The content of the invention
Decoupling control method between a kind of hydraulic-driven joint type legged type robot joint
Decoupling control method is realized according to the following steps between hydraulic-driven joint type legged type robot joint:
Step A, set up between joint and be crosslinked coupling model:
The application is studied the coupling behavior of machine, liquid coupled in common as hydraulic-driven joint type legged type robot,
Based on the leg mechanical structure to hydraulic-driven joint type legged type robot and the analysis of hydraulic servo driving system, according to mechanism
Dynamics and hydraulic principle, set up the kinetic model and leg hydraulic servo driving system of leg mechanism of robot respectively
Model, finally set up the interarticular coupling model of hydraulic-driven joint type legged type robot, be that the uneoupled control of robot is carried
For foundation.
Because in motion process, the motion in each joint of hydraulic-driven joint type legged type robot belongs to low-speed motion,
Therefore, interarticular motion is influenceed smaller by coriolis force and centripetal force, can be neglected, but influenceed by inertia force and gravity
It is larger, for the ease of analyzing and solving problem, it is necessary to catch the principal contradiction of problem, therefore only consider the shadow of inertia force and gravity
Ring, ignore the influence of coriolis force and centripetal force, so, hydraulic-driven joint type legged type robot leg power model be changed into as
Lower form:
Then, the kinetics relation exerted oneself between hydraulic cylinder displacement in any two joint is as follows:
In formula,For inertial matrix,For gravity.
Laplace transformation is carried out to above formula, coupled relation formula can be obtained as follows:
All there is obvious coupling between hydraulic-driven joint type legged type robot any two joint it can be seen from formula
Close.
Then, kinetic model is brought into hydraulic system model, the model that just can obtain whole control system is as follows:
In formula, the elements in a main diagonal product represents the transmission function of single joint respectively, rather than diagonal term is joint
Between coupling terms.
Step B, the degree of coupling for calculating each branch road in leg joint:
It is provided with n input, the n coupling object exported:
Y (s)=C (s) R (s)
In formula:
Y (s)=[y1(s),y2(s)…yn(s)]T
R (s)=[r1(s),r2(s)…rn(s)]T
Wherein, R (s) is the input of object, and Y (s) is the output of object, and C (s) is coupling object matrix.
Object C (s) is divided into four parts, obtained:
In formula:
Wherein, C11(s) it is [y1(s) r1(s) controlling brancher].
If K is C (s) static gain matrix, i.e.,:
Then [y1(s) r1(s)] degree of coupling of branch road is defined as:
Similarly, [yi(s) rj(s)] degree of coupling of branch road is defined as:
In formula,K is scratched for the i-th row vector of matrix KijFormer tactic row vector is pressed afterwards;For matrix K
Jth column vector scratches KijFormer tactic column vector is pressed afterwards;KPFor matrix K scratch after the i-th row and jth row remaining element by
Former tactic matrix.
The summation of all pairing coupling factor of branch is the degree of coupling of system, then the degree of coupling of system is:
η=Σ Pij
Asked for the degree of coupling of each branch road, it is possible to understand the coupled characteristic of system, judged according to its coupled characteristic be
Whether system needs to be decoupled.The coupled characteristic that the degree of coupling is reflected can be summarized as follows:
Work as PijWhen=0, no coupling, it is not necessary to use decoupling measure;
Work as PijDuring > 0, there is coupling, coupling reduces the control action of the passage, it is necessary at this moment to take decoupling measure
's;
Work as PijDuring=∞, superpower coupling, system is not normally functioning.
Decoupling control method between step C, design hydraulic-driven joint type legged type robot joint:
Under motion state, the coupling between each joint of hydraulic-driven joint type legged type robot is actually that machine, liquid are common
The result of same-action, according to the coupling model set up, the application is converted by Jacobian matrix, by the mechanism of robot system
Dynamics Coupling power decomposes each joint fluid cylinder pressure, by the Dynamics Coupling masterpiece of mechanism be hydraulic system outer perturbed force, so
Uneoupled control is carried out to electrohydraulic servo system again afterwards, to reduce the crosslinking coupling influence of whole robot system.
There is the kinetic model of coupling according to hydraulic-driven joint type legged type robot leg, will be main in M (y), G (y)
Cornerwise non-coupled item removes, then can obtain corresponding bonding force and be:
In formula,For inertial matrix,For gravity.
FdAs bonding force decomposes the perturbed force in each fluid power system.
So converted by Jacobian matrix, regard the mechanism dynamic bonding force of each movement branched chain of robot as outer interference
Power is transformed into each joint fluid cylinder pressure, and control variable is transformed into joint space from working space, then hydraulic system carried out again
Uneoupled control, to realize the decoupling of whole robot system.
Invention effect:
The present invention is directed to the crosslinking coupled problem existed between each joint in hydraulic-driven joint type legged type robot leg, will
Machine, liquid coupled in common are studied as the coupling behavior of hydraulic-driven joint type legged type robot, are set up between joint of robot
Coupling model;Calculate each branch road in leg joint the degree of coupling, illustrate hydraulic-driven joint type legged type robot uneoupled control must
The property wanted;The interarticular coupled characteristic of hydraulic-driven joint type legged type robot is studied, the robot that changes commanders is become by Jacobian matrix
The mechanism dynamic bonding force of system is controlled as the outer perturbed force of hydraulic system, realizes the sufficient formula of hydraulic-driven joint type
Each interarticular uneoupled control of robot leg, improves the control accuracy of robot, and holding system has good control performance,
Promote the lifting of hydraulic pressure quadruped robot dynamic property and automatization level.
Embodiment:Uneoupled control problem between hydraulic-driven joint type legged type robot size leg joint
Step A, set up coupling model is crosslinked between thigh and calf joint:
The application is studied the coupling behavior of machine, liquid coupled in common as hydraulic-driven joint type legged type robot,
Based on the leg mechanical structure to hydraulic-driven joint type legged type robot and the analysis of hydraulic servo driving system, according to mechanism
Dynamics and hydraulic principle, set up the kinetic model and leg hydraulic servo driving system of leg mechanism of robot respectively
Model, finally set up the coupling model in two joints of robot thigh and shank, foundation provided for the uneoupled control of robot,
The theory diagram of its coupled relation is as shown in Figure 1.
In accompanying drawing 1, u2For thigh joint servo valve input voltage;u3For calf joint servo valve input voltage;y2For thigh
The output displacement in joint;y3For the output displacement of calf joint.
From accompanying drawing 1 as can be seen that the output y of big leg joint2By the output y of calf joint3Influence, and calf joint
Output y3It is similarly subjected to the output y of big leg joint2Influence, therefore, the big leg joint of hydraulic pressure quadruped robot and calf joint it
Between there is obvious coupling, moreover, from coupled relation, coupling influence between two joint not only with mechanism dynamic parameter
It is relevant, it is also relevant with hydraulic system parameters.
Step B, the degree of coupling for calculating each branch road in leg joint:
In order to understand the coupled characteristic of system, it is necessary to calculate the degree of coupling of each branch road, judged according to the size of the degree of coupling
Whether system, which needs, is decoupled.
The coupling object that can draw hydraulic-driven joint type legged type robot leg thigh and calf according to step A is:
Then static gain matrix K is:
So, obtaining degree of coupling matrix P by calculating is:
From above-mentioned degree of coupling matrix, the robot leg system uses [y2(s) u2(s)]、[y3(s) u3
(s) matching method], the motion with actual robot thigh and calf is consistent, and the degree of coupling of system is η=P11+P22=1.28, coupling
It is right larger, it is necessary to carry out uneoupled control, to improve the Control platform of system.
Decoupling control method between step C, design hydraulic-driven joint type legged type robot thigh and calf joint:
Under motion state, the coupling between hydraulic-driven joint type legged type robot thigh and shank be actually machine,
The coefficient result of liquid, according to the coupling model set up, the mechanism for becoming robot system of changing commanders using Jacobian matrix is moved
Coupling with Mechanics power decomposes each joint fluid cylinder pressure, and the Dynamics Coupling masterpiece of mechanism is come for the outer perturbed force of electrohydraulic servo system
It is controlled, uneoupled control then is being carried out to electrohydraulic servo system, to realize the uneoupled control of whole robot system.It is controlled
The principle of system is as shown in Figure 2.
According to the coupling model set up, the non-coupled item of leading diagonal in M (y), G (y) is removed, be can obtain corresponding
Bonding force is:
In formula,For inertial matrix,For gravity.
FdAs bonding force decomposes the perturbed force in each fluid power system.
Therefore, the bonding force that can further obtain between robot thigh, shank is:
So converted by Jacobian matrix, regard the mechanism dynamic bonding force of each movement branched chain of robot as outer interference
Power is transformed into each joint fluid cylinder pressure, and control variable is transformed into joint space from working space, then hydraulic system carried out again
Uneoupled control, to realize the decoupling of whole robot system.