Robust Tracking Control System Research Articles

Robust Control for Non-Minimum Phase Systems with Actuator Faults: Application to Aircraft Longitudinal Flight Control

This study is concerned with developing a robust tracking control system that merges the optimal control theory with fractional-order-based control and the heuristic optimization algorithms into a single framework for the non-minimum phase pitch angle dynamics of Boeing 747 aircraft. The main control objective is to deal with the non-minimum phase nature of the aircraft pitching-up action, which is used to increase the altitude. The fractional-order integral controller (FIC) is implemented in the control loop as a pre-compensator to compensate for the non-minimum phase effect. Then, the linear quadratic regulator (LQR) is introduced as an optimal feedback controller to this augmented model ensuring the minimum phase to create an efficient, robust, and stable closed-loop control system. The control problem is formulated in a single objective optimization framework and solved for an optimal feedback gain together with pre-compensator parameters according to an error index and heuristic optimization constraints. The fractional-order integral pre-compensator is replaced by a fractional-order derivative pre-compensator in the proposed structure for comparison in terms of handling the non-minimum phase limitations, the magnitude of gain, phase-margin, and time-response specifications. To further verify the effectiveness of the proposed approach, the LQR-FIC controller is compared with the pole placement controller as a full-state feedback controller that has been successfully applied to control aircraft dynamics in terms of time and frequency domains. The performance, robustness, and internal stability characteristics of the proposed control strategy are validated by simulation studies carried out for flight conditions of fault-free, 50%, and 80% losses of actuator effectiveness.

Analysis and Design of a Photovoltaic Tracker System

The movement of the earth leads to constant change in the intensity and the angle of solar irradiation. As a consequence, the cells of photovoltaic (PV) modules are only able to convert a fraction of the light energy from the sun into electric energy. A tracking system constantly adapts the angle of PV modules to face the sun, so that the irradiation angle and the light intensity remain constant and a maximum of electrical energy can be generated. This not only helps to exploit every minute of sunshine but also to make the best use of diffuse light all year round. The aim of this research is to design a robust tracking control system that will point the PV modules to the brightest point in the sky. This objective is achieved by the design of a specialized robust controller and application of the D-partitioning analysis method.

Robust nonlinear tracking control system design of an uncertain multivariable process driven by a distributed control system device

In this paper, by using a distributed control system (DCS) device, a robust tracking control system is proposed based on robust right coprime factorization for a heat exchanger actuated by a water level process with coupling effects and uncertainties. Firstly, nonlinear models of water level and temperature processes with coupling and uncertainties are given. Secondly, nonlinear feedback tracking control systems corresponding to a multi-input multi-output (MIMO) process are realized by using operator-based robust right coprime factorization. Meanwhile, stability of the control systems is guaranteed by using robust stability conditions compatible with the MIMO process including coupling effects, and to improve the output tracking performance, tracking controllers are designed. Finally, the effectiveness of the proposed design scheme is confirmed by simulation and experimental results.

Robust tracking control system design for a nonlinear IPMC using neural network-based sliding mode approach

In this paper, a robust nonlinear tracking control design for an ionic polymer metal composite (IPMC) with uncertainties is proposed by using neural network-based sliding mode approach. The IPMC, also called artificial muscle, is a novel smart polymer material, and many potential applications for low mass high displacement actuators in biomedical and robotic systems have been shown. In general, the IPMC has highly nonlinear property, and there exist uncertainties caused by identifying some physical parameters and approximate calculation in dynamic model. Moreover, the control input is subject to some constraints to ensure safety and longer service life of IPMC. As a result, for a nonlinear dynamic model with uncertainties and input constraints, an IPMC artificial muscles position tracking control system based on sliding mode control approach is presented, where, the improved exponential reaching law is used to design sliding mode controller, a saturation function is used in the sliding mode control law design to suppress chattering. The robust stability can be guaranteed. Moreover, in order to improve tracking performance, a quickly and precisely robust tracking system to the stabilised system is designed and the parameters of tracking controller are optimised by using neural network. Finally, the effectiveness of the proposed method is confirmed by simulation results.

Operator-based robust nonlinear control and fault detection for a Peltier actuated thermal process

In this paper, operator-based robust nonlinear control design scheme and fault detection technique using robust right coprime factorization approach are considered for a Peltier actuated thermal process. The Peltier actuated thermal process is a typical nonlinear control affine system, where the process temperature depends not only on input current, but also on the square of the input current. In addition, the real system is likely to contain a fault signal owing to various factors. As a result, it is difficult to stabilize the control system and to achieve high accurate control performance, and to detect the fault signal to guarantee the engineering safety when a fault occurs. In this paper, for pursuing robust stability and tracking performance of the nonlinear closed-loop control system, a design scheme of operator-based robust tracking control system is proposed by using robust right coprime factorization approach. Then, for the tracking operator control system, a fault detection design technique based on robust right coprime factorization approach is also investigated. Finally, simulation and experimental results are given to confirm the effectiveness of the proposed method.

Error Prediction Robust Tracking Control System Suppressing Harmonics Disturbance for Optical Disk Recording System

Recently, the memory capacity of media for the optical disk recording system has been increasing. The disk rotation speed has been increasing depending on the large memory capacity. However, the optical disk recording system has both periodic primary disturbance and periodic harmonics disturbance. Hence, the tracking control of the optical disk recording system is requested to maintain a high-precision tracking performance. We have proposed the robust tracking controller and zero-phase error tracking feed-forward control systems. Results of our study show that the primary disturbance is well suppressed by our conventional method, but it is difficult for our conventional method to suppress the harmonics disturbance. To overcome this problem, in this paper, we propose a new error prediction robust tracking control system suppressing harmonic disturbance. The experimental results show that the proposed tracking control system has a precise tracking response against both periodic primary disturbance and periodic harmonics disturbance.

高速光ディスク装置のための高性能エラー予測型ロバストトラッキング制御系

高速光ディスク装置のための高性能エラー予測型ロバストトラッキング制御系

High Speed Robust Tracking Servo System for an Optical Disk Recording System

This paper proposes a new high speed robust tracking control system based on both “Zero Phase Error Tracking” (ZPET) control system and robust servo system for an optical disk recording system. In the optical disk recording systems (for example CD-R), the tracking servo system must have the complete tracking response whose error is less than 0.1 [μm] for an amplitude of 100 [μm] of reference input signal. However, its detecting signal is only a tracking error. For this purpose, this paper proposes a new estimation method of the reference input signal by using only tracking error, and realizes the high speed robust tracking servo system with ZPET control. Moreover, this paper considers the saturation of controller output. The experimental and simulation results point out that the proposed system has a quick and precise tracking response.

マニピュレータのＰＤ型二重構造ロバスト追従制御 実システムによる実験

PD-Tyre Two-Stage Robust Tracking Control System for robot manipulators was proposed by Osuka et. al. in 1988. This controller has the following properties.(a) The desired trajectory can be specified.(b) The control accuracy can be specified.(c) The convergence characteristics of initial error can be specified.(d) The robustness to modelling errors and to measurement noises is ensured.(e) The structure of the controller is simple.In this paper, we applied the controller to DAIKIN Miniature Robot, and showed the effectiveness of the structure of Two-Stage Control Scheme with some experimental results. However, since the miniature robot has an undesirable property such as a magnitude of measurement noises in angular velocity is so big, we had to solve a few technical problems in order to design the controller for even such a special robot. Therefore, in the final part of this paper, we considered a way to overcome those problems.