For an autonomous mobile robot, online detection and avoidance of uncertain obstacles are some of the basic and necessary behaviors. The goal of this research is to develop tracking controllers in a perceptive frame which can deal with uncertain obstacles and ensure the stability of the controller. The new design method converts a controller designed by traditional time based approaches to a non-time based controller using any given action reference. The stability condition of noontime based tracking controller is developed and theoretically proved. Tracking control for simple paths such as straight lines, circles as well as complex paths such as ellipses and sine waves are developed and implemented on a Nomaic XR4000 mobile robot. With the help of sensors, obstacle avoidance is also tested. Equipped with these controllers, the command from deliberative and interactive layers can be executed nicely.
A mobile robot is a manipulator atop of a mobile robot. The mobile manipulator integrates the mobility of mobile robots and the ability of manipulation of robot arm. This integration undoubtedly increases the flexibility. However, the improved flexibility also increased the difficulty in control. The goal of this research to develop a unified model for the mobile manipulator which can be controlled in either path tracking mode or hybrid force/position mode. In a path tracking mode, the mobile manipulator will have a much larger working space than a fixed base manipulator. Singularities can be avoid by coordinating the motion of the mobile robot and the arm. In a hybrid force/position control mode, both mobility and desired force out can be ensured by make use of the redundancy of the mobile manipulator.
Autonomous mobile robots are designed as human helper in most of their applications. The interaction between human and mobile manipulator are studied. The purpose of the research is to convey the human command to the robot and transfer back the mobile manipulator action to the human. The general purpose internet are utilized for communication. The difficulty here is to overcome the uncertain delay existed in the internet. A real-time control of the mobile robot over the internet is tested.
The purpose of the this research is to find controllers to keep multiple vehicles in a required formation, and to coordinate the vehicles in the presence of unexpected environmental change. The developed controller can follow various coordination strategies in the presence of unexpected event. It is a decentralized control but it is easy to reconfiguration. Some useful coordination strategy such as movement with a leader, simultaneous movement, and series connections of formations are developed.