Pushing using compliance

TLDR: This paper presents an approach based on the rapidly-exploring random tree (RRT) algorithm that, besides paths through the open space, exploits the power of compliance.

Abstract: This paper addresses the problem of maneuvering an object by pushing it through an environment with obstacles. Instead of only pushing the object through open spaces, we also allow it to use compliance, e.g. allowing it to slide along obstacle boundaries. The advantage of using compliance is twofold: compliance does not only extend the number of situations in which a push plan can be found, it also allows for simpler (i.e. less complicated) paths in many cases. Here, we present an approach based on the rapidly-exploring random tree (RRT) algorithm that, besides paths through the open space, exploits the power of compliance

Figures

Figure 4: The push range. The path of the object is shown by the dotted arrow. (a) The (counter clockwise) push range if no friction is assumed between the object and the obstacle. (b) The push range if there is friction between O and the obstacle. (c) The (clockwise) push range if O is pushed around an endpoint of an obstacle (no friction). (d) Pushing cannot continue because P is forced outside the push range by an obstacle.

Figure 3: (a) An example of the compliant space CSro shown as the dotted lines. (b) The racetrack Rroγi of an obstacle γi. The position of O can be described by its compliant position.

Figure 10: (a) A scene consisting of 4 obstacles. As can be seen from the compliant space CSro (the dotted lines), the top 3 obstacles form a compliant component while the bottom obstacle is a compliant component on its own. (b) Even though the two obstacles form a compliant component, the object runs into a dead-end.

Table 1: Results of the experiments.

Figure 13: Ray shooting in the contact spaces. The rays are the dotted arrows. (a) A circular ray shoot in CSrp to collision check the contact transit. (b) A linear ray shoot in CSro to collision check the path of O. The arrow shows the point of collision. (c) A linear ray shoot in CSrp to collision check the wedges.

Figure 19: (a) Experimentation scene. At the left the start configuration is shown, in the center the goal configuration. (b) An example of a final path, the dotted lines represent non-compliant path segments, the solid lines represent compliant path segments.