Motion Function Design For Industrial Robot Controller With Sercos Ⅲ Bus

Traditional industrial robot controller based on’ PC+Motion Control Card’ control architecture gradually exposed closure, fewer synchronous linkage axes capability, high cost, maintenance difficulties and other defects in today’s industrial applications. With the rapid development of real-time Ethernet technology, robot control architecture based on real-time industrial Ethernet bus can greatly enhance the ability of communication and synchronization performance of the system, to achieve more linkage axes synchronization, while reducing implementation and maintenance costs. Therefore, researches and designs for industrial robot controllers based on real-time industrial Ethernet bus poss great value for industrial robot control.At present, the domestic robot productions have still no controller design based on real-time Ethernet bus technology for vertical 6-axis articulated industrial robot yet. This desscrtation, based on the’IPC+real-time operating system + real-time industrial Ethernet bus’ control architecture, aims at the motion function design and realizations, which the most basic and key issue of industrial robot controller researches.Firstly, this dissertation has designed and set up the industrial robot controller as well as its motion control system, based on Sercos III, the automatic real-time Ethernet bus, providing hardware foundation for the realization of industrial robot motion functions. Furtherly, this dissertation proposes innovative algorithms and strategies to meet the requirements of all kinds of motion instructions for smooth speed process and axes synchronization. Based on such theories, concrete steps for the trajectory planning of various motion instructions are designed. These solutions provide important information for motion function design. In order to test the proposed algorithms and strategies, an experiment system which includes’ KunShan NO.1’, the 6-axis industrial robot and a 2-axis positioner has been set up in the reserch, to realize the basic motion functions of industial robots.The main results of this dissertation are:(1) Based on Sercos Ⅲ bus technology, an industrial robot controller has been set up in this dissertation and achieved effective motion control of the servo motors. This work solves the problem of how to establish the Sercos Ⅲ bus communication between the industrial robot controller and servo motors, and achieve effective motion control from controller to the servo motors. At present, there is no no domestic institution or manufacturer to carry out this work. Some domestic industrial robot manifacturers have used the robot controllers based on Sercos Ⅲ bus in their robot production. However, the controllers are all imported from foreign countries. The manifacturers do not need to care about the method to set up the Sercos Ⅲ bus communication between the controller and servo motors.(2) An improved S-curve speed control algorithm as well as two kinds of synchronizaion strategies including simultaneous interpolation strategy and strict synchronous interpolation strategy, are proposed for the Point-To-Point(PTP) motion and Continuous Path(CP) motion trajectory planning. Compared with the traditional controller interpolation planning studies, this dissertation is more concerned about the speed smoothing algorithms and synchronization control strategies. Compared to the traditional ladder speed control algorithm that traditional controllers use, the acceleration curve of the proposed improved algorithm is continuous, and the speed curve is more smoothly; compared to the traditional seven-segment S-curve algorithm, the improved algorithm needs to consider fewer cases of piecewise vacancy issues and use less calculation time under normal circumstances, which is more conducive to synchronous the multi-axis control system.(3) A four-stage smooth speed control trajectory planning algorithm based on time-slice units is proposed for the manual teaching (JOG) instruction. As to the manual teaching instruction of general controller, the speed curve is not smooth. And it is difficult to move the small offset and easy to jog beyond the soft limit under high-speed. The jog speed smoothing algorithm proposed in this dissertation, can obtain excellent planned results with continuous acceleration curve, jog a small distance, as well as avoid the excessive mechanical shock during the jogging operation and the disability of timely smooth stop under high speed.PTP instruction, CP instructions, JOG instructions as well as coordination instructions between the robot and positioner have been successfully carried out on the 8-axis experiment system consisted by the vertical 6-axis articulated industrial robot’ Kunshan NO.l’and 2-axis positioner. The successful results have proven the reliability of Sercos-Ⅲ-bus-based industrial robot controller and the effectiveness of our proposed algorithms. Although the design in this dissertation is oriented to Sercos Ⅲ automatic bus, but the speed smoothing algorithms and synchronization control strategies proposed in this dissertation will also benefit the robot control system design based on other real-time Ethernet bus.