Measured and Simulated Motion of a Hopping Rotochute

Abstract

A new hybrid micro vehicle called the hopping rotochute has been developed to robustly explore rough and complex terrain. Unlike other jumping robots, the vehicle traverses an area by intermittently powering a small coaxial rotor system that allows the device to hop over obstacles of various shapes and sizes. Amovable internal mass controls the vehicle’s direction of travel, and the exterior shape and low mass center allow the vehicle to passively reorient itself to an upright attitude when in contact with the ground. This paper presents a dynamic model of the hopping rotochute used to assess the basic flight performance of the vehicle. The experimental methods used to estimate model parameters are described and comparisons between measured and simulated motion are presented. Basic flight performance predicted by dynamic simulation is reported, including maneuverability, jumping performance, and total range. The simulated results indicate that the hopping rotochute is capable of surmounting larger obstacles than current hoppers while being able to navigate with the use of a movable internal mass. Nomenclature CD = aerodynamic drag coefficient Clp, Cmq, Cnr = aerodynamic damping moment coefficients c1n, c1t = normal and tangential damping coefficients associated with body vertices c2n, c2t = normal and tangential damping coefficients associated with the ground face D = aerodynamic reference diameter