The Study On Hierarchical Architecture And Coordinated Control For Mobile Manipulator

Based on analyzing the movement character of mobile manipulator, this paper established kinematics sub-models of the manipulator and the wheeled mobile vehicle. Then the unified kinematics of mobile manipulator is analyzed. Using the Lagrangian approach, the unified dynamic of mobile manipulator subject to kinematic constrains is obtained. On the base of these, the dynamic sub-models of the manipulator and the wheeled mobile vehicle are considered. These establish foundation of the coordinated control for mobile manipulator.According to the kinematic and dynamic motioned above, a hierarchical intelligent controller based on neural network is proposed for the coordinated control of the mobile manipulator, which mimics human behavior. The basic principle of this developed controller is to identify and to compensate for the unknown mobile platform and manipulator dynamics by making use of neural network. It consists of three levels: decision level, processing level and execution level. Decision level is a task-planning unit;processing level includes two RBF neural network controllers, and in this level the unknown mobile platform and manipulator dynamics are identified by respective RBF, and compensated to the control torques;execution level controls the movement of each motor with control torques derived from execution level.In the end, the hardware system of the mobile manipulator is established. It includes a mobile platform and a 5 degree of freedom manipulator, CCD sensors, ultrasonic sensors and a wireless communication module, etc. The CCD sensor provides the video signal, ultrasonic sensors are used for collision avoidance, the wireless communication module charges for remote control. Then the software of mobile manipulator is introduced, and movement emulations making use of matlab are considered.