Sliding mode controller applied to coupled inductor dual boost inverter

A coupled inductor-dual boost-inverter (CIDBI) with differential structure has been presented to be applied to micro-inverter photovoltaic module system because of its turn ratio of high-voltage level. However, it is hard for CIDBI converter with conventional PI regulator to be designed stable and achieve good dynamic performance, given the fact that it is a high order system. In view of this situation, a sliding mode control (SMC) strategy is introduced in this paper, and two different sliding mode controllers (SMCs) are proposed and adopted in the left and right side of the two Boost sub-circuits respectively to implement corresponding regulation of voltage and current. The schemes of the SMCs have been elaborated in this paper including the establishment of the system variable structure model, the selection of the sliding surface, the determination of the control law, and the presentation of the reaching conditions and sliding domain. Finally, the mathematic analysis and the proposed SMC are verified by the experimental results

Robust position control of ultrasonic motor using VSS observer

Intrinsic properties of ultrasonic motor (high torque for low speed, high static torque, compact in size, etc.) offer great advantages for industrial applications. However, when load torque is applied, dead-zone occurs in control input. Therefore, sliding mode controller, which is a nonlinear controller, is adopted for ultrasonic motor. The state quantities, such as acceleration, speed, and position are needed to apply the sliding mode controller for position control. However, rotary encoder causes quantization errors in the speed information. This paper presents a robust position control method for ultrasonic motor by using Variable Structure System(VSS) observer. The state variables for sliding mode controller are estimated by the VSS observer. Besides, a small, low cost, and good response sliding mode controller is designed in this paper by using a micro computer that is essential in embedded system for the developments of industrial equipments. The effectiveness of the proposed method is verified by experimental results

Design stable robust intelligent nonlinear controller for 6- DOF serial links robot manipulator

In this research parallel Proportional-Derivative (PD) fuzzy logic theory plus Integral part (I) is used to compensate the system dynamic uncertainty controller according to highly nonlinear control theory sliding mode controller. Sliding mode controller (SMC) is an important considerable robust nonlinear controller. In presence of uncertainties, this controller is used to control of highly nonlinear systems especially for multi degrees of freedom (DOF) serial links robot manipulator. In opposition, sliding mode controller is an effective controller but chattering phenomenon and nonlinear equivalent dynamic formulation in uncertain dynamic parameters are two significant drawbacks. To reduce these challenges, new stable intelligent controller is introduce

Adaptive Sliding Mode Control of Chaos in Permanent Magnet Synchronous Motor via Fuzzy Neural Networks

In this paper, based on fuzzy neural networks, we develop an adaptive sliding mode controller for chaos suppression and tracking control in a chaotic permanent magnet synchronous motor (PMSM) drive system. The proposed controller consists of two parts. The first is an adaptive sliding mode controller which employs a fuzzy neural network to estimate the unknown nonlinear models for constructing the sliding mode controller. The second is a compensational controller which adaptively compensates estimation errors. For stability analysis, the Lyapunov synthesis approach is used to ensure the stability of controlled systems. Finally, simulation results are provided to verify the validity and superiority of the proposed method

A Discrete-Time Sliding Mode Controller for the Fermentation Process

This paper proposes a discrete-time sliding mode controller for the fermentation process, which is adequately approximated by the first-order plus dead time model. The contribution of the paper is an investigation into the suitable approximation of the time delay for discrete-time sliding mode controller. The dead time is considered in two ways by the first-order Taylor series approximation and the first-order Pade approximation. In the first case, the discrete-time sliding mode controller is based on the integral compensation of an output error, and in the second case, the stable system centre method is used. Numerical simulation examples of the yeast fermentation process are given to show the effectiveness of these two methods

Scaled bilateral teleoperation using discrete-time sliding mode controller

In this paper, the design of a discrete-time slidingmode controller based on Lyapunov theory is presented along with a robust disturbance observer and is applied to a piezostage for high-precision motion. A linear model of a piezostage was used with nominal parameters to compensate the disturbance acting on the system in order to achieve nanometer accuracy. The effectiveness of the controller and disturbance observer is validated in terms of closed-loop position performance for nanometer references. The control structure has been applied to a scaled bilateral structure for the custom-built telemicromanipulation setup. A piezoresistive atomic force microscope cantilever with a built-in Wheatstone bridge is utilized to achieve the nanonewtonlevel interaction forces between the piezoresistive probe tip and the environment. Experimental results are provided for the nanonewton-range force sensing, and good agreement between the experimental data and the theoretical estimates has been demonstrated. Force/position tracking and transparency between the master and the slave has been clearly demonstrated after necessary scalin

Terminal Sliding Mode Control of Mobile Wheeled Inverted Pendulum System with Nonlinear Disturbance Observer

A terminal sliding mode controller with nonlinear disturbance observer is investigated to control mobile wheeled inverted pendulum system. In order to eliminate the main drawback of the sliding mode control, “chattering” phenomenon, and for compensation of the model uncertainties and external disturbance, we designed a nonlinear disturbance observer of the mobile wheeled inverted pendulum system. Based on the nonlinear disturbance observer, a terminal sliding mode controller is also proposed. The stability of the closed-loop mobile wheeled inverted pendulum system is proved by Lyapunov theorem. Simulation results show that the terminal sliding mode controller with nonlinear disturbance observer can eliminate the “chattering” phenomenon, improve the control precision, and suppress the effects of external disturbance and model uncertainties effectively

Experimental robustness study of a second-order sliding mode controller

The design of a Second-Order Sliding Mode Controller is discussed and guidelines are given for tuning. The robustness to unmodeled dynamics and parameter-errors is investigated and tested in an experimental case study. The experimental results, as far as robustness to unmodeled dynamics is concerned, are not better than for a traditional PD-controller. When robustness to parameter-errors is concerned the Second-Order Sliding Mode Controller performs slightly better

Sliding mode control of an unmanned air-vehicle system

The objective of this study is to design a Controller that is stable under varying conditions of system parameters from the trim conditions and also robust for parametric variation for an Unmanned Air Vehicle (UAV) System. The PID and Sliding Mode Controller are the control models for the UAV system that are studied, designed and analyzed. The proposed Sliding Mode Controller was applied to a nonlinear second order system (Single Input Single Output (SISO)) and tested for stability and robustness of the system for parametric variation. The control model indicated chattering effect with switching (signum) function. Therefore, in order to negate this chattering effect Saturation and ATAN functions were proposed for the control input. It was observed that the modified system demonstrated robustness in presence of parameter uncertainties such as inertial mass, stiffness, damping, input gain and nonlinear gain. The same model is tested with a PID Controller and observed that the controller is stable but the tracking error is 10 times more than the sliding mode controller, this is due to inability of the linear PID controller to control nonlinear systems. The sliding mode controller was then extended to control a Single Input Two Output system for parametric variation. It was observed that the controller was able to stabilize the system and make the system robust. Then, Sliding Mode Controller based on Switching theory and Lyapunov\u27s theory was designed for Unmanned Air Vehicle System under uncertainty conditions. Stable sliding mode and robust asymptotic stability in uncertain UAV systems were investigated for variation in Velocity and Angle of Attack parameters. Finally, simulation results are presented to show the effectiveness of the design method

Investigation on the development of a sliding mode controller for constant power loads in microgrids

Abstract: To implement renewable energy resources, microgrid systems have been adopted and developed into the technology of choice to assure mass electrification in the next decade. Microgrid systems have a number of advantages over conventional utility grid systems, however, they face severe instability issues due to the continually increasing constant power loads. To improve the stability of the entire system, the load side compensation technique is chosen because of its robustness and cost effectiveness. In this particular occasion, a sliding mode controller is developed for a microgrid system in the presence of constant power loads to assure a certain control objective of keeping the output voltage constant at 480 V. After that, a robustness analysis of the sliding mode controller against parametric uncertainties was performed and the sliding mode controller’s robustness against parametric uncertainties, frequency variations, and additive white Gaussian noise (AWGN) are presented. Later, the performance of the proportional integral derivative (PID) and sliding mode controller are compared in the case of nonlinearity, parameter uncertainties, and noise rejection to justify the selection of the sliding mode controller over the PID controller. All the necessary calculations are reckoned mathematically and results are verified in a virtual platform such as MATLAB/Simulink with a positive outcome