机器人灵巧手抓持规划及抓持力优化方法研究

The robotic dexterous hands as the universal and intelligent end operator, will play an important part in the field of the modern industrial production, military, entertainment and service, but there is a large number of theoretical issues about grasp planning and operating of the dexterous hands to be researched. In the paper the grasp planning, the decomposition of constant force and planning of defective grasp, the optimization of grasping forces and the hydrodynamic modeling of the finger are researched deeply. The optimal grasping indicator- - the maximum volume of electrical external force ellipsoid and the minimum volume of electrical contact internal force ellipsoid in the accepted flattening and the grasp planning method based on task are put forward. Based on the decomposition of constant force subspace, the new evaluation indicator of defective grasp stability- - the maximum passive balanced external force is present and the defective grasp indicator of maximizing the passive balanced external force is raised. The linearization of point constant with friction and two kinds of soft-finger constant is completed, the optimization model with linear constraints as optimization constraints and with the minimum sum-of-squares of joint torques as objective function is set up, and the timely and effective algorithm of the active constraints method is carried out. Based on the hydrodynamics the effect factors of water environment to the dynamic model of the dexterous hands underwater are researched. The research of the grasp planning and optimization of grasping forces is significant for the robotic dexterous hands, and the theoretical basis is built up for the engineering applications of the robotic dexterous hands.

机器人灵巧手作为一种智能型通用机械手爪，在工业、军事、服务和娱乐等领域将扮演重要角色，但灵巧手在抓持规划，特别是退化抓持规划等方面理论问题尚待进一步的研究。本项目将针对机器人灵巧手的抓持规划、退化抓持接触力分解和退化抓持规划、抓持力优化和水下环境手指动力学建模进行深入的理论分析和实验研究。建立基于广义力椭球的最优抓持指标-允许扁平度下的广义外力椭球体积最大和广义接触内力椭球体积最小，并基于此提出面向任务的最优抓持规划方法；用极限被动平衡外力来表征退化抓持的稳定性，建立最大化极限被动平衡外力的退化抓持规划指标；完成各种抓持接触约束模型的线性化，确立以关节力矩平方和最小为目标函数的抓持力优化数学模型，建立出有效的基于关键约束集的抓持力优化方法；在水动力学基础上研究水下环境对于灵巧手手指动力学建模的影响问题。

机器人多指灵巧手作为一种智能型通用机械手爪，可夹持的对象范围更广，被夹持物体位姿调整更灵活，在工业、服务、医疗和娱乐领域具有广泛的应用前景。本项目对灵巧手的退化抓持规划指标、抓持规划方法、水下灵巧手动力学建模和关节力矩优化进行了研究。.在退化抓持的接触力分解基础上，将接触力表示为关节力矩和被动平衡外力的显示形式，推导了正(负)向极限被动平衡外力的求解方法，提出了以最大极限被动平衡外力为目标函数的抓持规划方法，并完成了两指三关节手抓持平面圆盘的退化抓持规划仿真分析。. 在求解机器人灵巧手关节力矩通解的基础上，提出了灵巧手抓持规划指标—允许扁平度下的广义外力椭球体积最大和广义接触内力椭球体积最小。然后以此指标为目标函数建立了基于任务的最优抓持规划方法，仿真和实验结果表明：按规划后的抓持位形和接触点位置进行抓持时，关节输出力矩的均方根和物体承受的接触内力都最小，关节力矩减少了25%，物体承受的接触内力减少了23%。. 以典型的侧摆型三关节手指为例，推导了具体的水阻力矩、附加质量力矩、水流冲击力矩和浮力矩的计算公式，完成了其水下动力学模型的建立和仿真分析，.仿真结果表明，水阻力和附加质量力影响最小，水流冲击和浮力影响最大。. 完成了硬指摩擦点接触、线性模型软指接触和椭球模型软指接触三类约束模型的线性化，并通过合理的选择线性化参数平衡了约束模型线性化的精度和实时性要求。在关节力矩空间提出了抓持力优化目标函数，完成了基于关键约束集的抓持力优化仿真和实验研究，实验结果表明，优化后的各关节力矩都有不同程度的减小，其中近指关节输出力矩减小程度显著。. 建立了由机械本体，上位机系统、任务规划系统，关节运动控制系统和手指尖力传感器处理系统组成的多指灵巧手实验系统，验证了多指灵巧手的退化抓持规划指标和关节力矩优化算法，实现了对椭球体、球体、长圆柱体、短圆柱体、细长杆、薄片体和多棱柱体等形状物体的高效稳定抓持。