Velocity control of a cylindrical rolling robot by shape changing

Locomotion of a Cylindrical Rolling Robot with a Shape Changing Outer Surface

“…The outer surface of the rolling robot is a flat strip of polyvinyl chloride plastic put into the shape of an open, elliptical cylinder. The outer surface is firm enough to provide a steady dynamic roll surface, yet it is limber enough to be reshaped by the pull of a linear actuator positioned along the diameter of the cylinder [15]. When the actuator is not being commanded to move, its static holding force maintains a constant cylindrical shape of the outer surface.…”

“…where M = 0.950 kg is total mass of the robot.Ḣ is the time derivative of the angular momentum of the robot about its center of mass, derived by modeling the robot as a collection of point masses that represent the outer surface and hardware components [15]. Equations (5)-(7) are combined into one equation of motion…”

“…where ρ 1 and ρ 2 are constant coefficients ofθ andθ, respectively, of theḢ term [15,19]. Variables x d and y d in Equation 8are expressed as:…”

“…Modular loops, while they are highly configurable and allow roboticists to experiment with different locomotion strategies and gaits, are bulky and mechanically complicated systems [13,14]. In contrast to modular loops, researchers in [15] presented a dynamic rolling robot whose outer surface was a thin, lightweight strip of plastic that morphed by means of a singular servo motor. The robot used all onboard sensing and power to achieve velocity control relative to a desired step profile.…”

“…Results of the research showed that when the robot was given a set of advantageous initial conditions, it was able to accelerate from rest and maintain constant average velocity with significant accuracy. The robot used for the investigation herein, the OSU Roller, is a modified version of the robot presented in [15].…”