JPH05228854A - Method for controlling arm having 7 degree of freedom - Google Patents

Abstract

PURPOSE:To control a slave arm having 7 degrees of freedom with one hand of an operator in a method for controlling position and posture of a slave arm having 7 degrees of freedom. CONSTITUTION:A master arm 10 is provided with a switch 10A, which can be operated by the tip of a finger, and an operator can operate the master arm 10 and the switch 10A simultaneously with one hand. Ordinary 6 command values are output to a slave arm 20 having 7 degrees of freedom by operating the master arm 10, and furthermore, one more command value is output to the slave arm 20 by operating the switch 10A. Position of joints of the slave arm 20 is decided on the basis of the command value from the switch 10A. The slave arm 20 having 7 degrees of freedom is controlled on the basis of these 7 command values. The slave arm 20 having 7 degrees of freedom, which has been operated by both hands of an operator, can be controlled by one hand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a 7-DOF arm control system for controlling the position and posture of a 7-DOF slave arm, and more particularly to a 7-DOF arm control capable of controlling the position of an elbow joint by an operator's handle operation. Regarding the scheme.

In recent years, research and development of a master-slave system in which a slave arm has seven degrees of freedom has been advanced. When this 7-DOF slave arm is used, it has one redundant joint for the 6-DOF slave arm. Therefore, the 7-degree-of-freedom slave arm can perform an operation similar to that of a human elbow joint, and the slave arm can rotate the elbow joint while the tip position is fixed.

[0003]

2. Description of the Related Art By the way, in a normal master arm, an operator grips a handle, and the three-dimensional position of the gripped hand,
Since the command values are sent to the slave arm depending on the posture, only six command values can be generated. This 6
The individual command values are, for example, the positions X, Y, Z of the master arm hands generated by using the master arm and the postures α, β, γ.
Is to determine. Therefore, when the slave arm has 6 degrees of freedom or less, the outer shape of the slave arm can be uniquely determined by a command from the master arm. However, if the slave arm has more than 7 degrees of freedom, the outer shape cannot be uniquely determined by the six command values of the master arm. Therefore, the operator uses the other hand other than the one holding the handle to send the command value necessary for the slave arm control.

[0004]

However, one operator may use two slave arms at the same time, if necessary. Therefore, it is not preferable to use both hands for one slave arm.

Further, as described above, in the case of a slave arm having 7 degrees of freedom, the hand position and posture are not changed,
The feature is that only the position of the elbow joint can be controlled arbitrarily. Therefore, conversely, depending on the position of the elbow joint, the slave arm may take a singular point. In that case, the position and posture of the singular point cannot be realized unless one joint of the slave arm moves very fast, and the operation of the slave arm becomes unstable.
Further, depending on the position of the elbow joint, it may come into contact with an obstacle or a surrounding work environment.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a 7-degree-of-freedom arm control system in which an operator can control a 7-degree-of-freedom slave arm with one hand.

Another object of the present invention is to be able to control a 7-degree-of-freedom slave arm to a preferable elbow joint position.

[0008]

1 and 2 are block diagrams of the principle of the present invention. In FIG. 1, the 7-degree-of-freedom arm control system of the present invention is a switch 10A that can be operated with a fingertip.
And a slave arm 20 having 7 degrees of freedom controlled according to a command value from the master arm 10.

In FIG. 2, the 7-degree-of-freedom arm control system of the present invention is, in addition to the configuration of FIG. 1, an evaluation means 30 for evaluating the outer shape of the slave arm 20 based on a command value from the master arm 10, and its evaluation means 30. And an elbow joint position change command means 40 for outputting a command to change the elbow joint position of the slave arm 20 when the evaluation means 30 evaluates poorly.

[0010]

In FIG. 1, the master arm 10 is provided with a switch 10A which can be operated with a fingertip. The operator
The master arm 10 and the switch 10A can be simultaneously operated with one hand. By operating the master arm 10, the normal six command values are changed to the switch 1
By operating 0A, another command value
It is output to the slave arm 20 having 7 degrees of freedom. The command value from the switch 10A is the slave arm 20
This is a command value that determines the position of the elbow joint. The slave arm 20 having 7 degrees of freedom is controlled based on the 7 command values. Therefore, the slave arm 20 having 7 degrees of freedom, which is conventionally operated by the operator using both hands, can be controlled with one hand. Therefore, the operation of the slave arm 20 having 7 degrees of freedom can be appropriately instructed in real time during execution of the work.

In FIG. 2, the evaluation means 30 evaluates the outer shape of the slave arm 20 based on the seven command values from the master arm 10. As a result of the evaluation, for example, when the slave arm 20 takes a singular point or the elbow joint of the slave arm 20 comes into contact with an obstacle or a surrounding work environment, the elbow joint position change command means 40 causes the elbow joint to change. A position change command is output. Therefore, the operator
Based on the elbow joint position change command, the slave arm 20 having 7 degrees of freedom can be controlled to a preferable elbow joint position. Therefore, when the work space is narrow or there is an obstacle, the elbow joint of the 7-DOF slave arm is prevented so that the elbow joint does not come into contact with the obstacle or the like without affecting the position and posture of the hand of the slave arm 20. The joint position can be controlled. Further, when the slave arm 20 is about to reach the singular point, the elbow joint position of the slave arm 20 can be controlled so as to avoid the singular point.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram showing the overall configuration of the 7-degree-of-freedom arm control system of the present invention. In the figure, an operator 61 operates the master arm 11 and a switch 11A provided on the master arm 11 to control the operation of the 7-DOF slave arm 21. This master arm 11 and switch 11
A will be described with reference to FIGS. 4 and 5.

FIG. 4 is a schematic view of the master arm. The operator 61 grasps the handle 12 of the master arm 11, moves the handle 12 in the up, down, left, right, front, and rear X, Y, and Z directions, and also rotates the handle 12 in three directions of α, β, and γ. Six command values can be sent to the slave arm 21 having 7 to 11 degrees of freedom. The position (X, Y, Z) and the posture (α, β, γ) of the hand of the 7-DOF slave arm 21 are determined by these 6 command values.

FIG. 5 is a view showing a switch provided on the handle. In the figure, the handle 12 is provided with a switch 11A. The switch 11A includes two buttons 111 and 112, and outputs a command value for controlling the elbow joint position (rotation angle of the elbow joint) φ of the slave arm 21 by the operation of the operator 61. Details of the elbow joint and the elbow joint position φ will be described later. When the button 111 is pressed out of the two buttons 111 and 112, a command value for rotating the elbow joint in the forward direction is output.
When is pressed, the command value to rotate in the opposite direction is output. While the operator 61 is pressing the buttons 111 and 112, the elbow joint of the slave arm 21 changes at a constant speed, and when the elbow joint reaches a desired position, the operator 61 will press the buttons 111 and 112.
Release your finger from 112.

Further, the switch 11A may be of a button type as in the case of FIG. 5, and the moving speed of the elbow joint position φ may be changed according to the depth of pushing of the button. In that case, the operator 61 may press the button strongly when he wants to move the elbow joint position φ quickly.

Thus, the handle 12 of the master arm 11 is provided with the switch 11A so that the operator 61 can simultaneously operate the handle 12 and the switch 11A with one hand. Therefore, the operator 61 can control the 7-DOF slave arm 21 with one hand, which is conventionally operated with both hands. Therefore, the operation of the 7-DOF slave arm 21 can be appropriately instructed in real time during execution of work.

The variable converter 51 shown in FIG.
1 and the seven command values sent from the switch 11A are converted to obtain and output an angle command value. That is, the command values for controlling the hand position (X, Y, Z) of the 7-DOF slave arm 21, its posture (α, β, γ) and the rotation angle φ of the elbow joint are converted into seven angle command values. And The seven angle command values are sent to the 7-degree-of-freedom slave arm 21,
The angles θ1 to θ7 of the seven axes of the seven-degree-of-freedom slave arm 21 are controlled by the seven angle command values. Next, the 7-degree-of-freedom slave arm 21 will be described with reference to FIGS. 6 and 7.

FIG. 6 is a diagram showing the structure of a 7-DOF slave arm. In the figure, a 7-degree-of-freedom slave arm 21
Numbers 1 to 7 assigned in order from the root 210 side of each are 7
The axes of the degrees of freedom slave arm 21 are shown, and from the root 210 side, 1 axis, 3 axes, 5 axes and 7 axes are rotation axes, and 2 axes, 4 axes and 6 axes are bending axes. A hand (arm tip) 211 is provided at the tip of the seven axes. FIG. 7 shows a case in which four axes are rotated about a straight line connecting two and six axes in such an arm configuration.

FIG. 7 is an explanatory view of an elbow joint of a 7-DOF slave arm. 6 axes with 7 degrees of freedom slave arm 21
When the four axes are rotated about a straight line connecting the axes, the four axes operate as an elbow joint between the two and six axes as shown in the figure. The position and posture of the hand 211 at that time are unchanged. That is, regardless of the position and posture of the hand 211, the positions of the four axes can be freely set. Here, the angle φ formed by the vertical plane including the two axes and the six axes and the plane including the two axes, the four axes, and the six axes is defined as the elbow joint position. This elbow joint position φ is determined by the handle 1 of the master arm 11 as described above.
It is controlled by the command value from the switch 11A provided on the No.2.

The evaluation unit 31 of FIG. 3 receives the angle command values of the seven axis angles θ1 to θ7 output from the variable converter 51, simulates the outer shape of the 7-degree-of-freedom slave arm 21, and the simulation is performed. The outer shape obtained by the evaluation is evaluated. The evaluation items include the distance between the outer shape and the singular point, the distance between obstacles and surrounding walls, and the like. When the evaluation by the evaluation unit 31 is poor, a command to change the elbow joint position φ is output from the display device 41 so as to take the elbow joint position φ so as to improve the evaluation. For example, when the 7-DOF slave arm 21 may approach a singular point or an obstacle, the display device 41 is instructed to change the elbow joint position φ so as to prevent the approach. In response to the instruction from the display device 41, the operator 61 uses the switch 11A provided on the handle 12 of the master arm 11 to instruct to change the elbow joint position φ,
7 together with the other 6 command values from the master arm 11
It controls the operation of the slave arm 21 having the degree of freedom.

Therefore, when the work space is narrow or when there is an obstacle, the fingertip 2 of the 7-DOF slave arm 21 is used.
The elbow joint position φ of the seven-degree-of-freedom slave arm 21 can be controlled so that the elbow joint of the seven-degree-of-freedom slave arm 21 does not come into contact with an obstacle or the like without affecting the position and posture of the eleventh degree of freedom. Also, 7-DOF slave arm 2
When 1 is about to reach the singular point, the elbow joint position φ can be controlled so as to avoid the singular point.

FIG. 8 is a view showing another example of the switch provided on the handle. In this example, the dial 113 is used as the switch 11A provided on the handle 12. Also in this case, the operator 61 can simultaneously operate the handle 12 and the dial 113 with one hand, and the dial 113 can be operated with, for example, the thumb.
By using this dial 113, the elbow joint position φ, that is, the rotation angle φ of the elbow joint can be directly commanded. When the dial 113 is turned to indicate the desired rotation angle φ, the elbow joint of the 7-degree-of-freedom slave arm 21 moves in that direction at a constant speed and stops at the instructed elbow joint position φ.

[0023]

As described above, according to the present invention, the master arm for controlling the operation of the 7-degree-of-freedom slave arm is provided with a switch that can be operated with a fingertip, and the master arm and the switch can be operated simultaneously with one hand. As configured. With this configuration, the operator can control the 7-degree-of-freedom slave arm with one hand, which is conventionally operated with both hands. Therefore, the operation of the 7-DOF slave arm can be appropriately instructed in real time during work execution.

Further, the external shape of the 7-DOF slave arm is evaluated based on the command value from the master arm, and the elbow joint position change command is output based on the evaluation. Therefore, the operator can control the 7-DOF slave arm to a preferable elbow joint position based on the elbow joint position change command. Therefore, when the work space is narrow or there is an obstacle, the 7-DOF slave arm does not affect the position and posture of the 7-DOF slave arm so that the elbow joint does not come into contact with the obstacle or the like. The elbow joint position of the arm can be controlled. Also, if the 7-DOF slave arm is about to reach a singularity,
The elbow joint position can be controlled to avoid the singularity.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a principle block diagram of the present invention.

FIG. 3 is a diagram showing an overall configuration of a 7-degree-of-freedom arm control system according to the present invention.

FIG. 4 is a schematic view of a master arm.

FIG. 5 is a diagram showing a switch provided on a handle.

FIG. 6 is a diagram showing a configuration of a 7-DOF slave arm.

FIG. 7 is an explanatory diagram of an elbow joint of a 7-DOF slave arm.

FIG. 8 is a diagram showing another example of a switch provided on the handle.

[Explanation of symbols]

 10, 11 master arm 10A, 11A switch 20 slave arm 21 7 degrees of freedom slave arm 30 evaluation means 31 evaluation section 40 elbow joint position change command means 41 display device

Claims (6)

[Claims] 1. A master arm (10) having a switch (10A) that can be operated with a fingertip in a 7-DOF arm control system for controlling the position and posture of a slave arm having 7-DOF, and the master arm (10) A 7-DOF arm control system having a 7-DOF slave arm (20) controlled according to the command value of. 2. The 7-DOF arm according to claim 1, wherein the switch (10A) outputs the command value for controlling the position of the elbow joint of the slave arm (20) having the 7-DOF. control method. 3. The seven-degree-of-freedom arm control system according to claim 2, wherein the switch (10A) comprises two switches for changing the position of the elbow joint in a forward direction and a backward direction. 4. The seven-degree-of-freedom arm control system according to claim 2, wherein the switch (10A) is a push-in button type, and the moving speed of the elbow joint is controlled by the push-in depth of the button. 5. The 7-degree-of-freedom arm control system according to claim 2, wherein the switch (10A) is of a type that directly commands a position (angle) of the elbow joint. 6. An evaluation means (30) for evaluating the outer shape of the slave arm (20) based on a command value from the master arm (10), and the slave when the evaluation by the evaluation means (30) is bad. Elbow joint position change command means (4) for outputting a command to change the position of the elbow joint of the arm (20).
0) and are included, The 7-degree-of-freedom arm control system according to claim 1.