Nonlinear Servo Control Research Articles

Passivity based-control technique incorporating genetic algorithm for design of a free piston Stirling engine

In this paper, a novel design philosophy of free piston Stirling engines based on passivity based-control technique incorporating genetic algorithm is presented. First, the design problem of an FPSE is expressed as a physical nonlinear servo control system with unknown parameters. Accordingly, the desired motions of power piston and displacer (i.e. design objectives) are regarded as the reference trajectories of the control loop. Then, the unknown design parameters of the nonlinear control system including cross sectional-area of the displacer rod, mass and spring stiffness of the power piston and displacer, phase difference, hot gas temperature, and control coefficients are found using a GA along with an error-based objective function. Next, the estimated values of unknown parameters are used to simulate the control system performance. Subsequently, the simulated control system response is compared to the desired trajectories. It is found that the simulated displacements and velocities for both pistons as well as the corresponding limit cycles are close to the desired references of the control system. Finally, simulated performance of the FPSE is verified through experimental results. The outcomes of this research clearly reveal the effectiveness of the proposed nonlinear control-based design technique of the free piston Stirling engine (SUTECH-SR-1).

Robust nonlinear servo control for improved regulation of motor position - Withdrawn

Robust nonlinear servo control for improved regulation of motor position - Withdrawn on 27th November 2017

Design and nonlinear servo control of MEMS mirrors and their performance in a large port-count optical switch

In this paper, we demonstrate full closed-loop control of electrostatically actuated double-gimbaled MEMS mirrors and use them in an optical cross-connect. We show switching times of less than 10 ms and optical power stability of better than 0.2 dB. The mirrors, made from 10-/spl mu/m-thick single-crystal silicon and with a radius of 400-450 /spl mu/m, are able to tilt to 8/spl deg/ corresponding to 80% of touchdown angle. This is achieved using a nonlinear closed-loop control algorithm, which also results in a maximum actuation voltage of 85 V, and a pointing accuracy of less than 150 /spl mu/rad. This paper will describe the MEMS mirror and actuator design, modeling, servo design, and measurement results.

トロイダル型無段変速機のゲインスケジュール型非線形サーボ制御装置の設計

トロイダル型無段変速機のゲインスケジュール型非線形サーボ制御装置の設計

A Gain Scheduled Non-linear Servo Controller for a Toroidal Continuously Variable Transmission

A Gain Scheduled Non-linear Servo Controller for a Toroidal Continuously Variable Transmission

評価関数に基づく非線形サーボ制御器の設計とニューラルネットによる近似

評価関数に基づく非線形サーボ制御器の設計とニューラルネットによる近似

A robust neurocontroller incorporating a priori knowledge of plant dynamics

This paper presents a nonlinear controller design method that integrates linear optimal control techniques and nonlinear neural networks. The multilayered neural networks (MNN's) are incorporated into a model-based linear optimal controller (LOR) to add nonlinear effects on the LOR. The proposed controller can tolerate a wider range of uncertainties than the LOR alone, because the MNN can compensate nonlinear system uncertainties that are not considered in the LOR design. The control performance is improved by using a priori knowledge of the plant dynamics as the system equation and the corresponding LOR. Using the similar technique, a nonlinear servo controller is designed by combining the MNN-based controller and the linear optimal servo controller. Computer simulations are performed to show the applicability and the limitation of the new nonlinear controllers.

Chaos from PWM Electrohydraulic Servo

The phenomenon of CHAOS for discret models control systems is discussed. A PWM electrohidraulic servo Is studied. This nonlinear servo control has Its fixed point determined, it has its stability regions delimited as a function of its parameters. We use Marotto's theorem to show the sufficient conditions to exist CHAOS. We make use of a digital simulation with nonlinear programming techniques to show these conditions and to observe the dynamic behavior of the system. The main results are the possibilité of application of CHAOS theory to to discret models control systems, description of the behavior of such systems in unstable regions and the identification and prevision of CHAOS.