Experimental characterization of Bowden cable friction

This paper presents a systematic method for experimental characterization of Bowden cable friction. A novel tension measurement method using a motion capture system and a spring is introduced. With the tension measurement method, the effects of nine variables on friction are investigated. Experimental results show that i) a combination of 7×19 FEP-coated stainless steel cable and double-sheaths has the highest force transmission efficiency; ii) smaller coefficient of friction material, smaller cable moving speed, shorter cable length, longer clamp distance, stiffer cable/sheath all help to increase the force transmission efficiency; and iii) the static friction pretension ratio only decreases as the coefficient of friction of cable/sheath decreases or as cable/sheath stiffness increases. We have generated guidelines for the Bowden cable performance which may help robotics researchers in choosing materials for the Bowden cables and designing control systems for actuation.