The objectives of this study were to characterize the active and passive contributions to joint kinetics during walking in healthy young and older adults, and assess whether isokinetic ankle strength is associated with ankle power output during walking. Twenty healthy young (18-35 years) and 20 healthy older (65-85 years) adults participated in this study. We measured subject-specific passive-e...

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...

Measures calculated from unperturbed walking patterns, such as variability measures and maximum Floquet multipliers, are often used to study the stability of walking. However, it is unknown if, and to what extent, these measures correlate to the probability of falling. We studied whether in a simple model of human walking, i.e., a passive dynamic walker, the probability of falling could be pred...

Inspired by locomotion in nature, researchers have developed the passive dynamic walking machine principle and applied it to the legged robotics (Coleman & Ruina, 1998; Collins et al., 2001; Garcia, 1999; McGeer, 1990; Wisse, 2004; Wisse & Frankenhuyzen, 2006). The passive dynamic walking machines provide human-like locomotion in legged robots that is more efficient than the precisely joint-ang...

Most of the existing control schemes for walking bipeds are based on the so-called zero-moment point (ZMP) stability condition. Such schemes have three common characteristics: 1) bending at knees thus to avoid singular positions; 2) closed-loop controllers for trajectory tracking at the joints, 3) using higher power actuators, in particular at ankles, to compensate for the rotational motion (fa...

1 Motivation and State of the Art The compass-gait biped and simplest walking model [1,2] have been useful as tools that abstract away the details of a specific walker, allowing the study of properties of the passive nonlinear dynamics. Similarly, the two-link brachiator of Gomes and Ruina [3] has demonstrated that energy-efficient brachiation is possible, i.e., “walking under the surface” (Fig...

Stiff-knee gait is a common walking problem in cerebral palsy characterized by insufficient knee flexion during swing. To identify factors that may limit knee flexion in swing, it is necessary to understand how unimpaired subjects successfully coordinate muscles and passive dynamics (gravity and velocity-related forces) to accelerate the knee into flexion during double support, a critical phase...

This work aims at finding optimal trajectory of compassgait biped walking robot in terms of energy consumption and passive dynamic walking. The planar biped model, an inverted double pendulum, has a free hinge at all joints, i.e., the hip and stance ankle. The impulsive external force is exerted on the swing ankle for short initial period. With the equation of motion, the power of external forc...

Captain Basile is a robot inspired from the cockroach and built to participate at the SAE Walking Machine Challenge 2004, an undergraduate competition of walking robots. The robot weighs 35 kg and is 86 cm long, 58 cm wide and 38 cm tall. Initially validated by the use of dynamic simulations, this pneumatic actuated hexapod is characterised by specialized legs, passive visco-elastic elements an...

Applying an evolutionary algorithm, we first develop the morphology of a simulated passive dynamic bipedal walking device, able to walk down a shallow slope. Using the resulting morphology and adding minimal motor and sensory equipment, a neural controller is evolved, enabling the walking device to walk on a flat surface with minimal energy consumption. The applied evolutionary algorithm fixes ...