Generation of whole-body optimal dynamic multi-contact motions
Generation of whole-body optimal dynamic multi-contact motions
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DOI：
10.1177/0278364913478990
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发表时间：
2013-08-01
影响因子：
9.2
通讯作者：
Kheddar, Abderrahmane
中科院分区：
文献类型：
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作者：
Lengagne, Sebastien;Vaillant, Joris;Kheddar, Abderrahmane
提出了一种规划多接触非步态过渡中最优全身动力学运动的方法。通过对活动关节进行b样条时间参数化，将运动规划问题转化为半无限规划问题，并利用非线性优化技术进行求解。我们的主要贡献在于为任何时间网格生成约束满足保证运动。实际上，我们使用泰勒级数展开来近似固定连续时间间隔内的动态和运动模型，并将问题（约束和成本函数）转换为时间多项式，其中系数是优化变量的函数。对约束条件的评估将其转化为给定求解器的极值（在每个时间区间内）的计算。我们还考虑了碰撞和自碰撞约束，这些约束在时间上没有封闭形式的表达式。我们解决了优化问题中的平衡问题，并证明了为复杂任务生成全身多接触动态运动是可能的，并且可以处理，尽管仍然耗时。我们深入讨论了HRP-2人形机器人的坐姿运动规划，并在其他几个复杂场景中评估了我们的方法。
We propose a method to plan optimal whole-body dynamic motion in multi-contact non-gaited transitions. Using a B-spline time parameterization for the active joints, we turn the motion-planning problem into a semi-infinite programming formulation that is solved by nonlinear optimization techniques. Our main contribution lies in producing constraint-satisfaction guaranteed motions for any time grid. Indeed, we use Taylor series expansion to approximate the dynamic and kinematic models over fixed successive time intervals, and transform the problem (constraints and cost functions) into time polynomials which coefficients are function of the optimization variables. The evaluation of the constraints turns then into computation of extrema (over each time interval) that are given to the solver. We also account for collisions and self-collisions constraints that have not a closed-form expression over the time. We address the problem of the balance within the optimization problem and demonstrate that generating whole-body multi-contact dynamic motion for complex tasks is possible and can be tractable, although still time consuming. We discuss thoroughly the planning of a sitting motion with the HRP-2 humanoid robot and assess our method with several other complex scenarios.