Reaction Force Control Device for Exoskeleton Systems and Variable Stiffness Actuator Used Therein

Variable Stiffness Actuator for Exoskeletons with Reaction Force Control via Translational Elastic Members

This technology enables real-time adjustment of reaction forces during joint movement using a variable stiffness actuator installed in the joint of an exoskeleton robot. By placing an elastic member between an inner rotor connected to the joint axis and an outer support, and using a linear actuator to shift the physical position of the elastic member, the system variably controls the radius of rotation and the level of elasticity.

Conventional exoskeleton systems lack a mechanism to actively adjust joint reaction forces (haptic feedback) to a user's desired level, which limits the optimization of gait assistance and rehabilitation therapy.

This technology features a cross-shaped inner rotor connected to the joint axis and a rectangular outer support frame fixed to the first link, with an elastic member positioned between them that can translate along a movement slot. An adjustment actuator (linear actuator) controls the position of the elastic member to increase or decrease reaction force, while a torque sensor measures the force, allowing the control unit to perform feedback-based regulation.

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Key Features:

• An inner rotor connected to the joint axis that rotates in unison, and an outer support fixed to the first link
• A variable elastic body including an elastic member positioned to translate between the inner rotor and outer support, providing reaction force during joint movement
• An adjustment actuator that increases or decreases reaction force by translating the position of the elastic member within the variable elastic body
• Movement slots formed in the inner rotor and outer support to guide the translational movement of both ends of the elastic member

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