Chih-Yang Chen

EP-based kinematic control and adaptive fuzzy sliding-mode dynamic control for wheeled mobile robots

This paper proposes a complete control law comprising an evolutionary programming based kinematic control (EPKC) and an adaptive fuzzy sliding-mode dynamic control (AFSMDC) for the trajectory-tracking control of nonholonomic wheeled mobile robots (WMRs). The control gains for kinematic control (KC) are trained by evolutionary programming (EP). The proposed AFSMDC not only eliminates the chattering phenomenon in the sliding-mode control, but also copes with the system uncertainties and external disturbances. Additionally, the convergence of trajectory-tracking errors is proved by the Lyapunov stability theory. Computer simulations are presented to confirm the effectiveness of the proposed complete control law. Finally, real-time experiments are done in the test field to demonstrate the feasibility of real WMR maneuvers.

Multifunctional Intelligent Autonomous Parking Controllers for Carlike Mobile Robots

An increasing number of carlike mobile robot (CLMR) studies have addressed the issues of autonomous parking and obstacle avoidance. An autonomous parking controller can provide convenience to a novice driver. However, if the controller is not designed adequately, it may endanger the car and the driver. Therefore, this paper presents a novel multifunctional intelligent autonomous parking controller that is capable of effectively parking the CLMR in an appropriate parking space, by integrating sensor data capable of obtaining the surrounding data of the robot. An ultrasonic sensor array system has been developed with group-sensor firing intervals. A binaural approach to the CLMR has been adopted for providing complete contactless sensory coverage of the entire workspace. The proposed heuristic controller can obtain the posture of a mobile robot in a parking space. In addition, the controller can ensure the ability of the CLMR to withstand collision to guarantee safe parking. Moreover, the CLMR can recognize the parking space and the obstacle position in dynamic environment. Therefore, the proposed controller installed in a car could ensure safe driving. Finally, practical experiments demonstrate that the proposed multifunctional intelligent autonomous parking controllers are feasible and effective.

Interval Type-2 Adaptive Fuzzy Sliding-Mode Dynamic Control Design for Wheeled Mobile Robots

A combined intelligent technique is proposed for controlling the trajectory-tracking of a nonholonomic wheeled mobile robot (WMR), which comprises kinematic control and an interval type-2 adaptive fuzzy sliding-mode dynamic control (IT2-AFSMDC). The kinematic model is introduced first, and then the control gains can be obtained from the back-stepping method as the input of the dynamic model. The IT2-AFSMDC is propounded for the dynamic part, a combination of the interval type-2 fuzzy logic control (IT2-FLC) and the adaptive fuzzy sliding-mode dynamic control (AFSMDC), which inherits the benefits of these two methods, and adaptive law is introduced to cope with the uncertainties and disturbances of the system. The trajectory-tracking stability is proved by the Lyapunov stability analysis. Computer simulations demonstrate the validity of the proposed method. The simulation results show that the tracking performance of the IT2-AFSMDC is better than that of the AFSMDC. SMC techniques [5, 14] provide discontinuous control laws to drive the system states to a specified sliding surface and to keep them on the sliding surface. The dynamic performance of the SMC has been adopted as an effective robust control approach for the problems of system uncertainties and external disturbances. But there still are some drawbacks in the SMC; for example, chattering characteristics occur when the system dynamics is close to the sliding surface. This problem should be eliminated or alleviated. The FSMC [15-16], a hybrid of the SMC and FLC, gives a simple way to design the controller systematically and provides the asymptotical stability of the system. In general, the FSMC can also reduce the rule number in the FLC and still possess robustness.

An autonomous surveillance and security robot team

The motivation of this paper is to set up a surveillance and security robot team (SSRT, three autonomous mobile robots and a surveillance and security control (SSC) center. The SSC center communicates with clients via the Internet which can assign patrol scheduler for each robot. The SSRT shares the environmental information among team members through a wireless communication network. The architecture of the SSRT can be divided into two parts. The first one is sensory feedback park. Each surveillance and security robot (SSR) can transmit and receive useful some data, for example, the electric energy residue and the result of patrol, to SSC center via the internet. The other one is mission assignment. The SSC center sorts out the priority of each SSR for the mission execution and assigns each SSR a suitable mission, for example, if any unusual event happens, the SSR will alarm and send the pictures to the SSC center, and then the center will announce the robot employer and assign the optimal patrol role for every robot. The most suitable robot will go to support the incident area, while the other robots will evacuate people to decrease any possible damage. A fuzzy logic decision algorithm is adopted to find the optimal path for each robot to reach the incident location. By combining RFID data with the vision system to recognize the bar-code characteristics in the environment, the self-localization and the patrol routine for each robot can be accomplished. Each robot possesses the auto-recharge function which can recharge itself automatically. Finally, real-time experiments are executed to demonstrate the feasibility and effectiveness of the proposed schemes.

A fully fuzzy trajectory tracking control design for surveillance and security robots

The motivation of this paper is to confer the study of omni-directional trajectory motion control implemented by the SOPC system. In the hardware architecture, four mutual orthogonal omni-directional wheels are horizontally established on the plane of the chassis and four optical encoders are equipped with DC motors to read the data of angular velocity and compute the posture of the surveillance and security robot (SSR). The robot will track the desired trajectory which has been generated by the trajectory generation system. We present a fully-fuzzy trajectory tracking system which can compensate for the errors of the velocity and regulate the errors of the position based on the dynamic model. After dealing with the information, the correct trajectory motion can be determined. Finally, the experimental results indicate that the proposed omni-directional trajectory control scheme can be successfully applied to the SSR.

Design of Lyapunov Function Based Fuzzy Logic Controller for a Class of Discrete-Time Systems

In this paper, we present a new fuzzy logic controller (FLC) for discrete-time systems. All the decision rules of FLC are automatically generated by the Lyapunov stability criterion. The proposed control scheme can be easily derived with minimum information of the controlled plant. Furthermore, the fuzzy inference scheme can successfully be applied to stabilize the nonlinear discrete-time systems. We introduce three discrete-time systems, including a linear plant, a nonlinear plant, and a delayed plant, to demonstrate the effectiveness of the proposed FLC.

Design and implementation of fuzzy ring univector field for robot soccer game

In this paper, the fuzzy ring univector field (FRUF) scheme is proposed for mobile robot to accomplish the obstacle-avoidance and goal-reaching missions. Application of FRUF method to the robot soccer game is also examined. According to the laws of F180 league of RoboCup, the active robots are not allowed to push the inactive robot a width of robot away when colliding. Tackling these problems, we also provide the ring univector field (RUF) in comparisons with the FRUF approach and the commonly used univector field method. The shooting action is incorporated to score a goal. Both computer simulations and experimental results illustrate that the proposed schemes can not only chase the ball and avoid collision with opponents but also successfully kick the ball in a real-time robot soccer game.

Design and implementation of intelligent driving controller for car-like mobile robot

This paper presents the design and implementation of the intelligent driving control and accomplishes it in a car-like mobile robot, which possesses the function to accept the command from the cellular phone through Bluetooth, and then estimates the environment by integration of ultrasonic sensors array and image sensors. We utilize the NIOS embedded system development board as a low level controller to compute these received data and then decide the reactive behavior. Furthermore, the system architecture of the car-like mobile robot contains the reconstruction of the chassis of the robot, NIOS development board, DC motor unit, servo motor unit, driver circuit, ultrasonic sensors, accelerometer, cellular phone, and image sensors. Additionally, this paper also addresses how to process and analyze the input signals of image sensors, ultrasonic sensors, and accelerometer. Finally, it is perceived that our intelligent driving controller is feasible and effective from the practical experiments.

Design and implementation of sensor fusion based behavior strategies for a surveillance and security robot team

This paper mainly covers the study of sensor fusion and behavior strategies for surveillance and security robot team (SSRT). The team consists of three robots, and is more effective and complete than one robot in surveillance and security. We arrive at the goal of surveillance and security at the robot mount the vision unit, ultrasonic unit, fire-detecting module, and self-location unit. The robot team shares the environmental information with one another through a wireless communication system. The robot can move faster and reduce the time using an omni-directional wheel. The robot team can work 24 hours by an automatic power recharge system. Sensor fusion and behavior strategies make robots complete the mission. The robot avoids an obstacle by fuzzy logic controller (FLC). We use an emergency decision algorithm (EDA) to detect accidents and present a path planning algorithm for periodic patrol behavior. Each robot can avoid an obstacle by an omni-directional move in the patrol process, detect a fire, and confirm the location using an RFID system, transmit the alert to a web-control center through a wireless communication system, and recharge the power autonomously. Finally, the efficiency and feasibility of the proposed system are demonstrated by practical experiments.