Abstract:In order to improve head-collision safety of flexible joint manipulators, an optimization method of flexible joint manipulator configuration based on the manipulator safety index and gradient projection method is proposed, and the methods of determining the safe collision direction and the safe configuration are given. Firstly, the equivalent model of head collision of the flexible joint manipulator is established, in which the influence of the flexibility of the manipulator joint is taken into account. Then, the method of determining the direction of safe collision under fixed configuration and the method of determining the safe configuration under fixed collision direction are given respectively. Based on the manipulator safety index, the gradient projection algorithm is used to optimize the configuration of continuous path of the redundant flexible joint manipulator. Finally, a closed-loop simulation system is established. The effectiveness of using the gradient projection method to reduce the safety index of the manipulator is verified by a planar 3-DOF (degree of freedom) manipulator and a space 7-DOF manipulator respectively. Two simulation results show that the optimized safety index of the manipulator is reduced by 83.86% and 26.42%, respectively.
[1] Zinn M, Roth B, Khatib O, et al. A new actuation approach for human friendly robot design[J]. International Journal of Robotics Research, 2004, 23(4-5):379-398.
[2] 何玉庆,赵忆文,韩建达,等.与人共融——机器人技术发展的新趋势[J].机器人产业,2015(5):74-80.He Y Q, Zhao Y W, Han J D, et al. Co-existence with humans-The new trend of robot technology development[J]. Robot Industry, 2015(5):74-80.
[3] Pervez A, Ryu J. Safe physical human robot interaction-Past, present and future[J]. Journal of Mechanical Science and Technology, 2008, 22(3):469-483.
[4] Pratt G A, Williamson M M. Series elastic actuators[C]//IEEE/RSJ International Conference on Intelligent Robots and Sys-tems. Piscataway, USA:IEEE, 1995:399-406.
[5] Wolf S, Hirzinger G. A new variable stiffness design:Matching requirements of the next robot generation[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA:IEEE, 2008:1741-1746.
[6] Wolf S, Eiberger O, Hirzinger G. The DLR FSJ:Energy based design of a variable stiffness joint[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA:IEEE, 2011:5082-5089.
[7] 张秀丽,谷小旭,赵洪福,等.一种基于串联弹性驱动器的柔顺机械臂设计[J].机器人,2016,38(4):385-394.Zhang X L, Gu X X, Zhao H F, et al. Design of a compliant robotic arm based on series elastic actuator[J]. Robot, 2016, 38(4):385-394.
[8] Chakarov D, Tsveov M, Veneva I, et al. Adjustable compliance joint with torsion spring for human centred robots[J]. International Journal of Advanced Robotic Systems, 2015, 12:No.180.
[9] Shin D, Yeh X, Khatib O. A new hybrid actuation scheme with artificial pneumatic muscles and a magnetic particle brake for safe human-robot collaboration[J]. International Journal of Robotics Research, 2014, 33(4):507-518.
[10] She Y, Su H J, Lai C, et al. Design and prototype of a tunable stiffness arm for safe human-robot interaction[C]//ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. New York, USA:ASME, 2016:No.V05BT07A063.
[11] She Y, Meng D S, Shi H L, et al. Dynamic modeling of a 2D compliant link for safety evaluation in human-robot interactions[C]//IEEE/RSJ International Conference on Intelligent Robots and Systems. Piscataway, USA:IEEE, 2015:3759-3764.
[12] Kuli? D, Croft E A. Safe planning for human-robot interaction[J]. Journal of Robotic Systems, 2005, 22(7):383-396.
[13] Kaipa K N, Morato C, Liu J, et al. Human-robot collaboration for bin-picking tasks to support low-volume assemblies[C]//2014 Robotics:Science and Systems Conference. 2014.
[14] Gao D, Wampler C W. Head injury criterion assessing the danger of robot impact[J]. IEEE Robotics and Automation Magazine, 2009, 16(4):71-74.
[15] Kim K H, Park I J, Choi J H, et al. Evaluation of head-collision safety of a 7-DOF manipulator according to posture variation[J]. Multibody System Dynamics, 2016, 37(1):95-105.
[16] 吴海彬,彭爱泉,何素梅.基于危险指数最小化的机器人安全运动规划[J].机械工程学报,2015,51(9):18-27.Wu H B, Peng A Q, He S M. Robot safe motion planning based on minimized danger index[J]. Journal of Mechanical Engineering, 2015, 51(9):18-27.
[17] 刘维惠,陈殿生,张立志.人机协作下的机械臂轨迹生成与修正方法[J].机器人,2016,38(4):504-512.Liu W H, Chen D S, Zhang Z L. Trajectory generation and adjustment method for robot manipulators in human-Robot collaboration[J]. Robot, 2016, 38(4):504-512.
[18] Bicchi A, Tonietti G. Fast and "soft-arm" tactics[J]. IEEE Robotics and Automation Magazine, 2004, 11(2):22-33.
[19] Khatib O. Inertial properties in robotic manipulation:An object-level framework[J]. International Journal of Robotics Research, 1995, 14(1):19-36.