Trajectory Optimization With Implicit Hard Contacts
Trajectory Optimization With Implicit Hard Contacts
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DOI：
10.1109/lra.2018.2852785
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发表时间：
2018-10-01
影响因子：
5.2
通讯作者：
Hutter, Marco
中科院分区：
文献类型：
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作者：
Carius, Jan;Ranftl, Rene;Hutter, Marco
我们提出了一个接触不变的轨迹优化配方，综合腿式机器人系统的运动。该方法是能够找到最佳的轨迹受到全身动态硬接触。接触开关是自动确定的。我们利用双层优化的概念，找到梯度的系统动力学，包括约束力，随后解决最优控制问题的无约束iLQR算法。我们的配方实现了快速的计算时间和规模以及接触点的数量。通过仿真实验和真实的硬件实验验证了所产生轨迹的物理正确性。我们展示了我们的方法单腿料斗跳跃和向前跳跃运动合成与任意数量的接触开关。跳跃轨迹可以在机器人上跟踪，并允许它安全地起飞和降落。
We present a contact invariant trajectory optimization formulation to synthesize motions for legged robotic systems. The method is capable of finding optimal trajectories subject to whole-body dynamics with hard contacts. Contact switches are determined automatically. We make use of concepts from bilevel optimization to find gradients of the system dynamics including the constraint forces and subsequently solve the optimal control problem with the unconstrained iLQR algorithm. Our formulation achieves fast computation times and scales well with the number of contact points. The physical correctness of the produced trajectories is verified through experiments in simulation and on real hardware. We showcase our method on a single-legged hopper for which jumping and forward hopping motions are synthesized with an arbitrary number of contact switches. The jumping trajectories can be tracked on the robot and allow it to safely liftoff and land.