Mohamad Noh Ahmad

Development of a Two-Wheeled Inverted Pendulum Mobile Robot

The research on two-wheeled inverted pendulum (T-WIP) mobile robots or commonly known as balancing robots have gained momentum over the last decade in a number of robotic laboratories around the world. This paper describes the hardware design of such a robot. The objective of the design is to develop a T-WIP mobile robot to be used as flexible platform comprises of embedded unstable linear plant intended for research and teaching purposes. Issues such as selection of actuators and sensors, signal processing units, modeling and control scheme was addressed and discussed. The system is then tested using a well-known pole-placement state feedback controller to verify its functionality.

Controller Design for Two-wheels Inverted Pendulum Mobile Robot Using PISMC

The research on two-wheel inverted pendulum or commonly call balancing robot has gained momentum over the last decade in a number of robotic laboratories around the world. This paper deals with the modeling of 2-wheels Inverted Pendulum and the design of proportional integral sliding mode control (PISMC) for the system. The mathematical model of 2-wheels inverted pendulum system which is highly nonlinear is derived. The final model is then represented in state-space form and the system suffers from mismatched condition. A robust controller based on sliding mode control is proposed to perform the robust stabilization and disturbance rejection of the system. A computer simulation study is carried out to access the performance of the proposed control law.

Sliding Mode Control with Linear Quadratic Hyperplane Design: An application to an Active Magnetic Bearing System

This paper deals with modeling and control of a nonlinear horizontal active magnetic bearing (AMB) system via current control scheme. The gyroscopic effect and mass imbalance inherited in the system are proportional to the rotor speed in which these nonlinearities cause high system instability as the rotational speed increases. In order to synthesize a robust controller that can stabilize the system under a wide range of rotational speed, the dynamic AMB model is transformed into a deterministic model to form a class of uncertain system. Then, based on Sliding Mode Control (SMC) theory and Lyapunov method, a new robust controller that stabilizes the system is proposed wherein the Linear Quadratic Regulator (LQR) is used to design the sliding surface. Under this control, the reaching condition is guaranteed and the closed loop system is stable. The performance of the controller applied to the AMB model is demonstrated through simulation works under various rotational speeds and system conditions.

Control of uncertain nonlinear systems using mixed nonlinear damping function and backstepping techniques

This paper depicts the design of control law to stabilize nonlinear system with mixed match-mismatch uncertainties with bounded disturbance. The design approach exploit the advantages and flexibility of backstepping technique. To compensate for the uncertainties and bounded disturbance, nonlinear damping function is augmented to the pre-designed unperturbed stabilizing function. Throughout the design, Youngs inequality and comparing squares method is used to avoid elimination of useful nonlinear terms as well as to obtain feasible control law.

Robust sliding mode control for robot manipulator tracking problem using a proportional-integral switching surface

This paper presents the development of a proportional-integral sliding mode controller for tracking problem of robot manipulators. A robust sliding mode controller is derived so that the actual trajectory tracks the desired trajectory as closely as possible despite the highly non-linear and coupled dynamics. The proportional-integral sliding mode is chosen to ensure the stability of the overall dynamics during the entire period i.e. the reaching phase and the sliding phase. Application to a two-link planar robot manipulator is presented.

Proportional-Integral sliding mode tracking controller with application to a robot manipulator

This paper presents the development of a Proportional-Integral sliding mode controller to control a class of uncertain systems. It is assumed that the plant to be controlled can be represented by its nominal and bounded parametric uncertainties. A robust sliding mode controller is newly derived so that the actual trajectory tracks the desired trajectory as closely as possible despite the non-linearities and input couplings present in the system. The Proportional-Integral sliding mode is chosen to ensure the stability of overall dynamics during the entire period i.e. the reaching phase and the sliding phase. The controller is applied to the control of a two-link planar robot manipulator.

A PI sliding mode tracking controller with application to a 3 DOF direct-drive robot manipulator

This paper deals with the tracking control of direct-drive (DD) robot manipulators. A robust proportional-integral (PI) sliding mode control law is derived for accurate tracking despite the highly nonlinear and coupled dynamics. It is shown mathematically that the proposed controller is capable of withstanding the expected variations and uncertainties present in the system. The performance of the proposed control law is evaluated by means of computer simulation studies on a 3 DOF revolute DD robot manipulator actuated with BLDCM motors.

Static sliding mode controller for permanent magnet stepper motor with disturbances

This paper addresses the design of sliding mode controller for permanent magnet stepper motor. The control scheme has been proposed since stepper motor has a poor response in open-loop operation, highly nonlinear plant and load torque perturbation and parameter uncertainties are also a common occurrence. The controller is designed based on differentially flat properties of stepper motor. The simulation is performed by applying various types of disturbance and parameter uncertainties conditions to evaluate the performance and the robustness of the controller.

Proportional Integral Sliding Mode Control of Hydraulic Robot Manipulators with Chattering Elimination

This paper is concerned with the application of a robust control approach based on sliding mode control (SMC) strategy with proportional integral switching surface in controlling the position trajectory of a hydraulic manipulator. This paper also addresses the suppression technique for the undesirable chattering phenomenon which usually occurs in SMC by replacing the discontinuous controller sign function with a proper continuous function. Chattering is unwanted because it leads to an excessive usage and damages the actuators and therefore the control law may become impractical. In this study, an integrated model of hydraulically actuated robot that considers both the manipulator linkage and actuator dynamics is used to provide a more suitable model for controller synthesis and analysis. The control technique is stable in the large based on Lyapunov theory. Its performance is evaluated and compared with the existing independent joint linear control (IJC) technique through computer simulation. The results prove that the controller has successfully force the robot manipulator to track the desired position trajectory for all times and has better performance than IJC

Variable Speed Wind Turbine with External Stiffness and Rotor Deviation Observer

Often in prominent literature, the appearance of external stiffness in wind turbine dynamical model has been neglected. The ignorance of external stiffness eliminates the presence of rotor-side angular deviation in the system dynamic. In order to give more practical look of the variable speed control system structure, we develop a linear observer to estimate the rotor angular deviation. We use Linear Quadratic Regulator (LQR) to design the observer gain, as well as the estimation error gain. To facilitate observer design, the system is linearized around its origin by using Jacobian matrix. By using the estimated rotor angular deviation, we design a variable speed control via Lyapunov and Arstein to enhance power output from the turbine.