Kinematic Analysis And Control Of Mobile Manipulator For Measurement And Maintenance In Dangerous Environment

Due to the harmfulness of deleterious chemistry leakage, the measurement and maintenance of chemistry reactors and carrying pipeline has arosed the attention of researchers. The mobility and manipulation capability of a mobile manipulator provides convenience to accomplish some tasks in dangerous environment. This dissertation is carried on the research to the dynamics and control technology for the mobile manipulator designed, supported by the China National Hi-tech R&D Program (863 Program)—Study on the mobile manipulator for measurement and maintenance of chemistry reactors (Granted No.2003AA421040).1. The structure of P3-AT mobile manipulator designed is described. The kinematics character of 2 DOF mobile platform and 5 DOF manipulator is analyzed. The kinematics modeling of mobile platform and manipulator is studied respectively, then the kinematics modeling of mobile manipulator system is derived. And the forward and inverse kinematics equations are derived. Based on the research above, the simulation model of 5 DOF manipulator is developed in the software ADAMS, which can be used to analyze motion space and dynamics visually.2. The strategy of coordination-motion planning for the mobile manipulator is presented, and a simple mechanism system model of the mobile manipulator is built. Then the dynamic modeling of the system is studied through the method of Newton-Euler. By dynamic computer simulation, the interaction between mobile platform and manipulator is analyzed. The analysis result indicated that the larger is the acceleration of mobile platform, the larger the force of manipulator applied by the platform is. It is harmful effects for position accuracy of mobile manipulator. And the theoretical dynamic models of them are derived by the method of Newton-Eular and Lagrange separately. By the computer simulation, dynamic characteristic of two subsystem is analyzed. The relation between joint moment and posture of manipulator is displayed, and the bad postures of manipulator are obtained. The mobile platform may achieve motion trace and alter azimuth as demand.3. Based on 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. It consists of three levels: decision-making level, processing level and execution level. Decision-making level is a task-planning unit. Processing level includes two RBF neural network controllers, in which unknown mobile platform and manipulator dynamic parameters are identified and compensated. Execution level controls the movement of each motor of mobile manipulator, based on the output control torques from processing level. In RBF neural network controllers, generalized Lyapunov equations of two subsystem (mobile platform and manipulator) and mobile manipulator system are derived, using Lyapunov stability theory. Then the simulation of sample training in RBF neural network is completed by Matlab software. The result shows the training in RBF neural network is effective and reliable.4. The hardware system of the mobile manipulator is designed. It includes a mobile platform and a 5 DOF manipulator, CCD sensors and ultrasonic sensors module, etc. The control program of mobile manipulator is developed, including movement program in PMAC and central control program in PC of the mobile platform. Then the motion and control simulation of manipulator is completed by Matlab software, which displays the action accuracy of manipulator. In the end, a experiment of mobile manipulator is accomplished. The experiment and simulation results show that kinetic control of manipulator is precise and reliable.