In the last decades the increment of processing power of digital controllers has lead to noteworthy improvements in planning and robot control. Interesting results have been achieved in the impedance control of stiff actuators, where, thanks to very accurate force measurements and fast control loops, it has been possible to perform challenging interaction tasks. More recently, roboticists have ...

This paper reports on the design of a biorobotic actuator intended for use in a powered, below-knee prosthesis. Design requirements for the artificial muscle and tendon are based on the properties of the natural limb. As biological properties often exhibit significant variability, data from a variety of vertebrate species are extracted from published reports in the biological literature and use...

Many stroke patients are expected to rehabilitate at home, which limits their access to proper rehabilitation equipment, treatment, or assessment by therapists. We have developed a novel telerehabilitation system that incorporates a human-upper-limb-like device and an exoskeleton device. The system is designed to provide the feeling of real therapist-patient contact via telerehabilitation. We a...

In many applications, robots can benefit from compliant elements integrated in their structure: Shock resistance and superior force control performance are two out of many advantages compared to stiff robots. In contrast, stiff robots are often superior compared to compliant (soft) robots in terms of position accuracy and bandwidth. We are trying to merge the best of these two worlds by combini...

Important robotic tasks could be most effectively done by powerful and accurate manipulators. However, high accuracy is generally unattainable in manipulators capable of producing high task forces due to such factors as high joint, actuator, and transmission friction and link elastic and geometric distortions. A method called Base Sensor Control (BSC) has been developed to compensate for nonlin...

A novel model is described for predicting the static behavior of a piezoelectric cantilever actuator with an arbitrary configuration of elastic and piezoelectric layers. The model is compared to deflection measurements obtained from 500m-long ZnO cantilever actuators fabricated by surface micromachining. Modeled and experimental results demonstrate the utility of the model for optimizing device...

The aim of the present work is to simulate and understand dynamics of partially debonded axisymmetric piezoactuators. The mathematical and computer models are based on a semi-analytical integral approach. Simulation results are analyzed and compared with experimental data. The wavefields have integral representations of Fourier transforms of Green’s matrix of an elastic layer and surface load g...

Hysteresis nonlinearity of piezoelectric actuator deteriorates its control performance. Unlike traditional model-based control scheme, this paper employs a novel adaptive control algorithm without modeling of hysteresis to achieve a precise tracking control. The piezoelectric actuator system in question consists of models in the form of a linear time-invariant dynamic system in series with a di...