Spring-assisted cable drive mechanism

Cable-driven mechanism with spring and auxiliary motor for torque reduction

This technology features a cable-driven joint mechanism that incorporates a spring, an auxiliary motor, and a variable reduction ratio unit to distribute joint driving torque. It utilizes the elastic energy of the spring to reduce the load on the main motor, while the auxiliary motor and a variable reduction ratio unit—using an eccentric spool or elliptical gear—reduce the control torque required to maintain specific angles.

Wearable robot joint actuators often suffer from large volumes and high moments of inertia, making high-speed response difficult. Furthermore, generating the high torque required for joint movement necessitates large-capacity motors, leading to increased power consumption and weight.

This technology connects a spring unit to the drive motor to assist with rotational torque. By using a variable reduction ratio unit (eccentric spool or elliptical gear) connected to an auxiliary motor, it optimizes the load and position-holding torque of the auxiliary motor, thereby improving the energy and operational efficiency of the entire system.

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Key Features:

• A joint unit configured to rotate, and a joint cable with one end wound around the joint unit to transmit rotational force
• A drive motor unit connected to the other end of the joint cable to transmit rotational force to the joint unit during operation
• A spring unit with one end wound around the drive motor unit to assist with rotational force when the drive motor rotates in one direction, and an auxiliary motor unit that controls the tension of the spring unit
• A variable reduction ratio unit connected to the other end of the spring unit that changes the reduction ratio of the auxiliary motor to reduce the torque required to maintain a set angle

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