the presence of van der waals (vdw) force can lead to mechanical instability in freestanding nano-scale actuators. most of the previous researches in this area have exclusively focused on modeling the instability in actuators with one actuating components. while, less attention has been paid to actuators consist of two actuating components. herein, the effect of the vdw force on the instability...

In this paper, hysteretic behavior modeling, system identification and control of a mechanism that is actuated by shape memory alloy (SMA) wires are presented. The mechanism consists of two airfoil plates and the rotation angle between these plates can be changed by SMA wire actuators. This mechanism is used to identify the unknown parameters of a hysteresis model. Prandtl–Ishlinskii method is ...

Large (>1 m) deformable mirrors are attractive for adaptive optics on ground-based telescopes; the mirrors typically have hundreds or thousands of actuators. The use of force actuators instead of position actuators has the potential to significantly reduce total system cost. However, the use of force actuators results in many lightly-damped structural resonances within the desired bandwidth of ...

Abstract Electro-mechanical flight control actuators have become a viable option as replacement for conventional hydraulic in future more electric aircraft. A rotor angle measurement is generally required field-oriented of the electrical machine and usually obtained from safety-critical resolver. It contributes, however, to rising local hardware complexity with negative impact on space allocati...

This paper presents the first results of an optimal control approach to piezoceramic actuators. A one-dimensional free energy model for piezoceramics recently proposed by Smith and Seelecke is briefly reviewed first. It is capable of predicting the hysteretic behavior along with the frequency-dependence present in these materials. The model is implemented into an optimal control package, and tw...

Adjustable compliance or variable stiffness actuators comprise an additional element to elastically decouple the actuator from the load and are increasingly applied to human-centered robotic systems. The advantages of such actuators are of paramount importance in rehabilitation robotics, where requirements demand safe interaction between the therapy system and the patient. Compliant actuator sy...