the problem of relative motion control for spacecraft formation flying in eccentric orbits is considered in this paper. due to the presence of nonlinear dynamics and external disturbances, a robust fuzzy sliding mode controller is developed. the slopes of sliding surfaces of the conventional sliding mode controller are tuned according to error states using a fuzzy logic and reach the pre-define...

In this design, a VTOL aircraft system is used as the controlled object. Aiming at trajectory tracking problem of its position and attitude output, control method based on double closed-loop PD adopted to design. The decomposed into track subsystem roll subsystem. At same time, structure outer loop inner constructed, controller feedforward compensation designed. pole assignment set select param...

distance relays are used to protect ehv and hv transmission lines. over the past decades many algorithms have emerged for digital distance relays. these are based on the calculation of the transmission line impedance from the relaying to fault points. in this paper a novel method for digital distance relaying is proposed. in the method the tracking procedure is implemented. the method uses the ...

This paper presents a complete trajectory tracking controller design for an Unmanned Air Vehicle using Linear Parameter Varying design methods. The longitudinal and lateral controllers are designed using an inner loop – outer loop structure with the inner loop LPV controller designed using μsynthesis. The inner-loop is then approximated with a reference model and the outer loop is designed usin...

This paper constructs a relationship between attitude and translational movement of a quadrotor, and presents a PD logic tracking control design algorithm capable of not only stabilizing attitude but also tracking a desired trajectory accurately. In contrast to conventional flight control systems, the artificial inner/outer-loop structure is eliminated via using a third-order time optimal track...

This paper presents a novel sensing technique which uses a piezoelectric strain sensor for damping and accurate tracking of a nanopositioning stage. Piezoelectric elements have been used effectively as sensors for vibration control of smart structures. However, complications arise when one uses a piezoelectric strain sensor in a feedback loop for tracking. This is due to the high-pass character...

An eficient timing synchronization technique for a low complexdp FFT based multi-carrier direct sequence spread spectrum IF/baseband transceiver is presented. The timing synchronization control loop consists of a robust acquisition loop and a tracking loop that eliminates the timing phase ofiset caused by the transmission delay, sampiing error, and channel noise. The acquisition loop reduces th...

A new adaptive timing error detector (TED) embedded in a code-tracking loop for RAKE reception of directsequence-CDMA signals is presented. The loop consists of a digital coherent TED and a loop filter with lowpass characteristic. In a multipath fading environment, one such loop can be allocated for each finger in a RAKE receiver and the interference from adjacent paths can be mitigated by adap...

Propagation of radio occultation (RO) signals through the lower troposphere results in high phase acceleration and low signal to noise ratio signal. The excess Doppler estimation accuracy in lower troposphere is very important in receiving RO signals which can be estimated by sliding window spectral analysis. To do this, various frequency estimation methods such as MUSIC and ESPRIT can be adopt...

Optimal performance of delay tracking loops in a binary linearly-modulated system is investigated, which is compared with the Cramer-Rao lower bound and the performance of a tracking loop suggested by the maximumlikelihood timing estimation.