Driving device, controlling method, robot, program, recording medium, and method of manufacturing article

Abstract

To provide a technology capable of detecting torque applied to an output link with high accuracy, in a joint mechanism supporting the output link through a plurality of bearings.SOLUTION: A driving device displacing a second link with respect to a first link, is equipped with a driving part that is equipped with an output part outputting driving force for displacing the second link, a sensor that obtains information on force, a sensor connecting member that connects the output part and the sensor, and a first bearing and a second bearing. The sensor is connected with the second link. The first bearing and the second bearing are disposed on the driving part side rather than the sensor, in a force transmission path from the driving part to the second link.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a driving device or the like equipped with a torque sensor for use in a robot or the like. [Background technology]

[0002] In recent years, the uses of articulated robot manipulators have expanded, and they are being applied to fields that require flexible movements, such as collaborative work with humans and factory assembly work. Since such robots require stable, wide-bandwidth force control functions to follow external forces, it is desirable to configure a control system based on joint-level torque control (torque servo) instead of a motion control system based on joint position control (position servo). For this reason, a joint mechanism that can accurately detect the output torque is required.

[0003] The output torque measurement mechanism (torque sensor) is generally configured to be installed between the output side of the drive unit consisting of a motor and a reduction mechanism, and the output link. The torque sensor is composed of an elastic member that deforms according to the applied torque, and measures the output torque by detecting the amount of deformation or distortion. In addition, to ensure the mechanical robustness and operational stability of the joint, the output link is supported via multiple bearings.

[0004] Patent Document 1 describes a joint mechanism equipped with a torque sensing mechanism for measuring the torque output by a drive unit. This joint mechanism includes a first link which is a base-end link and a second link which is a distal-end link, and the second link is supported via multiple bearings. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-242114 A Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the second link, which is the output link, is supported via multiple bearings, but there are cases where the torque sensor cannot measure the torque output by the drive unit with high accuracy. Therefore, when driving a joint with torque control (torque servo), the control accuracy cannot be sufficiently improved, and it is difficult to realize a robot that performs, for example, precision assembly work. Therefore, when the output link is supported via a plurality of bearings, a technology is required that can detect the torque applied to the output link with high accuracy. [Means for solving the problem]

[0007] A first aspect of the present invention is a drive device that displaces a second link relative to a first link, comprising: a drive unit having an output unit that outputs a drive force that displaces the second link; a sensor that acquires information regarding force; a sensor connecting member that connects the output unit and the sensor; a first bearing and a second bearing, wherein the sensor is connected to the second link; and the first bearing and the second bearing are arranged on the side of the drive unit rather than the sensor in the force transmission path from the drive unit to the second link.

[0008] A second aspect of the present invention is a control method for a drive device that displaces a second link relative to a first link, the drive device comprising: a drive unit having an output unit that outputs a drive force that displaces the second link; a sensor that acquires information regarding force; a sensor connecting member that connects the output unit and the sensor; a first bearing and a second bearing; the sensor is connected to the second link; the first bearing and the second bearing are arranged on the drive unit side of the sensor in a force transmission path from the drive unit to the second link; and a control unit controls the drive unit based on the information regarding force acquired by the sensor.

[0009] In addition, a third aspect of the present invention is a robot that displaces a second link relative to a first link, comprising: a drive unit having an output unit that outputs a drive force that displaces the second link; a sensor that acquires information regarding force; a sensor connecting member that connects the output unit and the sensor; a first bearing and a second bearing, wherein the sensor is connected to the second link; and the first bearing and the second bearing are arranged on the side of the drive unit relative to the sensor in a force transmission path from the drive unit to the second link.

[0010] In addition, a fourth aspect of the present invention is a control method for a robot that displaces a second link relative to a first link, the robot comprising: a drive unit having an output unit that outputs a drive force that displaces the second link; a sensor that acquires information regarding force; a sensor connecting member that connects the output unit and the sensor; a first bearing and a second bearing; the sensor is connected to the second link; the first bearing and the second bearing are arranged on the side of the drive unit relative to the sensor in a force transmission path from the drive unit to the second link; and a control unit controls the drive unit based on the information regarding force acquired by the sensor. Effect of the Invention

[0011] According to the present invention, when the output link is supported via a plurality of bearings, the torque applied to the output link can be detected with high accuracy. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic cross-sectional view for explaining a joint mechanism according to the embodiment. [Diagram 2] 1 is an example of a robot including a joint mechanism according to an embodiment. [Diagram 3] 2A is a front view showing the external shape of the joint mechanism 200. FIG. [Figure 4]FIG. 3 is a cross-sectional view illustrating the structure of the joint mechanism 200. [Diagram 5] FIG. 11 is a diagram showing a state in which a side cover member 1112 is removed. [Figure 6] FIG. 2 is an external perspective view showing the internal structure of the joint mechanism 200 with parts removed. [Figure 7] 1A is a diagram showing an external shape of an example of a torque sensor, and FIG. 1B is a schematic diagram for explaining the operation principle and configuration of the torque sensor. [Figure 8] 1A is a front view showing the external shape of the joint mechanism 300. FIG. [Figure 9] 1A is a front view showing the external shape of a joint mechanism 500. FIG. [Figure 10] 11 is a cross-sectional view showing an embodiment in which a first bearing mechanism 211 rotatably supports a sensor connection member 205 relative to a first link 1100. FIG. [Figure 11] FIG. 3 is a schematic cross-sectional view of a joint mechanism 3000 of a reference embodiment taken along a central axis of rotation 3220. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The inventors have conducted extensive research into the phenomenon in which a torque applied to an output link cannot be detected with high accuracy in a conventional joint mechanism that supports an output link via a plurality of bearings, and have discovered the cause. First, the cause discovered by the inventors will be described with reference to the embodiment.

[0014] [Reference form] 11 is a schematic cross-sectional view of a joint mechanism 3000 of a reference embodiment taken along a rotation center axis 3220 of an output link (second link 3200). The joint mechanism 3000 includes a first link 3100, a second link 3200, a first bearing mechanism 3211, a second bearing mechanism 3212, a drive unit 3202, and a torque sensor 3203.

[0015] The first link 3100 is a fixed link connected to the base side of the robot arm, and the second link 3200 corresponds to a distal link, i.e., an output link, which is rotationally driven by the driving unit 3202. The driving unit 3202 includes an electric motor having a stator 3202S (stator) and a rotor 3202R (rotor), and a reduction mechanism. The stator 3202S (stator) of the electric motor is fixed to the first link 3100.

[0016] An output side of the driving unit 3202 (output side of the reduction gear mechanism) is connected to one end of the torque sensor 3203, and the other end of the torque sensor 3203 is connected to the second link 3200. The rotational torque output by the driving unit 3202 is transmitted to the second link 3200 via the torque sensor 3203.

[0017] A first bearing mechanism 3211 is disposed between the first link 3100 and the output side of the drive unit 3202, and rotatably supports the two. A second bearing mechanism 3212 is disposed between the first link 3100 and the second link 3200, and rotatably supports the two. When viewed along the rotation center axis 3220, the first bearing mechanism 3211 and the second bearing mechanism 3212 are disposed at a distance from each other so that the second link 3200 is mechanically and firmly supported relative to the first link 3100, forming a so-called double-support structure. In FIG. 11, arrows are diagrammatically shown to explain how force is transmitted when a torque T (moment) acts on the second link.

[0018] Here, the arrows T1 and T2 show schematic transmission paths through which the torque T acting on the second link 3200 is transmitted to the first link 3100. The torque applied to the second link 3200, i.e., the torque T to be measured / controlled, can be transmitted to the first link 3100 via the first transmission path T1 and the second transmission path T2. Specifically, the first transmission path T1 is a path through which the torque is transmitted to the first link 3100 via the torque sensor 3203, the first bearing mechanism 3211, and the drive unit 3202. The second transmission path T2 is a path through which the torque is transmitted from the second link 3200 to the first link 3100 via the second bearing mechanism 3212.

[0019] Regarding the second transmission path T2, since the rotatable second bearing mechanism 3212 is interposed therebetween, ideally the torque transmitted is zero and there is no effect on the force transmitted to the torque sensor 3203 via the first transmission path T1. However, in reality, resistance (running torque) generated with the rotation of the second bearing mechanism 3212 and friction torque generated in response to an external torque when stationary, etc., act as a reaction moment (T loss Therefore, not all of the torque T to be measured is transmitted to the torque sensor 3203 via the transmission path T1, and the torque transmitted to the torque sensor 3203 is generated as a reaction moment (T loss The torque that can be measured by the torque sensor 3203 is reduced by T ts Then, T ts =TT loss The reaction moment (T loss ) there occurs an area (dead zone) that cannot be measured by the torque sensor 3203.

[0020] Therefore, in a joint mechanism such as the reference embodiment, the torque applied to the output link cannot be accurately measured by the torque sensor provided in the joint, resulting in reduced sensitivity of torque control and reduced responsiveness of the torque servo. In a multi-joint robot equipped with such a joint mechanism, the accuracy of control and measurement of the force at the tip of the robot arm is reduced, making it difficult to accurately perform, for example, precision assembly work.

[0021] [Embodiment] Hereinafter, a driving device and the like according to an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment shown below is merely an example, and those skilled in the art can appropriately modify and implement the detailed configuration, for example, without departing from the spirit and scope of the present invention.

[0022] In the drawings referred to in the following description of the embodiments, elements denoted by the same reference numerals have the same functions unless otherwise noted. When a plurality of identical elements are arranged in a drawing, the reference numerals and their descriptions may be omitted.

[0023] In addition, since the drawings may be represented diagrammatically for the convenience of illustration and explanation, the shape, size, arrangement, etc. of the elements depicted in the drawings may not strictly correspond to the actual objects.

[0024] [Joint mechanism] 1 is a schematic cross-sectional view for explaining a joint mechanism (drive device) according to an embodiment, showing a cross section of a joint mechanism 200 cut along a rotation center axis CA of an output link. The joint mechanism 200 includes a first link 1100, a second link 1200, a first bearing mechanism 211, a second bearing mechanism 212, a drive unit 202, and a torque sensor 203.

[0025] The first link 1100 is a fixed link connected to the base side of the robot arm, and the second link 1200 corresponds to a distal link, i.e., an output link, that is rotationally driven by the drive unit 202. The second link 1200 is configured to be displaceable with respect to the first link around a rotation center axis CA.

[0026] The driving unit 202 includes an electric motor having a stator 202S and a rotor 202R, and a reduction gear mechanism. The stator 202S of the electric motor is fixed to the first link 1100.

[0027] An output side of the drive unit 202 (output side of the reduction gear mechanism) is connected to a sensor connection member 205 via a connection part CP1. The sensor connection member 205 is connected to one end of the torque sensor 203 via a connection part CP2, and the other end of the torque sensor 203 is connected to the second link 1200 via a connection part CP3. The rotational torque output by the drive unit 202 is transmitted to the second link 1200 via the torque sensor 203. For ease of explanation, in the torque transmission path, the side of the drive unit 202 relative to the torque sensor 203 may be referred to as a drive unit side torque transmission path, and the side of the second link 1200 relative to the torque sensor 203 may be referred to as an output link side torque transmission path.

[0028] A first bearing mechanism 211 is disposed (sandwiched) between the first link 1100 and the output side of the driving unit 202, and supports the first link 1100 and the second link 1100 so that they can rotate relative to each other. A second bearing mechanism 212 is disposed (sandwiched) between the sensor connection member 205 and the first link 1100, and supports the first link 1100 and the second link 1200 so that they can rotate relative to each other. When viewed along the rotation center axis CA, the first bearing mechanism 211 and the second bearing mechanism 212 are disposed at a distance from each other so that the second link 1200 is mechanically and firmly supported relative to the first link 1100, forming a so-called double-support structure. That is, by configuring the second link so that at least a part of the second link is positioned between the first bearing and the second bearing when viewed along the direction of the rotation axis, the second link can be firmly supported relative to the first link.

[0029] In the above-mentioned reference embodiment, in the torque transmission path, the first bearing mechanism 3211 is disposed closer to the drive unit 3202 than the torque sensor 3203, and the second bearing mechanism 3212 is disposed closer to the output link (second link 3200) than the torque sensor 3203. Therefore, of the torque T (moment) applied to the second link 3200, the reaction moment (T loss ) was not transmitted to the torque sensor 3203 and could not be detected by the torque sensor 3203. In other words, in the reference embodiment, a bearing mechanism is disposed in the torque transmission path on the output link side, so the reaction moment (T loss ) was not transmitted to the torque sensor, and the torque sensor was not able to accurately detect the torque applied to the output link.

[0030] In contrast, in the joint mechanism of the embodiment, the first bearing mechanism 211 and the second bearing mechanism 212 constituting the double-supported support structure are both installed in the torque transmission path on the drive unit side of the torque transmission path, and no bearing mechanism is installed in the torque transmission path on the output link side. That is, the first bearing mechanism 211 and the second bearing mechanism 212 support a member that is arranged on the drive unit side of the torque transmission path relative to the torque sensor 203. Therefore, the torque applied to the second link 1200 is not lost as a reaction moment until it is transmitted to the torque sensor 203 via the connection part CP3. Therefore, the rotational torque applied to the output link (second link 1200) can be detected with high accuracy by the torque sensor 203.

[0031] In the joint mechanism of the embodiment, the second link is supported firmly against the first link by adopting a double-support structure, that is, a structure in which at least a part of the second link is located between the first bearing and the second bearing when viewed along the direction of the rotation axis. Furthermore, it is possible to measure and control the joint torque that drives the link with high sensitivity and high accuracy without being affected by the reaction force (torque disturbance) generated in the bearing mechanism. By using the joint mechanism of the embodiment, it is possible to improve the responsiveness of the torque control in, for example, a multi-joint robot, and it is possible to realize a robot that performs, for example, a precise assembly work. In this case, it is not necessary to complicate the control of the robot, and it is not necessary to obtain the reaction force generated in the bearing in advance by an experiment and store it as correction data in the control unit of the robot. In addition, it is not necessary to have the control unit calculate the reaction force generated in the bearing based on the bending angle, bending speed, etc. of the joint to correct the driving force. In this way, by using the joint mechanism according to the present embodiment, it is possible to improve the sensitivity and accuracy of the torque control of the joint mechanism without using a complicated control method.

[0032] [Robot device] Next, a robot device including a joint mechanism according to an embodiment will be described. Fig. 2 shows the appearance of a multi-joint type robot device 1 as an example of a robot including a joint mechanism according to an embodiment.

[0033] The robot device 1 includes a robot 2 and a control device 3 serving as a control unit for controlling the robot 2. The robot 2 includes a vertical multi-joint robot arm 20 having a plurality of joint mechanisms (e.g., joint mechanisms 100 to 600), and a robot hand 21 serving as an end effector.

[0034] The robot arm 20 has a plurality of links (for example, links 1000 to 1600), and each of the links 1000 to 1600 is connected by a joint mechanism provided on the base end side of each of the links 1000 to 1600. The joint mechanisms 100 to 600 may be referred to as joints J1 to J6 from the base end side to the distal end side.

[0035] In this embodiment, the robot arm 20 is composed of six joints J1 to J6, and the three axes of the joints J2, J3, and J5 are configured to be swingable, and the three axes of the joints J1, J4, and J6 are configured to be rotatable. Note that being swingable may be rephrased as being rotatable or bendable.

[0036] A link 1000, which is the base end (base portion) of the robot arm 20, is fixed to a stand. The links 1000 to 1600 are connected in series by joint mechanisms 100 to 600. A torque sensor is provided on the output side of each joint to measure the torque transmitted to the link via the joint.

[0037] The robot hand 21, which is an end effector, is attached to and supported by a link 1600 at the tip of the robot arm 20, and its motion (position and posture) and force (force and moment) are adjusted by the operation of the robot arm 20. The robot hand 21 includes a hand body 24 and a plurality of fingers 23 disposed movably relative to the hand body 24. The robot hand 21 can grasp, for example, a workpiece using the fingers 23.

[0038] The end effector is not limited to the exemplified robot hand 21, and various devices may be attached depending on the work to be performed by the robot. Peripheral devices (external extension devices) such as a camera (hand eye), a wrist multi-axis force sensor (force / torque sensor: F / T sensor), and a proximity sensor (not shown) may be mounted on the link at the tip or wrist of the robot.

[0039] The robot 2 and the control device 3 are connected by a wiring member 5 including electric wires such as signal lines and power lines. If the robot 2 has an arm or end effector that is driven by a fluid such as air pressure or hydraulic pressure, the wiring member 5 may include fluid piping and the like. The wiring member 5 is flexible, and is disposed from the base end (fixed end) to the tip end (free end) of the robot arm 20. The electric wires and piping that constitute the wiring member 5 branch out as appropriate and are connected to the actuators and sensors of the joints J1 to J6, the actuators and sensors of the robot hand 21, and peripheral devices.

[0040] The oscillating joint mechanism 200 has the configuration described with reference to Fig. 1, and the oscillating joint mechanism 300 and the joint mechanism 500 also have similar configurations. Therefore, in these joint mechanisms, while firmly supporting the link with a double-support structure, it is possible to measure and control the joint torque that drives the link with high sensitivity and high accuracy without being affected by the reaction force (torque disturbance) generated in the bearing mechanism.

[0041] [Details of the swing joint mechanism] The basic configurations of the swingable joint mechanisms 200, 300, and 500 included in the robot 2 have already been described with reference to FIG. 1, but will be described in further detail below.

[0042] Fig. 3(a) is a front view showing the external shape of the joint mechanism 200, and Fig. 3(b) is a side view. The joint mechanism 200 of the J2 joint connects a first link 1100, which is a fixed link, and a second link 1200, which is an output link located on the peripheral side. The first link 1100 has a joint support member 1101 and a joint support member 1102, and supports the second link 1200 from both sides by the joint support member 1101 and the joint support member 1102.

[0043] Fig. 4 is a cross-sectional view for explaining the structure of the joint mechanism 200, showing a cross section taken along line AA in the side view of Fig. 3(b). The joint mechanism 200 is provided with side cover members 1111 and 1112 for protecting the inside of the joint, and wiring and piping 206 are stored inside.

[0044] 5 and 6 are perspective views with some parts removed to show the three-dimensional shapes of the members constituting the joint mechanism 200. Fig. 5 shows a state in which the side cover member 1112 of the joint support member 1102 is removed, and shows the state of the internal wiring arranged inside the joint mechanism, i.e., the wiring and piping 206. Fig. 6 is an external perspective view showing the internal structure of the joint mechanism 200 with the second link 1200, which is the output link, the second bearing mechanism 212, and the joint support member 1102 further removed to specifically explain the method of fixing the wiring and piping 206.

[0045] Below, we will explain the configuration of each part of the joint mechanism 200. The joint mechanism 200 is configured by rotatably connecting a first link 1100, which is a fixed link, and a second link 1200, which is an output link, via a first bearing mechanism 211 and a second bearing mechanism 212, which are joint support mechanisms.

[0046] The first link 1100 has two support members, a joint support member 1101 and a joint support member 1102. The joint support member 1101 is connected to a first bearing mechanism 211, and the joint support member 1102 is connected to a second bearing mechanism 212.

[0047] The first bearing mechanism 211 and the second bearing mechanism 212 constrain the second link 1200 relative to the first link 1100 so that the second link 1200 can only rotate about the drive axis of the joint relative to the first link 1100. A cross roller bearing is preferably used as the first bearing mechanism 211, and a ball bearing is preferably used as the second bearing mechanism 212. However, the bearings that can be used in the embodiments are not limited to this, and for example, multiple angular bearings may be used, or bearing mechanisms of other types may be combined.

[0048] Components of a drive mechanism required for driving the joint are stored on the side of the joint support member 1101 in the first link 1100. The arrangement of the components and the operating principles of the joint drive operation and torque measurement will be described below.

[0049] The driving unit 202 is a driving unit that generates a rotational torque between the first link 1100 and the second link 1200, and includes an electric motor having a stator 202S and a rotor 202R, and a reduction mechanism 202G. The rotor 202R is an output end of the motor power, and is connected to an input end of the reduction mechanism 202G. As the electric motor, a built-in motor in which the frame member of the link also serves as the case of the electric motor can be used.

[0050] A rotary encoder 204 is provided at an end of the electric motor, and the rotary encoder 204 measures the rotation angle of the electric motor and transmits it to the control device 3. The driving unit 202 is equipped with a brake mechanism (not shown) for maintaining the motor rotation angle, etc. A wiring cable is connected to the driving unit 202 for driving the motor, exchanging signals with the rotary encoder, and controlling the opening and closing operation of the brake.

[0051] A strain wave gear mechanism composed of three components, an input end, an output section, and a fixed section, is preferably used as the reduction mechanism 202G, and the reduction ratio is, for example, 1:80, but can be changed as appropriate. In this embodiment, the inner ring of the cross roller bearing, which is the first bearing mechanism 211, is integrated with the output section of the reduction mechanism 202G, and the outer ring is integrated with the fixed section of the reduction mechanism. The rotor 202R of the electric motor, which is the driving source, rotates and drives the input end of the reduction mechanism 202G. The reduction mechanism 202G amplifies the torque generated by the electric motor by the reduction ratio and simultaneously reduces the rotation angle by the reduction ratio, and outputs the expanded rotation torque from the output section. The torque generated by the electric motor is amplified by the reduction mechanism 202G to a level suitable for driving the joint, and the torque output from the reduction mechanism 202G actively rotates and drives the second link 1200 supported by the joint support mechanism (bearing).

[0052] In general, the torque that a small electric motor can efficiently generate is much smaller than the torque required to drive a joint, and the rated rotational speed is much larger than the rotational speed required for the output shaft of the joint. For this reason, most robots generally use a reduction mechanism with a high reduction ratio of about 1:30 to 1:200. In such a drive mechanism, torque loss due to friction and rotational resistance accompanying deceleration becomes large, so the rotational torque applied to the output link of the joint mechanism cannot be accurately grasped by only measuring the motor torque. The same is true even if the motor current is measured instead of directly measuring the motor torque. Since such torque loss is difficult to precisely model and has poor reproducibility, it is also difficult to predict the loss and correct the output torque of the electric motor. For this reason, it is necessary to accurately measure the torque applied to the output link of the joint mechanism by a torque sensor.

[0053] As already described, in this embodiment, the output side of the driving unit 202 (the output side of the reduction gear mechanism) is connected to the sensor connecting member 205 via a connecting part CP1. The sensor connecting member 205 is connected to one end of the torque sensor 203 via a connecting part CP2, and the other end of the torque sensor 203 is connected to the second link 1200 via a connecting part CP3. The rotational torque output by the driving unit 202 is transmitted to the second link 1200 via the torque sensor 203.

[0054] Fig. 7(a) shows an example of the external shape of the torque sensor 203. Fig. 7(b) shows a schematic diagram for explaining the operating principle and configuration of the torque sensor. As shown in Fig. 7(a), the torque sensor 203 includes two disk-shaped members 203IF1 and 203IF2 arranged opposite each other, and the two disk-shaped members are integrally connected by a plurality of beam members 203E. One of the disk-shaped members 203IF1 and 203IF2 can be called the first end of the torque sensor, and the other can be called the second end of the torque sensor.

[0055] The disk-shaped member 203IF1 and the disk-shaped member 203IF2 are provided with fixing bolt holes (not shown) for mechanically connecting them to elements disposed before and after the torque sensor in the torque transmission path.

[0056] The beam member 203E is formed of a thin elastic member so as to have a smaller rigidity than the disk-shaped member 203IF1 and the disk-shaped member 203IF2. A plurality of thin elastic members (e.g., 12) are radially arranged to connect the disk-shaped member 203IF1 and the disk-shaped member 203IF2.

[0057] The torque sensor 203 includes an encoder 203OE as a displacement measuring device. That is, a displacement detector 203OED is provided on the disk-shaped member 203IF1, and a scale 203OES is provided on the disk-shaped member 203IF2. The displacement detector 203OED and the scale 203OES are provided facing each other, and function as an optical encoder that measures the relative displacement of the two disk-shaped members.

[0058] The torque sensor 203 is equipped with multiple sets (e.g., three sets) of optical encoders, and performs digital signal processing to multiply the output of each encoder by a sensor stiffness matrix, thereby converting the measured displacement into an applied torque and outputting it.

[0059] That is, when a rotational torque AT around a central axis caused by an external force acts on the torque sensor 203, the torque sensor 203 measures the relative displacement (displacement in the circumferential direction) between the two disk-shaped members, thereby detecting the rotational torque acting on the torque sensor 203. In other words, the torque sensor 203 is a sensor that obtains information regarding the torque acting between the first end and the second end.

[0060] Returning to Fig. 4, in the first link 1100, the joint support member 1101 and the joint support member 1102 are connected by a bolt, and the joint support member 1102 holds a second bearing mechanism 212. As shown in Figs. 1 and 4 to 6, the sensor connection member 205 has a tubular shape (for example, a cylindrical shape) extending in the direction of the rotation center axis CA of the joint mechanism. One end of the sensor connection member 205 extending from the connection part with the drive unit 202 toward the second link 1200 is supported between the first link 1100 and the sensor connection member 205 by the second bearing mechanism 212.

[0061] As a desirable aspect of this embodiment, it is preferable to employ a dustproof and waterproof structure by sealing the gap between the sensor connecting member 205 and the second link 1200. For example, a relatively elastic sealing member such as an O-ring or an oil seal can be provided, as in the sealing member 209 shown in Fig. 4. One of the features of the joint mechanism of this embodiment is that even if such a sealing structure is introduced, the torque measurement performance is not significantly deteriorated.

[0062] Next, a method for mounting the wiring member inside the joint in the joint mechanism of the embodiment will be described. In Fig. 4, a first link 1100 has two support members, a joint support member 1101 on the left side of the figure and a joint support member 1102 on the right side of the figure. In the internal space of the joint mechanism defined by a side cover member 1111 and a side cover member 1112, the drive unit 202 is installed on the joint support member 1101 side, but the wiring / piping 206 is stored on the joint support member 1102 side. With such an arrangement, wiring can be stored on a large scale in the intra-joint space.

[0063] 4 to 6, the wiring and piping 206 is a bundle of power wiring for driving the motors of each joint, signal wiring to sensors, fluid piping for driving actuators, etc. The wiring and piping 206 installed inside each joint is configured by bundling wiring and piping to joints and end effectors located on the peripheral side of the joint.

[0064] The wiring / piping 206 introduced into the internal space of the joint mechanism 200 is fixed to the joint support member 1101 of the first link 1100 by a base end side fixing part 208. The wiring / piping 206 is then guided through the inside of a cylindrical sensor connecting member 205 to the second link 1200 side, and is fixed to a wiring support mechanism 207 in the vicinity of the second link 1200.

[0065] 6, the wiring support mechanism 207 is fixed to the sensor connecting member 205. The sensor connecting member 205 has a cylindrical shape with a relatively large diameter, and an opening is formed in a part of the side surface of the cylinder in order to arrange a path for passing the wiring / piping 206. The wiring / piping 206 is guided into the inside of the second link 1200 through this opening.

[0066] 4 to 6, the sensor connection member 205 is made cylindrical with a comparatively large diameter, and the wiring / piping 206 is fixed to the sensor connection member 205 using a wiring support mechanism 207 at a fixing position 207P on the second link side away from the rotation center of the joint. With this configuration, the wiring / piping 206 can bend without being hindered in movement due to interference with other members, even when the joint oscillates, and is structured to be stably supported without generating excessive stress.

[0067] In addition, by supporting the wiring / piping 206 inside the joint in this manner, in this embodiment, the torque sensor 203 can measure the joint torque with high accuracy and high sensitivity without being affected by the reaction force generated by the wiring member that bends with the rocking motion of the joint. This is because the reaction force generated by the wiring member acts on the sensor connection member 205 and does not affect the torque applied to the torque sensor 203. Therefore, it is not necessary to complicate the control of the robot, and for example, it is not necessary to obtain the reaction force generated by the wiring / piping in advance by experiment and store it as correction data in the control unit of the robot. Also, it is not necessary to have the control unit calculate the reaction force generated by the wiring / piping based on the bending angle, bending speed, etc. of the joint to correct the driving force. In this way, it is possible to improve the sensitivity and accuracy of the torque control of the joint mechanism without using a complicated control method.

[0068] A specific description has been given of the configuration of the swingable joint mechanism 200 provided in the robot 2. As described with reference to FIG. 1, the joint mechanism 300 and the joint mechanism 500 are also swingable joint mechanisms, and have the same basic configuration as the joint mechanism 200.

[0069] Fig. 8(a) is a front view showing the external shape of the joint mechanism 300, and Fig. 8(b) is a side view. Fig. 9(a) is a front view showing the external shape of the joint mechanism 500, and Fig. 9(b) is a side view. Although these joint mechanisms have different external shapes from the joint mechanism 200, they have similar effects to the joint mechanism 200 in terms of the support method using the sensor connecting member, the installation method of the seal member, and the support method for the wiring and piping.

[0070] [Other embodiments] The present invention is not limited to the above-described embodiment, and many modifications are possible within the technical concept of the present invention.

[0071] 1 etc., the first bearing mechanism 211 and the second bearing mechanism 212 for rotatably supporting the output link in a double-supported structure are arranged in the drive unit side torque transmission path, which is closer to the drive unit 202 than the torque sensor 203 in the torque transmission path. As long as the bearing mechanisms are not arranged in the output link side torque transmission path, which is closer to the second link 1200 than the torque sensor 203, the arrangement method of the bearing mechanisms in the embodiments is not limited to the above-mentioned example.

[0072] The first bearing mechanism 211 may rotatably support the rotor 202R of the electric motor of the driving unit 202 with respect to the first link 1100, or may rotatably support an output unit of the speed reduction mechanism 202G of the driving unit 202. Alternatively, as shown in the cross-sectional view of FIG. 10, the first bearing mechanism 211 may rotatably support the sensor connecting member 205 with respect to the first link 1100.

[0073] In order to make the joint structure stronger, three or more bearing mechanisms may be provided in one joint mechanism, as long as they are not disposed in the output link side torque transmission path closer to the second link 1200 than the torque sensor 203.

[0074] Although the drive unit is exemplified as a combination of an electric motor and a reduction mechanism, the form of the drive unit is not limited to this, and for example, a direct drive type motor that does not use a reduction mechanism may be used. The electric motor is not limited to a built-in motor in which the frame member of the link also serves as the case of the electric motor. In addition, the supply source of the drive torque is not limited to an electric motor, and a drive unit using a fluid drive type such as hydraulic or pneumatic pressure may be used depending on the required output level and output characteristics.

[0075] The torque sensor is not limited to the illustrated configuration, and may be integrated with other members constituting the joint. For example, the wiring support part and the primary connection part of the sensor may be integrated, or the secondary connection part of the torque sensor and the second link may be connected via a member. Also, the wiring support part may be integrated with the output mechanism of the drive part.

[0076] The robot according to the embodiment is not limited to a form equipped with a six-axis vertical articulated arm as illustrated in FIG. 2, but may have various forms such as a vertical articulated type with a different number of axes, a parallel link type, or a linear joint type.

[0077] The operations to be executed by the robot device having the joint mechanism according to the embodiment are typically operations related to the manufacture of articles, such as parts assembly operations, conveyance operations, processing operations (including cutting, polishing, drilling, painting, bonding, welding, etc.), cleaning operations, etc. However, the robot device may be made to execute operations other than those.

[0078] The joint mechanism according to the embodiment can be applied to various machines and equipment, such as industrial robots, service robots, and processing machines that operate under numerical control by a computer. For example, the joint mechanism can be applied to the joints of machines and equipment that can automatically perform operations such as expansion and contraction, bending and stretching, vertical movement, horizontal movement, or rotation, or a combination of these operations, based on information in a storage device provided in a control device. A control method and a control program for operating a robot equipped with the joint mechanism according to the embodiment, and a computer-readable recording medium storing the control program are also included in the embodiments of the present invention.

[0079] The present invention can also be realized by a process in which a program for implementing one or more functions of the embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more functions.

[0080] This specification discloses at least the following: [Matter 1] A drive device for displacing a second link relative to a first link, a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link; A drive device characterized by: [Matter 2] the first bearing supports the first link and the output portion or the sensor connecting member, The second bearing supports the first link and the sensor connecting member. 2. The driving device according to item 1, [Matter 3] At least a portion of the second link is located between the first bearing and the second bearing. 3. The drive device according to item 1 or 2, [Matter 4] The drive unit includes an electric motor, and the first bearing supports a rotor of the electric motor and the first link. 4. The drive device according to any one of claims 1 to 3. [Matter 5] The drive unit includes a reducer, and the first bearing supports the output unit of the reducer and the first link. 4. The drive device according to any one of claims 1 to 3. [Matter 6] The sensor connection member includes a fixing portion that fixes a wiring extending from the first link to the second link. 6. A drive device according to any one of claims 1 to 5. [Matter 7] the sensor connection member is cylindrical, the fixing portion is provided at a fixing position on the second link side, and the wiring is fixed by the fixing portion; 7. The drive device according to item 6, [Matter 8] a seal member provided between the sensor connecting member and the second link; 8. A drive device according to any one of claims 1 to 7. [Matter 9] The first bearing and / or the second bearing include either a roller bearing or a ball bearing; 9. A drive device according to any one of claims 1 to 8. [Matter 10] The second link is displaced about a rotation axis, When viewed along the direction of the rotation axis, the first bearing and the second bearing are disposed at a distance from each other. 10. A drive device according to any one of claims 1 to 9. [Matter 11] A method for controlling a drive device that displaces a second link relative to a first link, comprising the steps of: The drive device is a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link, A control unit controls the drive unit based on the information about the force acquired by the sensor. A control method comprising: [Matter 12] A robot that displaces a second link relative to a first link, a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link; A robot characterized by: [Matter 13] A method for controlling a robot that displaces a second link relative to a first link, comprising the steps of: The robot comprises: a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link, A control unit controls the drive unit based on the information about the force acquired by the sensor. A control method comprising: [Matter 14] 14. A program for causing the control unit to execute the control method according to item 11 or 13. [Matter 15] 15. A computer-readable recording medium having the program according to item 14 recorded thereon. [Matter 16] Controlling the robot according to item 12 to perform a task of manufacturing an article; A method for producing an article. [Matter 17] The work includes at least one of a part transport work, an assembly work, a processing work, and a cleaning work. 17. A method for producing an article according to item 16, [Explanation of symbols]

[0081] 1···Robot device / 2···Robot / 3···Control device / 5···Wiring component / 20···Robot arm / 21···Robot hand / 23···Fingers / 24···Hand body / 100, 200, 300, 400, 500, 600···Joint mechanism / 202···Drive unit / 202G···Reduction mechanism / 202R···Rotor / 202S···Stator / 203···Torque sensor / 205···Sensor connection component / 206· ··Wiring and piping / 207···Wiring support mechanism / 207P···Fixing position / 208···Base end fixing portion / 209···Sealing member / 211···First bearing mechanism / 212···Second bearing mechanism / 1000, 1300, 1400, 1500, 1600···Link / 1100···First link / 1101, 1102···Joint support member / 1200···Second link / CA···Rotation central axis / CP1~CP3···Connection portion

Claims

1. A drive device for displacing a second link relative to a first link, a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link; A drive device characterized by:

2. the first bearing supports the first link and the output portion or the sensor connecting member, The second bearing supports the first link and the sensor connecting member.

2. The drive device according to claim 1 .

3. At least a portion of the second link is located between the first bearing and the second bearing.

2. The drive device according to claim 1 .

4. The drive unit includes an electric motor, and the first bearing supports a rotor of the electric motor and the first link.

4. The drive device according to claim 1, wherein the drive device is a drive unit.

5. The drive unit includes a reducer, and the first bearing supports the output unit of the reducer and the first link.

4. The drive device according to claim 1, wherein the drive device is a drive unit.

6. the sensor connection member includes a fixing portion that fixes a wiring extending from the first link to the second link; 4. The drive device according to claim 1, wherein the drive device is a drive unit.

7. the sensor connection member is cylindrical, and the fixing portion is provided at a fixing position on the second link side, and the wiring is fixed by the fixing portion; 7. The drive device according to claim 6.

8. a seal member provided between the sensor connecting member and the second link; 4. The drive device according to claim 1, wherein the drive device is a drive unit.

9. the first bearing and / or the second bearing comprise either a roller bearing or a ball bearing; 4. The drive device according to claim 1, wherein the drive device is a drive unit.

10. The second link is displaceable about a rotation axis, When viewed along the direction of the rotation axis, the first bearing and the second bearing are disposed at a distance from each other.

4. The drive device according to claim 1, wherein the drive device is a drive unit.

11. A method for controlling a drive device that displaces a second link relative to a first link, comprising the steps of: The drive device is a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link, A control unit controls the drive unit based on the information about the force acquired by the sensor. A control method comprising:

12. A robot that displaces a second link relative to a first link, a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link; A robot characterized by:

13. A method for controlling a robot that displaces a second link relative to a first link, comprising the steps of: The robot comprises: a drive unit including an output unit that outputs a drive force for displacing the second link; A sensor for obtaining information regarding a force; a sensor connection member that connects the output unit and the sensor; A first bearing and a second bearing, Equipped with the sensor is connected to the second link; the first bearing and the second bearing are disposed on a side of the driving unit relative to the sensor in a force transmission path from the driving unit to the second link, A control unit controls the drive unit based on the information about the force acquired by the sensor. A control method comprising:

14. A program for causing the control unit to execute the control method according to claim 11 or 13.

15. A computer-readable recording medium having the program according to claim 14 recorded thereon.

16. A method for controlling the robot according to claim 12 to perform a task of manufacturing an article. A method for producing an article.

17. The operation includes at least one of a part transport operation, an assembly operation, a processing operation, and a cleaning operation. The method of claim 16 .

Images