Directional Stiffness Modulation of Parallel Robots With Kinematic Redundancy and Variable Stiffness Joints
Directional Stiffness Modulation of Parallel Robots With Kinematic Redundancy and Variable Stiffness Joints
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DOI：
10.1115/1.4043685
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发表时间：
2019-10
期刊：
影响因子：
--
通讯作者：
A. Orekhov;N. Simaan
中科院分区：
文献类型：
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作者：
A. Orekhov;N. Simaan
并联机器人作为具有刚度调制能力的潜在机构，通过使用驱动冗余来改变内部预紧力。本文通过结合使用运动冗余和变刚度作动器来研究实时刚度调制。利用已知的方向刚度概念来指导并联机器人的实时几何重构和指令关节级刚度的变化。提出了一种加权梯度投影冗余解决方法，用于解决Gough/Stewart并联机器人的运动冗余，同时满足所需的方向刚度和避免腿间的奇异性和碰撞。进行了仿真研究，以描述在使用或不使用可变刚度作动器时使用运动冗余的影响。此外，整个刚度矩阵的调制被证明是调制定向刚度方法的扩展。
Parallel robots have been primarily investigated as potential mechanisms with stiffness modulation capabilities through the use of actuation redundancy to change internal preload. This paper investigates real-time stiffness modulation through the combined use of kinematic redundancy and variable stiffness actuators. A known notion of directional stiffness is used to guide the real-time geometric reconfiguration of a parallel robot and command changes in joint-level stiffness. A weighted gradient-projection redundancy resolution approach is demonstrated for resolving kinematic redundancy while satisfying the desired directional stiffness and avoiding singularity and collision between the legs of a Gough/Stewart parallel robot with movable anchor points at its base and with variable stiffness actuators. A simulation study is carried out to delineate the effects of using kinematic redundancy with or without the use of variable stiffness actuators. In addition, modulation of the entire stiffness matrix is demonstrated as an extension of the approach for modulating directional stiffness.