This paper studies an effect of vibration on twisted string actuation inside conduit at high curvature angles. In our previous work. we have mentioned that twisted string actuators can be used to transmit power even at significant curvature angles of the conduit. However, several undesirable effects, namely pull-back, hysteresis, and chattering, were present during actuation due to friction between strings and the internal sheath of the conduit. This paper reports the results of experimental study on effects of vibration on twisted string actuation inside curved conduits. We have demonstrated that applying vibration generated near natural frequency of the system during the stages of twisting and untwisting cycles helped reduce pull-back and hysteresis and increase string contraction. In case when sheath was deflected by 180° under a constant load of 3 kg, we were able to achieve over 40% decrease in pull-back and 30% decrease in hysteresis, compared with no vibration case.

Abstract
1. 서 론
2. 이론적 배경
    2.1 TSA의 기구학적 모델
    2.2 편향된 도관과 꼬인 줄 사이의 마찰력 관계
3. 실험 장치 및 절차
    3.1 실험 장치
    3.2 실험 준비 및 절차
4. 실험적 평가
5. 결론 및 향후 과제
References

• 이동휘(School of Mechanical Engineering, KOREATECH) | Donghyee Lee
• 이고르 가포노브(School of Mechanical Engineering, KOREATECH) | Igor Gaponov
• 유지환(Dept. of Civil and Environmental Engineering, KAIST) | Jee-Hwan Ryu Corresponding author