Articulated robots such as legged robots hold the promise to lead to versatile, multi purpose machines that eventually become useful in many application scenarios such as construction sites, disaster recovery, service robotics and remote inspection. For these tasks a great deal of kinematic flexibility and dexterity is required. As the inspiring examples in biology show, arms and legs are usefu...

A Hybrid Dynamical Systems Theory for Legged Locomotion

This paper investigates the possible sources of stochasticity and their relative role in metastability of legged locomotion in its simplest form. Passive locomotion of a rimless wheel suggests that stochasticity is an intrinsic–and thus unavoidable– property of legged locomotion. Numerical test results of several hypotheses have been presented on the source of stochasticity of walking: the stoc...

In human and animal locomotion, compliant structures play an essential role in the body and actuator design. Recently, researchers have started to exploit these compliant mechanisms in robotic systems with the goal to achieve the yet superior motions and performances of the biological counterpart. For instance, compliant actuators such as series elastic actuators (SEA) can help to improve the e...

Lizards bend their trunks laterally with each step of locomotion and, as a result, their locomotion appears to be fundamentally different from mammalian locomotion. The goal of the present study was to determine whether lizards use the same two basic gaits as other legged animals or whether they use a mechanically unique gait due to lateral trunk bending. Force platform and kinematic measuremen...

Abstract Until recently, most four-legged robots have lacked a feature that is found again and in nature—a tail. Studies of animal locomotion the laboratory indicate leaving out tails has been design drawback. In fact, research conducted by our lab at Virginia Tech shown an articulated robotic tail can effectively maneuver stabilize quadruped both for static dynamic locomotion.

The analysis of terrestrial locomotion over the past half century has focused largely on strategies of mechanical energy recovery used during walking and running. In contrast, we describe the underlying mechanics of legged locomotion as a collision-like interaction that redirects the centre of mass (CoM). We introduce the collision angle, determined by the angle between the CoM force and veloci...

We present a novel locomotion strategy called legless locomotion that allows a round-bodied legged robot to locomote approximately when it is high-centered. Typically, a high-centered robot is stuck since the robot’s legs do not touch the ground. Legless locomotion uses the legs as a reaction mass to set up oscillatory body rotations which when coupled with ground contact gradually translate th...