This work explores regulation of forward speed, step length, and slope walking for the passive-dynamic class of bipedal robots. Previously, an energy-shaping control for regulating forward speed has appeared in the literature; here we show that control to be a special case of a more general time-scaling control that allows for speed transitions in arbitrary time. As prior work has focused on po...

Autonomous walking bipedal machines, possibly useful for rehabilitation and entertainment purposes, need a high energy efficiency, offered by the concept of ‘Passive Dynamic Walking’ (exploitation of the natural dynamics of the robot). 2D passive dynamic bipeds have been shown to be inherently stable, but in the third dimension two problematic degrees of freedom are introduced: yaw and roll. We...

Previous research indicates that an increased amount of step width variability in humans is associated with an unstable locomotive pattern. For example, the elderly have an increased amount of step width variability compared to their younger counterparts (Ownings & Grabiner, 2004). This notion is further supported by simulations from passive dynamic walking models. Twodimensional passive dynami...

This paper is concerned with the passive walking of an underactuated biped robot. First, we present the modelling of the biped robot (that is a 7 DOF robot). Then, we focus on the study of the almost passive dynamic walking. In particular, we show that the application of a nonlinear feedback control to stabilize the torso and knees leads the biped robot to perform a stable almost-passive dynami...

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...

This paper presents the simplest walking model with an upper body. The model is a passive dynamic walker, i.e. it walks down a slope without motor input or control. The upper body is confined to the midway angle of the two legs. With this kinematic constraint, the model has only two degrees of freedom. The model achieves surprisingly successful walking results: it can handle disturbances of 8% ...

Human walking can be approximated as a mechanical process governed by Newton’s laws of motion, and not controlled. Tad McGeer first demonstrated, and we have confirmed, that a two-dimensional legged mechanism with four moving parts can exhibit stable, human-like walking on a range of shallow slopes with no actuation and no control (energy lost in friction and collisions is recovered from gravit...

We consider passive dynamic walking machines of the kind originally studied by McGeer. For passive walking on arbitrarily small slopes, we show that any existing gaits must be correspondingly slow. The argument is rst presented for nonsingular mass distributions, where it is shown that small slopes preclude long steps and that small steps imply low speeds. The argument is then extended to singu...

A two-straight-legged walking mechanism with flat feet is designed and built to study the passive dynamic gait. It is shown that the mechanism having flat feet can exhibit passive dynamic walking as those with curved feet, but the walking efficiency is significantly lower. It is also shown that the balancing mass and its orientation are etfective for controlling side-to-side rocking and yaw, wh...

INTRODUCTION As shown by McGeer (1990), the passive dynamics of the legs are sufficient to walk down a gentle slope with no external control, and no external energy input save from gravity. Here we consider different models based on passive dynamics, including actively powered models that still make use of passive dynamic principles. We consider the stability of these models, and the implicatio...