基于EtherCAT的并联六自由度平台设计

Development of a 6DOF Platform Based on EtherCAT

摘要:

在设计六自由度运动平台时,运动精度是重要的评价指标,为了能够降低位姿跟踪误差并提高各轴的协同控制,在对平台进行位姿正反解的基础上,设计了一套基于EtherCAT总线的六自由度运动平台,通过EtherCAT网络进行数据帧的快速传输；系统硬件由工控机、EtherCAT网络、伺服电机、Stewart型平台构成,系统软件则采用VC++进行上位机界面的开发,由TwinCAT进行下位机控制程序的开发,通过电子凸轮实现平台各轴的同步控制,其中上下位机通过ADS进行通讯；由实验结果可知,六自由度平台平移跟踪误差小于0.04 mm,转动跟踪误差小于0.01°,静态定位精度优于0.1%,达到预定的控制要求；基于EtherCAT的六自由度平台具有良好的同步性能和位姿精度,也表明EtherCAT在多轴同步伺服控制上具有较好的响应速度和控制精度。

关键词:六自由度平台;EtherCAT;电子凸轮

Abstract:

Motion precision is a important evaluation index when design a 6DOF Platform .In order to reduce pose tracking error and boost synergy control, a multi-axis servo application based on EtherCAT is proposed on the basis of platform pose calculation of positive and negative resolving,and data is swiftly transmited by EtherCAT net. The hardware is mainly made up of IPC, EtherCAT, servomotor and Stewart platform. The software is developed by VC++ and TwinCAT,and ADS is used for communication.Electronic CAM is employed to achieve synchronous control between different axies. Experiment result show that the translational tracking error is less than 0.04 mm, turn tracking error is less than 0.01°, static tracking error is less than 0.1%. In a word, it can achieve the control requirements.A 6DOF platform based on EtherCAT has favourable synchron performance and pose precision.It also showed that EherCAT used in multi-axis synchron control has good response rate and control precision.

Key words:6DOF platform; EtherCAT; electronic CAM