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This paper describes a new approach to estimate speed of the induction machine from measured terminal voltages and currents. In this approach, the speed is assumed to be unknown constants, because it changes slowly compared to electrical variables such as currents and fluxes. Based on this assumption, a state observer is defined to eliminate the flux information of the machine. Then, a Lyapunov function and a new candidate expression for the time derivative of Lyapunov function that guaranties the stability conditions of the system dynamics are developed from which the speed of the machine is derived. The proposed system is analyzed and verified by both simulation and experiment. [ABSTRACT FROM AUTHOR]

A chattering-free sliding mode controller (CFSMC) is proposed to realize level position control of liquid level system for two coupled water tanks, as is often encountered in practical process control. The controller is used due to its robustness against large parameter variation, disturbances rejection and reduction in chattering. Experimentation of the coupled tank system is realized in two different configurations: configuration 1 and configuration 2. In configuration 1, the water level in the top tank is controlled by a pump. In 2, the water level in the bottom tank is controlled by the water flow coming out of the top tank. The validity of the proposed controller is verified by means of a practical testing on an experimental liquid level control device. [ABSTRACT FROM AUTHOR]

In this paper, sliding mode control (SMC) of a bioreactor is considered and is compared with PID control. The magnitude of the error in SMC is found to be lower than that in PID control. Moreover, the magnitudes of cells and nutrients were very close to the selected reference values in SMC, whereas they were quite different in PID control. Overall, SMC was more robust against disturbances and had better performance than PID control. [ABSTRACT FROM AUTHOR]