JPH10193290A - Robot control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely realize relaxation of external force, so that high accurate work can be realized. SOLUTION: In this device, by switching control of a first/second change over switch 12, 16, in a position control mode, based on a position command value and a position/speed value of a robot 10, robot is position controlled. In a compliance control mode, based on a compliance control position command value and a position/speed value calculated by a force/torque value applied to the robot 10, it is position controlled. Or based on an active limp control position command value and a position/speed value calculated from an integration compensation value and a position command value of the compliance control position command value, the robot can be selectively switching set to an active limp control mode position controlling the robot.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot control device suitable for operation control of an articulated robot mounted on, for example, a spacecraft and used for various operations.

[0002]

2. Description of the Related Art As is well known, in the field of space development, an articulated robot is mounted on a working spacecraft, and the spacecraft navigates through space to perform various operations such as construction of a space station. There is a plan to carry out the work. As means for controlling the joint angle of such a multi-joint robot, a target value for the joint angle is set, and the operation is controlled by driving the joint angle in accordance with the target value.
A method of performing desired work content is adopted.

By the way, when such a robot performs a highly accurate operation such as a grasping / contacting operation on the work object, the work object is damaged or damaged by controlling a force applied to a hand. The operation is controlled so that the desired operation can be performed safely and with high accuracy without any trouble.

[0004] As a method of controlling the force of such a robot, a method called compliance control for reducing the external force applied to the tip of the arm by executing operation control of the robot so as to indirectly realize a virtual impedance is used. It has been known. That is, the compliance control executes a position control that absorbs an external force to be applied by providing a virtual spring mass damper to the position command value given to the robot arm.

However, in the above-described compliance control, it is possible to effectively reduce the contact force of the hand of the robot to the point where the external force and the spring mass damper are suspended, but more external force is applied. In addition, there is a problem that the reduction is difficult.

According to this, when designing a control system, it is necessary to take into account the external force to be applied, so that there is a restriction on the use condition. When an external force exceeding the design is applied, the hand of the robot may be broken, Alternatively, there is a problem in that handling operations are very troublesome because the operation requires skill because there is a possibility of damaging the work target.

[0007]

As described above, the conventional robot controller has a problem that it is difficult to reduce the external force when a large external force is applied to the hand of the robot. The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a robot control device that can realize a high-precision work by reliably realizing an external force with a simple configuration.

[0008]

According to the present invention, there is provided a position control means for generating a joint drive signal of the robot based on a position command value and a position / velocity value of the robot to control the operation thereof, and a force / torque applied to the robot. A first calculating means for calculating a virtual spring mass characteristic based on the value to calculate a compliance control correction value, and a variable contact amount of the robot by integrating and compensating for the compliance control correction value calculated by the first calculating means. A second calculating means for calculating an active limp control correction value to be set; and a second calculating means for selecting one of the compliance control correction value calculated by the first calculating means or the active limp correction value calculated by the second calculating means. A first selecting means, and the first or second position command correction value selected by the first selecting means determines an arm position of the robot. Coordinate conversion means for converting to a reference system to calculate a first or second position command correction value, and compliance based on the first or second position command correction value calculated by the coordinate conversion means and the position command value. A third calculating means for calculating a control position command value or an active limp control position command value and outputting the calculated position command value to the position control means as a position command value; and the first or second position for the third calculating means. A second selecting means for selectively outputting a command correction value to select a position control mode, a compliance control mode, or an active limp control mode; and a position control mode for controlling operation of the first and second selecting means. And a mode control means for performing a control control for switching to a compliance control mode or an active limp control mode. A.

According to the above configuration, the mode switching means controls the operation of the second selection means to execute the position control of the robot based on the position command value and the position / speed value of the robot. The operation of both of the second selecting means is controlled, and the first is calculated based on the force / torque value applied to the robot.
The compliance control for controlling the position of the robot based on the position command value and the position / speed value is executed, and the active limp control position command value and the position / speed based on the second position command correction value are executed. The active limp control for performing position control based on the value is executed.

[0010] With this configuration, the switching operation of the mode switching means opposes the so-called external force, such as compliance control for executing position correction so as to reduce the force applied from an external force, or reducing the externally applied force to zero. Active limp control is possible, and diversification in robot operation can be achieved, and high-precision work can be facilitated and safely performed.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a robot control device according to an embodiment of the present invention.
Here, as the robot 10, a shoulder joint (first joint),
A case where a three-joint type of an elbow joint (second joint) and a wrist joint (third joint) is mounted on a spacecraft is shown.

That is, the adder 11 has one input terminal connected to an operation unit (not shown) and the other input terminal connected to the fixed contact a of the first switch 12 for switching. The output terminal of the adder 11 has a position control unit 13.
And outputs the input position command value, the compliance control position command value described later, or the active limp control position command value to the position control unit 13.

The position / speed value of the robot 10 is input to a position control unit 13 from a detection sensor (not shown). The position / speed value, a position command value from the operation unit (not shown), a compliance Based on the control position command value or the active limp control position command value, a control drive signal is generated for each mode to drive and control each joint of the robot 10, and to control the position of the hand position in accordance with the target value.

The movable contact b of the first changeover switch 12
Is connected to the output terminal of the coordinate conversion unit 14, and the input terminal of the coordinate conversion unit 14 is connected to the output terminal of the adder 15. The fixed point c of the second changeover switch 16 is connected to one input terminal of the adder 15. The output terminal of the compensation calculation unit 17 is connected to the movable contact d of the second changeover switch 16. The output terminal of the operation unit 18 is connected to the input terminal of the compensation operation unit 17.

The other input terminal of the adder 15 is connected to the output terminal of the operation unit 18. The arithmetic unit 18 includes
A virtual spring mass damper represented by a force control coordinate system by executing a calculation of (MS ² + CS + K) ⁻¹ based on the force / torque value applied to the robot 10 from a detection sensor (not shown) based on the force / torque value. The characteristic is calculated, and this value is output to the compensation calculation unit 17 as a compliance correction value.

M is a virtual mass, C is a virtual viscosity,
K is a virtual rigidity, and S is a time differential operator. Further, the compensation operation unit 17 performs integral compensation on the compliance correction value from the operation unit 18 and outputs the integral compensation value to the movable contact d of the second changeover switch 16, via the second changeover switch 16. And outputs it to the adder 15. Adder 15
Adds the compliance control position command value and the integral compensation value and outputs the result to the coordinate conversion unit 14.

Here, the coordinate conversion unit 14 converts the compliance correction value or the integral compensation value input via the adder 15 from the force control coordinate system to the arm reference coordinate system of the robot 10 and performs a first conversion. Output to the changeover switch 12.

The first and second changeover switches 12, 1
6 has a mode switching control unit 1 at its signal input end.
9 is connected. The mode switching control section 19 is connected to a mode switching command section (not shown). When a position control mode command signal is input from the mode switching command section (not shown), the mode switching control section 19 shown in FIG. Thus, the first and second changeover switches 12 and 16 are switched off. Here, a position command value is input to the position control unit 13 via the adder 11, and position control is performed based on the position / velocity value of the robot 10 as described above.

When the compliance control mode command signal is input from the mode switching command unit (not shown), the mode switching control unit 19 switches the first switch 12 on. While controlling, the second changeover switch 16 is switched off and connected (see FIG. 2).

Here, the operation mode of the control system is switched to the compliance control mode, the compliance control correction value calculated by the arithmetic unit 18 is input to the adder 15, and this compliance control correction value is converted into a coordinate conversion unit. 14 to the first changeover switch 12. First
Switch 12 outputs the input compliance control correction value to the adder 11. The adder 11 calculates a compliance control position command value by adding the compliance control correction value and the position command value, and outputs the calculated compliance control position command value to the position control unit 13. Then, the position control unit 13 generates a compliance control drive signal based on the output of the adder 11, and executes the compliance control of the robot 10.

When an active limp control mode command signal is input from the mode switch command section (not shown), the mode switch control section 19 switches the first switch 12 on. While controlling, the second changeover switch 16 is controlled to be turned on (see FIG. 2).

Here, the operation mode of the control system is switched and set to the active limp control mode, and the adder 15 receives the integral compensation value calculated by the compensation calculator 17 from the second changeover switch 16, the adder 15, It is input via the coordinate converter 14 and the first switch 12, adds the integral compensation value and the position command value, and outputs an active limp control position command value to the position controller 13. Then, the position control unit 13
The active limp control of the robot 10 is executed by generating an active limp control drive signal based on the output of the adder 11.

In the above configuration, the mode switching control unit 19
Selectively switches on and off the first and second switches 12, 16 in response to a command signal from the mode switching command section (not shown), and controls the operation mode of the control system by position control. Mode, compliance control mode, or active limp control mode.

That is, when the position control mode command signal is input from the mode switch command unit (not shown), the mode switch control unit 19 responds to the input and outputs the first control signal as shown in FIG. The changeover switch 12 is turned off and the control system is set to the position control mode.

Here, the position command value is directly input to the position control unit 13 via the adder 11, and the position command value and the position of the robot 10 detected by the detection sensor (not shown) are detected. / A position control mode drive signal is generated based on the speed value to drive and control the joint of the robot 10, and the hand position is controlled based on the position command value. Accordingly, the robot 10 performs a desired operation on the operation target 20 under the position control based on the position command value.

When the compliance control mode command signal is input from the mode switching command unit (not shown), the mode switching control unit 19 responds to this by receiving the signal shown in FIG.
As shown in (1), the first changeover switch 12 is set to be turned on, and the second changeover switch 16 is controlled to be turned off to set the control system to the compliance control mode.

Here, as described above, the operation unit 18 determines the compliance of the force control coordinate system of each joint of the robot 10 based on the force / torque value applied to the robot 10 detected by the detection sensor (not shown). The control correction value is calculated and output to the coordinate conversion unit 14 via the adder 15.

A coordinate converter 14 converts the input compliance control correction value into an arm reference coordinate system of the robot 10 and converts the corrected value into an adder 11 via a first switch 12.
Output to The adder 11 generates a compliance control position command value by adding the compliance control correction value to the position command value, and outputs the generated compliance control position command value to the position control unit 13.

Here, the position control unit 13 generates a compliance control mode drive signal based on the input compliance control position command value and the position / velocity value of the robot 10, drives and controls the joints of the robot 10, and controls the external control. The compliance control that performs the position control so as to reduce the force applied from the (work target) is executed. As a result, the robot 10 performs a desired operation while reducing the force applied to the operation target 20 under compliance control based on the position command value.

When an active limp control mode command signal is input from the mode switching command section (not shown), the mode switching control section 19 responds to the first signal as shown in FIG. The changeover switch 12 is set to ON, and the second changeover switch 16 is controlled to be turned ON.
Set the control system to the active limp control mode.

Here, the calculation unit 18 calculates and compensates for the compliance control correction value of the force control coordinate system as described above based on the force / torque value applied to the robot 10 from the detection sensor (not shown). Output to the operation unit 17.
The compensation calculation unit 17 integrates the input compliance control correction value to calculate an integral compensation value, and outputs the integrated compensation value to the adder 15 via the second switch 16. At the same time, the compliance control correction value is input to the adder 15, and the compliance control correction value and the integral compensation value are added to calculate an active limp control correction value, which is output to the coordinate conversion unit 14.

The coordinate conversion unit 14 converts the input active limp control correction value into a coordinate system for the arm 10 of the robot 10 and converts the coordinate value into the adder 11 via the first switch 12.
Output to The adder 11 calculates the active limp control position command value by adding the input active limp control correction value and the position command value, and outputs the calculated active limp control position command value to the position control unit 13.

The position controller 13 generates a compliance control mode drive signal based on the input compliance position command value and the position / velocity value of the robot 10 from the detection sensor (not shown) to generate a joint control And active limp control for performing position control so as not to oppose an external force such that the force applied from the work target 20 is set to “0”. As a result, the robot performs active limp control based on the position command value and executes a desired operation by setting the force applied to the operation target 20 to “0”.

As described above, the robot control device controls the position of the robot 10 based on the position command value and the position / velocity value of the robot 10 by controlling the switching of the first and second switches 12 and 16. A control mode, a compliance control mode in which the position of the robot is controlled based on a compliance control position command value and a position / speed value calculated from a force / torque value applied to the robot 10, or an integral compensation value and position of the compliance control position command value The active limp control mode is configured to be selectively switched to the active limp control mode for controlling the position of the robot based on the active limp control position command value calculated from the command value and the position / velocity value.

According to this, the compliance control for executing the position control so as to reduce the force applied from the work object 20, or the so-called force from the work object 20 such that the force applied from the work object 20 is set to “0” It is possible to select the active limp control that does not oppose the operation, and diversification in operation can be achieved. Is achieved.

Therefore, high-precision robot operation can be easily realized without skill in operation of the robot 10, and high-precision operation contents including positioning operation can be performed safely and easily. .

In the above embodiment, the description has been given of the case where the present invention is applied to a three-joint type articulated robot system. However, the present invention is not limited to this and can be applied to various other robot systems.

Further, in the above-described embodiment, the case where the robot system is constructed in a space navigation body has been described. However, the present invention is not limited to this use form, and can be configured. There is expected.

Further, in the above-described embodiment, the operation mode is switched and set to the position control mode, the compliance control mode, or the active limp control mode using the two switches of the first and second changeover switches 12 and 16. Although described in the case of such a configuration, the present invention is not limited to this mode selection means, and various other mode selection means can be configured. Therefore, it is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0040]

As described above in detail, according to the present invention, there is provided a robot control apparatus which can realize a high-precision operation with a simple structure, reliably reducing an external force. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing a robot control device according to an embodiment of the present invention.

FIG. 2 is a view shown for explaining a mode switching operation of FIG. 1;

[Explanation of symbols]

 10 ... Robot. 11, 15 ... Adder. 12, 16: First and second changeover switches. 13 ... Position control unit. 14 Coordinate conversion unit. 17 ... compensation operation unit. 18 ... Calculation unit. 19: Mode switching control unit. 20… Work target.

Claims (4)

[Claims] 1. A position control means for generating a joint drive signal of the robot based on a position command value and a position / velocity value of the robot and controlling the operation thereof, and a virtual spring mass characteristic based on a force / torque value applied to the robot. A first calculating means for calculating and calculating a compliance control correction value; and an active limp control correction value for variably setting a contact amount of the robot by integrating and compensating the compliance control correction value calculated by the first calculating means. A second calculating means for calculating; a first selecting means for selecting one of the compliance control correction value calculated by the first calculating means or the active limp correction value calculated by the second calculating means; The first or second position command correction value selected by the first selection means is converted into a coordinate system for determining an arm position of the robot. Is a coordinate conversion means for calculating a second position command correction value; and a compliance control position command value or active limp control based on the first or second position command correction value calculated by the coordinate conversion means and the position command value. A third calculating means for calculating a position command value and outputting it as a position command value to the position control means; and selectively outputting the first or second position command correction value to the third calculating means. A second selection means for selecting a position control mode, a compliance control mode, or an active limp control mode; A robot control device comprising: a mode switching unit that controls switching to a mode. 2. The robot control device according to claim 1, wherein the coordinate conversion means converts the value calculated in the force control coordinate system into an arm reference coordinate system. 3. The robot control device according to claim 1, wherein the robot is mounted on a spacecraft. 4. The robot control device according to claim 1, wherein the robot is an articulated robot.