In this paper one solution for control of electromechanical linear drive with timing-belt, in the SMC framework is presented. In such a system the elasticity of the timing-belt along with large friction forces represent a major nonlinearity causing wide change of the system parameters and the oscillation of the load. Proposed solution is based on introduction of sliding mode motion and selection of the controller structure based on the predefined structure of the time derivative of Liapunov function candidate. By selecting appropriate form of the Liapunov function time derivative the resulting control is continuous and chattering is minimized. The simulation and experimental results are presented showing that the proposed design can satisfy technical requirements of the system.

A structure of the induction machine flux and speed observer is proposed. The observer is designed in the stationary frame of references to avoid errors affiliated with the coordinate transformations. In order to ensure the convergence in any operational conditions a nonlinear additional term is added to the observer structure. Full stability analysis based on the Lyapunov stability method is derived. The results are confirmed by the simulation results.

Abstract Induction motor speed sensorless torque control, which allows operation at low and zero speed, optimizing both torque response and efficiency, is proposed. The control is quite different than the conventional field-oriented or direct torque control. The produced torque is explicitly continuous output variable of control. A new stator and rotor flux controller/observer based on continuous sliding mode and Lyapunov theory are developed. A smooth transition into the field weakening region and the full utilization of the inverter current and voltage capability are possible. The reference tracking performance of torque and rotor flux is demonstrated in terms of transient characteristics by experimental results.

Abstract A novel approach to the speed sensorless torque and flux tracking sliding mode control of induction motor is presented in the paper. The main contribution of the paper is a new structure of induction machine rotor flux observer aimed for the sensorless operation. Proposed approach addresses the problem sensorless induction machine servo-drive at both, low and high speed, where rapid speed changes can occur. The idea is realized by introducing an non-linear stator frequency dependant gain in the rotor flux observer and thus enabling the operation at low and high speeds. The adaptation algorithm for stator resistance is included. Observer is robust to the parameter uncertainties, especially to rotor resistance. The performance is investigated and verified with simulations and experiments.

A new simple sliding mode controller for the motion control systems is proposed to avoid the problems related to chattering. The proposed control is based on the time delay estimation used in the time-delay-control (TDC) method. By introducing the concept of time delay estimation into the sliding mode control, the difficulty of the stability analysis of TDC may be resolved. It has been shown that the switching component of the proposed control is not determined by the magnitude of the system's uncertainty but by its change during specified time delay. That leads to much smaller magnitude of the switching component in comparison with other sliding mode controllers. For the proposed control scheme the sliding mode reaching and existence conditions for a class of systems like a robotic manipulator are presented. The experimental examples are shown to confirm the validity of the proposed controller.

Novel induction motor control optimizing both torque response and efficiency is proposed, The control is quite different than the conventional field-oriented control. First, the produced torque is explicitly continuous output variable of control plant. Second, a new rotor flux observer, which allows speed sensorless operation of induction motor (IM) by low and zero speed, was developed. Control is executed in a,b-coordinates (stator frame) and transformation is performed only with the use of observed transformation angle of rotor flux. The proposed approach addresses the problems of torque and flux control without the measurement of the speed of the motor, i.e. speed sensorless drive. Such a control strategy differs from the conventional field oriented control approach. The torque and the stator and rotor flux are controlled instead of the components of stator current i/sub sd/ and i/sub sq/. A new stator and rotor flux observer based on sliding mode control and Lyapunov theory are developed. The output of the closed-loop rotor flux determines the magnitude and orientation angle of the field orientation of induction motor. Simulations and experimental tests on a 1.5 kW motor drive are provided to evaluate the consistency and the performance of the proposed control technique.

In this paper a direct flux and torque control scheme for electric vehicle (EV) induction motor (IM) drive is presented. The control algorithm utilizes the stator flux as the control variable and the flux level is selected in accordance with the torque demand of EVs to achieve the efficiency optimized drive performance. The proposed scheme allows a smooth transition into the field weakening region and the full utilization of the inverter current capability during acceleration or regenerative braking of EV. The drive system, including an 18 kW 4 pole 6000 RPM 120 V battery powered IM and a 30 kVA IGBT inverter, has been applied to a pick up truck. The road test on the truck verified that the proposed control strategy is practical.

This paper deals with basic concepts, design aspects and application to power electronics and motion control systems of sliding mode control (SMC) systems. The salient features of the variable structure systems (VSS) with sliding modes are order reduction, decoupling design procedure, insensitivity in plant parameter changes and disturbances rejection. Simple implementation makes concepts of sliding mode control very attractive in power electronics and motion control systems.

The robustness property of sliding-mode controllers (SMCs) makes them attractive for industrial control applications. However, this property is valid only under ideal sliding-mode conditions. Additionally, practical SMCs are likely to exhibit high-frequency oscillations in the plant output, called chattering, and to excite unmodeled dynamics. A novel, chattering-free sliding-mode control algorithm design, based on Lyapunov stability criteria, is considered in this paper. The control algorithm developed is experimentally implemented on a direct-drive manipulator for various payload configurations. It is seen that the controller carries a certain amount of robustness property, the trajectory-following performance being only slightly affected by the changes in the payload. A comparison of the experimental results with those obtained by a well-tuned proportional-derivative control is also given.

A sliding mode based controller is designed to achieve the end-point tracking of a flexible arm, with minimum transient and steady-state error. The information on deflection is derived through a sliding mode observer, providing data on the variables, q/sub 1/ and q/sub 2/ and their derivatives. The sliding mode technique utilized both for the observer and the controller provides robustness against the nonlinearities and uncertainties of the system. The obtained simulation results demonstrate the fulfilment of the performance goals and thus, motivate the implementation of the method on a DSP-based flexible arm test-bed.

Trajectory control of robotics manipulators is considered. Due to the coupled and nonlinear dynamics, robot control is a challenging problem. The effects of the complicated dynamics are more significant when the payload is large and time varying. Variable structure control methodologies are proposed in the literature to solve the problems encountered. High frequency oscillations in the joint velocities-chattering-may occur if discontinuities are introduced in the control input artificially to generate a sliding mode. A chattering free sliding mode control algorithm design is considered in this paper. Variable structure systems and Lyapunov designs are combined in the algorithm implemented. The controller possesses robustness properties of sliding mode systems. Experiments are carried out on a direct drive SCARA type manipulator for various payload configurations. A comparison of the results obtained with the chattering free sliding mode controller and a well tuned conventional PD control scheme is presented.

This study is about the chattering-free sliding mode based control of a single link flexible arm with a mass at the end-point. The model for this system is obtained using Lagrange's method and the control is developed aiming the angular position of the hub unit to follow a desired trajectory, while the strain is forced to be zero. Experimental results obtained on a DSP32 based single link arm system with and without control on the strain, demonstrate the improved performance caused by the strain control in terms of the transient and steady state and robustness.