Design consideration for shock-absorbing spring at the tail of firefighter-assistive robot

This paper deals with the design consideration for torsional spring at the tail of firefighter-assistive robot in order to improve the shock resistance with increasing its compliance mechanically. The tail was frequently broken during the robot dropped on the floor and crashed against objects in fire site. To decrease fracture of the tail and preserve functions of the robot, the spring interconnected with the tail´s shaft can be devised. The stiffness and preload are selected as design parameters to evaluate the capacity of spring to endure impact. The open angle of the tail after dropping and the torque consumption of the robot until settling time when the robot reaches a desired speed are chosen as design measures to determine the best values of the design parameters within a specified range. Two different types of simulation show that the higher stiffness can lead to the smaller open angle but the stiffness has little to do with the torque consumption. It is also evident that the amount of the preload has very little affected the open angle and the torque consumption.