Distributed Control System Of A Six-DOF Manipulator

With the development of technology and society, the application of robots has become more and more popular in various areas, such as industrial production and manufacture, daily life, education and entertainment. Manipulator is the most important implementing mechanism of robot, which is a time-variable, strong coupling and nonlinear system. As a result, the design of the manipulator control system is of great significance in both project and theory.In this paper, a scheme of distributed controllers based on RS-485 bus is proposed to design the control system of the 6 degree-of-freedom manipulator in the National 863 Project of the Humanoid Robots Technique and System. In the distributed system, a PC computer is used as the central computer for monitoring, and the motion control of every motor is accomplished by an independent joint controller based on DSP. A set of communication protocol is designed for the distributed system. The kinetic equation of the manipulator is deduced using the Denavit-Hartenberg method and the inverse kinetic solutions are also obtained. In addition, the trajectory planning arithmetic of the manipulator is designed in both joint space and the orthogonal coordinate space. Position and velocity control are realized in DSP. Finally, some experiments are carried out to evaluate the design of the distributed control system.Experiment results show that the kinetic equation and trajectory planning arithmetic of the manipulator are correct and effective. Motors can be controlled real-time to follow the trajectory precisely by the distributed system based on RS-485 bus. The distributed control system designed in the paper has satisfied the requirements.