KR20170101775A - Articulated robot arm equipped with counterbalance mechanism - Google Patents

Abstract

The present invention relates to a vertical articulated robot manipulator, comprising: a first link; a second link connected to the first link by a first joint to rotate towards the first link; a third link connected to the second joint distanced from the first joint to rotate towards the second link; an input link connected to the first link to rotate towards the first link separately from the second link; a coupler link whose one side is rotatably connected to the third link, and whose other side is rotatably connected to the input link; a first joint driving unit installed in the first link to rotate the second link around the first joint, providing a driving force to the second link; a second joint driving unit installed in the first link to rotate the third link around the second joint by the input link and the coupler link, and to rotate the input link; and a counterbalance mechanism installed in the first link to apply an elastic force to one or both of the second link and the input link. The present invention is to provide a vertical articulated robot manipulator with a counterbalance mechanism capable of realizing effective compensation of gravity to a joint to which a great gravity torque is applied.

Description

[0001] ARTICULATED ROBOT ARM EQUIPPED WITH COUNTERBALANCE MECHANISM [0002]

The present invention relates to a robot manipulator, and more particularly, to a spring-based gravity compensation device capable of canceling a gravity torque applied to a joint due to its own weight during posture maintenance and driving of the robot manipulator, To a gravitational compensation device capable of minimizing the driving force of the driving unit.

Currently, in various industrial fields, process automation is actively performed to improve efficiency, and accordingly, a robot manipulator that can be flexibly used for various tasks is becoming more important. In particular, the vertical articulated robot manipulator is used for various operations such as transportation, assembling, welding, and painting of heavy objects, and has been developed and used in various sizes depending on the target work.

Vertical articulated robot When gravity of a manipulator is maintained or driven, a gravity torque due to its own weight is applied to a joint that moves the link in the direction of gravity. As the size of the robot manipulator becomes larger, the size of the robot becomes larger, and a greater driving force is required for the joints. In order to reduce the required motor and reducer capacity, some industrial robots are equipped with a weight on the opposite side of the point of action to reduce the distance of the center of gravity, or to compensate the weight of the link through the spring, Is being used.

However, the use of weights increases the influence of the inertia due to the increase of the weight of the robot manipulator, which makes it difficult to apply it to the multi - degree - of - freedom robot. The conventional methods of applying gravity compensation to joints of multi-degree-of-freedom robots based on mechanical elements such as springs and wires have limitations in application to robotic manipulators due to their complicated structure. Therefore, a simpler and more reliable multi- A compensation device is required. Further, in the case of the conventional coil spring-based gravity compensation device, the gravity compensation performance tends to be degraded due to the deformation of the spring due to long-term operation. In this case, the spring must be disassembled by disassembling the robot manipulator. not.

Patent Registration No. 1190228 (Oct. 12, 2012) Patent Registration No. 1270031 (Feb. 31, 2013)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide a gravity compensator capable of realizing effective gravity compensation for a joint to which a gravity torque is applied by applying a multi- And to provide a joint robot manipulator.

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

According to an aspect of the present invention, there is provided a vertical articulated robot manipulator including: a first link; A second link connected to the first link and the first joint so as to be rotatable with respect to the first link; A third link connected to the second link and a second joint disposed apart from the first joint so as to be rotatable about the second link; An input link connected to the first link so as to be rotatable about 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 drive unit installed on the first link to rotate the second link around the first joint and to provide a driving force to the second link; A second joint drive part installed on the first link to rotate the input link so that the third link can be rotated about the second joint through the input link and the coupler link; And to apply an elastic force to at least one of the second link and the input link to compensate for a gravity torque due to the own 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 in the first link.

Wherein the gravity compensation device includes an elastic member supported on the first link and a rotation center of the first link of 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 the connecting rod and operable with respect to the first link so as to elastically deform the elastic member in association with the movement of the connecting rod; And a movable member to be installed.

The gravity compensation device may further include a support frame assembled to the first link, wherein the elastic member is coupled to the support frame, and the movable member is slidably coupled to the support frame.

The gravity compensation device may further include a guide bar coupled to the support frame so as to extend in a sliding direction of the movable member, wherein the elastic member has a spring structure wound around an outer periphery of the guide bar, And may be slidably coupled to the guide bar so as to compress the elastic member.

Wherein the connecting rod of the gravity compensation device comprises a first head portion rotatably coupled to either the second link or the input link and a second rod body having a first rod body extending from the first head portion, And a second rod body having a second rod body extending from the second head portion and assembled with the first rod body of the first rotating rod in a rotatably coupled manner to the movable member, . ≪ / RTI >

The gravity compensation device includes a first elastic member supported on the first link and a second elastic member provided on the second link so as to be spaced apart from a rotation center of the second link with respect to the first link for transmitting the elastic force of the first elastic member A first connecting rod rotatably connected to the first connecting rod and rotatably connected to the first connecting rod, and a second connecting rod rotatably connected to the first connecting rod to elastically deform the first elastic member, A second elastic member supported on the first link, and a second counterweight balancer disposed on the input link for transmitting an elastic force of the second elastic member to the input link, A second connecting rod rotatably connected to a portion of the link spaced apart from the center of rotation of the first link; 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.

Wherein the first counterbalance further includes a first support frame that is assembled with the first link, the first elastic member is coupled to the first support frame, and the first movable member is coupled to the first support frame, Wherein the second counterbalance further comprises a second support frame that is assembled to the first link, the second elastic member is coupled to the second support frame, The member may be slidably coupled to the second support frame.

Wherein the first connecting rod includes: a first rotating portion rotatably coupled to the second link; a first rotating rod having a first rod body extending from the first head portion; And a second rotary rod having a second rod body extending from the second head and coupled to the first rod body of the first rotary rod in a prefabricated manner.

Wherein the second connecting rod includes: a first rotary head rotatably coupled to the input link; a first rotary rod having a first rod body extending from the first head; And a second rod having a second rod body extending from the second head and coupled to the first rod body of the first rotatable rod.

The first counterbalancer and the second counterbalance may be disposed to face each other such that the moving direction of the first movable member and the moving direction of the second movable member are mutually parallel.

The vertical articulated robot manipulator according to the present invention may further include an articulated 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 by a base joint and rotating the first link about the base joint.

The vertical articulated robot manipulator provided with the gravity compensation device according to the present invention is a vertical articulated robot manipulator provided with an elastic member for providing an elastic force, a movable member for transmitting an elastic force of the elastic member, and a counter balancer , It is possible to mechanically compensate torque generated due to gravity in a component having a weight such as a link mechanism. Therefore, it is possible to reduce the load that should be generated in the joint driving part by not providing the torque for canceling the gravity torque from the joint driving part, and to cope with a larger load using the same output joint driving part, Joint drive parts can be used.

The vertical articulated robot manipulator according to the present invention realizes gravity compensation using a simple structure gravity compensation device, thereby maximizing the payload, reducing the torque load at the joints, and minimizing the turning force, It is possible to perform an accurate operation without using a driving part of the motor.

In addition, when the vertical articulated robot manipulator according to the present invention is applied to an actual multi-axis articulated robot, the capacity of the joint driving parts such as a motor and a speed reducer can be greatly reduced, and manufacturing costs can be drastically reduced.

In addition, the vertical articulated robot manipulator according to the present invention enables a stable structure gravity compensation through a simple structure of a counter balancer and a compact structure, thereby enabling a compact structure to maximize utilization in various fields.

Also, the vertical articulated robot manipulator according to the present invention can greatly reduce time and cost due to maintenance by designing a gravity compensation device in a modular structure so as to facilitate the installation of the gravity compensation device and the replacement of the gravity compensation device according to the service life.

1 is a side view of a vertical articulated robot manipulator according to an embodiment of the present invention.
2 is a rear view of a vertical articulated robot manipulator according to an embodiment of the present invention.
FIG. 3 and FIG. 4 are perspective views illustrating the vertical articulated robot manipulator according to an embodiment of the present invention at different angles.
5 is a conceptual diagram briefly illustrating a four-bar linkage structure of a vertical articulated robot manipulator according to an embodiment of the present invention.
FIG. 6 illustrates a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention, in which a gravity compensation device is separated.
FIG. 7 illustrates a coupling structure of a first counterbalancer of a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention.
8 is a view illustrating a coupling structure of a second counterbalancer of a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention.
FIG. 9 is an exploded view of a second counter balancer of a vertical articulated robot manipulator having a gravity compensation apparatus according to an embodiment of the present invention.
FIG. 10 is a simplified conceptual diagram for explaining the operation principle of the gravity compensation apparatus of a vertical articulated robot manipulator having a gravity compensation apparatus according to an embodiment of the present invention.
11 is a graph showing compensation torque according to a joint rotation angle when a design parameter is appropriately selected to explain an effect of a gravity compensation device of a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention .
12 is a conceptual diagram briefly illustrating gravity torque applied to each pitch joint of a 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 drawings.

FIG. 1 is a side view of a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view showing a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention. 3 and 4 are perspective views of a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention, and FIG. 5 is a perspective view illustrating a vertical articulated robot manipulator according to an embodiment of the present invention. FIG. 6 is a schematic view illustrating a four-bar linkage structure of a vertical articulated robot manipulator having a gravity compensation device according to an embodiment of the present invention. FIG. 6 is a diagram illustrating a vertical articulated robot manipulator having a gravity compensation 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 apparatus according to an embodiment of the present invention includes a first link 110, a first link 110, A link mechanism 115 connected to the joint J1 and a gravity compensator 142 for compensating for gravity torque due to the self weight of the link mechanism 115. [ The first link 110 is connected to the base unit 180 via a base joint Jb and the multiple link unit 182 is connected to one end of the link mechanism 115. An end effector (not shown), which may be implemented as a roll motor or a gripper, may be installed at the end of the multi-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, a base unit 180, and a base unit 180) composed of three joints of a roll-pitch-pitch capable of determining the position of a robot end- 1 link 110 and link mechanism 115) and a wrist part (multi-joint unit 182) composed of three joints for determining the orientation of the robot end. In order to implement gravity compensation for the two pitch joints (first joint J1 and second joint J2) of the arm part, a parallel four-bar linkage structure is formed between the first joint J1 and the second joint J2 And the gravity compensation device 142 may be connected to the link mechanism 115 to cancel the gravity torque applied to the first joint J1 and the second joint J2.

The first link 110 is connected to the base unit 180 by a base joint Jb and is rotatable with respect to the base unit 180. That is, the first link 110 can rotate about the axis (Z-axis) perpendicular to the plane of the drawing as the rotation center axis. The base unit 180 may be provided with a driving unit for providing a driving force to the first link 110. The first link 110 includes a bottom frame 111 connected to the base unit 180 and a first sidewall frame 112 and a second sidewall frame 113).

The link mechanism 115 is connected to the first link 110 so as to be movable with respect 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, 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 by a first joint J1 and rotated about the first link 110. [ That is, the second link 120 can rotate within a certain angle range with the axis (X-axis) horizontal to the ground as the rotation center axis. The second link 120 includes a second link right side body 121 rotatably connected to the first side wall frame 112 of the first link 110 and a second link right side body 121 spaced apart from the second link right side body 121, A second link left body 122 rotatably connected to the second sidewall frame 113 of the first link 110 and a second link right body 121 and a second link left body 122 And a connection body 123 for connection. A second link pivotal connection 125 (see FIG. 7) is provided on one side of the second link right side body 121. The second link pivot connection portion 125 is for connecting the first connecting rod 158 provided in the first counter balancer 144 of the gravity compensator 142 to be described later, 2 link 120 at a predetermined distance from the rotation center axis.

The third link 127 is connected to the second link 120 and the second joint J2 disposed apart from the first joint J1 so as to be rotatable with respect to the second link 120. [ The third link 127 can rotate within a certain angle range with the axis (X axis) horizontal to the ground as the rotation center axis. The third link 127 is coupled to the multi-joint unit 182, and the multi-joint unit 182 is moved along the movement of the third link 127.

The input link 130 is connected to the first link 110 so as to be rotatable about the first link 110 separately from the second link 120. [ The input link 130 can rotate within a certain angle range with the axis (X axis) horizontal to the ground as the rotation center axis. The rotation center axis of the input link 130 is the same as the rotation center axis of the second link 120. [ The input link 130 includes a rotation part 131 rotatably coupled to the second sidewall frame 113 of the first link 110 and an eccentric rotation part 131 extending in the radial direction of the rotation part 131 on the outer circumferential surface of the rotation part 131. [ And includes a connection portion 132. An input link pivot connection 134 (see FIG. 8) is provided on one side of the rotation part 131. The input link pivot connection part 134 is for connecting the second connecting rod 177 provided in the second counter balancer 170 of the gravity compensation device 142 to be described later, 131 at a predetermined distance from the rotation center axis.

The coupler link 136 is rotatably connected to the third link 127 on one side and rotatably connected to the input link 130 on the other side to connect the third link 127 and the input link 130. One end of the coupler link 136 is rotatably connected to a portion of the third link 127 spaced from the second joint J2 and the other end of the coupler link 136 is connected to the eccentric connecting portion 132 of the input link 130 As shown in Fig.

Thus, the link mechanism 115 has a four-bar link structure in which the second link 120, the third link 127, the input link 130, and the coupler link 136 are connected. 5, each end of the second link 120 and the input link 130 is rotatably connected to the first link 110, and the third link 127 is connected to the second link 110 And both ends of the coupler link 136 are rotatably connected to the third link 127 and the input link 130 so as to be rotatably connected to the third link 127 and the input link 130, Lt; / RTI >

The link mechanism 115 of the four-bar link structure is moved by the first joint drive part 138 and the second joint drive part 140 provided on the first link 110. The first joint drive unit 138 is installed on the first sidewall 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 driving part 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 driving part 140 is transmitted to the third link 127 through the input link 130 and the coupler link 136 in order, and the third link 127 is transmitted to the driving force of the second joint driving part 140 And can rotate about the second joint J2 with respect to the second link 120. [ That is, the second joint driving part 140 can rotate the third link 127 about the second joint J2 through the input link 130 and the coupler link 136. [

The posture of the link mechanism 115 may vary in various ways due to the action of the first joint drive part 138 and the second joint drive part 140. [ The angle of the second link 120 with respect to the first link 110 is changed by the first joint drive part 138 and the angle of the second link 120 is changed by the second joint drive part 140. [ The angle of the third link 127 with respect to the third link 127 can be varied to adjust the position of the multi-joint unit 182 coupled to the third link 127.

In order for the link mechanism 115 to maintain a certain position and posture in space, the first joint drive portion 138 and the second joint drive portion 140 must provide drive torque necessary for movement. When the posture changes, the required torque of the first and second joint drive parts 138 and 140 also changes due to the change in gravity torque due to its own weight. Conventionally, the position and posture of a robot manipulator are measured through an encoder mounted on a joint of a robot manipulator and an angle of rotation is measured, a required gravity torque is calculated, and a necessary torque is generated through control of a driving unit to compensate gravity torque Was used.

In contrast, the present invention uses gravity compensation device 142 capable of providing an elastic force, so that gravity compensation can be automatically performed for all positions and postures of the vertical articulated robot manipulator 100 without the aid of a separate sensor, controller, It is possible to mechanically generate a torque that compensates for the torque. Therefore, the required torque of the joint driving parts 138 and 140 for compensating the gravity torque can be made close to zero.

2 to 4 and 6 to 9, the gravity compensation device 142 is provided with a link mechanism 115 for providing elastic force to compensate for the gravity torque due to the self weight of the link mechanism 115, And is installed in the link 110. The gravity compensation device 142 includes a first counter balancer 144 for applying an elastic force to the second link 120 of the link mechanism 115 for gravity compensation, And a second counter balancer 170 for applying an elastic force for compensation. The first counter balancer 144 and the second counter balancer 170 have the same structure and function as those of the first counter balancer 144 and the second counter balancer 170,

The first counterbalancer 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 connecting rod 158 connecting the first movable member 152 and the second link 120 of the link mechanism 115 to each other, . The second counterbalancer 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 connecting rod 177 connecting the input link 130 of the second movable member 175 and the link mechanism 115 to each other. Here, the components constituting the gravity compensator 142 are divided into first and second groups according to the first counter balancer 144 and the second counter balancer 170, The distinction of these names does not indicate the difference in structure or function. Hereinafter, the first counter balancer 144 will be described with reference to the components of the second counter balancer 170 shown in FIG. 9 for some of the components.

The first support frame 145 of the first counterbalancer 144 is coupled to the first sidewall frame 112 of the first link 110. The first support frame 145 may be detachably coupled to the first sidewall frame 112 through a fixing member such as a screw or bolt. The first support frame 145 is provided with a guide rail 146 for guiding the movement of the first movable member 152.

One pair of the first elastic members 148 are spaced apart from each other on the first support frame 145. A guide bar 149 is coupled to the first support frame 145 for the installation of the first elastic member 148. The pair of guide bars 149 are arranged in parallel to each other. These guide bars 149 are coupled to a fixing table 150, one end of each of which is fixed to the first supporting frame 145. The first elastic member 148 has a spring structure wound around the outer periphery of the guide bar 149.

The first movable member 152 is slidably mounted on the first support frame 145. The first movable member 152 can reciprocate linearly along the guide rails 146 of the first support frame 145. The first movable member 152 includes a pressing portion 153 that is slidably coupled to the pair of guide bars 149 and a pressing portion 153 that is connected to the pressing portion 153 and is slidably coupled to the guide rail 146 And a connecting rod connecting portion 154. At one side of the connecting rod connecting portion 154, a slider pivot connecting portion 156 for coupling the first connecting rod 158 is provided. This first movable member 152 is moved by the first connecting rod 158 and can be elastically deformed by pressing the first elastic member 148 with the pressing portion 153. [

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

The first head portion 159 of the first connecting rod 158 is connected to the second link 120 through the second link pivot connection portion 125 provided on the second link right side body 121 of the second link 120, As shown in Fig. The first head portion 159 of the first connecting rod 158 when the second link 120 rotates is positioned at the center of the second link 120, And can move along the rotation center 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 pivotal connection portion 156 of the first movable member 152. [

The first head portion 159 of the first connecting rod 158 moves along the rotation center of the second link 120 when the second link 120 rotates, 2 head portion 160 can 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 is transmitted through the first movable member 152 and the first connecting rod 158 2 < / RTI > Therefore, it is possible to provide the second link 120 with a compensating torque that can compensate for the gravity torque due to the weight of the link mechanism 115 when the second link 120 rotates, The drive torque of the first joint drive part 138 for the first joint drive part 138 can be reduced.

The first connecting rod 158 can 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 rotating rod 163 and the second rod body 167 of the second rotating rod 166 may be detachably coupled through a fixing member such as a screw or bolt. In this way, the first connecting rod 158 is separated from the first connecting rod 158 and the first movable member 152 so that the first connecting rod 158 can be separated from the first linking rod 152, Assembly and disassembly become easy.

The first rotating rod 163 and the second rotating rod 166 of the first connecting rod 158 are connected to the second link 120 and the first movable member 152 The first support frame 145 is coupled to the first link 110 and the first rotation rod 163 and the second rotation rod 166 are coupled to each other, 144 can be assembled.

When the parts of the first counter balancer 144 are 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, The first counter balancer 144 can be easily separated by a method of separating the frame 145 from the first link 110.

Thus, by taking a modular structure in which the first counter balancer 144 is assembled to the first link 110, when repairing or replacing the components of the first counter balancer 144, the first counter balancer 144 144 can be easily separated and assembled easily. Therefore, it is possible to save time and cost for maintenance work.

The second counter balancer 170 is provided on the first link 110 to transmit a compensating torque that can compensate for the gravity torque due to the weight of the link mechanism 115 to the link mechanism 115 separately from the first counter balancer 144. [ To the input link 130 of FIG. The second counterbalancer 170 is disposed between the first counterbalancer 144 and the first counterbalancer 144 so that the moving direction of the second movable member 175 is parallel to the moving direction of the first movable member 152 of the first counterbalancer 144 Respectively.

The second support frame 171 of the second counterbalancer 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 a fixing member such as a screw or bolt. The second support frame 171 is provided with a 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.

A pair of the second elastic members 173 are installed on the second support frame 171 so as to be spaced apart from each other. A guide bar 149 is coupled to the second support frame 171 for the installation of the second elastic member 173. The pair of guide bars 149 are arranged in parallel to each other. These guide bars 149 are coupled to a fixing table 150, one end of each of which is fixed to the second support frame 171. The second elastic member 173 has a spring structure wound around the outer periphery of the guide bar 149 like the first elastic member 148.

The second movable member 175 is slidably mounted on the second support frame 171. The second movable member 175 can reciprocate linearly along the guide rail 146 of the second support frame 171. The second movable member 175 includes a pressing portion 153 that is slidably coupled to the pair of guide bars 149 and a pressing portion 153 that is connected to the pressing portion 153 and is slidably coupled to the guide rail 146 And a connecting rod connecting portion 154. At one side of the connecting rod connecting portion 154, a slider pivot connecting portion 156 for coupling the second connecting rod 177 is provided. The second movable member 175 is moved by the second connecting rod 177 so that the second elastic member 173 can be elastically deformed by the pressing portion 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 includes a first head portion 159 connected to the input link 130, a second head portion 160 connected to the slider pivotal 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 connection portion 134 provided on the rotation portion 131 of the input link 130. The first head portion 159 of the second connecting rod 177 is connected to the input link 130 when the input link 130 rotates because the input link pivot connection portion 134 is eccentric from the rotational center of the input link 130. [ As shown in FIG. The second head portion 160 of the second connecting rod 177 is rotatably connected to the second movable member 175 through the slider pivotal connection portion 156 of the second movable member 175.

The first head portion 159 of the second connecting rod 177 moves around the center of rotation of the input link 130 during rotation of the input link 130 so that the second head of the second connecting rod 177, The portion 160 can 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 inputted through the second movable member 175 and the second connecting rod 177 May be transmitted to the link (130). The input link 130 can be provided with a compensating torque that can compensate for the gravity torque due to the weight of the link mechanism 115 during the rotation of the input link 130, The driving torque of the joint driving part 140 can be reduced.

The second connecting rod 177 can 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 rotating rod 163 and the second rod body 167 of the second rotating rod 166 may be detachably coupled through a fixing member such as a screw or bolt. The second connecting rod 177 is separated from the second connecting rod 177 by a portion of the second counterbalance 170 that is coupled to the input link 130 and a portion of the second movable member 175 that is coupled to the second movable member 175, Or disassembly becomes easy.

In this manner, by taking the modular structure in which the second counter balancer 170 is assembled to the first link 110, when the parts of the second counter balancer 170 are repaired or replaced, the second counter balancer 170 can be easily separated and can be easily assembled. Therefore, it is possible to save time and cost for maintenance work.

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

FIG. 10 is a simplified conceptual diagram for explaining the operation principle of the gravity compensation apparatus of a vertical articulated robot manipulator having a gravity compensation apparatus according to an embodiment of the present invention. FIG. FIG. 12 is a graph illustrating a compensation torque according to a joint rotation angle when a design parameter is appropriately selected to explain an effect of a gravity compensation device of a vertical articulated robot manipulator having a compensation device. FIG. FIG. 3 is a conceptual view briefly illustrating a gravity torque applied to each pitch joint of a vertical articulated robot manipulator having a gravity compensation device. FIG.

10, the length of the connecting rod 158 (177) of the gravity compensation device 142 is denoted by lrod, the length between the points of connection of the connecting rods 158 and 177 from the rotational center of the link mechanism 115 The spring constant of the elastic members 148 and 173 is k, the rotation angle of the link mechanism 115 is? And the rotation angle of the connecting rods 158 and 177 is? The moving distance s of the movable members 152 and 175 with respect to the rotation can be expressed by the following equation.

The compression distance of the elastic members 148 and 173 due to the movement of the movable members 152 and 175 depends on the moving distance of the movable members 152 and 175, It is equal to the sum of si. The restoring force Fr of the elastic members 148 and 173 due to the compression of the elastic members 148 and 173 is obtained by multiplying the rigidity of the elastic members 148 and 173 by the compression distances of the elastic members 148 and 173, As shown in Fig.

Assuming that the force applied to the connecting rods 158 and 177 is F, the following relationship holds between F and Fr.

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, in the first joint J1, a compensation torque Tc, which is represented by the product of the force transmitted through the connecting rods 158 and 177 and the moment arm, is generated as follows.

On the other hand, the rotation angle? Of the connecting rod 158 (177) and the rotation angle? Of the link mechanism 115 are constrained by the following equations.

Therefore, the compensation torque Tc generated by the gravity compensation device 142 in accordance with the rotation angle? Of the link mechanism 115 is determined by the four design variables R, k, si and lrod, ), The gravitational torque Tg appearing in the form of a sinusoidal wave can be canceled.

For example, if the compensating torque generated when R is 25 mm, lrod is 100 mm, k is 2.9 N / mm, and si is 75 mm is shown in a graph, it has a sinusoidal shape as shown in FIG. In the case of the gravity compensation device 142 developed in the present invention, since the formula of the compensation torque does not completely mathematically match with the formula mgsin? Of the gravity torque, the gravity compensation device 142 completely compensates the gravity torque due to the self weight of the manipulator I can not. However, when the gravity compensation device is designed by optimizing the design parameters, the error between the gravity torque and the compensation torque is insignificant. Therefore, it is possible to lower the driving force of the manipulator by compensating the gravity torque.

12, in the case of a robot manipulator having three links L1, L2 and L3 and provided with the pitch joint 2 (Jp1) and the pitch joint 3 (Jp2) on the roll joint 1 (Jr) It can be shown that the following gravity torque is applied to each pitch joint Jp1 (Jp2).

Where m2 and m3 are the masses of the links L2 and L3, lc2 and lc3 are the center-of-gravity distances of the links L2 and L3, and l2 is the distance between the pitch joint 2 (Jp1) and the pitch joint 3 (Jp2) And? 2 and? 3 are rotation angles of the pitch joints Jp1 and Jp2. In the gravity torque equation of the pitch joint 2 (Jp1), since the first component (m2glc2 + m3gl2) sin? 2 is a function of only the angle? 2, it is possible to compensate by appropriately adjusting the design parameters of the gravity compensator. However, since the second component m3glc3sin (θ2 + θ3) must reflect both the pitch joint 2 (Jp1) and the pitch joint 3 (Jp2), it is difficult to compensate by applying the simple gravity compensator. It can be seen that this expression is the same as that of the gravity torque applied to the pitch joint 3 (Jp2), which indicates that the torque equal in magnitude to the gravity torque applied to the pitch joint 3 (Jp2) ) To the pitch joint 2 (Jp1). Therefore, if the torque due to the action-reaction is transmitted to the base through a structure other than the link, the torque applied to the pitch joint 2 (Jp1) is left only on the rotation angle of the pitch joint 2 (Jp1) It is possible to compensate for the gravity torque.

The gravitational torque Tg3 applied to the pitch joint 3 (Jp2) is determined by the sum of the rotation angles of the pitch joint 2 (Jp1) and the pitch joint 3 (Jp2) (? 2 +? 3) And the rotation angle of the link 3 (L3) on the basis of the direction of gravity. Therefore, it is possible to compensate the gravity torque due to the link 3 (L3) by applying the gravity compensator based on the direction of gravity in the pitch joint 3 (Jp2).

In order to compensate the gravity torque of a robot manipulator composed of two pitch joints Jp1 and Jp2, it is necessary to apply a torque generated by link-1 It is necessary to implement a gravity compensating device that always operates based on the direction of gravity, regardless of the mechanism that can be transmitted to the first axis L1 and the rotation of the other joint.

As shown in Fig. 5, the present invention can solve this problem by constructing a parallel quadrilateral link between two pitch joints J1 and J2. The rotational reference of the input link 130 constituting the parallel four-bar link is not affected by the rotation of the second link 120 because the rotation reference of the input link 130 is on the first link 110 like the second link 120. Therefore, when the gravity compensator 142 is applied to the input link 130 of the parallel four-bar link, it is always possible to operate the second joint J2 with reference to the gravity direction.

Since the gravity torque applied to the second joint J2 is transmitted to the first link 110 via the coupler link 136 of the parallel four-bar linkage, the first joint J1 is moved in the same direction as the gravity of the second joint J2 Only the component corresponding to the rotation angle of the first joint J1 remains in the first joint J1 without being influenced by the torque and the simple gravity compensator 142 can be applied. By constructing the two pitch joints J1 and J2 with the parallel four-bar linkage structure as described above, it is possible to apply gravity compensation through the elastic force to both joints J1 and J2.

The second joint driving part 140 is positioned on the first link 110 like the first joint driving part 138 so that the rotation of the second joint J2 does not affect the rotation of the first joint J1 . And the torque of the second joint J2 is transmitted to the first link 110 through the coupler link 136 and the input link 130 so that 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 compensates gravity torque for two joints J1 and J2, which are most affected by gravity torque, in accordance with the structure of a general industrial vertical articulated robot. can do. Therefore, when the posture of the vertical articulated robot manipulator 100 is maintained and driven, the torque required for each of the joints J1 and J2 drastically decreases to lower the power required by the joint drive units 138 and 140, The manufacturing cost of the articulated robot manipulator 100 can be reduced.

Also, since the vertical articulated robot manipulator 100 according to the present invention can use much less power to perform the same operation due to the gravity compensation, it is possible to obtain energy saving effect in the operation of the robot. Also, the maintenance problem of the vertical articulated robot manipulator 100 can be solved by modularly designing the gravity compensator 142 to facilitate the installation of the gravity compensator 142 and the replacement of the gravity compensator 142 according to the life of the component.

Although the preferred embodiments of the present invention have been described above, the scope of the present invention is not limited to those described and illustrated above.

For example, in the figure, the vertical articulated robot manipulator 100 is embodied in the form of a robot arm having a multi-jointed arm part and a multi-jointed wrist part, The manipulator can be changed to various other structures with varying numbers of links and joint numbers.

Also, although the figure shows the link mechanism 115 as a four-bar link structure, the link mechanism can be changed to another structure including a link 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.

The figure also shows a gravity compensation device 142 which includes a first counter balancer 144 for providing a compensating torque to the second link 120 of the link mechanism 115 and a second counter 142 for providing a compensating torque to the input link 130. [ The gravity compensation device may be modified to have a different structure with one counter balancer providing compensation torque to at least one of the second link 120 and the input link 130 have.

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 and may be variously modified. 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 may be connected to the movable member, which transmits the elastic force of the elastic member, The structure of the rod can also be varied in various ways.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Those skilled in the art will appreciate that numerous modifications and variations can be made in the present invention without departing from the spirit and scope of the appended claims.

100: Vertical articulated robot manipulator
110: first link 111: bottom frame
112, 113: first and second sidewall frames 115: link mechanism
121: second link right side body 122: second link left side body
125: second link pivot connection 127: third link
130: input link 131:
132: eccentric connection part 134: input link pivot connection part
136: coupler link 138, 140: first and second joint drive parts
142: gravity compensation device 144, 170: first and second counter balancers
145, 171: first and second support frames 146: guide rails
148, 173: first and second elastic members 149: guide bars
150: fixed base 152, 175: first and second movable members
153: pressing portion 154: connecting rod connecting portion
156: slider pivot connection portion 158, 177: first and second connecting rods
159, 160: first and second head parts 161:
163, 166: first and second rotary rods 164, 167: first and second rod bodies
180: base unit 182: multi-joint unit

Claims (12)

A first link;
A second link connected to the first link and the first joint so as to be rotatable with respect to the first link;
A third link connected to the second link and a second joint disposed apart from the first joint so as to be rotatable about the second link;
An input link connected to the first link so as to be rotatable about 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 drive unit installed on the first link to rotate the second link around the first joint and to provide a driving force to the second link;
A second joint drive part installed on the first link to rotate the input link so that the third link can be rotated about the second joint through the input link and the coupler link; And
And an elastic force is applied to at least one of the second link and the input link to compensate for a gravity torque due to a self weight of a link mechanism including the second link, the third link, the input link, And a gravity compensation device installed on the first link.
The method according to claim 1,
Wherein the gravity compensation device comprises:
An elastic member supported on the first link,
A connecting rod rotatably connected to a portion of the second link or the input link spaced apart from a center of rotation of the first 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 with respect to the first link so as to elastically deform the elastic member in conjunction with movement of the connecting rod, Robot manipulator.
3. The method of claim 2,
Wherein the gravity compensation device comprises:
Further comprising a support frame assembled to the first link,
Wherein the elastic member is coupled to the support frame, and the movable member is slidably coupled to the support frame.
The method of claim 3,
Wherein the gravity compensation device comprises:
And a guide bar coupled to the support frame to extend in a sliding direction of the movable member,
Wherein the elastic member comprises a spring structure wound around an outer periphery of the guide bar, and the movable member is slidably coupled to the guide bar so as to compress the elastic member.
The method of claim 3,
Wherein the connecting rod of the gravity compensation device comprises:
A first rotary rod rotatably coupled to either the second link or the input link and having a first rod body extending from the first head;
And a second rotary rod having a second rod portion rotatably coupled to the movable member and a second rod body extending from the second head portion and coupled to the first rod body of the first rotary rod in a prefabricated manner Wherein the manipulator is a vertical manipulator.
The method according to claim 1,
Wherein the gravity compensation device comprises:
A first elastic member supported on the first link and a second elastic member rotatably disposed on a portion of the second link spaced from a center of rotation 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 to which the first connecting rod is rotatably connected and is operable with respect to the first link so as to elastically deform the first elastic member in conjunction with the movement of the first connecting rod; A first counterbalancer having a first movable member to be installed,
A second elastic member supported on the first link and rotatably connected to a portion of the input link spaced from a center of rotation of the input link to transmit an elastic force of the second elastic member to the input link A second connecting rod rotatably connected to the second connecting rod and movable relative to the first link so as to elastically deform the second elastic member in association with the movement of the second connecting rod; And a second counterbalancer having a first movable member and a second movable member.
The method according to claim 6,
Wherein the first counterbalance further includes a first support frame that is assembled with the first link, the first elastic member is coupled to the first support frame, and the first movable member is coupled to the first support frame, Respectively,
Wherein the second counterbalance further includes a second support frame that is assembled to the first link, the second elastic member is coupled to the second support frame, and the second movable member is coupled to the second support frame, Wherein the manipulator is slidably coupled to the main body.
8. The method of claim 7,
The first connecting rod
A first rotary part rotatably coupled to the second link, a first rotary rod having a first rod body extending from the first head part,
And a second rod body having a second rod body extending from the second head and coupled with the first rod body of the first rotating rod in a rotatably coupled manner to the first movable member, And a manipulator for manipulating the manipulator.
8. The method of claim 7,
The second connecting rod
A first rotary head rotatably coupled to the input link, a first rotary rod having a first rod body extending from the first head,
And a second rod body having a second rod body extending from the second head and coupled with the first rod body of the first rotating rod in a rotatably coupled manner to the second movable member, And a manipulator for manipulating the manipulator.
The method according to claim 6,
Wherein the first counter balancer and the second counter balancer are disposed to face each other such that a moving direction of the first movable member and a moving direction of the second movable member are mutually parallel.
The method according to claim 1,
And a multi-joint unit having a plurality of joints and coupled to the third link.
The method according to claim 1,
And a base unit connected to the first link by a base joint to rotate the first link about the base joint.

Images