Design of a Real-time Robot Control System oriented for Human-Robot Cooperation

An open real-time control system based on the EtherCAT fieldbus communication technology is proposed to fulfill the high real-time requirement of the human-robot cooperation controller in this paper. An open source real-time kernel of Xenomai is employed as the real-time software platform of the robot control system. Based on this, four-layer interfaces architecture are accomplished, which are human-machine cooperation control layer, motion control layer, robot axis control layer and hardware abstraction layer, through the corresponding four real-time tasks to meet the demand of human-robot cooperation operations. In addition, the scheduling task is developed to manage the 4 real-time tasks. The dual buffer communication mechanisms and priority-based scheduling strategy between layers was exploited to synchronize these real-time tasks. The underlying hardware abstract interface and the human-robot collaborative control algorithm interface are opened in the control system as the quadric exploitation interfaces to meet the need of developing application tasks in real-time space. Experiment results which are conducted on a self-developed 6-DOF collaborative robot show that the proposed control system is effective in real-time control applications of human-robot cooperative control at the control cycle of 5 milliseconds.