Friction Characterization of a Cable-Driven Differential Actuation System for Lower-Limb Exoskeletons

• URL: http://arxiv.org/abs/2606.15997v1
• Date: Sun, 14 Jun 2026 19:47:32 GMT
• Title: Friction Characterization of a Cable-Driven Differential Actuation System for Lower-Limb Exoskeletons
• Abstract summary: Lower-limb exoskeletons require actuation systems that can provide accurate joint torque control.<n> Conventional architectures often rely on independently actuated joints and joint-level torque sensors.<n>This paper presents a novel differential actuation architecture for hip-knee flexion/extension.
• Score: 42.628421392139
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Lower-limb exoskeletons require actuation systems that can provide accurate joint torque control while preserving low mass and encumbrance. Conventional architectures often rely on independently actuated joints and joint-level torque sensors, increasing system complexity and weight. This paper presents a novel differential actuation architecture for hip-knee flexion/extension, enabling cooperative torque sharing between two motors via a linear differential mapping between motor and joint. To compensate for transmission losses, a model-based friction estimation strategy is developed and experimentally implemented, allowing accurate joint torque estimation without the need for torque sensors. The proposed solution is validated on a physical prototype, demonstrating the feasibility of sensorless torque estimation in a differentially actuated hip-knee module of a lower-limb exoskeleton.

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