Per-Contact Iteration Method for Solving Contact Dynamics
Per-Contact Iteration Method for Solving Contact Dynamics
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DOI：
10.1109/lra.2018.2792536
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发表时间：
2018-04-01
影响因子：
5.2
通讯作者：
Hutter, Marco
中科院分区：
文献类型：
--
作者：
Hwangbo, Jemin;Lee, Joonho;Hutter, Marco
本文介绍一种求解接触动力学问题的新的迭代法。所提出的方法是基于一个有效的二分法，迭代每个接触。我们将我们的方法与相同模型的两种现有方法进行了比较，发现它的速度大约是现有方法的两倍。我们还介绍了四种不同的机器人模拟实验，并比较所提出的方法最常见的接触求解器，投影高斯-赛德尔（PGS）方法。我们表明，虽然这两种方法都是非常有效的解决简单的问题，所提出的方法显着优于PGS方法在更复杂的接触情况。用一个CPU内核模拟一个18自由度四足机器人的多触点运动，一个时间步的时间不到20 μ s。这至少比许多其他模拟器快一个数量级，这些模拟器采用多种松弛方法来提高计算速度。所提出的模拟方法也是稳定的，在50赫兹，由于其严格遵守的动态原则。虽然在如此低的更新速率下精度可能会受到影响，但这意味着我们可以模拟18自由度机器人，比真实的时间快上千倍。
This letter introduces a new iterative method for contact dynamics problems. The proposed method is based on an efficient bisection method which iterates over each contact. We compared our approach to two existing ones for the same model and found that it is about twice as fast as the existing ones. We also introduce four different robotic simulation experiments and compare the proposed method to the most common contact solver, the projected Gauss-Seidel (PGS) method. We show that, while both methods are very efficient in solving simple problems, the proposed method significantly outperforms the PGS method in more complicated contact scenarios. Simulating one time step of an 18-DOF quadruped robot with multiple contacts took less than 20 mu s with a single core of a CPU. This is at least an order of magnitude faster than many other simulators which employ multiple relaxation methods to the major dynamic principles in order to boost their computational speed. The proposed simulation method is also stable at 50 Hz due to its strict adherence to the dynamical principles. Although the accuracy might be compromised at such a low update rate, this means that we can simulate an 18-DOF robot more than thousand times faster than the real time.