Controller design for bipedal walking on dynamic rigid surfaces (DRSes), which are rigid surfaces moving in the inertial frame (e.g., ships and airplanes), remains largely uninvestigated. This paper introduces a hierarchical control approach that achieves stable underactuated bipedal robot walking on a horizontally oscillating DRS. The highest layer of our approach is a real-time motion planner that generates desired global behaviors (i.e., the center of mass trajectories and footstep locations) by stabilizing a reduced-order robot model. One key novelty of this layer is the derivation of the reduced-order model by analytically extending the angular momentum based linear inverted pendulum (ALIP) model from stationary to horizontally moving surfaces. The other novelty is the development of a discrete-time foot-placement controller that exponentially stabilizes the hybrid, linear, time-varying ALIP model. The middle layer of the proposed approach is a walking pattern generator that translates the desired global behaviors into the robot's full-body reference trajectories for all directly actuated degrees of freedom. The lowest layer is an input-output linearizing controller that exponentially tracks those full-body reference trajectories based on the full-order, hybrid, nonlinear robot dynamics. Simulations of planar underactuated bipedal walking on a swaying DRS confirm that the proposed framework ensures the walking stability under different DRS motions and gait types.
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本文研究了黑盒安全测试配置中基于方案的安全测试算法。对于与不同采样分布共享相同州行动集覆盖的算法,通常认为优先考虑探索高风险状态现象会提高采样效率。我们的提案通过引入不可能的定理来对上述直觉提出异议,该定理可证明显示上述差异的所有安全测试算法,同样具有相同的预期采样效率。此外,对于涵盖不同状态活动集的测试算法,采样效率标准不再适用,因为不同的算法不一定会收敛到相同的终止条件。然后,我们提出了基于几乎安全集合概念的测试攻击性定义,以及一种无偏和有效的算法,比较了测试算法之间的侵略性。还提出了来自两足球运动控制器和车辆决策模块的安全测试的经验观察,以支持提出的理论意义和方法。
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我们提出了一个框架,以使用基于适应性神经调节的线性反向摆(LIP)控制器来生成3D发导的两足机器人的周期性轨迹参考。我们使用LIP模板模型在当前步骤结束时估算机器人的质量(COM)位置和速度,并制定一个离散控制器,该控制器确定下一个脚步位置以实现所需的步行配置文件。该控制器配备了基于神经网络的自适应术语,该术语降低了模型不匹配的模型和物理机器人之间的不匹配,这特别影响了横向运动。然后,使用针对唇部模型计算的脚放置位置用于生成任务空间轨迹(COM和摇摆脚部轨迹),以使实际机器人实现稳定的步行。我们使用快速,实时的基于QP的逆运动算法,该算法从任务空间轨迹中产生联合参考,从而使配方独立于机器人动力学知识。最后,我们用数字机器人在两种情况下都获得了稳定的周期性运动,并在模拟和硬件实验中实施了建议的方法。
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