CN103878769A - Force feedback system for flexible environment of teleoperation - Google Patents

Abstract

A force feedback system for a flexible environment of teleoperation comprises a main robot, an auxiliary robot and a communication unit. The communication unit is arranged between the main robot and the auxiliary robot. The main robot comprises a main manipulator and a controller. A force feedback device is arranged on the main manipulator. An auxiliary manipulator is arranged on the auxiliary robot. When the tail end of the auxiliary manipulator touches a flexible environment operation, the auxiliary robot acquires deformation xe from the tail end of the auxiliary manipulator to a flexible environment touch point through measurement and calculation, and transmits the xe to the controller through the communication unit; after receiving the deformation xe at the flexible environment touch point, the controller acquires a force feedback numerical value and transmits the same to the force feedback device according to stored data of the known flexible environment.

Description

A kind of distant operation Flexible Environment force feedback system

Technical field

The present invention relates to a kind of distant operation Flexible Environment force feedback system, especially a kind of physical significance is clear, be convenient to performance evaluation, simple, computational speed faster power feel the distant operation Flexible Environment of telepresenc force feedback system.

Background technology

In distant operation task, environment refers in Teleoperation Systems, from the space of robot movable and from robot manipulation's object, as wants object of perception and crawl etc.Environment can be divided into static environment and dynamic environment from the angle of its state variation.Static environment refers to that working space does not change, and environmental knowledge is indeclinable in the known and process of executing the task before executing the task.The knowledge that dynamic environment refers to environment is before executing the task or all unknown, or part is unknown, in the process of executing the task, also will constantly change.The practicality of power feel telepresenc Teleoperation Systems and flexibility are embodied in just it and can be effectively operated in dynamic environment.

Flexible Environment belongs to the one of dynamic environment.In the time steadily contacting with Flexible Environment from mechanical arm tail end and exceed certain threshold value from the active force between mechanical arm tail end and environment, the variation of Flexible Environment surface deformation quality, deformation rigidity and deformation damping will be caused.Therefore, the dynamics of Flexible Environment presents non-linear.For this Nonlinear dynamic behaviors of Flexible Environment in accurate description power feel telepresenc remote control system, contact force is estimated accurately when steadily contacting with Flexible Environment from mechanical arm tail end, to ensure effectively carrying out of the distant operation task that comprises Flexible Environment contact.

Summary of the invention

Goal of the invention: the object of the present invention is to provide a kind of physical significance clear, be convenient to performance evaluation, simple, computational speed faster power feel the distant operation Flexible Environment of telepresenc force feedback system.

Technical scheme: distant operation Flexible Environment force feedback system of the present invention, comprise main robot, from robot, connect main robot and the link of communicating by letter from robot; Wherein main robot comprises main mechanical arm, controller, on described main mechanical arm, is provided with device for force feedback; Be provided with from mechanical arm from robot; Described during from the operation of mechanical arm tail end contact Flexible Environment, calculate from the deformation x of mechanical arm tail end and Flexible Environment contact point Flexible Environment from robot measurement _e, and by x _ebe sent to controller through communication link;

Described controller receives the deformation x at Flexible Environment contact point place _eafter, according to the data of the known flexible environment of storage, obtain as follows force feedback numerical value and be sent in device for force feedback:

(1) read the equiva lent impedance Z (s) of each second order spring-quality-damping body in the equally distributed a series of second order spring-quality-damping body square formations that are equivalent to Flexible Environment; Wherein, the particle of each second order spring-quality-damping body is positioned at free end, and the particle of the second order spring-quality-damping body of the stress point contacting with Flexible Environment from mechanical arm tail end is called to the first particle;

(2) according to the distance of each particle distance the first particle in second order spring-quality-damping body square formation by near to layering far successively, be that the first particle self is as ground floor using the stress point contacting with Flexible Environment from mechanical arm tail end, using with nearest 4 particles of the first particle as the second layer, by first, beyond two layers with nearest 4 particles of the first particle as the 3rd layer, beyond three layers of ground floors to the with nearest 4 particles of the first particle as the 4th layer, beyond four layers of ground floors to the with nearest 8 particles of the first particle as layer 5, by that analogy, calculate total equiva lent impedance:

$Z_e\left(s\right)=Z\left(s\right)(1+\underset{j=2}{\overset{T}{\mathrm{\Σ}}}\underset{i\∈\mathrm{layerj}}{\mathrm{\Σ}}(1-\frac{d_i}{x_e\tan \mathrm{\θ}})),$

Wherein i is the numbering of each particle in second order spring-quality-damping body square formation, d _ifor i particle before Flexible Environment stress deformation is to the distance of the first particle; J is the particle number of plies, and layerj is the set of all particle numbering of j layer; θ is the stress deformation angle of Flexible Environment, is the Flexible Environment characteristic constant recording in advance, and T is the particle number of plies of choosing;

(3) contact displacement signal is obtained to the complex frequency domain expression formula of contact displacement as Induction Solved by Laplace Transformation, then by the complex frequency domain expression formula of contact displacement and total equiva lent impedance Z _e(s) multiply each other, solve the complex frequency domain expression formula of contact force, then convert by anti-Lars, solve the contact force in time domain, more corresponding force feedback numerical signal is sent to device for force feedback.

Technical scheme concrete steps of the present invention are as follows:

Step 1, determine Flexible Environment surface and initial relative position from mechanical arm tail end, the geometrical model of setting up Flexible Environment shows as Fig. 2.

The kinetic model of the Flexible Environment of step 2, foundation, it comprises again:

(1) at the surface uniform of environment a large amount of equal second order spring-quality-damping bodies that distribute.In second order spring-quality-damping body, each mass body, is called particle.Physical connection between two adjacent particles is shown with tie segment table.The stress deformation of any one particle all may cause adjacent several particle that distortion to a certain degree occurs.The dynamic behavior of environment is exactly the coefficient result of all equally distributed second order spring-quality-damping bodies.

(2) input quantity using contact displacement as environment, the output quantity that masterpiece is environment, and definition be first particle position from the stress point of mechanical arm tail end and environmental exposure, other particle is according to providing from small to large numbering with the distance of first particle.Suppose that each particle is same second order spring-quality-damping body, the equiva lent impedance of each particle is Z (s), and the displacement that is first particle from the stress point of mechanical arm tail end and environmental exposure is x _e, and then it is as follows to provide the equiva lent impedance expression formula of environmental dynamics:

$Z_e\left(s\right)=\frac{U_e\left(s\right)}{I_e\left(s\right)}=\frac{I_e\left(s\right)Z\left(s\right)+I_e\left(s\right)h_{2}Z\left(s\right)+I_e\left(s\right)h_{3}Z\left(s\right)+...+I_e\left(s\right)h_{N}Z\left(s\right)}{I_e\left(s\right)}---\left(1\right)$

Z _e(s)＝Z(s)+h ₂Z(s)+h ₃Z(s)+…+h _NZ(s) (2)

In above formula, N represents the sum of particle, h _i(i=2,3 ..., N) and represent that the displacement of i particle transmits attenuation coefficient, namely after the first particle generation deformational displacement, cause adjacent with it i to put the degree of the displacement that deforms,

$h_i=\frac{x_i}{x_e}---\left(3\right)$

Because x _idue to x _ecaused, so h _i∈ [0,1].

(3) for avoiding the excessive environmental dynamics equiva lent impedance that causes of N to calculate too complexity and consuming time, adopt hierarchy to simplify the computational process of environmental dynamics equiva lent impedance.To be that first particle is as ground floor from the stress point of mechanical arm tail end and environmental exposure, using with first particle apart from 4 particles of minimum as the second layer, using beyond the second layer with first particle apart from 4 particles of minimum as the 3rd layer, using beyond the 3rd layer with first particle apart from 4 particles of minimum as the 4th layer, beyond the 4th layer with first particle apart from 8 particles of minimum as layer 5; By that analogy.By N particle according to center stressed point the distance of the first particle distance be divided into M layer, formula (2) can be rewritten as:

$Z_e\left(s\right)=Z\left(s\right)(1+\underset{i\∈\mathrm{layer}2}{\mathrm{\Σ}}{h}_i+\underset{i\∈\mathrm{layer}3}{\mathrm{\Σ}}{h}_i+...+\underset{i\∈\mathrm{layerM}}{\mathrm{\Σ}}{h}_i)---\left(4\right)$

Step 3, operator, by handling the main mechanical arm in Teleoperation Systems, control, from mechanical arm tail end, main mechanical arm tail end are carried out to real-time location following.Simultaneously, according to definite Flexible Environment surface and initial relative position from mechanical arm tail end, judge from mechanical arm tail end and whether come in contact with Flexible Environment.When from mechanical arm tail end and Flexible Environment come in contact, from robot according to from the current location of mechanical arm tail end, from the initial position of mechanical arm tail end, Flexible Environment surface and solve due to the displacement of going deep into Flexible Environment surface from mechanical arm tail end along Flexible Environment surface normal direction from the initial relative position of mechanical arm tail end, be called " contact displacement ", i.e. x _e.

Step 4, the conical indentation of areal deformation that flexible article is subject to after a contact force are described.The radius r that conical indentation region occurs after the receptor site contact force of Flexible Environment surface is

r＝x _etanθ (5)

In formula, θ is defined as the stress deformation angle of Flexible Environment, and it is a constant relevant with the characteristic of Flexible Environment.

Step 5, the maximum hierarchy number that is set in particle within conical indentation zone radius r are T, and this value is relevant to the length of side s of r and second order spring-quality-damping body square formation, and the less precision of s is larger.Calculate for simplifying, suitably choose s and make 2≤T≤6, formula (4) can further be expressed as follows:

$Z_e\left(s\right)=Z\left(s\right)(1+\underset{j=2}{\overset{T}{\mathrm{\Σ}}}\underset{i\∈\mathrm{layerj}}{\mathrm{\Σ}}{h}_i)---\left(6\right)$

$h_i=\frac{x_i}{x_e}=\frac{x_e-d_i/\tan }{x_e}=1-\frac{d_i}{x_e\tan \mathrm{\θ}}---\left(7\right)$

In formula, d _ifor i particle before environment stress deformation is to the distance of first particle.

Therefore can obtain:

$Z_e\left(s\right)=Z\left(s\right)(1+\underset{j=2}{\overset{T}{\mathrm{\Σ}}}\underset{i\∈\mathrm{layerj}}{\mathrm{\Σ}}(1-\frac{d_i}{x_e\tan \mathrm{\θ}}))$

Through type (8) can direct solution Flexible Environment nonlinear kinetics equiva lent impedance.

Step 6, by complex frequency domain expression formula and the Z of contact displacement _e(s) multiply each other, solve the complex frequency domain expression formula of contact force.Convert by anti-Lars again, solve the contact force in time domain.

The present invention compared with prior art, its beneficial effect is: adopt equally distributed second order spring-quality-damping body to represent the deformation dynamics of Flexible Environment, and the power of using it for is felt the estimation of contact force while steadily contact with Flexible Environment from mechanical arm tail end in telepresenc remote control system.The method is compared with environmental dynamics model in the past, have that physical significance is clear, model structure simply, feature accurately.Physical significance is clear simultaneously, algorithm is simple, computational speed is very fast, can solve the equiva lent impedance of Flexible Environment, utilizes this equiva lent impedance to be convenient to remote control system to carry out performance evaluation.

Brief description of the drawings

Fig. 1 is the workflow diagram of a kind of distant operation Flexible Environment force feedback system of the present invention;

Fig. 2 is equally distributed second order spring-quality-damping body square formation of the equivalent Flexible Environment in a kind of distant operation Flexible Environment force feedback system of the present invention;

Fig. 3 is the situation of some stress deformations of Flexible Environment supposed in a kind of distant operation Flexible Environment force feedback system of the present invention;

Fig. 4 is the hierarchical description non-linear dynamic model schematic diagram of the environment supposed in a kind of distant operation Flexible Environment force feedback system of the present invention;

The displacement relation of each particle when Fig. 5 is the Flexible Environment stress deformation of supposing in the Flexible Environment force feedback system of a kind of distant operation of the present invention.

Detailed description of the invention

Below technical solution of the present invention is elaborated, but protection scope of the present invention is not limited to described embodiment.

Embodiment 1:

The distant operation Flexible Environment force feedback system of the present embodiment, comprise main robot, from robot, connect main robot and the link of communicating by letter from robot; Wherein main robot comprises main mechanical arm, controller, on described main mechanical arm, is provided with device for force feedback; Be provided with from mechanical arm from robot; Described during from the operation of mechanical arm tail end contact Flexible Environment, calculate from the deformation x of mechanical arm tail end and Flexible Environment contact point Flexible Environment from robot measurement _e, and by x _ebe sent to controller through communication link;

Described controller receives the deformation x at Flexible Environment contact point place _eafter, according to the data of the known flexible environment of storage, obtain as follows force feedback numerical value and be sent in device for force feedback:

(1) read the equiva lent impedance Z (s) of each second order spring-quality-damping body in the equally distributed a series of second order spring-quality-damping body square formations that are equivalent to Flexible Environment; Wherein, the particle of each second order spring-quality-damping body is positioned at free end, and the particle of the second order spring-quality-damping body of the stress point contacting with Flexible Environment from mechanical arm tail end is called to the first particle;

(2) according to the distance of each particle distance the first particle in second order spring-quality-damping body square formation by near to layering far successively, be that the first particle self is as ground floor using the stress point contacting with Flexible Environment from mechanical arm tail end, using with nearest 4 particles of the first particle as the second layer, by first, beyond two layers with nearest 4 particles of the first particle as the 3rd layer, beyond three layers of ground floors to the with nearest 4 particles of the first particle as the 4th layer, beyond four layers of ground floors to the with nearest 8 particles of the first particle as layer 5, by that analogy, calculate total equiva lent impedance:

$Z_e\left(s\right)=Z\left(s\right)(1+\underset{j=2}{\overset{T}{\mathrm{\Σ}}}\underset{i\∈\mathrm{layerj}}{\mathrm{\Σ}}(1-\frac{d_i}{x_e\tan \mathrm{\θ}})),$

Wherein i is the numbering of each particle in second order spring-quality-damping body square formation, d _ifor i particle before Flexible Environment stress deformation is to the distance of the first particle; J is the particle number of plies, and layerj is the set of all particle numbering of j layer; θ is the stress deformation angle of Flexible Environment, is the Flexible Environment characteristic constant recording in advance, and T is the particle number of plies of choosing;

(3) contact displacement signal is obtained to the complex frequency domain expression formula of contact displacement as Induction Solved by Laplace Transformation, then by the complex frequency domain expression formula of contact displacement and total equiva lent impedance Z _e(s) multiply each other, solve the complex frequency domain expression formula of contact force, then convert by anti-Lars, solve the contact force in time domain, more corresponding force feedback numerical signal is sent to device for force feedback.

As mentioned above, although represented and explained the present invention with reference to specific preferred embodiment, it shall not be construed as the restriction to the present invention self.Not departing under the spirit and scope of the present invention prerequisite of claims definition, can make in the form and details various variations to it.

Claims (1)

1. a distant operation Flexible Environment force feedback system, is characterized in that, comprise main robot, from robot, connect main robot and the link of communicating by letter from robot; Wherein main robot comprises main mechanical arm, controller, on described main mechanical arm, is provided with device for force feedback; Be provided with from mechanical arm from robot; Described during from the operation of mechanical arm tail end contact Flexible Environment, calculate from the deformation x of mechanical arm tail end and Flexible Environment contact point Flexible Environment from robot measurement _e, and by x _ebe sent to controller through communication link;

Described controller receives the deformation x at Flexible Environment contact point place _eafter, according to the data of the known flexible environment of storage, obtain as follows force feedback numerical value and be sent in device for force feedback:

(1) read the equiva lent impedance Z (s) of each second order spring-quality-damping body in the equally distributed a series of second order spring-quality-damping body square formations that are equivalent to Flexible Environment; Wherein, the particle of each second order spring-quality-damping body is positioned at free end, and the particle of the second order spring-quality-damping body of the stress point contacting with Flexible Environment from mechanical arm tail end is called to the first particle;

(2) according to the distance of each particle distance the first particle in second order spring-quality-damping body square formation by near to layering far successively, be that the first particle self is as ground floor using the stress point contacting with Flexible Environment from mechanical arm tail end, using with nearest 4 particles of the first particle as the second layer, by first, beyond two layers with nearest 4 particles of the first particle as the 3rd layer, beyond three layers of ground floors to the with nearest 4 particles of the first particle as the 4th layer, beyond four layers of ground floors to the with nearest 8 particles of the first particle as layer 5, by that analogy, calculate total equiva lent impedance:

$Z_e\left(s\right)=Z\left(s\right)(1+\underset{j=2}{\overset{T}{\mathrm{\Σ}}}\underset{i\∈\mathrm{layerj}}{\mathrm{\Σ}}(1-\frac{d_i}{x_e\tan \mathrm{\θ}})),$

In formula, i is the numbering of each particle in second order spring-quality-damping body square formation, d _ifor i particle before Flexible Environment stress deformation is to the distance of the first particle; J is the particle number of plies, and layerj is the set of all particle numbering of j layer; θ is the stress deformation angle of Flexible Environment, is the Flexible Environment characteristic constant recording in advance, and T is the particle number of plies of choosing;

(3) contact displacement signal is obtained to the complex frequency domain expression formula of contact displacement as Induction Solved by Laplace Transformation, then by the complex frequency domain expression formula of contact displacement and total equiva lent impedance Z _e(s) multiply each other, solve the complex frequency domain expression formula of contact force, then convert by anti-Lars, solve the contact force in time domain, more corresponding force feedback numerical signal is sent to device for force feedback.

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