Adaptive Iterative Learning Identification And Control For A Class Of Time-varying Systems

In practical engineering applications, there are many time-varying systems. Thephenomena of time-varying parameters are widely existed in robot control, process controland aerospace areas. Study on the identification and control for rapid time-varying systemsis one of hot points concerned by control researchers.In the dissertation, adaptive iterative learning identification (AILI) and adaptiveiterative learning control (AILC) based on model reference are studied for a class oftime-varying systems which are repeatable in a finite time interval. To the dynamic systemof a robotic manipulator with time-varying payload, two kinds of AILC law are proposedfor trajectory tracking. The main contents are concluded as follow:1) By the combination of model reference adaptive identification with AILC, theconcept of iterative learning identification for linear time-varying (LTV) systems isproposed for the first time. The identification problem is studied for a class of time-varyingsystems which is repeatable in a finite time interval. By introducing the parameter learninglaw along iterative horizon, time-varying parameters are identified pointwisly. It need notknow the structures of time-varying parameters, and does not require the parametersvarying slowly. So the shortcomings of the traditional adaptive identification applied intime-varying systems are overcome. For a class of first order and high order linearsystem with all parameters time-varying, two AILI algorithms with parameters updatedalong the iterative horizon pointwisely are given. For a class of time-varying systems withtime-invariant and time-varying unknown parameters, a combined AILI scheme isproposed. The convergence speed can be hurried up. With Lyapunov technique, theboundedness and convergence of the estimated parameters are proved. It is proved for thethree proposed AILI schemes that the tracking error can converge to zero uniformly withrespect to the finite time interval when the number of iteration tends to infinite. Theconditions that the estimated parameters converge to their actual values along the iterativehorizon pointwisely are discussed.2) For a class of first order and high order LTV systems with unknown time-varyinginertia parameters and unknown time-invariant high frequency gain, two combined modelreference AILC laws are presented. For the first order LTV systems with time-varyinginertia parameter and high frequency gain, a model reference AILC law with estimating theChange rate of high frequency gain is presented. Based upon Lyapunov technique, it is proved for the three proposed AILC schemes that the tracking error converge to zerouniformly with respect to the finite time interval when the number of iteration tends toinfinite.3) The dynamic model of a robotic manipulator with time-varying payload isderived and analyzed. The influence of the payload to the dynamic properties of themanipulator is disclosed. To the problem of trajectory tracking with high speed and highperformances, an AILC law is proposed for the robotic manipulator with time-varyingpayload. For the systems with some time-invariant and some time-varying unknownparameters, a combined AILC algorithm is given. Both of the approaches can be used totrack different desired trajectories, and their convergence is proved with Lyapunovtechnique. With both of the AILC schemes for the manipulator with time-varying payloadit can be ensured that the tracking error converges to zero uniformly with respect to thefinite time interval when the number of iteration tends to infinite.4 For the key project of Jiangsu Province——Development and Application ofIndustrial Robot (Convey Robot), the servo systems of the six freedoms joint styleconvey robot were designed. Debugging was completed for the overall system and thedesigned requirements were satisfied.5 According to the requirements of the convey robot with application in a pouringproduct line, the problem of trajectory tracking with high performance is investigated. Asimplified dynamic model of the three coupled joints for the convey robot withtime-varying payload is established. The proposed AILC laws are applied to the robotsystem. The feasibility of the schemes being applied in the pouring robot is verified bysimulation.