The regulation of motor variable positions in robots with elastic elements has been solved using PD linear controllers in the absence of gravity and with the addition of a model-based feedforward term when gravity is present. When the mass of the links is not known, an iterative learning scheme can be derived to obtain the same result for both joint elasticity and link flexibility. An extension...

In any compartment with stiff walls the excess pressure of fluid within is determined by a combination of the volume of fluid and the elasticity of the walls. The elastance of the space as a whole can be represented as a change in pressure for unit change in volume (dP/dV or mm. Hg/ml.). It follows that within the knee joint higher pressures will develop in the presence of effusions and when th...

Series elastic actuation that takes inspiration from biological muscle-tendon units has been extensively studied and used to address the challenges (e.g. energy efficiency, robustness) existing in purely stiff robots. However, there also exists another form of passive property in biological actuation, parallel elasticity within muscles themselves, and our knowledge of it is limited: for example...

The spring-mass model is a valid fundament to understand global dynamics of fast legged locomotion under gravity. The underlying concept of elasticity, implying leg stiffness as a crucial parameter, is also found on lower motor control levels, i.e. in muscle-reflex and muscle-tendon systems. Therefore, it seems reasonable that global leg stiffness emerges from local elasticity established by ap...

this study evaluated the effects of end to end joint types of athel stripes at three level (end to end basic, end to end mitrated and end to end half lap joint) used in core layer veneered with three wood species (fir, beech and oak) and glued with three different ratio of melamine formaldehyde/urea formaldehyde resin (0:100, 25:75 and 50:50) on the bending strengths of bloakboard. according to...

When is the level of entry of buyers or sellers effi cient in markets with search and matching frictions? This paper generalizes the well-known Hosios condition for constrained effi ciency to a wide range of dynamic search and matching environments where the expected match output depends on the market tightness. The generalized Hosios condition is simple and intuitive: entry is constrained effi...

Physically-based elastic body simulation has been applied to medical image registration to enforce physical constraints, since each organ in the image can be viewed as an elastic body. However, it requires hand adjustment for the material properties to achieve the desired output shape, and the boundary conditions (forces or displacements on boundary nodes) cannot be acquired directly from the i...

An adaptive architecture for feedforward control oj industrial robots with standard positional controller is presented. This approach explicitly considers robots with elastical joints. It assumes that the real position of the TCP can be recorded for ofline evaluation. Compensation of elasticity is trained in a feedforward controller. Adaptation takes place without any knowledge of the physical ...

For robots with joint elasticity, discrepancies exist between the motor side information and the load side (i.e., end-effector) information. Therefore, high tracking performance at the load side can hardly be achieved when the estimate of load side information is inaccurate. To minimize such inaccuracies, it is desired to calibrate the load side sensor (in particular, the exact sensor location)...