Realization of natural and energy-efficient dynamic walking has come to be one of the main subjects in the research area of robotic biped locomotion. Recently, many approaches considering the efficiency of gait have been proposed and McGeer’s passive dynamic walking (McGeer, 1990) has been attracted as a clue to elucidate the mechanism of efficient dynamic walking. Passive dynamic walkers can w...

The research on the principles of legged locomotion is an interdisciplinary endeavor. Such principles are coming together from research in biomechanics, neuroscience, control theory, mechanical design, and artificial intelligence. Such research can help us understand human and animal locomotion in implementing useful legged vehicles. There are three main reasons for exploring the legged locomot...

Today, commercially available ankle-foot prostheses are completely passive, and consequently, their mechanical properties remain fixed with walking speed and terrain. Conversely, normal human ankle stiffness varies within each gait cycle and also with walking speed [1][2][3]. Furthermore, some studies have indicated that one of the main functions of the human ankle is to provide adequate energy...

In this paper a novel rotational actuator with adaptable compliance is presented. First the importance of adaptable compliance for bipedal walking is explained, and then a number of comparable designs are given with their possible drawbacks. The MACCEPA concept and design is described in detail. The formula to calculate the generated torque is derived. It is shown, depending on the design param...

The planar passive compass-gait biped robot on sloped surfaces is the simplest model of legged walkers. It is a two-degrees-of-freedom impulsive mechanical system known to exhibit, in response to an increase in the slope angle of the walking surface, a sequence of period-doubling bifurcations leading to chaos before falling down at some critical slope without any explanation. The fall is found ...

Passive dynamic walkers (PDWs) are simple dynamical systems that have been used to study the fundamentals of normal human walking. In essence, they are a collection of links and joints capable of “walking” down shallow slopes with a surprisingly human-like gait. PDWs have no active motors or control system, rather they are “powered” by gravity. With judicious choice of model parameters and init...

This article presents a virtual prototyping study of a semi-active lower limb prosthesis to improve the functionality of an amputee during prosthesis-environment interaction for level ground walking. Articulated ankle-foot prosthesis and a single-axis semi-active prosthetic knee with active and passive operating modes were considered. Data for level ground walking were collected using a photogr...

When dealing with walking or hopping biped robots, one of the main objectives is to stand for stable periodic trajectories during regular displacements. From a state space point of view, such objective may correspond to achieve stable limit cycles (e.g. [1] [2] [3]). In such case, the major problem is to look for these potential limit cycles (i.e to prove their existence), and, if existing, to ...