Design of Linear Quadratic Error and Sliding Mode Control for Position Control of BLDC Motor with Nonlinear Load Torque in a Simulator Platform

• Main Author: Faswia Fahmi, Monika
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42092
• Institution: Institut Teknologi Bandung

The locomotive simulator platform is one of the research at Institut Teknologi Bandung which is used to user training, locomotive model testing and as a platform to simulate the real locomotive movement. Generally, simulator platform consists of visual simulation system and movement simulation system. The visual simulation system is used to simulate the environmental conditions visually to the user while the movement simulation system is used to simulate the sensation of real locomotive movement to the user. The simulator platform is designed to move in 4 motions (4DOF), such as pitch, roll, surge and sway. Pitch and surge motion are used to represent longitudinal acceleration while roll and sway motion are used to represent lateral acceleration. Four BLDC motor are installed in locomotive simulator as an actuator to drive the cabin. The output response of BLDC motor position is required to track the reference position so that the platform simulator move in the desired position. However based on the mechanical construction of simulator platform, the main problems that occurs is nonlinear load torque which disturb the BLDC motor drive system. Recently, using the PI internal control preinstalled in the ASDA-driver, nonlinear load torque disturbance causes the response of position BLDC motor have a steady state error of 4.49%. Therefore, it is necessary to develop an external control system to improve the performance of position BLDC motor due to the nonlinear load torque disturbance. In this study, as a first stage, Linear Quadratic Error (LQE) will be designed. This control system is used for linear system that obtained from the linearization process of nonlinear system at one operating point. From the simulation and implementation, this control system have a performance that does not satisfy the required platform simulator criteria because it has an overshoot of 4.51%. Thus, the Sliding Mode Control (SMC) control system is designed for nonlinear system at all operating points. This control system consists of two development scheme, such as SMC using the signum function and SMC using the saturation function to reduce chattering. The design process consists of modeling nominal plant, design of Linear Quadratic Error (LQE) and design of Sliding Mode Control (SMC). The modeling nominal plant devided into three step such as modeling for a linear part, for a nonlinear part and combine of both. The LQE design consist of three main steps, such as linearization of the nominal plant at one operating point, solve Algebra Riccati Equation (ARE) and optimal gain feedback design. While the SMC design consists of three main steps, such as reduction of nominal plant order, sliding surface design and control signal design. Based on the simulation and implementation, the SMC with saturation function has a smoother and not chattering response compared to the SMC with signum function, that is with an overshoot of 0.018%. But on the other hand the response time is slow such as settling time of 11.85 seconds and rise time of 8.22 seconds. From the comparison between the developed control system, it can be concluded that the SMC control system with saturation function is the best control system for satisfy the performance of platform simulator to overcome steady state error due to nonlinear load torque disturbance.