Moment analysis of virtual human joint based on JACK

Abstract

The purpose of this study is to explore the torque size of the joints of the ankle, knee, and hip under the static posture of car driving when an external force is exerted to the low limb joint. Twenty five anthropometric parameters of ten participants were sampled. The personalized digital model of ten participants was set up with sampled anthropometric data in the senior digital modeling of JACK. By simulating the driving posture and using the static strength prediction module of JACK, external force was imposed on front foot to calculate moment of low limb joint when the degree of ankle joint and knee joint was changed. The results indicated that the moment of knee joint and ankle joint produced by external force gradually decrease with the increase of ankle joint angle and the rate of decrease was faster and faster. The moment of hip joint gradually decreased with the increase of ankle joint angle and the decrease amplitude was uniform and linear trend. The moment of ankle joint monotonously increase with the increase of knee joint angle and the increase rate was slower and slower. The moment of knee joint first decreased and then increased with the increase of knee joint angle and the moment of knee was minimum when the angle of knee joint is 110°. The moment of hip joint gradually increased and made a linear increase with the increase of knee joint angle. The results calculated by JACK were compared to the data measured by Primus RS system and their results were consistent. Conclusions can be made from the result: the drivers can properly increase their ankle joint angle or decrease their knee joint angle, so as to reduce the low limb joints torque produced by external force imposed on foot because of braking; it is suggested that 108° to 113°of knee joint angle is the best.