Apex height control of a two-mass robot hopping on a rigid foundation. (November 2016)

• Record Type: Journal Article
• Authors: Mathis, Frank B.; Mukherjee, Ranjan
• Is Part Of: Mechanism and machine theory. Volume 105(2016:Nov.)
• Page Start: 44
• Page End: 57
• Publication Date: 2016-11
• Subjects: Two-mass hopping robot -- Apex height control -- Inelastic impact -- Hybrid dynamics -- Hybrid control -- Periodic orbit; Machine theory -- Periodicals; Machinery -- Periodicals; Machines -- Périodiques; Génie mécanique -- Périodiques; Machine theory; Machinery; Periodicals; 621.81
• DOI: 10.1016/j.mechmachtheory.2016.06.014
• Languages: English
• ISSNs: 0094-114X

Abstract

Highlights: Apex height control of a hopping robot is achieved using a hybrid controller. Controller accounts for inelastic impact of robot with the ground. Experimental verification establishes feasibility of implementation of controller. Abstract: The spring loaded inverted pendulum (SLIP) model is commonly used to describe the dynamics of hopping robots. A fundamental limitation of the SLIP model is that it fails to account for impact with the ground; this is due to the fact that the leg is modeled as a massless spring. Assuming that the ground is rigid, a two-mass model with inelastic impact is proposed for more accurate description of hopping dynamics. A control scheme is developed to converge the maximum jumping height of the center-of-mass of the robot to a desired value. The control scheme utilizes feedback linearization in continuous time and update of a control parameter in discrete time. Simulation results are first presented to show the efficacy of the control scheme. Experimental results based on a voice-coil actuator show good match with simulation results despite actuator saturation.