Design of a Walking Assistance Lower Limb Exoskeleton for Paraplegic Patients and Hardware Validation Using CoP

Abstract

The design of an assistive lower limbexoskeleton robot for paraplegic patients that canmeasurethecentreofpressureispresented.Incontrastwithmostbipedwalkingrobots,thecentreofpressure(CoP) or zero moment point (ZMP) has not beenactivelyusedintheoperationofexoskeletonrobots.Inorderto measure CoP in our exoskeletonrobot,twokinds of force sensor units are installed in theexoskeleton:lowprofileforcesensorsinfootmodulesto measure the human weight transferred to thegroundandaloadcellattheshankframetomeasurethesupportingforce.TheCoPoftheexoskeletonrobot is calculated from the above force sensors, aninclinometeratthewaist,andthepositionsof14DOFexoskeleton joints with an algorithm to change thefixedpivotusingafootcontactsensor.Experimentsonan able‐bodied person wearing the designedexoskeletonandwalkingonthegroundareperformedto validate the designed hardware system. Throughthe experiments, the trajectory of the CoP of heexoskeletonwithawearerarecalculatedbasedontheproposedalgorithmanditiscomparedwiththevaluemeasured by a commercial pressure measurementsystem.