Kind Of Robust Controller Research Articles

LMI–based robust controller design approach in aircraft multidisciplinary design optimization problem

This article proposes a linear matrix inequality–based robust controller design approach to implement the synchronous design of aircraft control discipline and other disciplines, in which the variation in design parameters is treated as equivalent perturbations. Considering the complicated mapping relationships between the coefficient arrays of aircraft motion model and the aircraft design parameters, the robust controller designed is directly based on the variation in these coefficient arrays so conservative that the multidisciplinary design optimization problem would be too difficult to solve, or even if there is a solution, the robustness of design result is generally poor. Therefore, this article derives the uncertainty model of disciplinary design parameters based on response surface approximation, converts the design problem of the robust controller into a problem of solving a standard linear matrix inequality, and theoretically gives a less conservative design method of the robust controller which is based on the variation in design parameters. Furthermore, the concurrent subspace approach is applied to the multidisciplinary system with this kind of robust controller in the design loop. A multidisciplinary design optimization of a tailless aircraft as example is shown that control discipline can be synchronous optimal design with other discipline, especially this method will greatly reduce the calculated amount of multidisciplinary design optimization and make multidisciplinary design optimization results more robustness of flight performance.

Robust control for permanent magnet synchronous motors based on Hamiltonian function

Hamiltonian system theory is an important reflearch tool for nonlinear systems, and has been widely used in motor speed regulation and control during reflent years. Aiming at the chaotic phenomenon in permanent magnet synchronous motors, a design method of robust controller based on the Hamiltonian function is preflented for the chaotic systems. The dynamic model of permanent magnet synchronous motor is transformed into a model similar to the Lorenz chaotic equation, and the model is chaotic at certain parameters according to the Lyapunov exponent and the Lyapunov dimension calculated. Let the rotator speed of the motor track a set of values, an error equation is obtained accordingly. Because the error equation does not satisfy the standard form of Hamilton exactly, it can be transformed into the Hamiltonian system containing uncertain disturbance terms. While the uncertain disturbance terms as well as the load term are regarded as a total disturbance term to the system, a kind of robust controller is designed. The controller consists of two parts. One part is based on the method of interconnection and damping assignment, and can make the rotator speed track any value well; The other part is used as a disturbance compensator. Simulation result shows that the controller drives the permanent magnet synchronous motor out of the chaotic state rapidly and the rotator speed tracks the set of values well. It is proven that the controller is feasible and effective. The method mentioned in this paper extends the range of application of Hamiltonian function and has a certain advantage.

Position control of linear electromechanical actuator for spoiler system base on the inverse system method

A kind of robust control of linear electromechanical actuator (LEMA) spoiler system for thrust vector control (TVC) in a spacecraft was investigated. This paper presents an inverse system method (ISM) to achieve precise motion control for the LEMA spoiler system, which is based on a voice coil motor. The dynamic model of the LEMA spoiler system is established, and the inverse system of the LEMA spoiler is obtained. By linearization of the nonlinear LEMA spoiler system, the state feedback control is used to control the spoiler to follow the desired spoiler motion. A state variable observer is designed to estimate the unmeasurable state variables. Simulations and experimental setup are used to demonstrate the effectiveness of the proposed control method. The performance of proportional-integral-differential (PID) control is compared to the ISM control in simulation and ISM control is robust to large parameter variations of 50%. The experimental results show close agreement with the simulation results. The proposed method proved effective by achieving a transient time of 5.5 ms and system bandwidth of 20 Hz, so that ISM control method can more effectively handle the parameters’ perturbation, load disturbance, the variation of work temperature, and the LEMA's nonlinearity.

Robust stabilization of a class of singularly perturbed discrete bilinear systems

This paper presents two kinds of robust controllers for stabilizing singularly perturbed discrete bilinear systems. The first one is an /spl epsi/-dependent controller that stabilizes the closed-loop system for all /spl epsi//spl isin/(0, /spl epsi//sub 0/*), where /spl epsi//sub 0/* is the prespecified upper bound of the singular perturbation parameter. The second one is an /spl epsi/-independent controller, which is able to stabilize the system in the entire state space for all /spl epsi//spl isin/(0, /spl epsi/*), where /spl epsi/* is the exact upper /spl epsi/-bound. The /spl epsi/* can be calculated by the critical stability criterion once the robust controller is determined. An example is presented to illustrate the proposed schemes.

Robust controller design based on simplified triangular model

In this paper a simplified triangular model is suggested for approximating the impulse response of a stable system. The triangular model has only three parameters and is easy to identify. Both dead-beat controller and extended horizon predictive controller are redesigned based on this triangular model. Under simple conditions the robust stability and zero tracking error of the resulted closed-loop system are guaranteed. Simulations show that two kinds of robust controllers are effective and work well even with unknown piecewise-constant disturbances.