Development Of Master Controller For Dual-arm Robot Based On EtherCAT

With the continuous progress of Chinese manned space technology,space exploration capabilities continue to enhance,in the near future,our country will set up a permanent space laboratory.However,in the process of building a space laboratory,heavy and complex assembly tasks relying solely on astronauts are dangerous and inefficient.Therefore,using dual-arm robot to replace or assist astronauts to complete the space tasks will become the inevitable trend.In order to achieve force position control of single arm’s manipulation or dual-arms’coordination during implementing plugging,gripping,aligning and screwing action,the communication cycle of dual-arm robot controller needs to be less than 1ms,and the control frequency needs to be greater than 1 kHz.The traditional robot controller via CAN bus.USB or RS485 serial bus communication is unable to meet the communication bandwidth,response speed and real-time demand due to high frequency of control requirement.Therefore,it is necessary to design a high communication bandwidth and strong real-time controller to solve this problem.In view of the exsiting problems of dual-arm robot controller,this paper combined with real-time industrial Ethernet EtherCAT technology characteristics,and used embedded hardware and software technology,complete the dual-arm robot master controller design based on EtherCAT.The main research contents are as follows:Study on EtherCAT technology in-depth firstly,and then complete the design of dual-arm robot control protocol based on EtherCAT,including EtherCAT network configuration module and interface design,state machine module and interface design,data frame structure and mechanical arm control interface design.In terms of hardware,analysis the computing power requirements the controller firstly,and then determine to take two Virtex-5 FPGA chips which embedded with two PPC440 hard core processors as the core to construct the four processors hardware SOC platform.In terms of software,base on the embedded real-time operation system Xilkernel,this paper designed master controller system software architecture in the Xilinx EDK embedded development environment platform,and discussed the design of each function module and each sub module of the EtherCAT protocol stack in detail.On the basis of completion of software and hardware design,the main station controller test platform is set up in order to complete the function and performance test of the master controller.The experimental results show that the functions of the master controller are all satisfied.