CN110116409A - A kind of four-way remote operating bilateral control method based on disturbance observer - Google Patents

Abstract

The invention discloses a four-channel teleoperation bilateral control method based on a disturbance observer. By establishing the nonlinear system dynamics model of the bilateral teleoperation system, a globally stable nonlinear sliding mode controller design method based on a disturbance observer is proposed to solve the nonlinearity, uncertainty and external disturbance of the teleoperation system and other major issues. Aiming at the nonlinear problem of the bilateral teleoperation system, the present invention designs a four-channel structure suitable for the nonlinear bilateral teleoperation system, through the position of the master end, the operator's operating torque, the position of the slave end, and the environmental operation torque signal in the communication The transmission between channels achieves better system transparency. Aiming at the uncertainty and external interference problems of the bilateral teleoperation system, the present invention designs ideal trajectory generators at the master end and slave end respectively, and a nonlinear sliding mode controller based on a disturbance observer, and guarantees based on Lyapunov theory the global stability of the system.

Description

A Four-Channel Teleoperation Bilateral Control Method Based on Disturbance Observer

technical field

The invention belongs to the field of teleoperation control, and specifically relates to a four-channel teleoperation bilateral control method based on a disturbance observer, aiming at improving the transparency of a nonlinear teleoperation system.

Background technique

With the development of automation and robot technology, relying on the teleoperation technology of human-computer interaction, that is, the operator can operate the master robot to realize the motion control of the slave robot and realize remote operation. In view of the characteristics of high presence and near-real-time synchronous operation of teleoperation technology, it has broad application prospects in space exploration, underwater operations, nuclear environment monitoring, remote surgery and other fields.

Transparency has been widely studied as an important index of teleoperation system. Among them, the four-channel structure is an effective method to improve the transparency of the remote control system. By matching the impedance coefficients of the master and slave ends, the ideal transparency conditions are obtained. However, most of the currently existing four-channel structures are used for linear teleoperation systems. With the complexity and refinement of tasks, this type of linear teleoperation system based on four-channel structures cannot perform tasks well. Therefore, in order to cope with complex and delicate tasks, considering the nonlinearity, uncertainty and external interference of multi-degree-of-freedom master-slave robots, the patent of this invention proposes a four-channel teleoperation bilateral control method based on disturbance observers , overcome the influence of the nonlinearity, uncertainty and external interference of the master-slave robot on the performance of the teleoperation system, and improve the transparency of the teleoperation system.

Contents of the invention

The purpose of the present invention is to propose a four-channel teleoperation bilateral control method based on a disturbance observer to solve technical problems such as transparency, nonlinearity and uncertainty in traditional teleoperation systems.

In order to achieve the above object, the specific content of the technical solution of the invention is as follows:

A four-channel teleoperation bilateral control method based on a disturbance observer, comprising the following steps:

1) Establish the nonlinear system dynamics model of the bilateral teleoperation system, specifically:

1-1) Establish the dynamic model of the master-slave robot

Among them, θ _m , and θ _s , Represents the position, velocity and acceleration signals of the master-slave robot, M _m0 and M _s0 represent the known mass inertia matrix, C _m0 and C _s0 represent the known Coriolis force/centripetal force matrix, G _m0 and G _s0 represent the known Gravity matrix, d _m and d _s represent external disturbance and model error, u _m and u _s represent control input, τ _h and τ _e represent the operator's operating torque or environmental operating torque.

The dynamic model of the above-mentioned master-slave robot has the following characteristics:

① and is a skew symmetric matrix;

②

③

1-2) Establish a mass-spring-damping environmental dynamics model

Among them, M _e , C _e , and G _e represent environmental parameters.

2) Design the sliding mode controller of the main robot based on the disturbance observer, specifically:

2-1) Design the ideal trajectory generator at the master end as follows:

Among them, avrg{·} represents the average value of ·, k _fm represents the scale parameter, M _dm , C _dm , G _dm represent the planning parameters.

By inputting θ _s into formula (4), the reference trajectory θ _mr can be obtained, Then by selecting appropriate M _dm , C _dm , G _dm , formulas (5) and (6) can get the ideal trajectory θ _md ,

2-2) Define the sliding mode surface s _m of the main robot controller as follows:

Among them, e _m ＝θ _m -θ _md , λ _m ＝diag{λ _m1 ,...,λ _mi ,...,λ _mw }, i=1,2,...,w represent the freedom of the main robot number of degrees.

2-3) Calculate the first derivative of s _m as follows:

2-4) Design the main controller according to (8) to ensure the asymptotic stability of the main robot. The designed controller u _m is:

in, ν _m =diag{ν _m1 ,...,ν _mi ,...,ν _mw },

ν _mi0 >0.

In the controller (9), sat(s _m ) represents a saturation function to avoid chattering of the sliding mode controller, which can be defined as:

Among them, β represents the boundary layer;

Represents a nonlinear disturbance observer, which can be defined as:

in, H _m represents a reversible matrix, which can be calculated by linear matrix inequality.

3) Design the sliding mode controller of the slave robot based on the disturbance observer, specifically:

3-1) Design the ideal trajectory generator from the end as follows:

Among them, avrg{·} represents the average value of ·, k _fs represents the scale parameter, M _ds , C _ds , G _ds represent the planning parameters.

By inputting θ _m into formula (12), the reference trajectory θ _sr can be obtained, Then by selecting appropriate M _ds , C _ds , G _ds , formulas (13) and (14) can get the ideal trajectory θ _sd ,

3-2) Define the sliding mode surface _s from the robot controller as follows:

Among them, e _s =θ _s -θ _sd , λ _s =diag{λ _s1 ,...,λ _si ,...,λ _sw }, i=1,2,...,w represent the freedom from the robot number of degrees.

3-3) Calculate the first derivative of s _s as follows:

3-4) Design the slave controller according to (16) to ensure the asymptotic stability of the slave robot. The designed controller u _s is:

in, ν _s =diag{ν _s1 ,...,ν _si ,...,ν _sw }, ν _si0 >0.

In the controller (17), sat(s _s ) represents a saturation function to avoid chattering of the sliding mode controller, which can be defined as:

Among them, β represents the boundary layer;

Represents a nonlinear disturbance observer, which can be defined as:

in, H _s represents a reversible matrix, which can be calculated by linear matrix inequality.

4) Design the Lyapunov function based on the sliding mode controller of the master-slave robot to ensure the global stability of the teleoperating system, specifically:

4-1) Design the global Lyapunov function V as follows:

V＝V _m +V _s +V _m0 +V _s0 (20)

in,

4-2) When ||s _m ||,||s _s ||≤β, the global Lyapunov function V will converge to:

in, and Indicates the observation error value of the master-slave observer.

Compared with the prior art, the present invention has the following beneficial effects:

1. Design a disturbance observer to improve the anti-interference performance of the nonlinear bilateral teleoperation system by observing and compensating the model error and external disturbance of the teleoperation system;

2. Design the saturation function to eliminate the chattering problem existing in the traditional sliding mode controller;

2. The nonlinear sliding mode control method based on the disturbance observer can enable the slave robot to track the position signal of the master robot in real time, overcome the influence of nonlinearity, uncertainty and external interference on the performance of the bilateral remote control system, and improve the transparency of the system sex;

4. Using the Lyapunov function, the boundedness of all signals is guaranteed, thereby ensuring the stability and convergence of the nonlinear bilateral teleoperation system.

Description of drawings

Fig. 1 is a four-channel teleoperation bilateral control block diagram based on disturbance observer proposed by the present invention;

Fig. 2 is the position tracking and force feedback curves of the master robot and the slave robot proposed by the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

Implementation technical scheme of the present invention is:

(1) Establishment of nonlinear system dynamics model of bilateral teleoperation system

The dynamic model of the master-slave robot is as follows:

Among them, θ _m , and θ _s , Represents the position, velocity and acceleration signals of the master-slave robot, M _m0 and M _s0 represent the known mass inertia matrix, C _m0 and C _s0 represent the known Coriolis force/centripetal force matrix, G _m0 and G _s0 represent the known Gravity matrix, d _m and d _s represent external disturbance and model error, u _m and u _s represent control input, τ _h and τ _e represent the operator's operating torque or environmental operating torque.

The dynamic model of the above-mentioned master-slave robot has the following characteristics:

① and is a skew symmetric matrix;

②

③

The environmental dynamics model based on mass-spring-damping is as follows:

Among them, M _e , C _e , and G _e represent environmental parameters.

(2) Design the sliding mode controller of the main robot based on the disturbance observer

The ideal trajectory generator at the master end is designed as follows:

Among them, avrg{·} represents the average value of ·, k _fm represents the scale parameter, M _dm , C _dm , G _dm represent the planning parameters.

By inputting θ _s into formula (4), the reference trajectory θ _mr can be obtained, Then by selecting appropriate M _dm , C _dm , G _dm , formulas (5) and (6) can get the ideal trajectory θ _md ,

The sliding mode surface s _m of the main robot controller is defined as follows:

Among them, e _m ＝θ _m -θ _md , λ _m ＝diag{λ _m1 ,...,λ _mi ,...,λ _mw }, i=1,2,...,w represent the freedom of the main robot number of degrees.

Then, calculate the first derivative of s _m as follows:

Design the main controller according to (8) to ensure the asymptotic stability of the main robot. The designed controller u _m is:

in, ν _m =diag{ν _m1 ,...,ν _mi ,...,ν _mw },

ν _mi0 >0.

In the controller (9), sat(s _m ) represents a saturation function to avoid chattering of the sliding mode controller, which can be defined as:

Among them, β represents the boundary layer;

Represents a nonlinear disturbance observer, which can be defined as:

in, H _m represents a reversible matrix, which can be calculated by linear matrix inequality.

(3) Design the sliding mode controller of the robot based on the disturbance observer design

Design the ideal trajectory generator from the end as follows:

Among them, avrg{·} represents the average value of ·, k _fs represents the scale parameter, M _ds , C _ds , G _ds represent the planning parameters.

By inputting θ _m into formula (12), the reference trajectory θ _sr can be obtained, Then by selecting appropriate M _ds , C _ds , G _ds , formulas (13) and (14) can get the ideal trajectory θ _sd ,

Define the sliding mode surface _s from the robot controller as follows:

Among them, e _s =θ _s -θ _sd , λ _s =diag{λ _s1 ,...,λ _si ,...,λ _sw }, i=1,2,...,w represent the freedom from the robot number of degrees.

Then, calculate the first derivative of s _s as follows:

According to (16), the slave controller is designed to ensure the asymptotic stability of the slave robot. The designed controller u _s is:

in, ν _s =diag{ν _s1 ,...,ν _si ,...,ν _sw }, ν _si0 >0.

In the controller (17), sat(s _s ) represents a saturation function to avoid chattering of the sliding mode controller, which can be defined as:

Among them, β represents the boundary layer;

Represents a nonlinear disturbance observer, which can be defined as:

in, H _s represents a reversible matrix, which can be calculated by linear matrix inequality.

(4) Designing the Lyapunov function of the sliding mode controller based on the master-slave robot

Design the global Lyapunov function V as follows:

V＝V _m +V _s +V _m0 +V _s0 (20)

in,

When ||s _m ||,||s _s ||≤β, the global Lyapunov function V will converge to:

in, and Indicates the observation error value of the master-slave observer.

Based on (21), s _m , s _s , is bounded, so that e _m , e _s , and u _m , u _s are bounded. Therefore, all signals in the nonlinear teleoperation system are bounded, and the system is globally stable.

(5) Carry out simulation experiment verification

In order to verify the feasibility of the above theory, a simulation experiment was carried out under MATLAB, and the simulation experiment verified the effect of the four-channel teleoperation bilateral control method based on the disturbance observer.

The simulation parameters are selected as follows:

Take the main controller (9) and the disturbance observer (11), where λ _m =diag{10,10}, ν _m =diag{0.2,0.2}, β=0.05, M _dm =diag{4.0,4.0}, C _dm =diag{0,0}, G _dm =diag{4.9,4.9}* _θmd , τ _fm =0.025, H _m =diag{0.28,0.38}.

Take the slave controller (17) and the disturbance observer (19), where, λ _s =diag{10,10}, ν _s =diag{0.2,0.2}, β=0.05, M _ds =diag{4.0,4.0} , C _ds =diag{0,0}, G _ds =diag{5.8,5.8}*θ _sd , τ _fs =0.025, H _s =diag{0.28,0.38}.

The environmental parameters are taken as M _e =diag{-2.0,-2.0}, C _e =diag{0,0}, G _e =diag{-0.9,-0.9}*θ _s .

Take the operator's operating torque as τ _h =[-2 sin t 4 sin t] ^T .

Define the master-slave robot as a mechanical arm with 2 degrees of freedom, and the parameters are:

Wherein, j=m, s represent the master robot and the slave robot respectively, and g=9.8m/s ² .

Figure 2 is the position tracking and force feedback curves of the master robot and the slave robot. It can be seen from the figure that the slave robot can track the position signal of the master robot well, and the operator can feel the force feedback signal, and pass the formula ( 6) Provide an ideal tracking trajectory for the main robot. Therefore, the nonlinear teleoperation system is transparent.

Claims (7)

1. The bilateral control method based on the four-channel teleoperation of disturbance observer, is characterized in that, comprises the following steps: 1) Establish the nonlinear system dynamics model of the bilateral teleoperation system, specifically: 1-1) Establish the dynamic model of the master-slave robot Among them, θ _m , and θ _s , Represents the position, velocity and acceleration signals of the master-slave robot, M _m0 and M _s0 represent the known mass inertia matrix, C _m0 and C _s0 represent the known Coriolis force/centripetal force matrix, G _m0 and G _s0 represent the known Gravity matrix, d _m and d _s represent external disturbance and model error, u _m and u _s represent control input, τ _h and τ _e represent the operator's operating torque or environmental operating torque; 1-2) Establish a mass-spring-damping environmental dynamics model Among them, M _e , C _e , G _e represent environmental parameters; 2) Design the sliding mode controller of the main robot based on the disturbance observer, specifically: 2-1) Design the ideal trajectory generator at the master end as follows: Among them, avrg{·} represents the average value of ·, k _fm represents the scale parameter, M _dm , C _dm , G _dm represent the planning parameters; By inputting θ _s into formula (4), the reference trajectory θ _mr can be obtained, Then by selecting appropriate M _dm , C _dm , G _dm , formulas (5) and (6) can get the ideal trajectory θ _md , 2-2) Define the sliding mode surface s _m of the main robot controller as follows: Among them, e _m ＝θ _m -θ _md , λ _m ＝diag{λ _m1 ,...,λ _mi ,...,λ _mw }, i=1,2,...,w represent the freedom of the main robot number of degrees; 2-3) Calculate the first derivative of s _m as follows: 2-4) Design the controller according to (8) to ensure the asymptotic stability of the main robot. The designed controller u _m is: in, ν _m =diag{ν _m1 ,...,ν _mi ,...,ν _mw }, ν _mi0 >0; 3) Design the sliding mode controller of the slave robot based on the disturbance observer, specifically: 3-1) Design the ideal trajectory generator from the end as follows: Among them, avrg{ } represents the average value of , k _fs represents the scale parameter, M _ds , C _ds , G _ds represent the planning parameters; By inputting θ _m into formula (12), the reference trajectory θ _sr can be obtained, Then by selecting appropriate M _ds , C _ds , G _ds , formulas (13) and (14) can get the ideal trajectory θ _sd , 3-2) Define the sliding mode surface _s from the robot controller as follows: Among them, e _s =θ _s -θ _sd , λ _s =diag{λ _s1 ,...,λ _si ,...,λ _sw }, i=1,2,...,w represent the freedom from the robot number of degrees; 3-3) Calculate the first derivative of s _s as follows: 3-4) Design the controller according to (16) to ensure the asymptotic stability of the slave robot. The designed controller u _s is: in, ν _s =diag{ν _s1 ,...,ν _si ,...,ν _sw }, ν _si0 >0; 4) Design the Lyapunov function based on the sliding mode controller of the master-slave robot, specifically: 4-1) Design the global Lyapunov function V to ensure the global stability of the nonlinear teleoperation system; 4-2) When ||s _m ||,||s _s ||≤β, V will converge to: in, and Indicates the observation error value of the master-slave observer. 2. the four-channel teleoperation bilateral control method based on disturbance observer according to claim 1, is characterized in that, in described step 1-1), the dynamic model of master-slave robot has following characteristics: ① and is a skew symmetric matrix; ② ③ 3. the four-channel teleoperation bilateral control method based on disturbance observer according to claim 1, is characterized in that, in described step 2-4), sat (s _m ) represents a kind of avoiding chattering of sliding mode controller The saturation function of is defined as: where β represents the boundary layer. 4. the four-channel teleoperation bilateral control method based on disturbance observer according to claim 1, is characterized in that, in described step 2-4), Represents a nonlinear perturbation observer, defined as: in, H _m represents a reversible matrix, which can be calculated by linear matrix inequality. 5. the four-channel teleoperation bilateral control method based on disturbance observer according to claim 1, is characterized in that, in described step 3-4), sat (s _s ) represents a kind of avoiding chattering of sliding mode controller The saturation function of is defined as: where β represents the boundary layer. 6. The four-channel teleoperation bilateral control method based on disturbance observer according to claim 1, characterized in that, in the step 3-4), Represents a nonlinear perturbation observer, defined as: in, H _s represents a reversible matrix, which can be calculated by linear matrix inequality. 7. the four-channel teleoperation bilateral control method based on disturbance observer according to claim 1, is characterized in that, in described step 4-1), the global Lyapunov function V of design is as follows: V＝V _m +V _s +V _m0 +V _s0 (20) in,