Passive Hierarchical Impedance Control Via Energy Tanks
Passive Hierarchical Impedance Control Via Energy Tanks
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DOI：
10.1109/lra.2016.2645504
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发表时间：
2017-04
影响因子：
5.2
通讯作者：
Alexander Dietrich;Xuwei Wu;Kristin Bussmann;C. Ott;A. Albu-Schäffer;S. Stramigioli
中科院分区：
文献类型：
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作者：
Alexander Dietrich;Xuwei Wu;Kristin Bussmann;C. Ott;A. Albu-Schäffer;S. Stramigioli
具有大量驱动自由度的现代机器人系统可用于同时执行多个任务，同时遵循给定的优先顺序。最常用的方法是应用零空间投影来实现这种严格的层次结构，其中，只要较低优先级的任务不干扰任何较高优先级的目标，就执行它们。然而，引入零空间投影仪不可避免地破坏了被动的有益和与安全相关的特征。在这里，提出了两个控制器来恢复无源性：一个在每个层次结构级别上有局部能量罐，另一个在整个系统上有一个全局能量罐。无源性的形式证明表明，这些控制器不会产生能量。一旦油箱空了，被动仍然是保证的，但代价是一些控制性能。在力矩控制机器人上的仿真和实验验证了该方法的有效性，并为其在安全相关应用中的应用奠定了基础。
Modern robotic systems with a large number of actuated degrees of freedom can be utilized to perform several tasks at the same time while following a given order of priority. The most frequently used method is to apply null space projections to realize such a strict hierarchy, where lower priority tasks are executed as long as they do not interfere with any higher priority objectives. However, introducing null space projectors inevitably destroys the beneficial and safety-relevant feature of passivity. Here, two controllers are proposed to restore the passivity: one with local energy tanks on each hierarchy level and one with a global tank for the entire system. The formal proofs of passivity show that no energy is generated by these controllers. Once the tanks are empty, passivity is still guaranteed at the cost of some control performance. Simulations and experiments on a torque-controlled robot validate the approaches and predestine them for the usage in safety-relevant applications.