Figure 22: Cycle of steps to displace robot
The motion of the legs can be descibed as a sequence of stages that form a cycle (see Figure 22) which can be iterated as many times as necessary to achieve translation of the robot in the same direction. In each stage, only 1 leg is shifted while the others are kept in the same position. This is to sequentially alter the distribution of weight on the 4 legs of the robot to prepare the centre of mass of the robot to translate forward. If all 4 legs of the robot move in the same direction simultaneously, there would be no forward displacement of the entire robot because the weight distribution amongst the 4 legs remains unchanged and the robot would simply swing back to its original position once the actuation voltage is removed.
In stage 1, all 4 legs are actuated in the same direction (e.g. all 4 front films are actuated making all the legs swing backwards). In stage 2, 1 of the hindlegs is actuated in the opposite direction (e.g. 1 of the hindlegs swings forward) while the other 3 legs are kept actuated in the original position. In stage 3, the other hindleg is then actuated in the same direction as the first hindleg while keeping the positions of the forelegs unchanged (e.g. 2 forelegs of actuated backwards, 2 hindlegs actuated forwards). In stage 4, 1 of the forelegs is actuated in the same direction as the 2 hindlegs. In stage 5, the last stage, the other foreleg is actuated in the same direction as the rest of the legs. At the end of the cycle, all four legs are shifted simultaneously such that the robot takes the same configuration as in stage 1 and the cycle repeats.