For a viewpoint of controllability, characterization and control method of a surface acoustic wave (SAW) motor were studied. The speed of the SAW motor has strong non-linearity in relation to the driving voltage i.e. the dead zone. Then, influence on drive performance by dead zone of SAW motors was examined. The experimental results show the threshold of the dead zone didn’t change while the mo...

Using numerical MHD simulations, we have studied the evolution of the magnetorotational instability in stratified accretion disks in which the ionization fraction (and therefore resistivity) varies substantially with height. This model is appropriate to dense, cold disks around protostars or dwarf nova systems which are ionized by external irradiation of cosmic rays or high-energy photons. We f...

High-speed machining offers several advantages such as increased flexibility and productivity for discrete-part manufacturing. However, excessive heat generation and resulting high temperatures on the tool and workpiece surfaces in high-speed machining leads to a shorter tool life and poor part quality, especially if the tool edge geometry and cutting conditions were not selected properly. In t...

In this work we use the radiation hydrodynamic code TRAMP to perform a twodimensional axially symmetric model of the layered disc. Using this model we follow the accumulation of mass in the dead zone due to the radially varying accretion rate. We found a new type of instability which causes the dead zone to split into rings. This ”ring instability” works due to the positive feedback between the...

Circadian oscillation provides selection advantages through synchronization to the daylight cycle. However, a reliable clock must be designed through two conflicting properties: entrainability to synchronize internal time with periodic stimuli such as sunlight, and regularity to oscillate with a precise period. These two aspects do not easily coexist, because better entrainability favours highe...

Abstract. This work presents a cascade controller for the trajectory tracking control of a hydraulic actuator by using adaptive algorithms to deal with parametric uncertainties together with an adaptive dead-zone compensation scheme. The hydraulic actuator is modeled as a forth order nonlinear system including the valve dynamic as a first order linear system and considering a valve with a dead-...

This paper proposes a compensation PWM technique for the extension of output voltage ranges in three-phase VSI applications using three shunt resistors. The proposed technique aims to solve the dead zone, which occurs in high modulation indexes. In the dead zone, two phase currents cannot be sampled correctly, so that the three-phase VSI cannot be operated up to the maximum output voltage. The ...

The adaptive control of continuous-time linear dynamic systems preceded by an unknown dead-zone in state space form is discussed. A lemma to simplify the error equation between the plant and the matching reference model is introduced which allows the development of a robust adaptive control scheme by involving the dead-zone inverse terms. This adaptive control law ensures global stability ofthe...

As is well known, dead-zone nonlinearity often exists in practical actuators and unknown actuator failures may occur during system operation. However, available results based on adaptive approaches to compensate unknown failures of such actuators are still very limited. In this paper, we address such a problem by considering a class of uncertain nonlinear systems with dead-zone hysteresis nonli...