Generalising human demonstration data by identifying affordance symmetries in object interaction trajectories

Abstract

The distinctive feature of modular robots consists in their reconfigurable mechanical structure, as they are assembled on-demand from basic mechatronic units. This implies that kinematic models of the robots need to be computed on a caseby-case basis for each specific assembly, which is a manual and hence time-consuming and error-prone procedure. We propose to automate this process by automatically computing such kinematic models starting from simple descriptions of the modules and their assemblies. This automated computation is supported by our toolchain for programming arbitrary modular robots in arbitrary configurations, presented in this paper.We contribute two novel results through this approach. First, a high-level programming language that provides kinematic abstractions for arbitrary modular robots, in contrast to the robot-specific solutions currently available. Second, a programming abstraction to subsume multiple kinematically equivalent robot assemblies into a so-called kinematic configuration, hence eliminating the need to explicitly enumerate and program each of them. These contributions advance current techniques for modular robot programming by demonstrating a tool that a) targets multiple mechanical platforms, offering the first general solution for modular robot programming, and b) raises the abstraction level by allowing users to reason and program in terms of standardized kinematic models that are automatically mapped to physical robot configurations by the toolchain.

Exploiting affordance symmetries for task reproduction planning

“…The argument for considering affordance symmetries in RPbD and behavior classification was made in [7]. The essence of that paper can be described as follows.…”

“…This section will summarize the extrinsic affordance symmetry concept as presented in previous work [7]. It can be explained as follows.…”

“…It can be visualized as a simpler 2D flow revolved about the axis. In [7] a method was proposed for identifying such symmetries. For the sake of completeness and convenience for the reader the approach will be summarized.…”

“…Using the methods of our previous work [7] the system attempts to guess any extrinsic affordance symmetries important to the task. These are confirmed or denied by the user through a simple interactive process.…”

“…The manifold resulting from this extrusion is illustrated in Figure 5. Such a formulation can easily specify the redundancy in the linear or cylindrical symmetries discussed in [7], but will also cover a broad range of possibilities. The manifold is then discretized as described in the next subsection to enable a conveninent distance measure.…”