This work introduces a novel control algorithm for close proximity multiple spacecraft autonomous maneuvers, based on hybrid linear quadratic regulator/artificial potential function (LQR/APF), for applications including autonomous docking, on-orbit assembly and spacecraft servicing. Both theoretical developments and experimental validation of the proposed approach are presented. Fuel consumptio...

One-cycle control (OCC) is a kind of nonlinear control technology. It is the most advanced reactive power compensation and harmonic suppression method. In the paper, a three-phase four-wire active power filter (APF) with one-cycle control is presented. This method does not need any measured quantities of three-phase input voltages and three-phase load currents, and also not need multipliers. Th...

Corobots have a potential for numerous applications that are available for educational purposes in the robotics lab for students use. Easily programmable corobots generates opportunities for students to learn robotics and discover their potential. Being inexpensive, the hardware of these corobots limits the detection of obstacles. The challenge is to find a good obstacle avoidance algorithm whi...

There is concern that the ingestion of fluoride (F) from topical application of 1.23% APF gel may cause gastric irritation and other side effects. In this in vitro study, a newly developed APF-based foam was tested. Sound human enamel was treated for 4 rain with APF foam or a conventional APF gel (Nupro®), both containing 1.23 % F. Enamel biopsies were obtained using the acid-etch technique. Th...

PURPOSE The purpose of this descriptive scanning electron microscopic study was to characterize surface alterations in primary tooth enamel after in vitro argon laser irradiation alone and combined with topical fluoride treatment either before or after argon laser irradiation. METHODS Twenty extracted or exfoliated primary teeth underwent soft tissue debridement and a fluoride-free prophylaxi...

Three-phase shunt active power filter (APF) is often used to compensate the harmonic and reactive current derived from non-linear load. But many non-ideal factors, such as the limited bandwidth of output current loop and the time lag of signal sensing circuit and reference current generation etc, will deteriorate the compensation effect. Proportion-Integral (PI) controller cannot be used simply...

This paper deals with a three-phase unified power quality conditioner (UPQC), with a combination of shunt active power filter and series active power filter is used to eliminate supply current harmonics, compensate reactive power, voltage sag and voltage swell compensation on distribution network. The performance of the active power filter mainly depends on control strategy used to generate ref...

OBJECTIVES This in vitro study evaluated the shear bond strength (SBS) of resin composite to feldspathic porcelain after acidulated phosphate fluoride (APF) gel treatment over different periods of time. METHODS One hundred and fifty-six feldspathic specimens were divided into 12 groups. Group C received no treatment (control group). Groups APF1 through APF10, ten experimental groups, were tre...

This paper presents a novel control strategy of a threephase four-wire Unified Power Quality (UPQC) for an improvement in power quality. The UPQC is realized by integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a thee-phase, four leg voltage source inverter (VSI) and the series APF is realized using a three-phase, thre...