There have been many algorithms proposed for adaptivecontrol which will provide globally asymptotically stable controllers if some stringent conditions on the plant are met. The conditions on the plant cannot be met ...
详细信息
There have been many algorithms proposed for adaptivecontrol which will provide globally asymptotically stable controllers if some stringent conditions on the plant are met. The conditions on the plant cannot be met in practice as all plants will contain high frequency unmodeled dynamics. This paper uses a linearization analysis of a nonlinear adaptivecontroller to demonstrate analytically some design guidelines which alleviate some of the problems associated with adaptivecontrol in the presence of unmodeled dynamics. The points made are further demonstrated by simulation results.
The use of discontinuous control in adaptivemodel-following continuous control systems with nonlinear time-varying plant is described. The first approach is based on the theory of variable structure systems. Hypersta...
详细信息
The use of discontinuous control in adaptivemodel-following continuous control systems with nonlinear time-varying plant is described. The first approach is based on the theory of variable structure systems. Hyperstability theory is the basis of the second scheme; the third one results by combining the previous approaches. The link among the three approaches is explored by studying the error dynamics. Practical implementation and applications are discussed.
The stability and robustness properties of adaptivecontrol systems are examined using input-output stability theory, i.e. passivity and small-gain theory. A generic adaptive error system is developed based on the con...
详细信息
The stability and robustness properties of adaptivecontrol systems are examined using input-output stability theory, i.e. passivity and small-gain theory. A generic adaptive error system is developed based on the concept of a tuned system—an ideal converged (nonadaptive) closed-loop system. Using this error system with passivity theory gives conditions for global stability where only boundedness (in norm) is required on the external inputs, e.g. disturbance, reference and initial conditions. Small gain theory is used to develop local stability results where the magnitudes of the external inputs are restricted. In the global case, a particular system operator (not the plant) is required to be strictly-passive, a condition which is unlikely to hold in actual use due to unmodeled dynamics. The local results, however, are not so restricted and allow for unmodeled dynamics. In this latter case an estimate of the stability margin is given under a persistent excitation condition.
A new scheme for designing model reference adaptive control systems using only input and output measurements is presented. With the proposed scheme, the requirement on the commonly assumed a priori knowledge of (i) th...
详细信息
A new differentiator-free Lyapunov MRAC scheme with a new error model is suggested. It does not require (2n or 4n) additional filters and generation of auxiliary signals, even when the plant relative degree n * ≧ 2; ...
详细信息
A new differentiator-free Lyapunov MRAC scheme with a new error model is suggested. It does not require (2n or 4n) additional filters and generation of auxiliary signals, even when the plant relative degree n * ≧ 2; instead, it uses positive feedback in an inner loop. Employing a “filtered error” equation and a new Lyapunov function, stable ‘P+I’ form adaptive laws are derived. It does not emplov KY lemma and does not require any transfer function to be positive real. Flexibilities of the scheme in using other forms of laws, in choosing a referencemodel with or without zeros, and in improving speed of error convergence are indicated. Comparative examples with simulation results are presented.
This paper discusses a model reference adaptive control for a multi-input multi-output continuous system in matrix fraction description. The controller is of Monopoli-Narendra type with a time-varying gain matrix in t...
详细信息
This paper discusses a model reference adaptive control for a multi-input multi-output continuous system in matrix fraction description. The controller is of Monopoli-Narendra type with a time-varying gain matrix in the parameter adaptation law. The transfer matrix of the given plant with an adjustable controller is made to approach to that of the referencemodel asymptotically. It is shown that, under some plausible assumptions such as on the knowledge of an interactor matrix, the algorithm for a single-input single-output system can be appropriately extended to a multi-input multi-output system. The convergence of an adaptation law is proved with some stability theory and the stability of the overall system is asserted by an analytical investigation.
Dynamic behaviours of driver-car systems in critical road situations are investigated for the purpose of traffic safety. The characteristics of car dynamics change suddenly when a car runs on from dry to wet surface o...
详细信息
Dynamic behaviours of driver-car systems in critical road situations are investigated for the purpose of traffic safety. The characteristics of car dynamics change suddenly when a car runs on from dry to wet surface of road. Moreover when running on curve, un-balanced lateral force and moment are added to the system. According to an experiment using a driving simulator, adaptive behaviours of driver-car systems are found in this critical situation. In order to explain the adaptive behaviours, a new mathematical model of human driver is developed by use of the theory of model reference adaptive control and predictive control. The computer simulation with this model is carried out, where a compensation gain of driver is change-able, depending on changes of car parameters. It is verified that the model proposed here is good enough to take account of the dynamical behaviours of driver-car system in the critical situation when confronting suddenly appearing wet surface on curve.
A model following type of adaptivecontrol scheme for the control of excitation of a synchronous generator is described. The ability of the generator to follow a model of reduced order is tested. It is shown that the ...
详细信息
A model following type of adaptivecontrol scheme for the control of excitation of a synchronous generator is described. The ability of the generator to follow a model of reduced order is tested. It is shown that the controlled system response is relatively unaffected by plant parameter variations.
Two adaptivecontrol techniques are evaluated by application to a realistic mathematical model of a suspension PVC reactor. Both techniques, the hyperstable direct modelreferenceadaptive technique and the self-tunin...
详细信息
Two adaptivecontrol techniques are evaluated by application to a realistic mathematical model of a suspension PVC reactor. Both techniques, the hyperstable direct modelreferenceadaptive technique and the self-tuning regulator, prove to be very robust and give excellent control of the rate of conversion in the PVC reactor by controlling the cooling water flowrate into the reactor. Satisfactory regulation of the conversion rate and the reactor temperature is obtained even in the presence of step disturbances in the cooling water flowrate temperature and changing heat transfer coefficient. In the case of reactor operation under isothermal conditions, setpoint tracking of step changes in reactor temperature was evaluated and found to be very satisfactory.
A digital computer simulation study is presented for a class of discrete modelreferenceadaptive systems designed using Lyapunov’s direct method. Plant output measurements are assumed to contain uniformly distribute...
详细信息
A digital computer simulation study is presented for a class of discrete modelreferenceadaptive systems designed using Lyapunov’s direct method. Plant output measurements are assumed to contain uniformly distributed additive noise. It is shown that the design works well even when such noise is relatively extreme. A new result is presented pertaining to improving the convergence properties of these systems. This result is obtained by modifying the dynamic characteristics of the augmented error equation.
暂无评论