Differential drive robot: Spline-based design of circular path

Abstract

When moving a robot, acceleration of the robot varies. This is an important problem, when changes in acceleration are abrupt, all parts of the robot are subjected to these variations. Parts of the robot can bend or damages can appear. When using camera on-board (like RGB-D), you need to put it at a height such that you can see obstacles. Due to acceleration, the camera will swing and you need to stop the robot and wait till the end of oscillations to take the picture. To avoid this problem on a differentially driven robot (two motors), we need to have a constant rotation of the two wheels. Acceleration should be zero and has to be considered as a constraint. For the purpose of this paper, it is assumed that the robot moves on a path of shape of a circular arc. It should be noted that circular arc function does not fit all possible paths, which the robot might be required to take. This results in the need for adaptation of the path design and makes computing an optimal path not only an interesting but also an important problem. For its solution, the following has to be taken into account: physical features of the robot, dynamics of the robot and environments where the robot operates. In later sections of this paper, two possible adaptations are presented and discussed. The first one is based on a modification of a known algorithm, while the second one is authors’ own contribution to the problematic. Resulting adaptations of the design are then tested and assessed using simulation.