Hip Joint Linkage

Hip Joint Linkage for Wearable Robots Generating Multi-Directional Gait Moments via a Four-Bar Mechanism

This technology is a hip joint linkage for wearable robots that utilizes a four-bar mechanism consisting of multiple rotary joints and links to convert input torque from a single actuator into multi-directional output moments—including flexion, extension, abduction, and adduction—synchronized with the gait cycle.

Existing hip joint modules for wearable robots typically require multiple actuators to assist with multi-axial moments, leading to increased system weight and complexity.

This technology proposes a configuration where the drive unit is positioned at the first rotary joint, utilizing a four-bar linkage mechanism composed of six rotary joints and four links. By shifting the instantaneous axis of rotation, it can generate the appropriate output moment direction for each phase of the gait cycle—such as extension and abduction during the early phase, abduction during the mid-phase, and flexion and abduction during the late phase—using only a single actuator. Applicable to gait assistance, industrial strength support, and rehabilitation training, this solution significantly contributes to the lightweight design and cost reduction of wearable robots by enabling multi-directional assistance with a single motor.

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Key Features:

• A hip joint unit connecting the upper body link, which is fixed to the upper body of the wearable robot, to the femoral link connected to the thigh.
• The hip joint unit is configured with multiple rotary joints and links connected as a four-bar mechanism.
• The input moment is converted into output moments in specific directions depending on how it is transmitted through the rotary joints and links.
• Outputs moments in the direction of extension and abduction during the early gait phase, abduction during the mid-phase, and flexion and abduction during the late phase.