CN101799663B - Underactuated biped robot excitation planning and control method - Google Patents

Abstract

The invention discloses an underactuated biped robot excitation planning and control method, which has the advantages of high real-time property and strong engineering practicability. The method comprises the following steps: (1) establishing a mathematic model and converting the mathematic model into a system state equation; (2) selecting an excitation signal; (3) inputting the excitation signal; (4) taking joint angle positions, joint angle speeds and joint angle acceleration obtained in the step (3) as given values, recording an angle excitation plan for a passive joint to be qpd and recording an actual output angle of an underactuated joint to be qp; (5) performing sampling according to a sampling period and calculating an actual underactuated joint angle qp, an underactuated joint angle speed and underactuated joint angle acceleration by using a sensor; (6) comparing qpd with qp in each sampling period to obtain an error, determining the error with an expression and performing sliding mode variable structure control correction so as to make e tend to zero; (7) outputting an active joint control variable ua after the operation of the sliding mode variable structure control correction; and (8) repeating the steps (3) to (7) to obtain the active joint control variables of each sampling period.

Description

The excitation planning of underactuated biped robot and control method

Technical field

The present invention relates to the Robot Control Technology field, specifically is a kind of excitation planning and control method of underactuated biped robot.

Background technology

Underactuated biped robot is the essentially nonlinear system, and the dynamics constraint can not be amassed, and is the second order nonholonomic system, and its trajectory planning and control are difficult problems.Owing to lack tracking power to the free position space tracking, to owe in the drive system, the generation of tracks is more much bigger than general conventional system difficulty, the realizability of the track kinetics relation that places one's entire reliance upon.Owe drive system and belong to not exclusively controlled system, general smooth state feedback control method is to make its quelling.

At present a lot of researchists study to the situation that passive joint (owing to drive the joint) contains detent; And do not have the situation of detent for passive joint, still excitation planning and the control method less than the underactuated biped robot that real-time is high, engineering practicability is strong occurs.

Summary of the invention

The technical matters that the present invention will solve is, overcomes the shortcoming of above prior art, and the excitation planning and the control method of the underactuated biped robot that a kind of real-time is high, engineering practicability is strong is provided.

Technical scheme of the present invention is, a kind of excitation planning and control method of underactuated biped robot is provided, and realized by following steps:

(1) sets up the mathematical model of underactuated biped robot, and this mathematical model is converted into system state equation;

(2) selected pumping signal: discontinuity vibration moment sine function, or impulse function;

(3) input signal is according to calculated with mathematical model output joint angles position, joint angles speed, the joint angles acceleration of underactuated biped robot;

(4) excitation planning: the joint angles position that obtains in the step (3), joint angles speed, joint angles acceleration set-point, i.e. the angle excitation planning of underactuated biped robot as actual underactuated biped robot output; The angle excitation planning of note passive joint is q _p ^d, q _p ^dBe exactly the expectation value of passive joint angle, the actual output angle of owing to drive the joint is q _p

(5) by the sensor of underactuated biped robot by the sampling period sampling and calculate actual underactuated biped robot owe to drive joint angles q _p, owe to drive joint angles speed

Owe to drive the joint angles acceleration

(6) each sampling period all with q _p ^dQ with actual underactuated biped robot output _pCompare, obtain error, remember that this error is e, by expression formula Confirm, and carry out Sliding mode variable structure control and proofread and correct, make e trend towards zero;

(7) output active joint controlled quentity controlled variable behind the Sliding mode variable structure control correction calculation remembers that this controlled quentity controlled variable is u _a, said underactuated biped robot is according to u _aRemove to control the active joint servo driver or the active joint motor of underactuated biped robot;

(8) repeating step (3)～(7) obtain each working control amount in joint initiatively, simultaneously according to the motion of the said underactuated biped robot of control in real time of working control amount in sampling period.

After adopting said method; The present invention compared with prior art; Have following remarkable advantage and beneficial effect: because the excitation planning of underactuated biped robot of the present invention and control method are under the situation of passive joint brakeless device; The mathematical model that employing discontinuity vibration moment sine function or impulse function input signal are given underactuated biped robot, and calculate output active joint angles and carry out trajectory planning, utilize the Sliding mode variable structure control bearing calibration to realize the tracking Control of desired trajectory; Overcome a trajectory planning and a control difficult problem that nonholonomic system brings; And planning and control are accomplished in real time, and computing time is short, it is simple to calculate, so the excitation planning of underactuated biped robot of the present invention and control method have real-time height, advantage that engineering practicability is strong.

Description of drawings

Accompanying drawing is the excitation planning of underactuated biped robot of the present invention and the schematic diagram of control method.

Embodiment

Below in conjunction with accompanying drawing and specific embodiment the present invention is described further.

The planning of general underactuated biped robot and control comprise joint (initiatively joint and passive joint) angular position sensor, joint angles speed pickup, joint angles acceleration transducer, force cell, controller and servo-driver, and the excitation planning of underactuated biped robot of the present invention and control method need be called these existing hardware.

The excitation planning of underactuated biped robot of the present invention and the control procedure of control method are following:

(1) set up the mathematical model of underactuated biped robot, and this mathematical model is reduced to system state equation, the mathematical model of general underactuated biped robot is reduced to following mathematical model:

$\left[\begin{array}{cc}{M}_{\mathrm{aa}}& M_{\mathrm{ap}}\\ M_{\mathrm{pa}}& M_{\mathrm{pp}}\end{array}\right]\left[\begin{array}{c}{\stackrel{\·\·}{q}}_a\\ {\stackrel{\·\·}{q}}_p\end{array}\right]+\left[\begin{array}{c}{C}_a(q,\stackrel{\·}{q})\\ C_p(q,\stackrel{\·}{q})\end{array}\right]+\left[\begin{array}{c}{G}_a(q,\stackrel{\·}{q})\\ G_p(q,\stackrel{\·}{q})\end{array}\right]=\left[\begin{array}{c}{\mathrm{\τ}}_0\\ 0\end{array}\right]$

In this formula, subscript a representes initiatively joint, and p representes passive joint, q=[q _aq _p] ^TBe joint variable,

Be the passive joint acceleration of system, Be the active joint acceleration of system,

Be inertia matrix, and M _Ap(q)=M ^T _Pa(q);

Be coriolis force and centrifugal force item;

Be gravity and other power; τ _aBe active joint driving force; The driving force that passive joint is corresponding is zero

(2) selected pumping signal: selected excitation function is a sine function

Wherein,

Be the phasing degree, B is biasing, T ₀Be step-length;

(3) by underactuated biped robot calculated with mathematical model output joint angles position q=[q _aq _p] ^T, joint angles speed

The joint angles acceleration

(4) the set-point q that exports the joint angles position that obtains in the step (3), joint angles speed, joint angles acceleration as actual underactuated biped robot _d=q=[q _aq _p] ^T,

(5) to owe to drive the angle excitation planning in joint be q to note _p ^d, owe to drive the actual output angle q in joint _p

(6) each sampling period all with q _p ^dQ with actual underactuated biped robot output _pCompare, obtain error, remember that this error is e, by expression formula

Confirm, and carry out Sliding mode variable structure control and proofread and correct, make e trend towards zero;

(7) output active joint controlled quentity controlled variable behind the Sliding mode variable structure control correction calculation remembers that this controlled quentity controlled variable is u _a, said underactuated biped robot is according to u _aRemove to control the active joint servo driver or the active joint motor of underactuated biped robot,

$u_a=(M_{\mathrm{ap}}-M_{\mathrm{aa}}{M}_{\mathrm{pa}}^{-1}{M}_{\mathrm{pp}})(\mathrm{\ηsgn}\left(s\right)+\mathrm{\ξs}+\mathrm{\ζ}\stackrel{\·}{e})$

$-M_{\mathrm{aa}}{M}_{\mathrm{ap}}^{-1}(C_p(q,\stackrel{\·}{q})+G_p(q,\stackrel{\·}{q}))+C_a(q,\stackrel{\·}{q})+G_a(q,\stackrel{\·}{q})$

Wherein: η; ξ and ζ are suitable coefficient, sgn () is-symbol function;

(8) repeating step (3)～(7) obtain each working control amount in joint initiatively, simultaneously according to the motion of the said underactuated biped robot of control in real time of working control amount in sampling period.

Below only be described, but can not be interpreted as it is restriction claim with regard to preferred embodiment of the present invention.Structure of the present invention can have other variations, is not limited to said structure, such as: said excitation function can be impulse function.In a word, all various variations of in the protection domain of product independent claims of the present invention, being done are all in protection scope of the present invention.

Claims (2)

1. the excitation planning of a underactuated biped robot and control method is characterized in that,

Realize by following steps:

(1) sets up the mathematical model of underactuated biped robot, and this mathematical model is converted into system state equation;

(2) selected pumping signal: discontinuity vibration moment sine function, or impulse function;

(3) input signal is according to calculated with mathematical model output joint angles position, joint angles speed, the joint angles acceleration of underactuated biped robot;

(4) excitation planning: the joint angles position that obtains in the step (3), joint angles speed, joint angles acceleration set-point, i.e. the angle excitation planning of underactuated biped robot as actual underactuated biped robot output; The angle excitation planning that note owes to drive the joint does

Owe to drive the expectation value of joint angles exactly, the actual output angle of owing to drive the joint is q _p

(5) by the sensor of underactuated biped robot by the sampling period sampling and calculate actual underactuated biped robot owe to drive joint angles q _p, owe to drive joint angles speed

Owe to drive the joint angles acceleration

(6) all incite somebody to action in each sampling period

Q with actual underactuated biped robot output _pCompare, obtain error, remember that this error is e, by expression formula

Confirm, and carry out Sliding mode variable structure control and proofread and correct, make e trend towards zero;

(7) output active joint controlled quentity controlled variable behind the Sliding mode variable structure control correction calculation remembers that this controlled quentity controlled variable is u _a, said underactuated biped robot is according to u _aRemove to control the active joint servo driver or the active joint motor of underactuated biped robot;

(8) repeating step (3)～(7) obtain each working control amount in joint initiatively, simultaneously according to the motion of the said underactuated biped robot of control in real time of working control amount in sampling period.

2. the excitation planning of underactuated biped robot according to claim 1 and control method is characterized in that, selected pumping signal is a sine function

Wherein, Be the phasing degree, B is biasing, T ₀Be step-length.

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