Hou-Tsan Lee

Nonlinear adaptive backstepping motion control of linear induction motor

In this paper, we propose a nonlinear adaptive controller and an adaptive backstepping controller for linear induction motors (LIMs) to achieve speed/position tracking. A nonlinear transformation is proposed to facilitate controller design. Besides, the unique end effect of the LIM is also considered and is well taken care of in our controller design. Stability analysis based on Lyapunov theory is also performed to guarantee that the controller design is stable. Also, computer simulations and experiments are undertaken to demonstrate the performance of our controller designs.

Sensorless Adaptive Backstepping Speed Control of Induction Motor

This paper proposes an adaptive speed tracking control scheme for an induction motor subject to unknown load torque via backstepping analysis. The controller is developed under a special nonlinear coordinate transform such that speed control objective can be fulfilled. The underlying design concept is to endow the closed-loop system while lacking the knowledge of some key system parameters, such as the rotor resistance, motor inertia, and motor damping coefficient. The proposed control scheme comes along with a thorough proof derived based on Lyapunov stability theory. Experimental results are also given to validate the effectiveness of the proposed control scheme

Speed tracking control with maximal power transfer of induction motor

Proposes a speed tracking control of induction motors based on the input/output linearization method, which can also achieve the maximal power transfer. A simple group of observers are designed to estimate the rotor flux in order to determine the orientation of rotor flux. The control law of the maximal power transfer to the rotor gives the relationship between the stator voltage and the orientation of rotor flux in d-q frame. The speed tracking controller is also robust with respect to the variation of rotor resistance and load torque. Simulation results are given to show the effectiveness of the presented controller. Experimental results are also given to validate the performances.

Nonlinear control of induction motor with unknown rotor resistance and load adaptation

On the basis of a dynamic model obtained under a special nonlinear coordinate transform on a d-q axis model (the stationary reference frame) of an induction motor, a nonlinear adaptive controller for speed tracking control with unknown load torque is proposed in this paper. The controller is made to work under the condition that all the parameters except the rotor resistance of the induction motor are known a priori. The underlying control theories include the indirect vector control and the maximal power transfer of the motor. To be rigorous, the proposed control scheme is derived from the Lyapunov stability theory. The simulation results are also given to show the effectiveness of the presented control scheme.

Adaptive speed/position control of induction motor with unknown load torque

The paper proposes an adaptive speed/position tracking control of an induction motor subject to unknown load torque. The controller is developed based on a dynamic model obtained from the d-q-axis model (w.r.t. the stationary reference frame) of the motor under a special nonlinear coordinate transform so that either the speed or position control objective can be fulfilled. The underlying design concept is to endow the close-loop system with the so-called maximal power transfer property while under lack of knowledge of some key system parameters, such as the rotor resistance, motor inertia and motor damping coefficient. To be rigorous, we present a thorough proof of the proposed control scheme based on Lyapunov stability theory. Experimental results are also given to validate the effectiveness of the scheme.

Congestion control of transmission control protocol based on bandwidth estimation

Abstract This paper presents a framework for TCP congestion control, called “Bandwidth‐based TCP”, which differs from most TCP algorithms by using the bandwidth estimation as the congestion measure to control the window size increment. It tries to predict the equilibrium point of window size then make the congestion window approach this point in a round‐trip‐time. First of all, an overview of TCP and AQM is introduced. Then, the stability of the mechanisms is also investigated via linearization. Finally, through the simulations, the performance of the proposed scheme is shown to be better than TCP‐Vegas under homogeneous and heterogeneous environments.

Modular Design of a Reconfigurable Electromagnetic Robot

This paper discusses the modular design of distributed reconfigurable robots. The design concept, mechanical structure, electrical processing unit, actuator dissection and reconfiguration examples of the proposed robotic modules are presented in detail. The reconfigurable robotic motion is realized via a collection of the proposed modules with the capability of connecting and disconnecting with adjacent modules. The key actuation of the robotic reconfiguration is driven only by the E-type electromagnets and different shapes of the modules are implemented for versatile applications. Finally, the feasibility of the proposed robotic modules has been extensively tested.

Magnetic Force Analysis for the Actuation Design of 2D Rotational Modular Robots

This paper discusses the experimental testing on the actuation design and motion of one type of novel self-reconfigurable modular robot. The shape of the modular robot is octagonal and hence it is named as Octabot. Each module is equipped with one micro-controller and eight actuators. One each side of the modular robot, the actuator is driven by one set of electromagnet for both moving the module and connecting other modules. Multiple Octabots can be used to easily generate a large- scale robot formation. The magnetic field of the actuator is analyzed first in ANSYS and preliminary experimental tests of multiple Octabots are then performed to demonstrate the reconfigurable operation.

Indoor Surveillance Security Robot with a Self-Propelled Patrolling Vehicle

Self-propelled patrolling vehicles can patrol periodically in the designed area to ensure the safety like men do. The proposed vehicle cannot only save manpower, but also ensure the performance without mistakes caused by man. It is different from the traditional patrolling system which is limited by the manpower and the fixed camera positions. To improve such situation, this paper proposes a self-propelled patrolling vehicle which can move automatically to a wider range and record the monitored image by IPCAM within a predefined patrolling route. Besides, the user can use the mobile device or website to connect to the vehicle at anytime and anywhere and control it to move to the position to get the indoor image user wants. The position of self-propelled vehicles can be detected by the RFID reader as a feedback and be shown on the PC screen and smart phone. The recorded images can be also transmitted back to the server via WiFi system for face tracking and discriminating analysis. On the other hand, the self-propelled vehicle patrolling routes can be modified by the Android smart-phone remote-control module. When some defined events occur, the build-in MSN module will notice users by sending messages to PC and smart phone. Experimental results are given in the paper to validate its performance.

Design of the Octabot Self-Reconfigurable Robot

Abstract Self-reconfigurable robots are for the ability to change the shape of multiple cooperated robot modules that can be easily reconfigurable in the different working environment. Related work on two-dimensional robots is presented. A novel design for a self-reconfigurable robot, called “Octabot”, is described. The Octabot robot is a two-dimensional self-reconfigurable robot with modules composed of eight e-type electromagnets. After the magnetic force characteristics based on FEM analyses, mechanical design and system properties are described. The current designs only use single type actuator. The group of Octabots can be easily expanded to a large scale if needed in any case. Via examining the basic mechanical functions, the Octabot in self-reconfiguration shows its satisfactory performance .