The focus of this paper is the problem of foot rotation in biped robots during the single-support phase. Foot rotation is an indication of postural instability, which should be carefully treated in a dynamically stable walk and avoided altogether in a statically stable walk. We introduce the foot-rotation indicator (FRI) point, which is a point on the foot/ground-contact surface where the net g...

The focus of this paper is the problem of foot rotation in biped robots during the single-support phase. Foot rotation is an indication of postural instability, which should be carefully treated in a dynamically stable walk and avoided altogether in a statically stable walk. We introduce the foot-rotation indicator (FRI) point, which is a point on the foot/ground-contact surface where the net g...

Recent advances in computational technology have dramatically increased the use of muscle-driven simulation to study accelerations produced by muscles during gait. Accelerations computed from muscle-driven simulations are sensitive to the model used to represent contact between the foot and ground. A foot-ground contact model must be able to calculate ground reaction forces and moments that are...

During human and animal locomotion, the dynamics of the body can be represented with the help of simplified biomechanical models, such as the spring-mass model (often described as spring-loaded inverted pendulum, SLIP model). In this model, it is assumed that the force generated by each limb resembles that of a linear spring. Furthermore, it is assumed that force generated by the leg mainly act...

The walking of a bipedal robot is composed of different phases such as single support (SS) with flat foot, SS with foot rotation around the metatarsal axis and double support. During every walking phase there is a dynamic model and a contact with the ground. Thus, an appropriated control law has to be implemented for each phase. Generally, the type of contact with the ground is imposed but it i...

Introduction The rapid transmission and poor control policy response during recent Foot-and-Mouth disease (FMD) outbreaks have underscored the need for better decision support tools. At the foundation of these decision support tools are the epidemiological models that are parameterized with the data generated from pathogenesis studies of the FMD virus that contain contact transmission data. The...

Painlevé paradox occurs in rigid-body dynamics of mechanical systems with frictional contacts at configurations where the instantaneous solution is either indeterminate or inconsistent. Dynamic jamming is a scenario where the solution starts with consistent slippage and then converges in finite time to a configuration of inconsistency while the contact force grows unbounded. The goal of this pa...

In the age of an aging society, the prospective role of robots is turning gradually from just working machines to do monotonous work in a factories to partners who support human life. In recent years, a lot of autonomous humanoid robots have been actually realized (Hirai et al. (1998); Kaneko et al. (2008)). These robots can walk on two legs stably by means of the control based on ZMP (Zero Mom...