SG-CPG：严重度门控中枢模式发生器用于连续执行器退化下的自适应四足运动
SG-CPG: Severity-Gated Central Pattern Generators for Adaptive Quadruped Locomotion under Continuous Actuator Degradation
- Purdue University（普渡大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
受动物分级适应启发，提出SG-CPG，通过严重度门控（残余门和幅度门）扩展健康CPG策略，在连续执行器退化下保持四足运动，仿真和实物验证了其鲁棒性。
AI中文摘要：
肢体力量减弱的动物不一定会切换步态，而是会卸载受影响肢体、重新协调其余肢体，并根据损伤严重程度调整其反应。这种分级适应使得运动在肢体力量部分丧失的情况下仍能持续，而不需要在健康和失败之间进行离散转换。受此行为启发，我们提出了SG-CPG，一种用于连续执行器退化下四足运动的中枢模式发生器（CPG）。SG-CPG保留了一个冻结的健康CPG策略，并引入了两个严重度驱动的门：一个残余门，用于重新协调所有四条腿；以及一个幅度门，随着退化加剧，逐渐缩短虚弱腿的步幅。我们通过两种机制模拟渐进式退化：降低关节扭矩上限（上限机制）和缩放其底层控制器增益（增益机制），代表执行器弱化的不同形式。我们在Unitree Go2上的仿真表明，在95%关节强度损失下，SG-CPG在全方位指令调度中保持小跑步态，存活率为100%，同时指令跟踪误差在8%以内。在降低扭矩上限的情况下，移除任一严重度路径（残余的严重度观测或幅度门），在80%损失下，虚弱关节的裁剪步数比例从4.4%分别上升到13.6%和26.3%。在真实Go2上，SG-CPG在29次前进和转弯试验中存活28次，小腿扭矩退化高达93%。这些结果表明，严重度门控适应可以将健康运动策略扩展到渐进式执行器退化，而无需将故障视为离散失败。
英文摘要：
An animal with a weakened limb does not necessarily switch its gait, instead it unloads the affected limb, re-coordinates the remaining limbs, and scales its response with injury severity. This graded adaptation allows locomotion to persist despite partial loss of limb strength, rather than requiring a discrete transition between healthy and failed. Inspired by this behavior, we propose SG-CPG, a central pattern generator (CPG) for quadruped locomotion under continuous actuator degradation. SG-CPG preserves a frozen healthy CPG policy and introduces two severity-driven gates: a residual gate that re-coordinates all four legs and an amplitude gate that progressively shortens the weakened leg's stride as degradation increases. We emulate progressive degradation through two mechanisms: lowering the joint torque ceiling (ceiling mechanism) and scaling its low-level controller gains (gain mechanism), representing distinct forms of actuator weakening. Our simulations on a Unitree Go2 show that SG-CPG maintains a trot gait with 100% survival across an omnidirectional command schedule under 95% joint strength loss while tracking commands within 8%. Under a lowered torque ceiling, removing either severity path, the residual's severity observation or the amplitude gate, raises clipping at the weakened joint from 4.4% to 13.6% and 26.3% of steps at an 80% loss. On a real Go2, SG-CPG survives 28 of 29 forward and turning trials with up to 93% calf torque degradation. These results show that severity-gated adaptation can extend a healthy locomotion policy to progressive actuator degradation without treating the fault as a discrete failure.
