Unparameterized Optimization of the Spring Characteristic of Parallel Elastic Actuators
Unparameterized Optimization of the Spring Characteristic of Parallel Elastic Actuators
复制标题
并联弹性执行器弹簧特性的非参数化优化
DOI：
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发表时间：
2019
影响因子：
5.2
通讯作者：
M. Wisse
中科院分区：
文献类型：
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作者：
Linda F. van der Spaa;W. Wolfslag;M. Wisse
在电动机器人中，大部分能量损失是由于执行器的加热造成的。通过优化弹性元件，使其提供所需的大部分扭矩，可以大大减少平行弹性执行器的能量损失。以前使用的优化方法依赖于参数化弹簧特性，从而限制了在此基础上优化的弹簧特性集，从而可以获得减少损失的方法。这封信表明，这种参数化是不必要的；提出了一种以轨迹解析函数形式计算最优特性的方法。通过两个算例验证了该方法的有效性。第一个例子考虑了在行走过程中支撑人体脚踝的平行弹性致动器的最佳弹簧特性。第二个示例将该方法与轨迹优化相结合应用于执行特定拾取任务的单自由度机器人。手头的任务在拾取位置和放置位置之间存在高度差。利用解析式最优弹簧，表明机器人可以在没有外部电力供应的情况下回收足够的包装释放的能量。
In electrically actuated robots most energy losses are due to the heating of the actuators. This energy loss can be greatly reduced with parallel elastic actuators, by optimizing the elastic element such that it delivers most of the required torques. Previously used optimization methods relied on parameterizing the spring characteristic, thereby limiting the set of spring characteristics optimized over and with that the loss reduction that can be obtained. This letter shows that such parametrization is not necessary; a method is presented to compute the optimal characteristic as an analytic function of the trajectory. The efficacy of this method is demonstrated using two examples. The first example considers the optimal spring characteristic for a parallel elastic actuator supporting the human ankle during walking. The second example applies the method in combination with trajectory optimization on a single degree of freedom robot performing a specific pick-and-place task. The task at hand has a height difference between the pick and the place location. With the analytical optimal spring, it is shown that the robot can recover enough of the energy released by the package to function without external electric energy supply.