An instrumented glove for grasp specification in virtual-reality-based point-and-direct telerobotics.

Abstract

Hand posture and force, which define aspects of the way an object is grasped, are features of robotic manipulation. A means for specifying these grasping "flavors" has been developed that uses an instrumented glove equipped with joint and force sensors. The new grasp specification system will be used at the Pennsylvania State University (Penn State) in a Virtual Reality based Point-and-Direct (VR-PAD) robotics implementation. Here, an operator gives directives to a robot in the same natural way that human may direct another. Phrases such as "put that there" cause the robot to define a grasping strategy and motion strategy to complete the task on its own. In the VR-PAD concept, pointing is done using virtual tools such that an operator can appear to graphically grasp real items in live video. Rather than requiring full duplication of forces and kinesthetic movement throughout a task as is required in manual telemanipulation, hand posture and force are now specified only once. The grasp parameters then become object flavors. The robot maintains the specified force and hand posture flavors for an object throughout the task in handling the real workpiece or item of interest. In the Computer integrated Manufacturing (CIM) Laboratory at Penn State, hand posture and force data were collected for manipulating bricks and other items that require varying amounts of force at multiple pressure points. The feasibility of measuring desired grasp characteristics was demonstrated for a modified Cyberglove impregnated with Force-Sensitive Resistor (FSR) (pressure sensors in the fingertips. A joint/force model relating the parameters of finger articulation and pressure to various lifting tasks was validated for the instrumented "wired" glove. Operators using such a modified glove may ultimately be able to configure robot grasping tasks in environments involving hazardous waste remediation, flexible manufacturing, space operations and other flexible robotics applications. In each case, the VR-PAD approach will finesse the computational and delay problems of real-time multiple-degree-of-freedom force feedback telemanipulation.