動的なヒューマノイド脚のための非線形パラレル機構カップリングの設計と解析
Design and Analysis of a Nonlinear Parallel Mechanism Coupling for Dynamic Humanoid Legs
膝と足首のパラレル機構を非線形にカップリングし、アクチュエータを股関節近くに配置することで、脚の遠位慣性を低減しつつトルクと速度の要求を相互に補完する直列パラレル脚設計を提案・検証した。
著者: Rohit Kumar, Heiner Peters, Felix Wiebe, Franek Stark, Janne Janzen, Dennis Mronga, Shubham Vyas, Frank Kirchner
分類: cs.RO
原文アブストラクト
Humanoids increasingly demand lightweight leg mechanisms for agile, dynamic, and energy-efficient locomotion. Reducing distal inertia through proximal actuation has thus become a common design goal. Yet, compact transmissions that preserve torque capability and efficient force transmission remain hard to achieve. This paper presents a novel series-parallel leg design combining a knee parallel mechanism, an ankle parallel mechanism, and a nonlinear knee-ankle coupling where all actuators placed closer to the hip. As the knee flexes, the coupling passively assists ankle dorsiflexion for foot clearance and, as it extends it assists plantarflexion for push-off, redistributing ankle load through the knee transmission. We derive the coupling's nonlinear transmission models and validate them in simulation and on hardware. The design shows that the shared transmission lets both joints draw on each other's actuator capacity by easing the knee's peak torque demand under load and the ankle's peak speed demand during fast motion. %Together With the leg's proximal actuator placement, the leg achieves an effective reflected mass of 0.37kg at the foot for a 6kg leg, demonstrating very low distal leg inertia for dynamic humanoid robots.