KR101485003B1

KR101485003B1 - Device and method for controlling position and posture of walking robot

Info

Publication number: KR101485003B1
Application number: KR20140057825A
Authority: KR
Inventors: 박종현; 이정훈
Original assignee: 한양대학교 산학협력단
Priority date: 2014-05-14
Filing date: 2014-05-14
Publication date: 2015-01-27

Abstract

According to an embodiment of the present invention, there is provided an apparatus for controlling a position and an attitude of a robot, comprising: a sensor unit for sensing a disturbance generated on a robot and measuring a magnitude of the sensed disturbance; An impedance controller for performing a variable impedance control for changing a value of an impedance parameter corresponding to the magnitude of the measured disturbance; And a compensation unit for compensating for the position and attitude error of the robot by controlling a steady state error and a response speed generated according to the performance of the variable impedance control.

Description

TECHNICAL FIELD [0001] The present invention relates to a device and method for controlling a position and an attitude of a robot,

Embodiments of the present invention relate to an apparatus and method for controlling the position and attitude of a walking robot when disturbance occurs.

Research and development of robots that coexist with human beings in a human work and living space with a human-like joint system and are walking are actively proceeding. The walking robot is composed of a multi-legged walking robot having two or more legs or three or more legs, and actuators such as an electric motor and a hydraulic motor located at each joint must be driven for stable walking.

The driving method of the actuator is based on a position-based ZMP (zero moment point) control method in which a command angle of each joint, that is, a command position is given and controlled, and a command torque of each joint is given And a torque-based finite state machine (FSM) control method for controlling tracking.

Generally, the robot has a problem that its posture and position are always unstable due to disturbance when performing a task. In order to solve this problem, impedance control, which is a kind of force control, and methods for compensating the trajectory by an error are used.

Impedance control, which is a kind of force control, mainly uses a constant value parameter. If the magnitude of the disturbance exceeds the range that the parameter can compensate, it can not compensate properly. In addition, the damper part used in the impedance control plays an important role in absorbing the disturbance, but it is difficult to expect accurate and quick control.

A related prior art is the registered patent publication No. 10-1262840 entitled " Human-Robot Collaboration System ", and a method of assembling parts based on the method, filed on May 3, 2013.

In one embodiment of the present invention, the position and attitude of the robot are compensated through the variable impedance control, and the steady state error and the response speed generated at this time can be improved by a geometric method using gain. And methods.

The problems to be solved by the present invention are not limited to the above-mentioned problem (s), and another problem (s) not mentioned can be clearly understood by those skilled in the art from the following description.

The sensor unit may measure the disturbance magnitude by estimating the disturbance torque of the robot by sensing the joint position and the joint torque of the robot according to the disturbance.

The apparatus for controlling a position and an attitude of a robot according to an embodiment of the present invention may further include a memory unit for storing values of the impedance parameters according to magnitude of the disturbance.

The impedance control unit may refer to the memory unit to select a value of an impedance parameter matching the magnitude of the disturbance measured by the sensor unit and to change the value of the impedance parameter to the selected value to perform the variable impedance control have.

The impedance parameter may include at least one of a mass of the robot, a damping coefficient, and a spring constant.

Wherein the compensating unit comprises: a computing unit for computing a difference between a reference value and an actual value of the locus of the robot; And a feedback control unit for controlling the steady state error and the response speed based on feedback data according to the calculated difference value.

The feedback control unit may correct the reference value by applying a predetermined gain to the calculated difference value as the feedback data and control the steady state error and the response speed based on the corrected reference value have.

According to another aspect of the present invention, there is provided a method for controlling a position and an attitude of a robot, the method comprising: sensing disturbance generated in a sensor unit of a robot position and orientation control apparatus and measuring a magnitude of the sensed disturbance; Performing variable impedance control in an impedance control unit of the robot position and orientation control apparatus to change a value of an impedance parameter corresponding to a magnitude of the measured disturbance; And compensating a position and attitude error of the robot by controlling a steady state error and a response speed generated by performing the variable impedance control in a compensating unit of the robot position and attitude control apparatus.

The details of other embodiments are included in the detailed description and the accompanying drawings.

According to an embodiment of the present invention, the position and attitude of the robot are compensated through the variable impedance control, and the steady-state error and the response speed generated at this time are improved by a geometric method using gain, It is possible to efficiently control the position and posture of the robot even when disturbance occurs.

Fig. 1 is a view showing a robot operating in an ideal situation.
2 is a view showing a state in which a trajectory of a robot is distorted by a disturbance.
FIG. 3 is a block diagram illustrating an apparatus for controlling the position and orientation of a robot according to an embodiment of the present invention. Referring to FIG.
4 is a block diagram showing a detailed configuration of the compensating unit of FIG.
5 is a flowchart illustrating a method of controlling a position and an attitude of a robot according to an embodiment of the present invention.
6 is a flowchart illustrating a process of controlling steady state error and response speed according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and / or features of the present invention, and how to accomplish them, will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

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

FIG. 1 is a view showing a state where a robot operates in an ideal situation, and FIG. 2 is a view showing a state where a locus of a robot is distorted by a disturbance.

In the case of FIG. 1, the reference value and the actual value (sensing value) of the attitude and position of the robot coincide with each other. Accordingly, the locus drawn by the end effector of the robot normally appears.

However, when a disturbance occurs as shown in FIG. 2, the reference value and the actual value of the position and the position of the robot do not coincide with each other. Accordingly, the locus drawn by the end effector of the robot is distorted and appears abnormally.

Therefore, in the embodiment of the present invention, when disturbance occurs while the robot is walking, the parameter (impedance parameter) is appropriately changed according to the magnitude of the disturbance through variable impedance control, So that it can cope more actively.

In addition, in one embodiment of the present invention, by using the geometric compensation method together, it is possible to improve a steady state error and a slow response speed caused by a damper part serving to absorb disturbance.

In other words, in one embodiment of the present invention, by using the variable impedance control and the geometric compensation method in combination, it is possible to actively cope with the magnitude of the disturbance, as well as improve the steady state error and the slow response speed .

FIG. 3 is a block diagram illustrating an apparatus for controlling the position and orientation of a robot according to an embodiment of the present invention. Referring to FIG.

3, an apparatus 300 for controlling the position and orientation of a robot according to an exemplary embodiment of the present invention includes a sensor unit 310, a memory unit 320, an impedance control unit 330, a compensation unit 340, And may include a control unit 350.

The sensor unit 310 senses a disturbance generated with respect to the robot. The sensor unit 310 measures the magnitude of the sensed disturbance.

To this end, the sensor unit 310 senses the joint position and the joint torque of the robot according to the disturbance, and estimates the disturbance torque of the robot based on the sensed position and torque. Thus, the sensor unit 310 can measure the magnitude of the disturbance generated with respect to the robot based on the estimated disturbance torque.

The impedance controller 330 performs variable impedance control to vary the value of the impedance parameter according to the magnitude of the disturbance measured by the sensor unit 310. Here, the impedance parameter may include at least one of a mass of the robot, a damping coefficient, and a spring constant.

For this, the impedance controller 330 may use the memory unit 320. The memory unit 320 may previously store the impedance parameter values by matching the magnitude of the disturbance.

That is, the impedance controller 330 can select a value of the impedance parameter matching the magnitude of the disturbance measured by the sensor unit 310 with reference to the memory unit 320. [ The impedance controller 330 may change the value of the impedance parameter to the selected value to perform the variable impedance control.

At this time, the impedance controller 330 may perform the variable impedance control using Equation (1).

[Equation 1]

Where M is mass, B is damping coefficient, K is spring constant, and f is force. Also,

Represents the error value of the walking trajectory of the robot. M, B, and K denote impedance parameters as described above, and these values can be changed according to the magnitude of the disturbance generated in the robot through the variable impedance control.

The compensation unit 340 compensates for the position and attitude error of the robot by controlling the steady state error and the response speed generated in accordance with the performance of the variable impedance control.

For this, the compensation unit 340 may include an operation unit 410 and a feedback control unit 420, as shown in FIG. 4 is a block diagram showing a detailed configuration of the compensation unit 340 of FIG.

The operation unit 410 can calculate the difference between the reference value and the actual value with respect to the locus of the robot. For this, the operation unit 410 may calculate a reference value regarding the locus of the robot and compare the locus of the robot with the sensed actual value. The operation unit 410 may calculate and output a difference between two values according to the comparison result.

Here, the reference value regarding the locus of the robot is a value stored in advance in the memory unit 320, and the value may be changed according to the position and attitude of the robot. Since these reference values are already widely used in the related art, a detailed description thereof will be omitted.

The feedback control unit 420 may control the steady state error and the response speed generated according to the performance of the variable impedance control based on the feedback data according to the difference value calculated by the operation unit 410.

That is, the feedback controller 420 can correct the reference value by applying a predetermined gain to the difference between the reference value and the actual value as the feedback data. At this time, the feedback control unit 420 may correct the reference value by multiplying the difference (E) between the reference value and the actual value by the gain (G) (E * G). Accordingly, the pad back control unit 420 may correct the reference value to a value that is the same as or closest to the actual value.

The feedback controller 420 may control the steady state error and the response speed based on the corrected reference value. Accordingly, the compensation unit 340 can finally compensate for the position and attitude of the robot.

The controller 350 controls the position and orientation control apparatus 300 of the robot according to an embodiment of the present invention such as the sensor unit 310, the memory unit 320, the impedance control unit 330, (340), and the like.

As described above, the apparatus 300 for controlling the position and the attitude of the robot according to an embodiment of the present invention primarily performs position and attitude correction of the robot by performing variable impedance control through the impedance control unit 330, The steady-state error and the response speed generated by performing the impedance control can be finally compensated by controlling the compensating unit 340 to compensate the position and attitude of the robot.

Therefore, according to the embodiment of the present invention, it is possible to actively cope with the magnitude of the disturbance, and furthermore, by improving the steady state error and the slow response speed generated at this time, the position and attitude of the robot can be accurately controlled even when disturbance occurs .

5 is a flowchart illustrating a method of controlling a position and an attitude of a robot according to an embodiment of the present invention.

Referring to FIGS. 3 and 5, in step 510, the sensor unit 310 of the position and orientation control apparatus 300 of the robot senses a disturbance occurring to the robot.

Next, in step 520, the sensor unit 310 of the robot position and orientation control apparatus 300 measures the magnitude of the sensed disturbance.

Next, in step 530, the impedance controller 330 of the position and orientation controller 300 of the robot performs variable impedance control to change the value of the impedance parameter corresponding to the magnitude of the measured disturbance.

Next, in step 540, the compensating unit 340 of the robot position and attitude control apparatus 300 controls the steady state error and the response speed generated by performing the variable impedance control, Compensate for position error.

6 is a flowchart illustrating a process of controlling steady state error and response speed according to an embodiment of the present invention. The process corresponds to step 540 of FIG. 5, and the process will be described in more detail.

4 and 6, in operation 610, the operation unit 410 of the compensation unit 340 calculates a difference between a reference value and an actual value with respect to the locus of the robot.

Next, in step 620, the feedback controller 420 of the compensator 340 selects feedback data corresponding to the difference between the reference value and the actual value. Here, the feedback data may be selected as a gain value, depending on the difference between the reference value and the actual value.

Next, in step 630, the feedback control unit 420 of the compensating unit 340 calculates a steady state error (hereinafter referred to as " steady state error ") generated by a damper part And the response speed.

As described above, in the position and attitude control method of the robot according to an embodiment of the present invention, the position and attitude of the robot are compensated through the variable impedance control, and the steady state error and the response speed generated at this time are compensated by a geometric method The position and the posture of the robot can be finally compensated.

Embodiments of the present invention include computer readable media including program instructions for performing various computer implemented operations. The computer-readable medium may include program instructions, local data files, local data structures, etc., alone or in combination. The media may be those specially designed and constructed for the present invention or may be those known to those skilled in the computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floppy disks, and ROMs, And hardware devices specifically configured to store and execute the same program instructions. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Modification is possible. Accordingly, the spirit of the present invention should be understood only in accordance with the following claims, and all equivalents or equivalent variations thereof are included in the scope of the present invention.

310:
320:
330: Impedance control unit
340:
350:

Claims

A sensor unit for sensing a disturbance occurring to the robot and measuring a magnitude of the sensed disturbance;
An impedance controller for performing a variable impedance control for changing a value of an impedance parameter corresponding to the magnitude of the measured disturbance; And
And a compensating unit for compensating for the position and attitude error of the robot by controlling a steady state error and a response speed generated by performing the variable impedance control,
Lt; / RTI >
The compensation unit
An operation unit for calculating a difference between a reference value and an actual value with respect to the locus of the robot; And
A feedback control unit for controlling the steady state error and the response speed based on the corrected reference value by multiplying the calculated difference value by a predetermined gain to thereby correct the reference value,
/ RTI >
The impedance controller
Wherein the variable impedance control is performed using Equation (1) below.
[Equation 1]

Where M is mass, B is damping coefficient, K is spring constant, f is force,

Represents the error value of the walking trajectory of the robot.

The method according to claim 1,
The sensor unit
Wherein the controller measures the disturbance magnitude by estimating disturbance torque of the robot by sensing joint position and joint torque of the robot according to the disturbance.

The method according to claim 1,
A memory unit for storing a value of the impedance parameter for each magnitude of the disturbance,
And a controller for controlling the position and orientation of the robot.

The method of claim 3,
The impedance controller
Wherein the control unit selects the value of the impedance parameter matching the magnitude of the disturbance measured by the sensor unit with reference to the memory unit and performs the variable impedance control by changing the value of the impedance parameter to the selected value. Position and orientation control device.

The method according to claim 1,
The impedance parameter
Wherein the robot comprises at least one of a mass of the robot, a damping coefficient, and a spring constant.

delete

Sensing a disturbance generated in the sensor unit of the robot position and orientation control apparatus and measuring a magnitude of the sensed disturbance;
Performing variable impedance control in an impedance control unit of the robot position and orientation control apparatus to change a value of an impedance parameter corresponding to a magnitude of the measured disturbance; And
And compensating a position and attitude error of the robot by controlling a steady state error and a response speed generated by performing the variable impedance control in a compensating unit of the robot position and attitude control apparatus
Lt; / RTI >
The compensating step
Calculating a difference between a reference value and an actual value with respect to the locus of the robot in an operation unit of the compensation unit; And
The feedback control part of the compensation part corrects the reference value by multiplying the calculated difference value by a predetermined gain and controls the steady state error and the response speed based on the corrected reference value
/ RTI >
The step of performing the variable impedance control
Wherein the variable impedance control is performed using the following equation (1).
[Equation 1]

Where M is mass, B is damping coefficient, K is spring constant, f is force,

Represents the error value of the walking trajectory of the robot.