JP2005034960A - Conveyer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveyer capable of holding a workpiece by two manipulators placed in parallel and conveying the workpiece in an arbitrary direction in a three-dimensional space by operation force applied by a human to the workpiece. <P>SOLUTION: The conveyer includes workpiece holding means 14 and 15 for holding the workpiece 19 and an operation control section for controlling the manipulators 11 and 12 for conveying the workpiece 19. It includes two sets of force detection means 16 and 17 which are provided in parallel, an operation force detection section for detecting the operation force from outputs of the two sets of the detection means 16 and 17, and a force control section for moving the manipulators 11 and 12 according to the operation force detected by the detection section. In addition, the two sets of force detection means 16 and 17 are respectively mounted on the two manipulators 11 and 12 placed in parallel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transport device that transports heavy and long objects in cooperation between a robot manipulator and a human.

There is known a device in which a manipulator and a person cooperate to convey an object in such a way that a manipulator grasps one end of the object to be conveyed and a man grasps the other end and the manipulator assists an operation by human arm force. ing. This transport device is provided with a sensor for detecting translational force and moment at the manipulator hand, and the manipulator is operated in a direction to assist human operation by detecting an operation force applied by the human to the object with the sensor. An operation command is created (for example, Patent Document 1).
FIG. 3 is a configuration diagram of a conventional transport device. In the figure, reference numeral 31 denotes a manipulator, in which a hand 32 and an operator 33 grip a work 34, and an operation force applied to the work 34 by the operator 33 is detected by a force sensor 35 to convey the work 34. In the invention described in Patent Document 1, the amount of movement in the X-axis translation direction is calculated based on the value of Fx of the force sensor. Further, the amount of movement is calculated using the detected torque value Mz around the Z axis in the Y-axis direction and the detected torque value My around the Y-axis in the Z-axis direction. The rotation direction around the X axis is the torque detection value Mx around the X axis, My around the Y axis is My, and the movement around the Z axis is calculated based on Mz.
Further, Patent Documents 2 and 3 disclose inventions of a transport device that makes it easy for an operator to operate by limiting the calculated value of the movement amount so that translational movement does not occur in the Y-axis direction. Yes.
As described above, many conventional conveying devices detect force / torque applied to a workpiece by a force detection unit mounted on one manipulator, calculate an operation force, and cooperatively convey the workpiece. .
On the other hand, Non-Patent Document 1 discloses an example of an apparatus that detects a force / torque applied to a workpiece by a force detection unit mounted on two manipulators and conveys one object. This controls the manipulator based on the virtual impedance model set for each according to the external force detected by the force detector of each manipulator.
JP 2000-176872 A (page 3-5, FIG. 1) JP 2000-343469 A (page 3-4, FIG. 3) JP 2000-343470 A (page 3-4, FIG. 2) Kominato et al. "Mobile Robot Helper" Proc. IEEE Intl. Conf. On Robotics & Automation, 2000 p583-588

  Actually, there are many heavy and long workpieces that are conveyed by assisting humans using the force of the manipulator, and it may be difficult to stably convey the workpiece by gripping one end of the workpiece with only one manipulator. . However, the conventional transfer device is premised on one manipulator, and the above-described conventional example cannot be applied to two manipulators as they are. In particular, there is a case where a robot is configured as a human-type dual-arm manipulator type in order to transport a workpiece in cooperation with a human, and the work is performed by gripping both ends of the workpiece with the human and the robot dual-arm facing each other. At this time, the operation is easy in the longitudinal direction (the direction facing the robot), but it is difficult to directly apply the operation force to the other translation / rotation directions. This becomes more difficult as the distance between the robot and the operator increases. For this reason, there is a problem that the conventional operation using one manipulator cannot be transported by simply applying it to two manipulators. In addition, the control method according to the external force detected by the force detection unit of each of the two manipulators is also based on the premise that it is possible to apply an external force to each force detection unit in the direction intended by humans. For example, even if an operating force is applied in the lateral direction orthogonal to the longitudinal direction, only the longitudinal couple is detected in each force detection unit, and this method is not applicable to all directions. The present invention has been made in view of such problems, and grips a workpiece with two manipulators placed in parallel, and an operation force applied to the workpiece by a human being in any direction in a three-dimensional space. It is an object of the present invention to provide a transport apparatus capable of performing a transport operation.

  In order to solve the above-described problem, the present invention provides two sets of two units arranged in parallel in a transfer device including a workpiece gripping unit that grips a workpiece and a transfer control unit that controls a manipulator for transferring the workpiece. A force detection unit; an operation force detection unit that detects an operation force from outputs of the two sets of force detection units; and a force control unit that moves a manipulator in accordance with the operation force. Further, the two sets of force detecting means are mounted on each of the manipulators placed in parallel.

According to the first and second aspects of the invention, it is possible to transport a heavy object or a long object in an arbitrary direction in cooperation with a human by using two manipulators arranged in parallel.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a transport apparatus showing an embodiment of the present invention. In the figure, 11 is a right manipulator, 12 is a left manipulator, and each manipulator is fixed in parallel to 13 manipulator fixing bases. Reference numeral 14 denotes a hand attached to the hand of the right manipulator, and reference numeral 15 denotes a hand attached to the hand of the left manipulator. Reference numerals 16 and 17 denote force sensors attached to the bases of the hands of the respective manipulators, so that the force and torque applied to the hands can be detected. Reference numeral 19 denotes a workpiece which is conveyed in cooperation by an operator 18 who operates the robot and is held and fixed by the hands 14 and 15. The robot includes two sets of force detection units, and is configured to hold the workpiece 19 with the two hands 14 and 15, and the operation force applied to the workpiece 19 by the operator 18 is output from the two sets of force sensors. The part which is originally calculated is a characteristic part of the present invention.

  Next, a specific method for detecting the operation force in the translation / rotation direction from the outputs of the two sets of force sensors 16 and 17 will be described. The coordinate system ΣR of the hand 14 of the right manipulator 11 and the coordinate system ΣL of the hand 15 of the left manipulator 12 are set as shown in FIG. A control center coordinate system ΣC is set at the center of the right hand 14 and the left hand 15. The force / torque applied to the right hand 14 detected by the force sensor 16 attached to the right manipulator is {FxR, FyR, FzR, MxR, MyR, MzR}, and the force sensor 17 attached to the left manipulator. The detected force / torque applied to the left hand 15 is {FxL, FyL, FzL, MxL, MyL, MzL}. Further, the distance from the left and right hands 14 and 15 to the control center coordinate system origin is L1, and the length of the work 19 is L2.

  At this time, when the work 19 is a long object, that is, when L1 << L2, the operator 18 can apply an operating force to the left and right manipulators 11 and 12 in the longitudinal direction (X translation direction or rotation direction around the Y axis). Although easy, it is difficult to provide translational forces in the Y and Z directions. At the same time, when the workpiece 19 is gripped at two places as shown in FIG. 1, it is difficult to apply rotational torque about the X and Z axes. Therefore, the translation / rotation operation force is calculated by applying the output information of the two sets of force sensors to the moment balance condition around the control center coordinate system ΣC.

The translational force Fxc in the X-axis direction is balanced with the sum of the translational force FxR in the X-axis direction generated in the right hand 14 determined by the force sensor 16 and the translational force FxL in the X-axis direction generated in the left hand 15 determined by the force sensor 17. From this, the following formula is obtained.
Fxc = (FxR + FxL) (Formula 1)
The translational force Fyc in the Y-axis direction can be obtained by the following equation from the balance of moments around the control center C.
Fyc = (FxR-FxL) * (L1 / L2) (Formula 2)
The translational force Fzc in the Z-axis direction is obtained by using the control center C to calculate the moment MyR about the Y axis generated in the right hand 14 determined by the force sensor 16 and the moment MyL about the Y axis generated in the left hand 15 determined by the force sensor 17. It is obtained by the following formula by applying it to the balance formula of the surrounding moment.
Fzc =-(MyR + MyL) / L2 (Formula 3)
The moment Mxc about the X-axis is determined by the control center C based on the translational force FzR in the Z-axis direction generated in the right hand 14 obtained by the force sensor 16 and the translational force FzL in the Z-axis direction produced in the left hand 15 obtained by the force sensor 17. Since it is balanced with the moment generated around, it is obtained by the following formula.
Mxc = (FzL-FzR) * L1 (Formula 4)
The moment Myc about the Y axis is balanced with the sum of the moment MyR about the Y axis generated in the right hand 14 obtained by the force sensor 16 and the moment MyL about the Y axis generated in the left hand 15 obtained by the force sensor 17. It is obtained by the following formula.
Myc = (MyR + MyL) (Formula 5)
The moment Mzc about the Z-axis is controlled by the translation center FxR in the X-axis direction generated in the right hand 14 determined by the force sensor 16 and the translational force FxL in the X-axis direction generated in the left hand 15 determined by the force sensor 17. Since it is balanced with the moment generated around, it is obtained by the following formula.
Mzc = (FxR-FxL) * L1 (Formula 6)

  As described above, the translational force / rotational torque applied to the workpiece 19 by the operator 18 is obtained. These translational force and rotational torque become the operating force indicating the direction in which the operator 18 tries to move the workpiece 19. Next, a method of calculating the movement amounts of the left and right manipulators 11 and 12 based on these translational forces and rotational torques will be described with reference to FIG.

  FIG. 2 is a block diagram of a control apparatus showing an embodiment of the present invention. In the figure, reference numeral 21 denotes two sets of force detection units, which correspond to the force sensors 16 and 17 in FIG. Reference numeral 22 denotes an operating force calculation unit that converts the output of the force detection unit 21 into an operating force according to the above-described equations 1 to 6. The operating force is input to the force control unit 23, and an orthogonal movement amount corresponding to the operating force is calculated. In addition, when an operation command is input to the transport apparatus, the trajectory generator 24 generates a trajectory of the control center point ΣC and outputs an orthogonal position command. Here, the orthogonal position command of the control center point ΣC obtained by adding the orthogonal movement amount of the force control unit 23 to the orthogonal position command of the trajectory generation unit 24 is defined as XCref. At this time, in order to calculate the position command of the tip of the right manipulator 11, the orthogonal position command XCref of ΣC is converted into the orthogonal position command XRref of the hand 14 of the right manipulator 11 by the right manipulator position / posture conversion unit 25. Then, the right manipulator inverse kinematics conversion unit 26 outputs each joint angle command θRref of the right manipulator 11. At the same time, the ΣC orthogonal position command XCref is converted into the orthogonal position command XLref of the hand 15 of the left manipulator 12 by the left manipulator position / orientation conversion unit 27. Then, the left manipulator inverse kinematics conversion unit 28 outputs each joint angle command θLref of the left manipulator 12. The left manipulator position / posture conversion unit 27 obtains the position / posture of the left manipulator 12 so that the position / posture of the hand 15 of the left manipulator 12 does not always change relative to the hand 14 of the right manipulator. By doing in this way, it becomes possible to continue holding | grip the workpiece | work 19 currently hold | gripped with two sets of manipulators stably. Here, the position and orientation are calculated based on the right manipulator 11, but may be calculated based on the left manipulator 12. The manipulator is controlled by inputting the output angle commands θRref and θLref to the operation control unit 29.

With the above configuration, the transport apparatus of the present invention can transport workpieces such as heavy objects and long objects in cooperation with humans by using two sets of manipulators arranged in parallel. In the above embodiment, the two sets of manipulators are fixed to the manipulator fixing base 13, but the manipulator fixing base 13 may be a moving carriage. In the configuration in which the moving carriage is provided with two sets of manipulators, the movement amount of the control center point ΣC calculated by the force control unit 23 according to the operation force calculated by the equations 1 to 6 is used as the movement amount of the manipulator and the moving body. By appropriately distributing, not only the operation range of the manipulator but also a wide range of transfer operation is possible.
In the present embodiment, the dual-arm manipulator is exemplified. However, the present invention is not limited to the dual-arm manipulator, and any one having two sets of force detection units arranged in parallel may be used.
In this embodiment, a 6-axis (3 translational force, 3 moment) force sensor is used, but a 3-axis (X-axis direction and Z-axis direction translational force, Y-axis moment) force sensor is obtained. If you can, you may use it.

  Two sets of manipulators and human beings can be used as robots that transport workpieces in cooperation.

It is a block diagram of the conveying apparatus which shows the Example of this invention. It is a block diagram of a control device showing an example of the present invention. It is a block diagram of the conventional conveying apparatus.

Explanation of symbols

11 Right manipulator, 12 Left manipulator, 13 Manipulator fixing base,
14 right hand, 15 left hand, 16 force sensor, 17 force sensor, 18 operator,
19 workpieces, 21 force detection unit, 22 operation force detection unit, 23 force control unit,
24 trajectory generation unit, 25 right manipulator position / posture conversion unit, 26 right manipulator reverse kinematic conversion unit, 27 left manipulator position / posture conversion unit, 28 left manipulator reverse kinematic conversion unit, 29 motion control unit, 31 manipulator, 32 hand, 33 Operator,
34 work, 35 force sensor

Claims (2)

In a transport apparatus comprising a work gripping means for gripping a work and an operation control unit for controlling a manipulator for transporting the work,
Two sets of force detecting means arranged in parallel, an operating force detecting section for detecting an operating force from the outputs of the two sets of force detecting means, and a force control section for moving the manipulator according to the operating force A conveying device characterized by that. 2. The conveying apparatus according to claim 1, wherein the two sets of force detecting means are mounted on each of two manipulators placed in parallel.

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