Compliant In-hand Rolling Manipulation Using Tactile Sensing

Abstract

We investigate in-hand rolling manipulation using a multifingered robot hand, where each finger is compliant and equipped with a tactile fingertip providing contact location and wrench information. We derive the equations of motion for compliant quasistatic in-hand rolling manipulation and formulate a fingertip rolling manipulation controller for multiple fingers to achieve a desired object twist within a grasp. The contact mechanics are demonstrated in simulation and the controller is tested on an experimental robot system.

Figures (16)

• Figure 1: Most in-hand manipulation requires rolling, sliding, and/or spinning at finger contact patches, as illustrated in this example of three-fingered in-hand twisting of the lid of a jar.
• Figure 2: Three major categories of dexterous manipulation in a common example of tool use. The lower chopstick is held in a fixed grasp, the upper chopstick undergoes in-hand manipulation, and the chopsticks push the steamed bun (nonprehensile manipulation) before grasping it.
• Figure 3: A classification of types of dexterous manipulation. This paper focuses on quasistatic in-hand rolling manipulation of rigid bodies.
• Figure 4: Simplified model of a finger. The "anchor" is driven by high-impedance, effectively position-controlled, finger joints, typical of the highly-geared actuators used in many robot hands. The fingertip is mounted to the anchor by a 6-dof flexure, providing passive compliance and the possibility of force control for safe manipulation of rigid objects.
• Figure 5: The Barrett WAM robot arm and Allegro hand equipped with Visiflex tactile sensors.