Exploiting Visual Constraints in the Synthesis of Uncertainty-Tolerant Motion Plans

We introduce visual constraint surfaces as a mech- anism to effectively exploit visual constraints in the synthesis of uncertainty-tolerant robot motion plans. We first show how object features, together with their projections onto a camera image plane, define a set of visual constraint surfaces. These visual constraint surfaces can be used to effect visual guarded and visual compliant motions (which are analogous to guarded and compliant motion using force control). We then show how the backprojection approach to fine-motion planning can be extended to exploit visual constraints. Specifically, by deriving a configuration space representation of visual constraint surfaces, we are able to include visual constraint surfaces as boundaries of the directional backprojection. By examining the effect of visual constraints as a function of the direction of the commanded velocity, we are able to determine new criteria for critical velocity orientations, i.e. velocity orientations at which the topology of the directional backprojection might change.