Abstract:In order to ensure omni-directional stable moving for a quadruped robot with high payload, an intermittent gait planning method based on velocity vector is proposed. In this method, intermittent gait is selected as the main gait, and the translational and rotational velocity vectors are mapped to the turning around the center of rotation. Firstly, the coordinate of the center of rotation is derived from the turning centre theory, and the maximum rotation velocity is calculated according to the workspace of foot. Then, the starting position of the supporting phase is designed under the constraint of stability margin. To satisfy the no-impact condition, a modified cycloid curve trajectory planning method of the swinging leg is adopted. An incremental trajectory planning method is proposed, which can be easily realized to generate continuous motion commands by programming. Then the requirements are analyzed from four aspects:stability margin, continuity, moving speed and workspace, and the corresponding method of parameters design is put forward. Finally, the comparison experiment is carried out among three gaits respectively by using virtual prototype and physical prototype, and the results show that the gait has the least shaking measurements and variances when α=0.5. The results demonstrate that this method guarantees continuous and omni-directional moving trajectory of the quadruped robot with high payload and has good stability.
[1] Hu N, Li S Y, Huang D, et al. Crawling gait planning for a quadruped robot with high payload walking on irregular terrain[C]//19th World Congress of the International Federation of Automatic Control. IFAC, 2014:2153-2158.
[2] Gagliardini L, Tian X H, Gao F, et al. Modelling and trajectory planning for a four legged walking robot with high payload[C]//4th International Conference on Social Robotics. Berlin, Germany:Springer, 2012:552-561.
[3] Wang H B, Sang L F, Hu X, et al. Kinematics and dynamics analysis of a quadruped walking robot with parallel leg mechanism[J]. Chinese Journal of Mechanical Engineering, 2013, 26(5):881-891.
[4] McGhee R B, Frank A A. On the stability properties of quadruped creeping gaits[J]. Mathematical Biosciences, 1968, 3:331-351.
[5] Frank A A, McGhee R B. Some considerations relating to the design of autopilots for legged vehicles[J]. Journal of Terramechanics, 1969, 6(1):23-35.
[6] 黄博,赵建文,孙立宁.基于静平衡的四足机器人直行与楼梯爬越步态[J]. 机器人,2010,32(2):226-232.Huang B, Zhao J W, Sun L N. Straight walking and stair climbing gait of quadruped robot based on static balance[J]. Robot, 2010, 32(2):226-232.
[7] 王鹏飞.四足机器人稳定行走规划及控制技术研究[D]. 哈尔滨:哈尔滨工业大学,2007.Wang P F. Research on quadruped robot steadily walking planning and controlling technology[D]. Harbin:Harbin Institute of Technology, 2007.
[8] Tsukagoshi H, Hirose S, Yoneda K. Maneuvering operations of a quadruped walking robot on a slope[J]. Advanced Robotics. 1996, 11(4):359-375.
[9] Ma S G, Tomiyama T, Wada H. Omnidirectional static walking of a quadruped robot[J]. IEEE Transactions on Robotics, 2005, 21(2):152-161.
[10] 孟健,李贻斌,李彬. 四足机器人对角小跑步态全方位移动控制方法及其实现[J].机器人,2015,37(1):74-84. Meng J, Li Y B, Li B. Control method and its implementation of quadruped robot in omni-directional trotting gait[J]. Robot, 2015, 37(1):74-84.
[11] 张文宇.四足机器人斜面全方位静态步行及稳定性分析[D]. 青岛:中国海洋大学,2009. Zhang W Y. The study of omni-directional static walking and stability analysis of a quadruped robot on a slope[D]. Qingdao:Ocean University of China, 2009.
[12] Kuhlman M J, Joe H, Donald S, et al. Stabilizing task-based omnidirectional quadruped locomotion with virtual model control[C]//IEEE International Conference on Robotics and Automation. Piscataway, USA:IEEE, 2015:5171-5176.
[13] Douwe D, Michiel C, Jan B, et al. Control and omni-directional locomotion of a crawling quadruped[C]//4th International Conference on Simulation, Modeling, and Programming for Autonomous Robots. New York, USA:Springer-Verlag, 2014:486-497.
[14] Santos C P, Matos V. CPG modulation for navigation and omnidirectional quadruped locomotion[J]. Robotics and Autonomous Systems, 2012, 60(6):912-927.
[15] 高杉.四足机器人静态全方位步行的稳定性研究及实验仿真[D]. 青岛:中国海洋大学,2008. Gao S. The study of stability in omni-directional static walking of a quadruped robot and the simulation[D]. Qingdao:Ocean University of China, 2008.
[16] 王立鹏,王军政,汪首坤,等. 基于足端轨迹规划算法的液压四足机器人步态控制策略[J].机械工程学报,2013, 49(1):39-44. Wang L P, Wang J Z, Wang S K, et al. Strategy of foot trajectory generation for hydraulic quadruped robots gait planning[J]. Journal of Mechanical Engineering, 2013, 49(1):39-44.