Rafidah Ngadengon

Stabilization of Inverted Pendulum: A Multirate Output Feedback Based Discrete Time Sliding Mode Control

This paper presents the application of multirate output feedback with discrete time sliding mode control (SMC) for controlling the inverted pendulum system. The SMC are well known as completely insensitive to parameter variations and external disturbance. Normally, in order to design controller, the state feedback from the entire state variable is utilized. However not all of the state feedbacks are always available. Therefore, the concept of the multirate output feedback (MROF) in which the output state that are always available at any situation is proposed. The nominal plant model for inverted pendulum system is fourth order with additional of external disturbance. Simulation results verify the proposed controller’s performance even though nonlinearity present in the inverted pendulum system.

Controller design for inverted pendulum system using discrete sliding mode control

This paper presents discrete sliding mode control (DSMC) for nonlinear model of an inverted pendulum system. The reaching law method is used during the DSMC design. The uncertainties are structured in that system by considering the existence of an error during the pendulum angle measurement. The designed controller is compared with Linear Quadratic Regulator (LQR) controller to observe the capability for controlling the highly nonlinear system of the inverted pendulum. The performance and reliability of the proposed algorithm are determined by performing extensive simulation works using MATLAB/Simulink platform. The result shows that DSMC can produce better response as compared to LQR control strategy.

Multirate output feedback based discrete integral sliding mode control for system with uncertainties

This paper presents the design approach of Multirate Output Feedback (MROF) based Discrete Integral Sliding Mode Control (DISMC) for system with uncertainties. Firstly, the state representing the MROF has to be identified. The discrete integral sliding surface were selected in order to design the controller. The MROF that used output feedback with two different sampling times which are slow and fast rate is then combined with the DISMC to control the uncertain system. The reachability condition and stability are also considered and presented. Through extensive computer simulation, it shows that the proposed controller’s capable to track the reference input even though uncertainties present in the system. The findings demonstrated that the MROF based DISMC provided better system response as compared to the Discrete Linear Quadratic Regulator (DLQR) and discrete Proportional Integral Derivative (PID).

Head Pose Estimation from Undistorted Wide Field of View (WFoV) Kinect for Socially Acceptable Wheelchair

Socially acceptable wheelchairs require information about human location and pose to generate a motion that is safe and comfortable to the people around. A WFoV Kinect camera is one of the prominent sensors to obtain such information from a wide coverage of distant targets. However, the task is challenging since the expanded RGB and depth images suffers from distortion, and the head detection were far less than perfect. In this paper, we propose an empirical framework that can alleviate the mentioned problem using laser assisted undistortion strategy and depth based segmentation procedure. Initially, Kinect RGB and depth images are corrected using an inverse radial distortion model. Next, the depth data is rectified using a neural network filter based on laser-assisted training. Following that, possible human regions are validated by employing geometrical depth features. The verified depth regions are further processed in its corresponding RGB location, to determine plausible head regions using Haar-like features with the Adaboost classifier. Finally, the obtained head regions are fed to the pose estimation stage that constructed using boosted-based particle filter. Experimental results demonstrate the feasibility of the proposed approach.

Discrete Integral Sliding Mode Control for Motion Servo System

This paper presents a discrete integral sliding mode control (DISMC) to control motion servo system. In DISMC, the order of the motion equation is equal to the order of original system. The past value of the disturbance is taken as the estimate of its present value. The controller is designed to be capable to achieve tracking even for the uncertain system. The designed controller will be compared with Linear Quadratic Regulator (LQR) and discrete Proportional Integral derivative (PID) controller to observe the capability for controlling the system. Simulations demonstrate that the DISMC is highly robust to control although exist uncertainties in the system.