Development of a Cam‐Based Minimally Invasive Surgical Instrument With Reduced Backlash

BACKGROUND: Due to the joint characteristics and friction, continuum surgical instruments based on hinge joints suffer from issues such as slack and hysteresis, which affect the control precision. METHODS: This study introduces cam-based surgical instruments. The variation in cable length during hinge joint rotation was analysed, prompting a redesign of the cam's outer contour. An experimental platform was built to compare the precision of the traditional circular wheel and the cam mechanism. A prototype of surgical instrument with the proposed design was constructed, which was also put into precision testing. RESULTS: According to the experimental results, the backlash of the cam mechanism was 82% lower than that of the circular wheel. The backlash of our surgical instrument was reduced by 60% at a 20-degree rotation. CONCLUSIONS: This study shows great potential for improving the control precision of continuum surgical instruments with multiple pairs of hinge joints.