A Novel Low-Cost, Large Curvature Bend Sensor Based on a Bowden-Cable

Area of Science:

• Materials Science
• Mechanical Engineering
• Sensor Technology

Background:

• Existing bend sensors (conductive ink, optical fiber, electronic textiles) have limitations in performance, usability, and cost.
• Previous research treated Bowden cable inner wire displacement as a position error during sheath bending.

Purpose of the Study:

• To develop a new, low-cost bend sensor capable of measuring wide ranges of accumulated bend angles and large curvatures.
• To leverage the inherent 'position error' in Bowden cables for bend angle detection.

Main Methods:

• Utilized a Bowden cable (coil sheath and inner wire) as the core sensing element.
• Exploited the displacement of the inner wire, caused by sheath bending, to determine the bend angle.
• Employed Hall-effect sensors or potentiometers for inner wire displacement measurement.

Main Results:

• Demonstrated a linear relationship between the accumulated bend angle and the sensor signal (R-square up to 0.9969).
• Achieved a root mean square error of 2% of the full sensing range.
• Showcased robustness against bend curvature up to 80.0 m⁻¹, surpassing previous sensor limitations.

Conclusions:

• The proposed Bowden-cable-based bend sensor offers an affordable and accurate solution for measuring accumulated bend angles.
• The sensor's unique mechanism overcomes limitations of existing technologies and is suitable for diverse applications like motion capture and robotics.