Arm-based Motion Controller Study

Open numerical control (ONC)system based on SERCOS fieldbus is one of the most important development trend of the numerical control technique.Basis the development of NC technology in our country, researching the motion Controller based on the SERCOS Fieldbus has important practical significance.Through the depth research of the ONC and motion controller, choosing ARM,CPLD and SERCOS Fieldbus interface as the core to create a controller hardware platform,using VxWorks RTOS as a software design platform for task scheduling.Using feedforward-PD( Proportional Differential) control algorithm as its position feedback control ,the system achieves high speed and high precision real-time motion control, and experiments show that achieved good results.The paper researches and discusses on follow aspects,considering with the key techniques and main problems in the motion controller:After the analysis of the development status and trends of the CNC technology and the motion control technology, According to SERCOS Fieldbus structure, in accordance with the performance requirements of Motion Controller, the overall program design of ARM-based controller is brought up.A two-axis motion controller is Designed, which realizes motor control interfaces and common simulation and digital signal interfaces.The motion controller uses a 32-bit high performance and low price as the microprocessor S3C44B0X as the control chip , and used CPLD chip EPM7128 as the coprocessor to support the chief controller for the motion control, and use the SERCON816 as the SERCOS Fieldbus interface to exchange the data with PC. The motion controller uses a lot of the latest IC chip , thereby greatly simplified the circuit and increased the system's reliability and performance.Software is designed with the idea of modular, and uses VxWorks embedded real-time operating system for the task scheduling, which greatly improves the system's real-time performance, stability and anti-jamming capability.The CNC machine is controlled by the method of Off-line interpolation real-time control. PC deals the trajectory with rough interpolation and brings the data into the storage area. When need control for the processing, the system will send rough interpolation data to the motion controller by the control of SERCOS synchronous cycle strictly, and interpolator is completed by the motion controller. Motion Controller deals with the rough interpolation data by the feedforward -PD algorithm position control, and adjusts the position control parameters in the practical application. The purpose of stable and reliable high-speed and high-precision position control is achieved.The performance of Motion Controller is satisfied for the design through the integration experiment, and the capability is enhanced by adjusting the position control parameters. The experimental results show that the controller is a high-performance low-price open motion controller.