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Considering the external disturbances, this paper proposes a new control approach, with the intention of improving the trajectory flight control in the longitudinal-lateral trajectory plane with constant altitude, to design a nonlinear adaptive controller for an unmanned autonomous helicopter (UAH). The unknown external disturbances are considered within the system model and estimated through adaption...
DC-DC power converter is a most important power source for driving a DC system in contemporary power electronic systems. However, owing to the time-varying and nonlinear characteristics of load resistance, it is often very challenging issue to ensure the stability of such converters. This paper is concerned about the regulation of the output voltage of a DC-DC buck converter using a nonlinear robust...
A nonlinear adaptive controller for controlling the desired velocity of DC motors driven by DC-DC buck converters is proposed in this paper. The proposed controller is designed recursively based on the control Lyapunov function (CLF) to assure the desired control performance under varying the load torque of the DC motor as well as by considering the system parameters as unknown. These unknown parameters...
In this paper, a nonlinear adaptive controller for regulating the grid of a current source inverter (CSI) based three-phase grid-connected photovoltaic (PV) system is proposed. The proposed control structure is composed with an outer control loop-responsible for controlling the DC-side inductor current and the inner current control loop-responsible for controlling injected current into the utility...
A nonlinear robust controller based on the direct power control (DPC) approach for a voltage source inverter (VSI) based three-phase grid-connected solar photovoltaic (PV) system is proposed in this paper. The proposed robust controller is designed using the nonlinear backstepping theory based on the power dynamics rather than the usual current dynamics. One of the foremost advantages of this procedure...
A nonlinear adaptive controller for regulating the grid of a current source inverter (CSI) based three-phase grid-connected photovoltaic (PV) system is proposed in this paper. The proposed control structure is composed of an outer current loop which is responsible for controlling the DC-side inductor current and the inner current control loop is responsible for controlling injected current into the...
In this paper, a nonlinear adaptive controller is proposed to control the velocity of DC motors driven by DC-DC buck converters. The proposed controller is designed recursively based on the Lyapunov theory by considering the load torque of the DC motor is unknown. This unknown parameter is estimated through the adaptation law and the stability of the whole system is ensured based on the control Lyapunov...
A robust nonlinear adaptive controller design for unmanned autonomous vehicles (UAVs) for controlling the hovering flight is presented. The controller is premeditated recursively based on the control Lyapunov theory where the mass of the UAV in the model is considered as anonymous parameter. To illustrate the forcefulness property of the designed controller, the effects of external disturbances are...
A new direct power control (DPC) approach for a voltage source inverter (VSI) based three-phase grid-connected solar photovoltaic (PV) system is proposed in this paper. The proposed DPC is designed using the nonlinear backstepping control scheme based on the power dynamics rather than the conventional dp current dynamics. As a result, the inner current control loop is eradicated in this paper which...
This paper presents a nonlinear adaptive controller design with a recursive methodology based on the pulse width modulation (PWM) to drive a DC-DC boost converter. The proposed controller is designed based on the dynamical model of the boost converter where all parameters within the model are assumed as unknown. These unknown parameters are estimated through the adaptation laws and the stability of...
A robust adaptive backstepping technique is proposed in this paper to solve the speed-tracking problem of a series DC motor for improving transient response. The parameters of DC motor are considered as unknown and the external disturbances are incorporated into the dynamical model. The proposed controller is designed in such a way that it is adaptive to the unknown parameters of series DC motor and...
This paper presents a nonlinear control scheme to control the attitude of a small-scale rotary wing unmanned aerial vehicle (RUAV) in the presence of external disturbances. The proposed attitude controller is designed in such a way that it is robust to external disturbances. To prove the convergence of the attitude tacking error to zero, i.e., the actual attitude of the closed-loop system to reference...
This paper is concerned with the performance and cost analysis of different pulse shaping filters such as raised cosine, finite impulse response (FIR) Nyquist, FIR half-band and infinite impulse response (IIR) linear phase half-band for wireless applications. Note that the pulse shaping is the process of changing the waveform of transmitting pulses to reduce the interferences keeping a signal in an...
The Bit Error Rate (BER) and Peak to Average Power Ratio (PAPR) are the major concerns for wireless communication. This paper aims to analyze these two important parameters for different inputs and outputs block sizes of the discrete Fourier transform (DFT) based single carrier frequency division multiple access (SCFDMA) system by using the conventional raised cosine (RC) and square root raised cosine...
Signal length possesses a very important role in size estimation of underwater wireless sensor network (UWSN). As size estimation is very tough in UWSNs using conventional protocol techniques, a cross-correlation based technique is introduced to estimate the number of nodes. In UWSN, The greater the signal length, the more energy is required to perform the estimation. In this paper, we observe the...
This paper is concerned with the reduction of peak to average power ratio (PAPR) of 3rd generation partnership project (3GPP) LTE standard using the single carrier-frequency division multiple access (SCFDMA) for mobile uplink transmission. The PAPR reduction is done based on the discrete Fourier transform (DFT) spreading technique which is well known as DFT - SCFDMA and in case of LTE which can reduce...
In underwater network, it is very important to know the location of unmanned underwater vehicle (UUV). The unknown position of UUV considered as an unknown node that can be determined from the known node locations through underwater acoustic network. The known node locations considered here as fixed positioned node. The range data is measured between unknown node and known nodes. By exploiting these...
Bandwidth is the most monumental topic both for the terrestrial and underwater communications. For proper network operation the estimation of number of signal sources (N) is very important. Most of the protocol based techniques are failed to give the desired results of node estimation due to underwater properties (long propagation delay, high absorptions and dispersion). Node estimation technique...
We consider a confidential communication system in which a source sends a confidential information to the destination in the presence of an eavesdropper. Multiple relays are used to provide cooperative diversity to the destination. The destination and the eavesdropper are equipped with multiple antennas while each relay and source are equipped with single antenna. We are interested to protect the...
This paper aims to analyze the bit error rate (BER) and peak to average power ratio (PAPR) for discrete cosine transform (DCT) based single carrier frequency division multiple access (SCFDMA) system. Note that BER and PAPR are the major concerns for any wireless communication and for having lower PAPR till now discrete Fourier transform (DFT) based SCFDMA is implemented for the up-link communication...
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