Propeller Motion of a Devil-Stick using Normal Forcing

TL;DR

This paper presents a novel control method for inducing stable propeller motion in a devil-stick using only normal forces, employing virtual holonomic constraints and intermittent force application.

Contribution

It introduces a new control strategy for nonprehensile manipulation of an underactuated system using normal forces and virtual holonomic constraints.

Findings

Successfully stabilizes propeller motion through intermittent large forces.

Demonstrates stable motion without contact loss in simulations.

Provides conditions for stable propulsion in the devil-stick system.

Abstract

The problem of realizing rotary propeller motion of a devil-stick in the vertical plane using forces purely normal to the stick is considered. This problem represents a nonprehensile manipulation task of an underactuated system. In contrast with previous approaches, the devil-stick is manipulated by controlling the normal force and its point of application. Virtual holonomic constraints are used to design the trajectory of the center-of-mass of the devil-stick in terms of its orientation angle, and conditions for stable propeller motion are derived. Intermittent large-amplitude forces are used to asymptotically stabilize a desired propeller motion. Simulations demonstrate the efficacy of the approach in realizing stable propeller motion without loss of contact between the actuator and devil-stick.