JP2013094935A - Robot arm device - Google Patents

Robot arm device Download PDF

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Publication number
JP2013094935A
JP2013094935A JP2011242496A JP2011242496A JP2013094935A JP 2013094935 A JP2013094935 A JP 2013094935A JP 2011242496 A JP2011242496 A JP 2011242496A JP 2011242496 A JP2011242496 A JP 2011242496A JP 2013094935 A JP2013094935 A JP 2013094935A
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Japan
Prior art keywords
robot arm
force
axis
center
joint
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JP2011242496A
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Japanese (ja)
Inventor
Tetsuya Ishikawa
哲也 石川
Yuta Kimura
裕太 木村
Takafumi Fukushima
崇文 福島
Susumu Miyazaki
進 宮崎
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Honda Motor Co Ltd
本田技研工業株式会社
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Priority to JP2011242496A priority Critical patent/JP2013094935A/en
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Abstract

PROBLEM TO BE SOLVED: To provide a robot arm device which is of low cost and can be reduced in weight.SOLUTION: A robot arm device 1 includes a robot arm 2 in which a base body 4 and a link member 3 are connected by a first joint mechanism J, and the link member 3 and an end effector E are connected by a second joint mechanism J. The robot arm device 1 includes a first force detector Fthat detects a force acting on the base body 4 from the robot arm 2. An open part 4b for a control wiring 11 of the robot arm 2 is formed at an end face 4a of the base end part of the base body 4. Around the open part 4b, three or more force detectors Fare arranged, as a first force detector F, to be separated one another.

Description

  The present invention relates to a robot arm device provided with a robot arm.
  In a robot arm device including a multi-joint type robot arm in which a base body and a link member, and a link member and an end effector are connected by joint mechanisms, it is known to provide a force detection unit at the base end portion of the base body. .
  For example, Patent Document 1 describes a robot arm device (robot) in which a force detector that detects a force applied to a robot arm is provided on a base (robot base). In this robot, the contact force to the robot arm is detected by subtracting the amount corresponding to the external force generated by the operation of the robot arm itself from the entire external force detected by the force detector. The force detector is, for example, a 6-axis force sensor.
JP 2006-21287 A
  In a robot arm apparatus as described in Patent Document 1, in general, one 6-axis force sensor is used as a base of a base of a robot arm in order to accurately detect a force in each axis direction and a moment around each axis. It is arranged at the center of the end. Then, the six-axis force sensor is made hollow, and wiring such as a power supply cable and a signal line is passed through the hollow portion.
  However, the hollow six-axis force sensor has a problem that it is relatively expensive than the solid one. Further, since the force is detected by one 6-axis force sensor, there is a problem that the rated capacity is large and expensive and a large 6-axis force sensor is required, and the robot arm device is expensive and heavy.
  An object of the present invention is to provide a robot arm device that is inexpensive and can be reduced in weight in view of the problems of the prior art.
  A robot arm device according to the present invention is a robot arm device including a robot arm in which a base and a link member are connected by a first joint mechanism, and the link member and an end effector are connected by a second joint mechanism. A first force detector for detecting a force acting on the base from the robot arm, and an opening for driving and controlling wiring of the robot arm is formed on an end surface of the base end of the base, Around the opening, as the first force detector, three or more force detectors arranged apart from each other are arranged.
  According to the robot arm device of the present invention, even if the first force detectors are solid, the force detectors are spaced apart from each other, so that there is a space between the force detectors. Arise. Then, in this space, an opening formed in the end face of the base end of the base is provided for driving and control wiring of the robot arm passing through the inside of the robot arm, such as a power supply cable and a signal line to the actuator of each joint mechanism. It becomes possible to arrange | position through. Therefore, since it is not necessary to use a hollow force detector for passing wiring as in the conventional case, a solid and inexpensive force detector can be used as the first force detector.
  In addition, since the force is detected by three or more first force detectors, each force detector has a small rated capacity and is less expensive than the case where the force is detected by a single force detector as in the past. It can be made small.
  As described above, even if all the force detectors constituting the first force detector are added up, it is possible to reduce the cost and weight as compared with a conventional large force detector. .
  In the robot arm device of the present invention, three or more force detectors pass through the opening, have rotational symmetry about the axis as a normal to the end face, and a straight line extending in a direction perpendicular to the axis It is preferable that they are arranged with at least one of the mirror symmetry with respect to.
  Since a plurality of output signals are obtained from the plurality of force detectors by using a plurality of force detectors as described above, the force acting on the base from the robot arm by integrating the plurality of output signals. Is required. Here, if the arrangement of the plurality of force detectors is irregular, the calculation method for integrating the plurality of output signals becomes relatively complicated, and the detection accuracy of the force is reduced. There is a fear.
  However, a plurality of first force detectors have symmetry with respect to the axis or straight line, that is, are regularly arranged, so that a calculation method for integrating a plurality of output signals can be relatively reduced. The force detection accuracy is improved by the amount that can be simplified.
  Further, in the robot arm device of the present invention, the center of gravity position estimating means for estimating the center of gravity position of the robot arm with respect to the moving body based on the moving body provided with the base and the output of the first force detector. And a moving body control means for performing movement control of the moving body based on the gravity center position of the robot arm estimated by the gravity center position estimating means.
  In this case, not only the movement control of the robot arm is controlled based on the gravity center position of the robot arm estimated by the gravity center position estimation means, but also the movement control of the moving body is performed by the moving body control means. It becomes possible to keep reliably.
  In the robot arm device of the present invention, it is preferable that a second force detector that detects a force acting on the link member via the end effector is provided between the end effector and the link member.
  In this case, the force acting on the end effector from the outside can be estimated from the force detected by the second force detector, and it is possible to perform highly accurate work according to the estimated work state.
  Further, by referring to the force detected by the second force detector, the reaction force when the robot arm comes into contact with the external environment is estimated independently based on the force detected by the first force detector. It becomes possible.
Explanatory drawing which shows the structure of the robot apparatus which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. The control block diagram of a control apparatus.
  Hereinafter, a robot arm device 1 according to an embodiment of the present invention will be described with reference to the drawings.
  As shown in FIG. 1, the robot arm device 1 includes a robot arm 2. The robot arm 2 includes a link member 3 including a plurality of joint mechanisms and a plurality of links connected via the plurality of joint mechanisms.
The plurality of joint mechanisms include a first joint mechanism J 1 disposed on the proximal end side of the robot arm 2, a second joint mechanism J 2 disposed on the distal end side of the robot arm 2, It includes first and articulation mechanism J 1 and the second joint mechanism two intermediate joints middle is located between the J 2 mechanism I 1 and I 2 are. The intermediate joint mechanism may be omitted. The number of intermediate joint mechanisms can be arbitrarily changed.
The link member 3 of the present invention is composed of intermediate joint mechanisms I 1 and I 2 and a plurality of links. The first joint mechanism J 1 connects the link member 3 and the base 4 of the robot arm 2. The second joint mechanism J 2 is linked to the link member 3 and the end effector E.
The rotational degree of freedom of the first joint mechanism J 1 is 2 (pitch and yaw), and the rotational degree of freedom of the second joint mechanism J 2 is 3 (roll, pitch and yaw). The rotational freedom degree of the first intermediate joint mechanism I 1 is 1 (roll), and the rotational freedom degree of the second intermediate joint mechanism I 2 is 2 (pitch and yaw). The robot arm 2 includes joint angle sensors S i (i = 1, 2,...) Such as a rotary encoder that outputs a signal corresponding to a rotation angle (joint angle) corresponding to each degree of freedom of rotation of each joint mechanism. (See FIG. 3). Note that the degree of freedom of rotation of each joint mechanism may be arbitrarily changed.
The distal end portion of the robot arm 2 is connected to the end effector E through the second joint mechanism J2. The end effector E is configured as an appropriate jig for engaging with the handle of the valve, for example, in order to execute a task of opening and closing the valve.
The base body 4 present at the base end portion of the robot arm 2 is fixed to the moving body X. Here, the moving body X includes an XY stage X 1 and a carriage X 2 to which the XY stage X 1 is fixed.
Substrate 4 is connected to the upper table 5 of the XY stage X 1. XY stage X 1 is remotely operable, it is possible to move the robot arm 2 in the horizontal plane. XY stage X 1 is the details are not shown, for example, along the Y-axis rail extending in the Y-axis direction, the Y-axis table X-axis rails are provided extending in the X-axis direction is arranged movably, An X-axis table that is movable along the X-axis rail is disposed. In this case, the X-axis table becomes the upper table 5.
XY stage X 1 is fixed on the carriage X 2. Carriage X 2 is remotely operable, here is a vehicle using the wheel, may be a traveling device using the track.
The robot arm 2 includes a first six-axis force sensor F 1 disposed at the base end thereof. The first 6-axis force sensor F 1 is a signal corresponding to the relative force in the three axes (roll axis, pitch axis and yaw axis) between the robot arm 2 and the XY stage X 1 and the moment about the three axes. Is configured to output. Incidentally, the substrate 4, a gyro sensor for outputting a signal corresponding to the position of the XY stage X 1 in the world coordinate system (reference coordinate system) may be arranged.
The robot arm 2 includes a second six-axis force sensor F 2 and a first gyro sensor G 1 at the tip. The second six-axis force sensor F 2 outputs a signal corresponding to the relative force in the three axes (roll axis, pitch axis, and yaw axis) between the robot arm 2 and the end effector E and the moment about the three axes. It is configured to output. The first gyro sensor G 1 is configured to output a signal corresponding to the attitude of the end effector E (such as the inclination angle with respect to the horizontal direction) in the world coordinate system (reference coordinate system).
Further, the cart X 2 includes a second gyro sensor G 2 . The second gyro sensor G 2 is, is configured to output a signal corresponding to the position of the carriage X 2 in the world coordinate system. Incidentally, XY stage X 1 is fixed rigidly on the carriage X 2, the attitude of the XY stage X 1 and bogie X 2 is can be regarded as identical.
Robot arm 2, the end effector E, the at least one of XY stage X 1 and bogie X 2, the imaging apparatus is mounted, not shown, to place the image captured by the imaging device is apart from the robot arm 2 Displayed on the installed image device. The operator operates the XY stage X 1 and the carriage X 2 in addition to the joint operations of each joint mechanism constituting the robot arm 2 by operating the remote control device 10 (see FIG. 3) while viewing this image. Can be remotely controlled.
(Arrangement of the first six-axis force sensor)
The first six-axis force sensor F 1 is a force and moment acting on the base body via the first joint mechanism J 1 (hereinafter referred to as “force”, meaning any one of force, moment, force and moment). This is a force detector to detect, and is arranged at the base end portion (lower end portion) of the base 4 so as to be separated from each other.
The first six-axis force sensor F 1 includes three or more six-axis force sensor F 1-i (i = 1,2,3 , ...), these six-axis force sensor F 1-i, the substrate 4 Are arranged around an opening 4b (see FIG. 2) formed in the end face 4a of the base end of the base plate. This opening 4b is a drive and control wiring for the robot arm, in the embodiment, a wiring 11 such as a power supply cable or a signal line to the actuator A i , end effector E, joint angle sensor S i of each joint mechanism (see FIG. 2). ).
Thereby, even if each 6-axis force sensor F 1-i is solid, a space is generated between the 6-axis force sensors F 1-i , and the wiring 11 is arranged through the space and the opening 4b. Can be set. Therefore, it is not necessary to use a six-axis force sensor of the hollow for passing conventional wiring as inexpensive medium circumstances as first the six-axis force six-axis force sensor F 1 sensor F 1-i Things can be used.
Further, since the force is detected by three or more six-axis force sensors F 1-i , each of the six-axis force sensors F 1- is compared with the case where the force is detected by one six-axis force sensor as in the prior art. i can be made small and inexpensive with a small rated capacity. And even if all the 6-axis force sensors F 1 -i constituting the first 6-axis force sensor F 1 are summed, they are less expensive than a single large-sized 6-axis force sensor as in the prior art. It is possible to reduce the weight.
The three or more six-axis force sensors F 1 -i pass through the opening 4b and extend in a rotational symmetry around the axis as a normal line of the end surface 4a of the base 4 and in a direction perpendicular to the axis. They are arranged with at least one of mirror symmetry with respect to a straight line.
By three or more six-axis force sensor F 1-i is used, since a plurality of output signals are obtained from three or more of the six-axis force sensor F 1-i, the plurality of output signals are integrated Thus, the force acting on the base 4 from the robot arm 2 is obtained. Here, if the arrangement of the six-axis force sensors F 1-i is irregular, the calculation method for integrating a plurality of output signals becomes relatively complicated, and the detection of the force is performed. The accuracy may be reduced.
However, three or more six-axis force sensors F 1-i have a symmetry with respect to the axis or straight line, that is, are regularly arranged, so that calculation for integrating a plurality of output signals is performed. Since the method can be made relatively simple, the force detection accuracy can be improved.
In this embodiment, it consists of four 6-axis force sensors F 1-i (i = 1, 2, 3, 4) of the same type. Each six-axis force sensor F 1-i is disposed between the substrate 4c integrally provided with the base end portion of the base 4, and the upper table 5 of the XY stage X 1. A circular opening 4b is formed at the center of the substrate 4c, and rotational symmetry about the Z axis (axis as a normal line of the end surface 4a of the base 4) passing through the center O of the opening 4b, and X Four six-axis force sensors F 1-i are arranged with mirror symmetry with respect to the axis and the Y-axis (a straight line extending in a direction perpendicular to the Z-axis). Note that the joint center of the first joint mechanism J 1 is located directly above the opening center O, that is, on the Z axis.
In this embodiment, the centers of the two six-axis force sensors F 1-1 and F 1 -2 are arranged on the front side of the Y-axis (the X-axis positive direction side of the opening center O), and the other two The centers of the six-axis force sensors F 1-3 and F 1-4 are arranged on the rear side of the Y axis.
Although not shown, the centers of the two six-axis force sensors F 1-i are positioned on the X axis, and the centers of the other two six-axis force sensors F 1-i are positioned on the Y axis. Also good. As a result, the forces in the X-axis and Y-axis directions acting on the base body 4 from the robot arm 2 can be accurately detected by the 6-axis force sensors F 1 -i . However, the arrangement of the six-axis force sensors F 1 -i constituting the first six-axis force sensor F 1 is not limited to this.
By arranging the 6-axis force sensor F 1-i in this way, even if one 6-axis force sensor F 1-i breaks down, a normal 6-axis force sensor F 1 is provided on both sides including the X-axis. Since at least one -i exists, the force acting on the base 4 from the robot arm 2 in the left-right direction can be detected well.
When the end effector E protrudes forward (X-axis positive direction) and the center of gravity of the robot arm 2 is often shifted forward from the opening center O, the first force detector F 1 is configured. It is preferable that each 6-axis force sensor F1 -i to be arranged is arranged on the front side more than the rear side from the opening center O. Thus, by arranging the 6-axis force sensor F 1 -i , it is possible to accurately detect the force acting on the base body 4 from the robot arm 2 that protrudes from the end effector E and whose center of gravity moves forward.
In this case, even if one of the front six-axis force sensors F 1 -i breaks down, there is at least one normal six-axis force sensor F 1 -i arranged on the front side of the opening center O. The force acting on the base 4 from the robot arm 2 whose center of gravity has moved to the front side can be detected well.
Further, when the first six-axis force sensor F 1 is composed of three six-axis force sensors F 1-i (i = 1, 2, 3), the two six-axis force sensors F 1-1 , It is preferable that the center of F 1-2 is positioned on the front side from the Y axis, and the center of the other one of the six-axis force sensors F 1-3 is positioned on the rear side of the Y axis so as to be arranged symmetrically. Further, when the first six-axis force sensor F 1 is composed of five or more six-axis force sensors F 1-i (i = 1, 2, 3, 4, 5,...) It is preferable to arrange the mirrors symmetrically with respect to the X axis so that the number of centers is equal to or greater than the number of centers positioned behind the Y axis.
Further, when the end effector E performs a valve opening / closing operation, a force is applied to the base 4 in a non-uniform manner on the base 4 in each opening / closing operation. Here, since each 6-axis force sensor F 1-i is arranged symmetrically with respect to the X axis, it is possible to equally detect the lateral force acting on the base 4.
(Control based on output of 6-axis force sensor)
The first six-axis force sensor F 1 is attached to the base end portion of the base 4, and only the first six-axis force sensor F 1 is interposed at the connecting portion between the robot arm 2 and the upper table 5 of the XY stage. ing. Therefore, the first six-axis force sensor F 1 detects the force acting on the base 4 from the entire robot arm 2 including the base 4.
Also, the force which the first six-axis force sensor F 1 is detected is also a reaction force acting on the upper side of the table 5 of the XY stage X 1 from the substrate 4. Then, the rigidity of the XY stage X 1 and bogie X 2 is known, from the force which the first six-axis force sensor F 1 is detected to estimate the displacement of the XY stage X 1 and bogie X 2, further It becomes possible to estimate the inclination of the base end portion of the base body 4, that is, the robot arm 2, using an inverse kinematics model.
Further, a second 6-axis force sensor F < b > 2 that detects a force acting on the link member from the end effector E is provided between the end effector E and the link member 3. Therefore, the reverse kinematics model represents the force acting on the robot arm 2 from the end effector E, such as the reaction force when the end effector E opens and closes the valve, from the force actually detected by the second six-axis force sensor F2. Thus, it is possible to perform work with high accuracy according to the estimated work state.
  The force acting on the base body 4 due to the weight of the robot arm 2 can be estimated from the joint angle or the like using a kinematic model because the configuration of the link member 3 is known.
Therefore, the force acting on the base 4 from the robot arm 2 is estimated using a kinematic model by integrating the force due to the weight of the robot arm 2 and the force actually detected by the second six-axis force sensor F2. The detection value of the first six-axis force sensor F 1 when this force is applied can be estimated.
Therefore, by obtaining the difference between this estimated value and the detected value of the force actually detected by the first six-axis force sensor F1, the reaction force when the robot arm 2 comes into contact with an external environment such as an obstacle is obtained. Can be inferred using an inverse kinematics model.
In this way, by referring to the force detected by the second six-axis force sensor F2, the robot arm 2 is connected to the external environment based on the force actually detected by the first six-axis force sensor F1. It becomes possible to estimate the reaction force when contacted independently.
  Therefore, since the force acting on the robot arm 2 from the outside and the situation thereof can be estimated, the robot arm apparatus 1 can be controlled to perform a suitable operation according to the situation.
For example, when it is estimated that the robot arm 2 has come into contact with the external environment, it is possible to control the robot arm 2 so as to avoid the contact, and in addition to or alone, the XY stage X 1 or the carriage X Control can also be performed to move 2 .
  The robot arm device 1 includes a control device 6 shown in FIG. The control device 6 is configured by a programmable computer. The target motion trajectory of the end effector E is input to the control device 6 from the remote operation device 10. The “trajectory” of a variable means a time-series variable value representing a time change mode of the variable.
In addition to the first six-axis force sensor F 1 , the second six-axis force sensor F 2 , the first gyro sensor G 1, and the second gyro sensor G 2 , the control device 6 includes each joint mechanism. A signal output from the joint angle sensor S i of J 1 , J 2 , I 1 , I 2 is input.
Based on the input signal, the control device 6 generates operation control command signals for the joint mechanisms J 1 , J 2 , I 1 , I 2 , the XY stage X 1 , and the carriage X 2 of the robot arm 2. A control process of outputting the signal to the actuator A i is executed.
  Here, the control device 6 is configured to execute arithmetic processing when the CPU (central processing processing) constituting the control device 6 reads necessary software and data from a memory (storage device), and the software It is programmed that the said arithmetic processing is performed according to.
Further, the control device 6 estimates the center of gravity position of the robot arm 2 based on the output of the first six-axis force sensor F 1 , and the robot arm 2 estimated by the center of gravity position estimation means 7. A moving body control means 8 that performs movement control of the moving body X based on the position of the center of gravity is provided.
The center-of-gravity position estimating means 7 may estimate the center-of-gravity position of the robot arm 2 based only on the output from the first six-axis force sensor F 1 , the joint angle sensor S i , and the gyro sensor G 1. , G 2 may be included in the estimation. The center-of-gravity position estimating means 7 calculates the center-of-gravity position from the average value of the detected force values obtained based on the outputs from the respective six-axis axial force sensors F 1 -i constituting the first six-axis force sensor F 1. Although it may be estimated, the position of the center of gravity may be estimated in consideration of the arrangement position of each 6-axis force sensor F 1 -i .
If the center of gravity of the robot arm 2 to the center-of-gravity position estimation means 7 is estimated is shifted from a predetermined stable position, the mobile control unit controls the XY stage X 1 as its displacement is compensated. If this compensation control alone is not sufficient, compensation control is additionally performed for the first joint mechanism J 1 or the carriage X 2 or both.
For example, if the center of gravity of the robot arm 2 to the center-of-gravity position estimation means 7 is estimated is outside a predetermined area in the coordinate system relative to the carriage X 2, the possibility that the carriage X 2 overturning occurs, the robot arm 2 other operating itself, by a mobile control unit 8 may compensate controlled to move the XY stage X 1 and bogie X 2. Thus, for example, be a robot arm 2 becomes likely bogie X 2 too protrudes forward from overturning forward, to move the table XY stage X 1 backward, or carriage X 3 to move forward by control, it is possible to rebalance bogie X 2.
Further, when it is detected that the carriage X 2 from the second gyro sensor G 2 mounted on the carriage X 2 is greatly inclined, as carriage X 2 does not fall, moving the center of gravity of the robot arm 2 as, by the mobile control unit 8 to move the XY stage X 1, which together may be controlled so as to operate the robot arm 2. Thus, for example, even when about to Gawaten rightward while traveling carriage X 2 are uneven ground, controls the robot arm 2 and the XY stage X 1 to move the center of gravity of the robot arm 2 to the left by, it is possible to rebalance bogie X 2.
  Hereinafter, an embodiment of control by the control device 6 will be described with reference to the drawings. However, the control by the control device 6 is not limited to this.
As shown in FIG. 4, the control device 6 uses an estimated center-of-gravity position trajectory gc_act of the robot arm 2 as a configuration for performing compensation control of the XY stage X 1 , the first joint mechanism J 1 , and the carriage X 2. Depending on the position from the estimated control center of gravity position trajectory generating element 31 to be generated, the compensation control defining elements 32 and 33 for defining the case where the compensation control of each of the first joint mechanism J 1 and the cart X 2 is performed, and the compensation control defining element 32 and a angle conversion element 34 for converting the trajectory of the compensation amount to the angle compensating track θ_comp according to a first rotation angle of the joint mechanism J 1 (yaw axis and the angle around the pitch axis).
  The compensation control defining element 32 includes a limiter 321 and a first-order lag element 322 connected to the output side of the limiter 321. The compensation control defining element 33 includes a limiter 331 and a first-order lag element 332 connected to the output side of the limiter 331.
In this configuration, the control device 6 controls the robot arm according to the target motion trajectory of the robot arm 2 input to the control device 6 when controlling the XY stage X 1 , the first joint mechanism J 1 , and the carriage X 2. a target barycentric position trajectory gc_cmd a trajectory of the target barycentric position of 2, and the target stage position trajectory sp_cmd a trajectory of a desired position of the XY stage X 1, a trajectory of the first target rotation angle of the joint mechanism J 1 goal an angle track Shita_cmd, a carriage target position trajectory cp_cmd a trajectory of a desired position of the carriage X 2 determined.
Target barycentric position trajectory gc_cmd is represented as a track position on a predetermined reference plane relative to the carriage X 2, is set as the trajectory of the center of gravity of the robot arm 2, such as the posture of the robot arm mechanism 1 is most stable The Reference plane of the bogie X 2 is a plane as a horizontal when the carriage X 2 is positioned on a horizontal floor. Along this plane, XY stage X 1 is moved. Therefore, the target stage position trajectory sp_cmd is represented as a position along the reference plane of the bogie X 2. Target angle orbital θ_cmd is represented the XY stage X 1 or bogie X 2 as the first pitch and the angle of yaw axis of the joint mechanism J 1 as a reference.
The estimated center-of-gravity position trajectory generation element 31, generates an estimated center-of-gravity position trajectory gc_act of the robot arm 2 based on the first of the six-axis force sensor F 1 detection output trajectory F_act. In this case, for example, as described above, as the first six-axis force sensor F 1, in the case of employing four six-axis force sensor F 1-i which supports the XY stage X 1 at four points, each 6 Based on the force detected by the axial force sensor F 1 -i, the position of the center of gravity of the robot arm 2 can be calculated.
The centroid position is calculated as a position on the reference plane of the aforementioned carriage X 2. In the calculation, the inclination of the XY stage X 1 (cart X 2 ) obtained based on the second gyro sensor G 2 is taken into consideration.
Based on the deviation between the target center-of-gravity position trajectory gc_cmd and the estimated center-of-gravity position trajectory gc_act, a stage position compensation trajectory sp_comp is generated according to the relational expression (1). Stage position compensation trajectory sp_comp is the deviation from a stable position of the center of gravity of the robot arm 2, a trajectory for compensating the control of the XY stage X 1. “Kp” is a proportional gain coefficient, and “Kd” is a differential gain coefficient. One of Kp and Kd may be 0.
  sp_comp = (Kp + Kds) (gc_cmd-gc_act) .. (1).
  The target stage position trajectory sp_cmd is corrected according to the relational expression (2) based on the stage position compensation trajectory sp_comp, thereby generating a corrected target stage position trajectory sp_cmd_mdfd.
  sp_cmd_mdfd = sp_cmd + sp_comp .. (2).
By the XY stage X 1 is driven in accordance with the corrected target stage position trajectory Sp_cmd_mdfd, when the center of gravity of the robot arm 2 is offset from the target center-of-gravity position trajectory gc_cmd a stable position on the dolly X 2, the deviation amount only, XY stage X 1 is, the deviation direction is moved in the opposite direction. Accordingly, since it is controlled so as to be positioned in a stable position on the always bogie X 2 is the center of gravity of the robot arm 2, the posture of the robot arm device 1 is stabilized.
Only control of the XY stage X 1, when the deviation from the stable position of the center of gravity of the robot arm 2 can not be compensated, further the angle and yaw axis of the angle of the first pitch axis of the joint mechanism J 1 , the position of the carriage X 2 is controlled.
  That is, when the deviation between the target center-of-gravity position trajectory gc_cmd and the estimated center-of-gravity position trajectory gc_act exceeds the upper limit value Lmax of the limiter 321 or falls below the lower limit value Lmin, the first order lags according to the relational expression (3a) or (3b), respectively. Through element 322, a joint mechanism compensation trajectory j_comp is generated. When the deviation is not more than the upper limit value Lmax and not less than the lower limit value Lmin, the value of the joint mechanism compensation trajectory j_comp is 0 (zero).
  j_comp = (gc_cmd-gc_act-Lmax) K1 / (T1s + 1) .. (3a).
  j_comp = (gc_cmd-gc_act-Lmin) K1 / (T1s + 1) .. (3b).
Joint mechanism compensating track j_comp is an amount corresponding to the movement of the carriage X 2 to be described later, the movement as the center of gravity of the robot arm 2 in the opposite direction moves said, compensates for the first angle of the joint mechanism J 1 Orbit to do. T1 is a time constant and K1 is a gain constant.
Joint mechanism compensating track j_comp passes through an angle conversion element 34 is converted into a first a trajectory compensation amount, expressed in angle and the angle of yaw axis around the pitch axis of the joint mechanism J 1 angle compensation trajectory θ_comp . This conversion is performed by ordinary geometric calculation. Based on the angle compensation trajectory θ_comp, the target angle trajectory θ_cmd is corrected according to the relational expression (4), and a corrected target angle trajectory θ_cmd_mdfd is generated.
  θ_cmd_mdfd = θ_cmd + θ_comp .. (4).
  On the other hand, when the deviation between the target center-of-gravity position trajectory gc_cmd and the estimated center-of-gravity position trajectory gc_act exceeds the upper limit value Lmax of the limiter 331 or falls below the lower limit value Lmin, the first-order lags according to the relational expression (5a) or (5b), respectively. Through element 332, a carriage position compensation trajectory cp_comp is generated. When the deviation is not more than the upper limit value Lmax and not less than the lower limit value Lmin, the value of the carriage position compensation trajectory cp_comp is 0 (zero).
  cp_comp = (gc_cmd-gc_act-Lmax) K2 / (T2s + 1) .. (5a).
  cp_comp = (gc_cmd-gc_act-Lmin) K2 / (T2s + 1) .. (5b).
Carriage position compensation trajectory cp_comp the track to a deviation from a stable position of the center of gravity of the robot arm 2, the control of the carriage X 2, compensating in cooperation with the angle compensation of the first joint mechanism J 1 above It is. T2 is a time constant, and K2 is a gain constant. The magnitude relationship between the time constant T1 and the time constant T2 in the relational expressions (3a) and (3b) described above may be any of T1 = T2, T1> T2, or T1 <T2.
  The cart target position trajectory cp_cmd is corrected according to the relational expression (6) based on the cart position compensation trajectory cp_comp to generate a corrected target cart position trajectory cp_cmd_mdfd.
  cp_cmd_mdfd = cp_cmd-cp_comp .. (6).
The correction target carriage positions trajectory cp_cmd_mdfd actuator carriage X 2 is driven by a first actuator of the joint mechanism J 1 is driven by the correction target angle orbital Shita_cmd_mdfd.
Thus, carriage X 2 by an amount corresponding to the amount of deviation from the stable position of the center of gravity of the robot arm 2 (the target barycentric position Gc_cmd), so as to move in the direction of its displacement (carriage X 2 in the mobile In some cases, compensation control is performed so that the amount of movement in the direction of the deviation increases. The first joint mechanism J 1, as will its displacement direction center of gravity of the robot arm 2 in the opposite direction to move, the angle and yaw axis angle around the pitch axis is controlled. Thereby, the shift | offset | difference from the stable position of the gravity center position of the robot arm 2 is compensated more reliably.
In addition to the control of the position of the center of gravity, the control device 6 includes six-axis force sensors F 1 and F 2 , gyro sensors G 1 and G 2 , and joint mechanisms J 1 , J 2 , I 1 , and I 2 . By controlling the actuators A i of the joint mechanisms J 1 , J 2 , I 1 , and I 2 based on the output from the angle sensor S i , deflection compensation and compliance compensation can be performed.
In addition, this invention is not limited to embodiment mentioned above. For example, in the above-described embodiment, the link member 3 includes the intermediate joint mechanisms I 1 and I 2 and a plurality of links. However, the configuration of the link member 3 in the present invention is not limited to this. For example, the link member may consist of a single link. Moreover, the link member 3 may be comprised from the member which has movable mechanisms, such as an orthogonal coordinate system type | mold, a polar coordinate system type | mold, a cylindrical coordinate system type | mold, and a scalar type.
Further, in the embodiment described above, the mobile X is constituted by the XY stage X 1 and bogie X 2. However, the moving body X in the present invention is not limited to this. For example, instead of the XY stage X 1, it may be used other horizontal movement mechanism such as a linear stage or a two-dimensional linear stage. Instead of the carriage X 2, walking devices using legs, ship, may be used well-known mobile such as an aircraft. Furthermore, the mobile X include those similar to the XY stage X 1 and this, or may be configured as having at least one but similar to carriage X 2 and this.
  In the above-described embodiment, the end effector E is used as a jig, but instead, it may be used as a device having a passive function such as a measuring instrument.
  In the above-described embodiment, the six-axis force sensor is used as the force detector, but another force sensor such as a three-component force detector may be used instead.
DESCRIPTION OF SYMBOLS 1 ... Robot arm apparatus, 2 ... Robot arm, 3 ... Link member, 4 ... Base | substrate, 4a ... End surface, 4b ... Opening part, 4c ... Board | substrate, 5 ... Upper table, 6 ... Control apparatus, 7 ... Gravity center position estimation means , 8 ... moving body control means, 10 ... remote operation device, 11 ... wiring, J 1 ... first joint mechanism, J 2 ... second joint mechanism, F 1 ... first six-axis force sensor (first Force detector), F 1-i ... 6-axis force sensor (force detector), F 2 ... second 6-axis force sensor (second force detector), E ... end effector, X ... moving body, X 1 ... XY stage, X 2 ... truck.

Claims (4)

  1. A robot arm device comprising a robot arm in which a base and a link member are connected by a first joint mechanism, and the link member and an end effector are connected by a second joint mechanism,
    A first force detector for detecting a force acting on the substrate from the robot arm, and an opening for driving and controlling wiring of the robot arm is formed on an end surface of the base end of the substrate; In the robot arm apparatus, three or more force detectors arranged apart from each other are arranged as the first force detectors around the robot.
  2.   Three or more force detectors pass through the opening, have rotational symmetry about the axis as the normal of the end face, and mirror symmetry with respect to a straight line extending in a direction perpendicular to the axis The robot arm device according to claim 1, wherein at least one of the robot arm devices is arranged.
  3. A moving body provided with the substrate;
    A center-of-gravity position estimating unit that estimates a center-of-gravity position of the robot arm with respect to the moving body based on an output of the first force detector;
    Based on the center-of-gravity position of the robot arm estimated by the center-of-gravity position estimation means, the center of gravity of the robot arm is controlled to be positioned at a predetermined stable position by controlling the movable body and the first joint mechanism. The robot arm device according to claim 1, wherein the robot arm device is a robot arm device.
  4.   4. The apparatus according to claim 1, further comprising a second force detector that detects a force acting on the link member from the end effector between the end effector and the link member. 5. The robot arm apparatus as described.
JP2011242496A 2011-11-04 2011-11-04 Robot arm device Pending JP2013094935A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016032858A (en) * 2014-07-31 2016-03-10 ファナック株式会社 Mobile human cooperative robot
US10603798B2 (en) 2017-11-28 2020-03-31 Fanuc Corporation Robot

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016032858A (en) * 2014-07-31 2016-03-10 ファナック株式会社 Mobile human cooperative robot
US9669548B2 (en) 2014-07-31 2017-06-06 Fanuc Corporation Mobile collaborative robot
US10603798B2 (en) 2017-11-28 2020-03-31 Fanuc Corporation Robot

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