Design Of Open Multi-Axis Motion Control System Based On Fieldbus

With the development of industrial automation equipment, industrial robot (IR), as one of the most significant manufacturing facilities, has seen dramatically growing these years. According to authoritative estimate, the amount of domestic robot manipulators will increase by 25% every year. While being the core component of IR control system, multi-axis controllers are playing more and more important roles in industrial producing fields. The working performance and efficiencies of IR are largely depended on the quality of Multi-axis controllers. Based on the very experimental platform-- "Qianjiang-Ⅰ" 6-DOF Arc-welding IR and prior effective works by Huashan Liu and Jianbo Wu, this project aims at designing an update multi-axis motion controller(MAMC) by introducing in fielbus, in that case endows this control system more stability and make it a standardized module. The new edition of MAMC board has several advantages over previous and other kind of motion controllers, such as stronger capabilities to get it integrated into other systems and being more appropriate for self-expanding by connecting certain number of controllers together by fieldbus.The new MAMC system not only achieves real-time trajectory planning and coordination of 6 joints in welding process, but can be applied in the occasion where more than 6 joints controlling is needed. Before long, the new MAMC will be suitable for multi-robot communications in fully automatic manufacturing areas, because of fieldbus'ability of real-time data exchange.After full investigation into motion controllers both domestically and abroad, it is determined to adopt the PC+MAMC structure as the final solution. The MAMC system consists of two parts:main control board and port board. Main control board chooses DSP+CPLD as feature implementation chips, while port board functions as power supply isolator and signal filter. With the powerful data-processing capabilities of DSP and excellent logical control programming performance of CPLD, the new MAMC can be qualified to achieve motion controlling with high accuracy. Besides, CPLD can be used for I/O ports expand, which can receive more signals from servo units at one time.When it comes to fieldbus, CAN (Controller Area Network) fieldbus became the best choice due to its wide compatibility and reliability. All the instructions from PC to MAMC and feedback data are transferred through CAN bus.As to servo-motor control, this paper presents some algorithms for control strategy, after discussing control mode and introducing the methodology. The realization of these algorithms by programming together with debugging is also elaborated. Moreover, for trajectory tracking of robot manipulators with only position measurement, limited torques modeling uncertainties and disturbances, it proposed a novel adaptive PID control algorithm. Finally this algorithm is proved to be well performed in two-joint robot manipulator.The set of software achieves several functions:firstly, completing basic motor-controlling of MAMC, like CPLD and DSP instructions programming; then PC human-machine interaction interface and realization of CAN fieldbus communication protocols; and finally, the motion control algorithm.At the end of this paper, the problems during debugging both in hardware and software as well as respective solutions are demonstrated, for the sake of future improvement.