GOALI: Haptic Cobots

Northwestern University, Evanston IL

Investigators

Abstract

We propose research underlying the use of cobots for haptic display of solid models. The project brings together CAD graphics/haptics researchers at Ford Motor Company with haptics/cobot researchers at Northwestern University. A recently completed 3R haptic cobot will be the experimental testbed for the project. Large-scale haptic display opens up new opportunities, because people interact with large objects (arm size or larger) in a very different way from that in which they interact with small objects (hand size or smaller). An example is the current use of full-size "clay bucks" in automobile design. A sense of the feel and sweep of an automobile body panels cannot be obtained by touching a scale model of it with a finger, as current haptic displays permit. However a full sized virtual model experienced through the proprioception of whole arm motion, in conjunction with the excellent CAD graphics now available, could bring virtual prototyping and surface editing to a new level of utility. Cobot control for haptics differs markedly from robot control for haptics, because cobots use servo-steered rolling mechanisms, rather than servomotor actuators, to create virtual surfaces. The project addresses (1) development of a control methodology for the new power-injection architecture of the 3R cobot. (2) finding cobot-appropriate algorithms for haptic surface rendering directly from NURBS descriptions of surfaces. (3) deriving control laws for dynamic behaviors beyond hard surfaces, including compliant and viscous effects, inertia masking, and artificial potentials (4) finding algorithms for solid-model collision detection which allow the collision to be predicted and rendered by the cobot without exceeding its dynamic limits.