Phuc Thinh Doan

Adaptive Motion Controller Design for an Omnidirectional AGV Based on Laser Sensor

Automatic Guided Vehicles (AGVs) are used in many factories. This paper proposes an adaptive tracking controller of omnidirectional AGV (OAGV) with the constant unknown mass and the uncertain bounded friction and slip force vector exerted on the driving wheels. The OAGV consists of 3 wheels with three omnidirectional wheels are equally spaced 1200 from one another. The controller based on the dynamic modeling is designed based on Lyapunov stability theory to stabilize the OAGV to follow a sharp edge trajectory and OAGV doesn’t change heading direction during movement. A laser sensor device NAV200 is used to detect the OAGV position in door environment in real-time. The simulation and experiment results are presented to demonstrate the effectiveness of the proposed controller.

Trajectory tracking controller design for AGV using laser sensor based positioning system

This paper introduces a tracking controller for Automatic Guided Vehicles (AGV) to track a desired trajectory. The use of the nonlinear Lyapunov technique provides robustness for load disturbance and sensor noise. Based on kinematic model, a trajectory tracking controller of AGV is proposed. System stability is verified by Lyapunov stability. A laser sensor device NAV200 is used to detect the AGV position in door environment in real-time. For simulation and experiment, software and hardware are described. The AGV consists of 4 wheels with two passive wheels and two driving wheels. A controller is developed based on industrial computer. The effectiveness of the proposed controller is proved by simulation and experimental results.

Rotor Speed Estimation Based on Extended Kalman Filter for Sensorless Vector Control of Induction Motor

In this paper, a sensorless vector control method is introduced where rotor speed is estimated based on extended Kalman filter (EKF). The EKF is a recursive optimum stochastic state estimator. The proposed EKF is designed to obtain a small estimation speed error in both transient and steady state over a wide speed range. A major challenge at very low and zero speed is the lost coupling effect from the rotor to the stator, which makes the information on rotor variables unobservable on the stator side. To solve this problem, in the proposed EKF, the load torque and the rotor speed with unmeasurable information are estimated simultaneously. The rotor speed is considered via the equation of motion and the estimation of load torque, on the other hand, is performed as a constant parameter. Hardware and software for experiment of the AC induction motor drive are introduced. The experimental results are presented to show the effectiveness of the proposed system.

Trajectory tracking control of omnidirectional mobile robot using sliding mode controller

In this paper, a new tracking controller that integrates a kinematic controller (KC) with a new integral sliding mode dynamic controller (NISMC) is designed for an omnidirectional mobile robot (OMR) to track a desired trajectory at a desired velocity. First, a posture tracking error vector is defined, and kinematic controller (KC) is chosen to make the posture tracking error vector go to zero asymptotically. Second, an integral sliding surface vector is defined based on the angular velocity tracking error vector and its integral term. A new integral sliding mode dynamic controller (NISMC) is designed to make the integral sliding surface vector and the angular velocity tracking error vector go to zero asymptotically. The above controllers are obtained based on Lyapunov stability theory. The simulation results are presented to illustrate effectiveness of the proposed tracking controller.

Sliding-mode observer design for sensorless vector control of AC induction motor

In this paper, a sliding-mode observer is applied to control an AC induction motor. First, the modeling of AC induction motor is presented. After that, a sliding mode observer is proposed to estimate the motor speed, the rotor flux, the angular position of the rotor flux and the motor torque from monitored stator voltages and currents. The proposed sliding mode observer provides very good performance for both low and high speed motor operation. Furthermore, the proposed system is robust in motor losses and load variations. The proposed observer does not uses complicated observer gains and it is easy to setup for different types of motor. The convergence of the proposed observer is obtained using the Lyapunov theory. Hardware and software for experiment of the AC induction motor drive are introduced. The experimental results illustrate that fast torque and speed response with small torque ripples can be achieved. The proposed control scheme is suitable to the application fields that require high performance of torque response such as electric vehicles.

Application of Servo Controller Design for Speed Control of AC Induction Motors Using Polynomial Differential Operator

This paper proposes a servo controller design method for speed control of AC induction motors using polynomial differential operator. To do this task, the followings are done. First, nonlinear modeling for an induction motor is introduced and is linearized at equilibrium points using Taylor’s series. Second, an observer is designed to estimate flux, and an extended system incorporating the internal model principle to construct the extended system is shown using polynomial differential operator in case that the types of reference inputs are differential polynomials. Third, a state feedback control law for the extended system to track the given reference input is designed by a regulator design method. A control system is constructed for speed control of the 1.5 KW AC induction motor. The simulation and experimental results are shown to verify the applicability of the proposed controller compared to conventional PI controller for the AC induction motor with a step type of disturbance to track its speed of 3 types of the references such as step, ramp and parabola.

Active real-time tension control for coil winding machine of BLDC motors

This paper proposes a new active tension system which is used in coil winding machine for BLDC motor manufacturing. A comparison of winding condition between normal coil such as round shape coil, rectangle shape coil and BLDC coil is presented. To overcome the harsh winding condition of BLDC coil winding, a new wire accumulator is proposed to store or release a wire when the wire is stretched or sagging. Wire accumulator consists of a pneumatic cylinder which is driven by a servo valve and a spring. The system modeling result shows that this tension system is a MISO system. The traditional PID controller is adopted and drives the real tension according to the given reference tension. In order to evaluate the effectiveness of wire accumulator and the performance of the proposed controller, some simulation results are carried out.

Development of Digital Gas Metal Arc Welding System and Welding Current Control Using Self-tuning Fuzzy PID

This paper describes a new method for a digital gas metal arc welding (GMAW) system. The GMAW system is an arc welding process that incorporates the GMAW power source (PS-GMAW) with a wire feed unit (WFU). The PS-GMAW requires an electric power of constant voltage. A constant magnitude is maintained for the arc current by controlling the wire-feed speed of the WFU. A mathematical model is derived, and a self-tuning fuzzy proportional-integral-derivative (PID) controller is designed and applied to control the welding current. The electrode wire feeding mechanism with this controller is driven by a DC motor, which can compensate for both the molten part of the electrode and undesirable fluctuations in the arc length during the welding process. By accurately maintaining the output welding current and welding voltage at constant values during the welding process, excellent welding results can be obtained. Simulation and experimental results are shown to prove the effectiveness of the proposed controller.