. The method of claim 1, The gravity compensation device, A first elastic member supported by the first link and a portion spaced apart from a center of rotation of the second link of the second link to transmit the elastic force of the first elastic member to the second link. A first connecting rod connected to the first connecting rod and a first connecting rod rotatably connected to the first connecting rod so as to be movable relative to the first link so as to elastically deform the first elastic member in response to the movement of the first connecting rod. A first counter balancer having a first movable member installed; A second elastic member supported by the first link and rotatably connected to a portion spaced apart from a rotation center of the input link relative to the first link to transmit the elastic force of the second elastic member to the input link. And a second connecting rod and the second connecting rod are rotatably connected and movable to the first link so as to elastically deform the second elastic member in response to the movement of the second connecting rod. A vertical articulated robotic manipulator comprising a second counter balancer having a second movable member. The method of claim 6, The first counter balancer further includes a first support frame prefabricated to the first link, the first elastic member is coupled to the first support frame, and the first movable member is the first support frame. Is slidably coupled to, The second counter balancer further includes a second support frame prefabricated to the first link, the second elastic member is coupled to the second support frame, and the second movable member is the second support frame. Vertical articulated robot manipulator, characterized in that coupled to the sliding. The method of claim 7, wherein The first connecting rod, A first rotating rod having a first head portion rotatably coupled to the second link, a first rod body extending from the first head portion, A second rotating rod having a second head portion rotatably coupled to the first movable member and a second rod body extending from the second head portion and prefabricatedly coupled to the first rod body of the first rotating rod. Vertical articulated robot manipulator comprising a. The method of claim 7, wherein The second connecting rod, A first rotating rod having a first head portion rotatably coupled to the input link, a first rod body extending from the first head portion, A second rotating rod having a second head portion rotatably coupled to the second movable member and a second rod body extending from the second head portion and prefabricatedly coupled to the first rod body of the first rotating rod. Vertical articulated robot manipulator comprising a. The method of claim 6, And the first counter balancer and the second counter balancer are disposed to face each other such that the movable direction of the first movable member and the movable direction of the second movable member are parallel to each other. The method of claim 1, And a multiple joint unit coupled to the third link with a plurality of joints. The method of claim 1, And a base unit connected to the first link and the base joint to rotate the first link about the base joint.

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