1. From: Steinkamp's Toy Can Hop 100 Times But Can't Stand Up
Date of download: 11/1/2017
Copyright © ASME. All rights reserved.
From: Steinkamp's Toy Can Hop 100 Times But Can't Stand Up
J. Mechanisms Robotics. 2017;9(1): doi: /
Figure Legend:
Schematic of the simulation model. (a) The rigid body (gray) and the rigid leg (dark outline with white fill) are connected by a leaf spring (black). The “leg at rest” configuration (striped fill) corresponds to the leg configuration shown in Fig.1(b). The leaf spring allows displacement normal to its length and also rotation (the rotation is never so large as to cause leg collision with the counterweights on the body). The net effect is allowance of leg rotation (leg swing) about the nominal hip and of leg axial motion (body bounce). Horizontal motion of the leg, relative to the body, at the nominal hip, is effectively constrained to zero by the extension stiffness of the leaf spring. (b) In the 2D modeling, the body and leg each have two position coordinates and an angle. The constraint from leaf-spring's inextensibility is modeled using a pin in a slot. In one of our simulation models, the slot is in the body (shown), and in the other, the slot is in the leg. The leaf spring is modeled as a coupled torsion–extension viscoelastic spring in which torque and force both depend on displacement and rotation, with the elastic part determined by classical beam theory.