INTRODUCTION In general, two different models are employed when addressing animal and human locomotion on a simple mechanical level: the inverted pendulum model for walking, where the body is reduced to a point mass m at the center of mass (COM) vaulting over a rigid stance leg of length l0, and the spring-mass model for running or hopping, where the rigid stance leg is substituted by a compres...

This paper presents a deformable model that offers control of the isotropy or anisotropy of elastic material, independently of the way the object is tiled into volume elements. The new model is as easy to implement and almost as efficient as mass-spring systems, from which it is derived. In addition to controlled anisotropy, it contrasts with those systems in its ability to model constant volum...

In this paper we consider a linear wave equation with strong damping and dynamical boundary conditions as an alternative model for the classical spring-mass-damper ODE. Our purpose is to compare analytically these two approaches to the same physical system. We take a functional analysis point of view based on semigroup theory, spectral perturbation analysis and dominant eigenvalues.

We present and analyze different implementations of mass-spring systems for interactive simulation of deformable surfaces on graphics processing units (GPUs). For the amount of springs we target, numerical time integration of spring displacements needs to be accelerated and the transfer of displaced point positions for rendering must be avoided. To fulfill these requirements, we exploit feature...

We present an open source physics engine specialised for multi-cellular artificial organisms simulations. It is computationally efficient in comparison to gas-based and finite element models and more realistic than standard mass-springdamper systems. Introduction Morphogenetic engineering can often make good use of some biologically plausible improvements. Mechanics, in particular, are quite im...

Spring-mass systems are widely used in computer animation to model soft objects. Although the systems can be numerically solved either by explicit methods or implicit methods, it has been difficult to obtain stable results from explicit methods. This paper describes detailed discussion on stabilizing explicit methods in spring-mass simulation. The simulation procedures are modeled as a linear d...

We investigated the flexibility of body composition in relation to seasonally variable demands for endurance flight capacity and hyperphagia in a migratory shorebird. Migrating western sandpipers were sampled in spring and fall while refueling at a north temperate stopover and were compared with nonmigrating birds captured at a tropical wintering area in Panama. Sandpipers weighed 25% more at s...

In this study, we investigated dispersion curves and the band gap structure of a multiresonator mass-in-mass lattice system. The unit cell of the lattice system consists of three separate masses connected by linear springs. It was demonstrated that the band gaps can be shifted by varying the spring constant and the magnitude of the internal masses. By using the conventional monatomic (single ma...

The dynamics of human running can be modeled as a simple spring-mass system (McMahon and Cheng, 1990; Blickhan 1989). This model is highly robust in its ability to describe the dynamics of bouncing gaits in animals with 2, 4, 6, or even 8 legs (Blickhan and Full, 1993; Cavagna, G.A. et al., 1977). Independent studies have shown that one-legged and two-legged hopping both exhibit linear relation...

− This paper treats a relay-feedback mass measurement system that uses a relay with dead zone and feeds back the displacement of the object. The efficacy of the proposed method has been already confirmed experimentally. In actual measurement, however, the object to be measured was guided by a spring for avoiding rotation. The effect of stiffness produced by this spring on mass estimation has no...