Limb kinematics analysis of the cattle-like robot walking on soft ground

The walking procedure of the cattle on a paddy field before spring plowing was captured by the high-speed photography. The properties of the paddy soil used for tests and the geometrical configurations of the hooves of the cattle were examined. Combined with the fitted curve, the graphs of joint angle were drawn. The changes of the joint angles and the orientations of all limbs were analyzed, and then the characteristics of the cattle during walking on paddy field were discussed. The changes of the forelimb were more prominent compared with the hind-limb, moreover, the landing place of the hind-hooves were farther than the fore-hooves, which made the hind-limb have a larger movement space to prevent the interference between forelimb and hind-limb while the strides were increased. The movement of knee joint and elbow joint were very obvious after limb left the ground, the movements of hip joint and shoulder joint were steady to reduce the impact of the ground before limb touched down the ground. The results would provide some theoretical and practical references for bionic design for improving the reasonable motion of the walking mechanisms on soft ground. This work may provide the basic theory in developing cattle-like robot in structural design. Besides, it provides an important reference to study the other bionic robots.