Humans tend to swing their arms when they walk, a curious behaviour since the arms play no obvious role in bipedal gait. It might be costly to use muscles to swing the arms, and it is unclear whether potential benefits elsewhere in the body would justify such costs. To examine these costs and benefits, we developed a passive dynamic walking model with free-swinging arms. Even with no torques dr...

This work presents a systematic approach to optimizing the mechanical design of a novel Self-excited Tripedal Dynamic Experimental Robot, STriDER. Specifically, we present a numerical optimization-based formulation for the design of STriDER’s mechanical parameters that minimizes the amount of externally supplied actuation energy consumed while taking a single step. The optimal design is found w...

This paper continues our investigations into the period-three route to chaos exhibited in the passive dynamic walking of a compass-gait biped robot [8]. The further analysis on the resulting chaos is made by Lyapunov exponents and fractal dimension. The chaotic attractor, its first return and its basin of attraction are presented. In addition, the study of the period-3 passive gait is also perf...

Passive dynamic bipeds were first studied by McGeer (McGeer, 1990) as inspired by a bipedal toy described in (McMahon, 1984). Passive dynamic walkers can walk down a shallow slope without actuators and controllers(McGeer, 1990; 1993). McGeer has built passive walkers that exhibit steady motion using a Poincaré map, which he called as a stride function, to analyze the gaits(McGeer, 1990; 1993). ...

The purpose of this study was to investigate the contribution of passive mechanisms to lower extremity joint kinetics in normal walking at slow, comfortable, and fast speeds. Twenty healthy young adults participated in a passive testing protocol in which the relaxed lower limb was manipulated through full sagittal hip, knee, and ankle ranges of motion while kinematics and applied forces were si...

Research has indicated that human walking is more unstable in the secondary, rather than primary plane of progression. However, the mechanisms of controlling dynamic stability in different planes of progression during running remain unknown. The aim of this study was to compare variability (standard deviation and coefficient of variation) and dynamic stability (sample entropy and local divergen...

Sloped walking requires altered strategies for maintaining dynamic balance relative to level-ground walking, as evidenced by changes in sagittal-plane whole-body angular momentum (H) in able-bodied individuals. The ankle plantarflexor muscles are critical for regulating H, and functional loss of these muscles from transtibial amputation affects this regulation. However, it is unclear if a power...

The objective of this study is to obtain optimal cyclic gaits for a biped robot without actuated ankles. Two types of motion are studied: walking and running. For the walking, the gait is composed uniquely of successive single support phases and instantaneous double support phases that are modelled by passive impact equations. The legs swap their roles from one single support phase to the next ...