压电徽位移驱动器的高精度控制系统设计

论文设计了一种数字控制系统,对采用压电纤维复合材料(MFC)做传感器的压电微位移系统进行高精度控制.控制系统包括:一个8位单片机嵌入系统(HC908MR16),执行比倒和积分控制运算,使控制系统闭环工作;一个模数转换器(ADC)和一个倍增数模转换器(MDAC),实现高精度控制,使压电纤维微位移驱动器的输八输出特性线性化.实验表明:系统在0～900V控制电压范围内具有良好的线性输入输出特性.此外,论文考虑系统的稳定性,结合系统对细长梁结构形变的影响实验,分析研究了系统的微小误差及产生原因.     

An adaptive compensator for a vehicle driven by DC motors

A vehicle system driven by two independent DC motors is presented here, one of which is used for the right wheel and the other is used for the left wheel. An adaptive compensator using Takagi-Sugeno fuzzy systems is proposed to control the vehicle system. The compensator includes an adaptive model identifier and adaptive controller. An online method is used to adjust the parameters of the identifier model to match the behavior model of the vehicle system. Then, the parameters of the identifier model are employed in a standard parallel-distributed compensator to provide asymptotically stable equilibrium for the closed-loop vehicle drive system, in which the velocity and direction angle of the vehicle are controlled. Results demonstrate that the proposed controller structure is robust to load changes and follows different trajectories very well.     

Real-time output trajectory tracking neural sliding mode controller for induction motors

This paper deals with real-time discrete adaptive output trajectory tracking for induction motors in the presence of bounded disturbances. A recurrent high order neural network structure is used to design a nonlinear observer and based on this model, a discrete-time control law is derived, which combines discrete-time block control and sliding modes techniques. Applicability of the scheme is illustrated via experimental results in real-time for a three phase induction motor.     

利用Simocode-DP电机保护器实现马达的控制

马达作为现代工业生产的主要驱动设备,如何控制和保护它已成为企业运行维护管理的一个课题之一。本文介绍了一种化工生产中常用的西门子Simocode—DP电机保护器的主要保护功能及其相关设备特点,通过图例展示了其主要的参数设定及组态过程。     

Discrete-time command filtered adaptive fuzzy fault-tolerant control for induction motors with unknown load disturbances

In this paper, a command filtered fault-tolerant control (CFFTC) approach is investigated for induction motors (IMs) discrete-time system in the presence of actuator faults and unknown load disturbances. Firstly, the IMs system discrete-time model is obtained by Euler method. Then, the fuzzy logic systems (FLSs) is utilized to compensate for unknown actuator faults. Besides, introducing the error compensation mechanism into discrete-time systems via command filters, “complexity of computation” and noncausal problem can be conquered, and the filtering error is avoided concurrently. Finally, simulation results demonstrate the validity of the presented fault-tolerant method for IMs system.     

A real-time estimation and control scheme for induction motors based on sliding mode theory

In this paper a sliding mode position control for high-performance real-time applications of induction motors is developed. The design also incorporates a sliding mode rotor flux estimator in order to avoid the flux sensors. The proposed control scheme presents a low computational cost and therefore can be implemented easily in a real-time applications using a low cost Digital Signal Processor (DSP). The stability analysis of the observer and the controller, under parameter uncertainties and load torque disturbances, is provided using the Lyapunov stability theory. Finally simulated and experimental results show that the proposed controller with the proposed observer provides a good trajectory tracking and that this scheme is robust with respect to plant parameter variations and external load disturbances.     

A novel direct torque control method for brushless DC motors based on duty ratio control

Conventional direct torque control (DTC) suffers from large torque ripple and nonconstant switching frequency, which are caused by the hysteresis band amplitude and the motor speed. Many methods have been proposed to tackle these problems. However, these methods are usually complicated and parameter dependent. A novel DTC method for brushless DC motors based on duty ratio control is proposed to reduce torque ripple and maintain a constant switching frequency. During each switching period, an active voltage vector and a zero voltage vector are applied. A simple and effective method implemented to calculate the duty ratio relies only on the torque error, reducing the parameter dependence. The proposed method has the advantages of conventional DTC and effectively reduces torque ripple, which improves the performance of conventional DTC. Simulation and experimental results are given to confirm the method’s validity.     

Discrete-time adaptive fuzzy speed regulation control for induction motors with input saturation via command filtering

A discrete-time adaptive fuzzy control method is introduced to achieve the speed regulation for induction motors (IMs) with input saturation via command filtering in this paper. First, the continuous model of IMs drive system is transformed into discrete-time form by using Euler formula. Then, the fuzzy logic systems are used to approximate the unknown nonlinear functions in the discrete-time drive system. In addition, the command filtering control method is introduced to overcome the “explosion of complexity” problem in the design process of traditional backstepping method. It is verified that all the closed-loop signals are bounded and the outputs can track the given reference signals well. Finally, simulation results illustrate the validity of the discrete-time control method.     

Pulse-width-modulated speed control of d.c. motors

This paper deals with the analytical and experimental investigations of an open-loop pulse-width-modulated d.c. motor speed control system. The analysis is carried out by two different approaches, circuit approach and the lattice function approach. From the circuit approach, the relationship between the current-ripple-factor and the pulse width is obtained. The lattice function approach yields the relationship between pulse width and the speed variation. There is good correlation between the experimental and theoretical results.