The autonomous locomotion of a legged robot presents several challenges, such as stability and sensitivity to the ground slope. Complex sensory systems, accurate physical models, and demanding computational resources are often required to maintain balance, that together with precise servo control leads to high energy consumption levels. This paper addresses the problem of controlling the locomo...

The purpose of this study was to test the hypothesis that downslope treadmill walking decreases spinal excitability. Soleus H-reflexes were measured in sixteen adults on 3 days. Measurements were taken before and twice after 20 min of treadmill walking at 2.5 mph (starting at 10 and 45 min post). Participants walked on a different slope each day [level (Lv), upslope (Us) or downslope (Ds)]. The...

The focus of studies in the field of passive walking has often been on straight walking, while less attention has been paid to the field of turning motions. In this paper, the passive motions of a finite width rimless wheel as the simplest 3D model of passive biped walkers was investigated with a focus on turning motions. For this purpose, the hybrid model of the system consisting of continuous...

Unexpected changes in flexor-extensor muscle activation synergies during slope walking in the cat have been explained previously by 1) a reorganization of circuitry in the central pattern generator or 2) altered muscle and cutaneous afferent inputs to motoneurons that modulate their activity. The aim of this study was to quantify muscle length changes, muscle loads, and ground reaction forces d...

This study investigated the energetics of the human ankle during the stance phase of downhill walking with the goal of modeling ankle behavior with a passive spring and damper mechanism. Kinematic and kinetic data were collected on eight male participants while walking down a ramp with inclination varying from 0° to 8°. The ankle joint moment in the sagittal plane was calculated using inverse d...

Some modern walking robots are capable of walking over very rough terrain. However, these robots often require significantly more energy to do so than a human. Passive-dynamic walking robots are often quite energy-efficient, but are usually only able to walk over smooth surfaces. In this work, we examine the dynamics of a 2D rimless wheel, an often studied simple model for walking. This paper a...

There exists a class of two-legged machines for which walking is a natural dynamic mode: Once started on a shallow slope, such a machine will settle into a steady gait quite comparable to human walking, without active control or energy input. Interpretation and analysis of the underlying physics is straighgorward; the walking cycle, its stability, and sensitivity to parameter variations are eas...

Body accelerations during human walking were recorded by a portable measuring device. A new method for parameterizing body accelerations and finding the pattern of walking is outlined. Two neural networks were designed to recognize each pattern and estimate the speed and incline of walking. Six subjects performed treadmill walking followed by self-paced walking on an outdoor test circuit involv...

On the basis of differences in physiology, e.g., histochemical properties and spindle density, and the structural design of the cat soleus (SO) and medial gastrocnemius (MG) muscles, we hypothesized that 1) fascicle length changes during overground walking would be both muscle and slope dependent, which would have implications for the muscles' force output as well as sensory function, and that ...