Unidirectional creep compensator and twisted string actuator comprising the same

Unidirectional Compensator for Mechanical Creep Compensation

This technology relates to a unidirectional creep compensator and a twisted string actuator equipped with the same, designed to mechanically compensate for creep occurring in flexible material reduction elements.

Actuators using fiber materials, such as twisted string actuators, have historically suffered from performance degradation and reduced repeatability due to the accumulation of creep during prolonged use.

By applying continuous contractile force to the drive line using only an elastic structure and a one-way bearing, this technology compensates for creep, maintaining control performance and repeatability without the need for additional sensors or complex control systems.

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Key Features:

• A twisted string drive unit that generates tension in the drive string as a pair of twisted string units move in opposite directions.
• A joint member and output shaft that receive power from the twisted string drive unit to enable bidirectional motion control.
• An auxiliary drive unit connected to the output shaft of the joint member to directly control the bidirectional motion of the output shaft.
• An elastic structure that stores contractile force and applies it to the drive string when creep occurs to compensate for the displacement.

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of a compact, lightweight, high-performance, and highly durable safe drive module based on string twisting, utilizing string surface reinforcement, variable radius pulleys, and hybrid drive control, as well as support from the Ministry of Science and ICT for the second phase (third stage) of bionic wrist design technology development.