Tracking Command Research Articles

Integrated design of lateral-directional control law and vertical tail load for civil aircraft

According to new requirements of airworthiness regulation CS25.353, the advanced lateral-directional P-Beta control law design is studied in this paper. The LQR method based on the tracking command model is used to design the lateral-directional control law parameters. At the same time, the vertical tail load model of aircraft for yaw maneuver is introduced into the lateral-directional control law design model. The aim is to build the integrated design of control law and flight load. Finally, the simulation results show that the P-Beta control law can not only improve Dutch roll damping and coordination turn characteristics, but it can also reduce the yaw maneuver load by 18.5%. Thus, the structure weight of the aircraft’s vertical tail can be reduced.

Adaptive backstepping asymptotic consensus tracking control of multiple uncertain manipulators with disturbances

AbstractThis article studies the asymptotic consensus of multiple robots with uncertain parameters and external disturbances. A novel asymptotic tracking command filtered adaptive consensus control approach is proposed. The command filters avoid the differentials of virtual control functions in backstepping, meanwhile, the compensation mechanism is used to compensate filtering errors. Compared with current command filtered control algorithms for the consensus control of multiple robots, the consensus tracking errors can asymptotically converge to origin under the given approach, moreover, the design process is simplified by designing only one adaptive parameter for each manipulator. A simulation example verifies the given approach.

On the Performance of Sentinel-3 Altimetry over High Mountain and Cascade Reservoirs Basins: Case of the Lancang and Nu River Basins

Satellite radar altimetry has been widely utilized in hydrological research, particularly with the advent of Sentinel-3, a Synthetic Aperture Radar (SAR) altimeter operating globally and equipped with an innovative onboard tracking system referred to as the open-loop tracking command (OLTC). Utilizing a pseudo-DEM (Digital Elevation Model), controlled through the OLTC, holds significant promise for the reliable observation of inland water bodies. Nevertheless, the complex geographical conditions in high mountain and reservoir river basins pose challenges in defining an appropriate pseudo-DEM for hydrological targets, potentially leading to reduced performance of Sentinel-3. This study aims to comprehensively evaluate the performance of Sentinel-3 by selecting the Lancang and Nu River basins in southwest China as a case study. These two rivers have a similar natural environment, but cascade reservoirs distinguish the Lancang River basin. By analyzing waveform energy from echoes of virtual stations (VSs) in both river basins (27 VSs in the Lancang River basin and 39 VSs in the Nu River basin), the performance of Sentinel-3 in different tracking modes and OLTC versions were compared. The results indicated that the detection rate of Sentinel-3A increased when transitioning from the closed-loop mode to the open-loop mode and with the implementation of newer OLTC versions (36.8% increased to 47.4%, 60.5%, and 63.2% in OLTC V5.0, V6.0, and V6.1, respectively). Similarly, the detection rate of Sentinel-3B rose from 64.3% (OLTC V2.0) to 71.4% and 75.0% in OLTC V3.0 and V3.1, respectively. Additionally, the cascade reservoir causing river channel expansion results in a better performance of Sentinel-3A in the Lancang River compared to the Nu River in the closed-loop mode (13.0% and 35.7%, respectively). Nevertheless, the considerable fluctuations in water surface caused by reservoir impoundment led to a wrong pseudo-DEM, resulting in poor performance of Sentinel-3 in reservoir regions before OLTC V6.0 was updated. The detection rate of low altitude, broad water surfaces (>500 m) decreased from 100% in a closed-loop mode to 0% in an open-loop mode, but increased to 100% in OLTC V6.0 and V6.1, respectively. The detection rate of high altitude, narrow water surfaces (<500 m) increased from 0% in a closed-loop mode to 40.9% in OLTC V6.1. Although the detection ability of Sentinel-3 is improving with the implementation of newer OLTC versions, the seasonal variations (usually more than 60 m) of water levels in reservoirs exceeded the size of the range window (60 m), rendering a complete measurement impossible.

Design robust H∞ -PID controller for a helicopter system using sequential quadratic programming algorithm

ABSTRACT This paper proposes a new methodology for designing a controller for the tracking control problem in a 2 DoF helicopter system. The control problem is formulated as a nonlinear constraint optimization problem. Also, a sequential quadratic programming algorithm is applied to tune the PID gains according to the H infinity specifications. Tuning is done by selecting relevant objective functions and constraints. A nonlinear model of the 2 DoF helicopter is linearized and decoupled into two SISO systems (i.e. Yaw and Pitch models). Two independent controllers are designed for the models. For the purpose of demonstrating the robustness and superiority of the proposed method, the method is compared with a standard H infinity. Next, the performances of both controllers are examined. That allows the effects of system uncertainties, external disturbances and different tracking command signals take place.

Yaw/Heading optimization by Machine learning model based on MEMS magnetometer under harsh conditions

The paper's main goal is to accomplish a high accuracy of yaw/heading by Machine Learning approach when the motion range of vehicle/device calibration is limited. The nonlinear Random Forest (RF) Regression with proper training has a high potential to deal with the magnetometer uncertainty before calibration and during iron distortion cases. The proposed solution solely requires the magnetometer without other sensor's support. A Pan Tilt Unit-C46 (PTU-C46) with high precise positioning was used as a reference heading value to label the corresponding magnetic features in the learning model. The proposed approach helps yaw estimation to be carried out under harsh conditions, which resolve many difficulties in orientation tracking since the magnetometer is susceptible to hard iron and soft iron in the environment. In addition, many mechanical devices work only within the specific range and waste their dynamic motion around two axes or more just for calibration. Thus, the research focuses on the level rotation calibration around Z-axis within the restricted range of motion for practical application. The experiment was carried out using a low-cost platform equipped with Micro-Electro-Mechanical System (MEMS) sensors as gyroscope, accelerometer, and magnetometer. The 9 Degree of Freedom (DoF) Madgwick was implemented into the Microcontroller to compare with the proposed model. The sensor fusion can track the yaw value after the level calibration despite various error conduction. The RF model accomplishes a superior result with more stability and more minor error. Under iron disturbance or calibration absence, the ML model still maintains the good tracking command with maximum Mean Square Error of about 0.3°, while the Madgwick is unsuccessful in heading measurement due to huge error in these circumstances.

Comparative study of four MPPT for a wind power system

The Maximum power point tracking (MPPT) command makes it possible to find the optimal operating point of the wind generator following variations in the wind. Its principle is based on the automatic variation of the power coefficient to continuously maximize the power of the wind generator. This work is an attempt to study and discuss four most popular types of MPPT techniques such as: Perturbation and Observation (P&O), optimal torque (OT), On-Off control, and tip speed ratio (TSR). The Matlab-Simulink environment is used to analyse and then interpret the simulation results of these algorithms, and therefore show the performance and limitations of each algorithm. The comparison shows the efficiency and the superiority of the OT technique compared to the other MPPTs studied.

Modeling of a PV Panel and application of Maximum Power Point Tracking Command based on ANN

Modeling of a PV Panel and application of Maximum Power Point Tracking Command based on ANN

An Event-by-Event Approach for Velocity Estimation and Object Tracking With an Active Event Camera

An event-based camera has independent pixels that quickly respond to relative brightness changes and report them asynchronously with high temporal resolution (microsecond level). We present an event-by-event processing framework for sensing the velocity of a moving object and tracking it with an active event-based camera. This paper describes an event-by-event approach for estimating both local velocity and global velocity. Instead of accumulating events over a fixed period of time, we directly estimate the normal velocity of the pixel at which a new event occurs and update the estimate of the global velocity given the new estimate. Our proposed global velocity estimation algorithm is based on the Kalman filter which also provides a confidence measurement for the estimated velocity. Our active tracking system monitors the confidence of the velocity estimate and triggers a tracking command once the confidence reaches a certain threshold. We evaluated our velocity estimation algorithms and the active tracking system in our recently proposed simulator, AESIM. Our results demonstrate that our system can successfully track a moving object with low latency.

S3MPC: Improvement on Inland Water Tracking and Water Level Monitoring from the OLTC Onboard Sentinel-3 Altimeters

The Sentinel-3A and Sentinel-3B satellites were launched, respectively, on 16 February 2016 and 25 April 2018 as part of the European Copernicus program. The Sentinel-3 Surface Topography Mission makes use of the altimeter instruments onboard Sentinel-3A and Sentinel-3B to provide elevation measurements not only of the ocean water level but also of the inland waters and ice caps. For the first time, the altimeters onboard Sentinel-3A and Sentinel-3B are operated in Synthetic Aperture Radar mode over all Earth surfaces. They also benefit from elevation priors (the Open-Loop Tracking Command) allowing them to precisely position their receiving window to track the backscattered signal from the inland water targets to be monitored rather than relying on the traditional Closed-Loop tracking mode. This paper makes use of the Sentinel-3A/Sentinel-3B tandem phase to assess the benefits of the Open-Loop tracking mode compared to Closed-Loop. Longer time series are also used to highlight the improvements in terms of the percentage of points over which the altimeter hooks on water surfaces and water surface height estimation brought by the switch of Sentinel-3A from the Closed-Loop to Open-Loop tracking mode as well as the successive Open-Loop Tracking Command updates. In particular, it is shown that from a Level-3 water level product service perspective, the increase in the number of water bodies with valid water surface height estimates is of the order of 25% in Open-Loop with respect to Closed-Loop with similar precision. It is also emphasized that the Open-Loop Tracking Command update onboard Sentinel-3A from v. 4.2 to v. 5.0 yielded a 30% increase in the number of water bodies over which valid water surface height could be estimated. Eventually, the importance of knowing whether a water target was associated with a fine-tuned Open-Loop Tracking Command or an interpolated one is stressed and the recommendation to provide such a flag in the Sentinel-3 Level2 Payload Data Ground Segment products is emitted.

Intelligent Control of a Photovoltaic Generator for Charging and Discharging Battery Using Adaptive Neuro-Fuzzy Inference System

This paper presents a method of intelligent control of a photovoltaic generator (PVG) connected to a load and a battery. The system consists of charging and discharging a battery. An intelligent algorithm based on adaptive neuro-fuzzy inference system (ANFIS) is presented in this work. It performs two separate tasks simultaneously. First, it is used as a PVG Maximum Power Point Tracking (MPPT) command. This same algorithm is used secondly for protecting the battery against deep charges and discharges. A regulation of the DC bus voltage is also carried out by means of a PI corrector for a good supply of the load. The simulation results under MATLAB/Simulink show that the method proposed in this work allows the PV system to function normally by charging and discharging the battery whatever the weather conditions.

Evaluation of Sentinel-3 SRAL SAR altimetry over Chinese rivers

Satellite radar altimetry observations of water surface elevation (WSE) have become an important data source to supplement river gauge records. Sentinel-3 is the first radar altimetry mission operating with a synthetic aperture radar (SAR) altimeter at global scale and with a new on-board tracking system (i.e. open-loop), which has great potential in terms of delivering reliable observations of inland water bodies for the next two decades (several future missions include an open-loop tracking mode). In this context, it is very important to investigate the data quality at an early stage. In this study, a comprehensive evaluation of Sentinel-3A (S3A) is conducted at 50 virtual stations (VS) located on a wide range of rivers in China.The evaluation of Level 1 data shows that, over mountain rivers, a good prior surface elevation estimate on-board is vital to deliver useful datasets using the S3A open-loop tracking system. The Open-Loop Tracking Command version 5 (OLTC V5) has significantly improved the placement of the range window, which was misplaced and resulted in lack of data over many mountain rivers prior to OLTC V5 (March 2019). However, application of S3A over mountain rivers still requires careful evaluation, especially before March 2019.Four retrackers are evaluated including a physical SAR Altimetry Mode Studies and Applications retracker (SAMOSA+), a traditional Offset Center Of Gravity (OCOG), a Primary Peak Center Of Gravity (PPCOG), and a modified Multiple Waveform Persistent Peak (MWaPP+) retracker. For 26 VSs in plain areas, retracked WSE data achieved a root mean square error (RMSE) ranging from 0.12 m to 0.9 m. The comparison of retracking methods reveals that SAMOSA+, OCOG, and PPCOG are unable to handle multi-peak waveforms. But the MWaPP+ can significantly improve the accuracy of the estimated WSE over large rivers, especially when the waveforms are contaminated.Moreover, our result shows no considerable difference between medium (ca. 300 m wide) and large (wider than 500 m) rivers. Instead, surrounding topography and homogeneity of surroundings are very important factors influencing the shape of a waveform. For rivers surrounded by lakes, man-made channels etc., special care must be taken when processing altimetry data. Dedicated retracking methods, such as MWaPP+, and sophisticated methods for outlier detection are needed to improve precision over such rivers, as demonstrated here for the Yangtze River.

Benefits of the Open-Loop Tracking Command (OLTC): Extending conventional nadir altimetry to inland waters monitoring

Abstract In the past 25 years, radar altimeters have been designed and operated primarily for ocean observation. However, over the past decade there has been a growing interest for altimetry measurements over inland waters. Studying lakes, reservoirs and rivers water level is of prime importance for the hydrology community to assess the Earth’s global resources of fresh water. Satellite altimetry is key to providing such global and continuous datasets of water surface height. Indeed, much progress has been made in altimeters capability to acquire quality measurements over inland waters. In this paper we present an overview of major technical evolutions of the tracking function of altimeters, from Jason-2/POS3 and SARAL/AltiKa to Jason-3/POS3B and Sentinel-3/SRAL and the improvements brought by the Open-Loop Tracking Command (OLTC) to extend the altimeter observation domain to inland waters. The OLTC is an on-board feature used to set the altimeter waveforms reception window, containing a priori elevation information built from a dedicated database of hydrological targets. This paper focuses on the use of OLTC for acquiring reliable water signal rather than discussing the accuracy of the retrieved height, which constitutes a further step in the altimeter data processing chain. We show how Jason-3 and Sentinel-3 altimetry missions are currently able to observe and monitor about 70,000 hydrological targets over the globe and how it is contributing in building a global dataset of inland waters level, in preparation for future missions such as Sentinel-6 and the Surface Water Ocean Topography mission (SWOT).

Modelling, Command and Treatment of a PV Pumping System Installed in Tunisia

This paper studied the modeling, the command and the optimization of a photovoltaic (PV) pumping systems using performed strategies of command laws. The system is formed by a PV generator, a DC-DC converter with a maximal power point tracking (MPPT) command, a DC-AC converter with V/f command law and a submersed motor-pump. The first part of this paper presents the obtained models of the various components of the PV pumping system. Dynamic commands composed of a V/f and MPPT laws are calculated around the converters. The MPPT command insures the power adaptation between PV generator and load whereas the V/f command insures a PWM control of the asynchronous motor and a sinusoidal output signal. Some important results of simulation of the PV pumping system under the environment of MATLAB/SIMULINK are presented. In the second part of this paper some experimental results of a PV pumping system installed in Tunisia are developed. Those results are used to validate the simulating model and to test the performances of the command approach.

Tracking control of a class of non-linear systems with applications to cruise control of air-breathing hypersonic vehicles

A new tracking-control method for general non-linear systems is proposed. A virtual controller and some command references are introduced to asymptotically stabilise the system of the tracking error dynamics. Then, the actual controller and command references are derived by solving a system of linear algebraic equations. Compared with other tracking-control methods in the literature, the tracking-controller design in this paper is simple because it needs only to solve a system of linear algebraic equations. The boundedness of the tracking controller and command references is guaranteed by the solvability of the terminal value problem (TVP) of an ordinary differential equation. For non-linear systems with minimum-phase properties, the TVP is automatically solvable. A numerical example shows that the tracking-control method is still available for some systems with non-minimum-phase properties. To enhance the robustness of the tracking controller, a non-linear disturbance observer (NDO) is introduced to estimate the disturbance. The combination of the tracking controller and the NDO is applied to the tracking control of an air-breathing hypersonic vehicle.

Sharing Technology of the Tracking Telemetry and Command Software

The software sharing is the development trend of tracking telemetry and command software. How to develop quickly the tracking and controlling tasks software to adapt to the current experimental situation, and to ensure software quality, is a challenging subject placed in the face of software personnel. Using software middleware and software component technology, we can solve the problems of Tracking and Controlling Network acrossing operating system, Tracking and Controlling Software acrossing program languages, software reuse and other issues.

Robust Integral Voltage Tracking Control for PEM Fuel Cell Systems Under Varying Operating Current

This paper presents a robust controller design approach for nonlinear PEM fuel cell systems in a linear parameter varying system representation. The magnitude bounds on variations of the elements of system matrices corresponding to variational operating current are identified and addressed during control law construction via numerically tractable linear matrix inequality algorithms. In order to achieve voltage control with diminishing tracking error, integration of the tracking error is considered as an additional state and included in the fuel cell control system design. For a desired magnitude of voltage tracking command, the allowable magnitude constraints on gas flowrate are specified accordingly. The upper bound of the energy ratio between voltage tracking error and command is minimized in terms of \({\mathcal {H}^\infty}\) optimization. In time response simulation based on the parameters of a Ballard 5 kW PEM fuel cell, both constant step and variational sinusoid tracking commands are considered for verification. The situation of a sudden change of load resistance and output current is also included in the simulation study. As demonstrated, the proposed robust controller design can achieve the desired voltage tracking performance for the tracking command and gas flowrates with specified magnitude while the operating current varies within its specified range.

DESIGN OF A LOAD FOLLOWING CONTROLLER FOR APR+ NUCLEAR PLANTS

A load-following operation in APR+ nuclear plants is necessary to reduce the need to adjust the boric acid concentration and to efficiently control the control rods for flexible operation. In particular, a disproportion in the axial flux distribution, which is normally caused by a load-following operation in a reactor core, causes xenon oscillation because the absorption cross-section of xenon is extremely large and its effects in a reactor are delayed by the iodine precursor. A model predictive control (MPC) method was used to design an automatic load-following controller for the integrated thermal power level and axial shape index (ASI) control for APR+ nuclear plants. Some tracking controllers employ the current tracking command only. On the other hand, the MPC can achieve better tracking performance because it considers future commands in addition to the current tracking command. The basic concept of the MPC is to solve an optimization problem for generating finite future control inputs at the current time and to implement as the current control input only the first control input among the solutions of the finite time steps. At the next time step, the procedure to solve the optimization problem is then repeated. The support vector regression (SVR) model that is used widely for function approximation problems is used to predict the future outputs based on previous inputs and outputs. In addition, a genetic algorithm is employed to minimize the objective function of a MPC control algorithm with multiple constraints. The power level and ASI are controlled by regulating the control banks and part-strength control banks together with an automatic adjustment of the boric acid concentration. The 3-dimensional MASTER code, which models APR+ nuclear plants, is interfaced to the proposed controller to confirm the performance of the controlling reactor power level and ASI. Numerical simulations showed that the proposed controller exhibits very fast tracking responses.

Design, realization and optimization of a photovoltaic system equipped with analog maximum power point tracking (MPPT) command and detection circuit of the dysfunction and convergence the system (CDCS)

In this paper, we analyze the design, realization and optimization of a photovoltaic (PV) system equipped with a maximum power point tracking (MPPT) command and detection circuit of dysfunction and convergence the system (CDCS) to the new maximum power point (MPP) following a perturbation due to the meteorological variation (solar radiation, temperature, ..) and the load. We have analyzed in depth manner the structure and optimization the operation of the MPPT command realized during this work. The results obtained show very good agreement between simulation and experiment. The experimental system realized during cloudy days or by varying the load, shows that it operates under optimum conditions independently of the meteorological variations. At each perturbation, the CDCS circuit detects it and convergences the system without restart it. The good efficiency of the direct current to direct current (DC-DC) converter used and the low loss (less than 7%) shows that the system realized can be used in a PV system to minimize losses due to connecting the panels to the load and in particularly to minimize the cost of installations. Key words: Panels and photovoltaic system, photovoltaic conversion, maximum power point tracking (MPPT) command, the detection circuit of dysfunction and convergence (CDCS), direct current to direct current (DC-DC) converter, simulator Pspice, optimal functioning, energy losses.

Incorporating Prediction in Models for Two-Dimensional Smooth Pursuit

A predictive component can contribute to the command signal for smooth pursuit. This is readily demonstrated by the fact that low frequency sinusoidal target motion can be tracked with zero time delay or even with a small lead. The objective of this study was to characterize the predictive contributions to pursuit tracking more precisely by developing analytical models for predictive smooth pursuit. Subjects tracked a small target moving in two dimensions. In the simplest case, the periodic target motion was composed of the sums of two sinusoidal motions (SS), along both the horizontal and the vertical axes. Motions following the same or similar paths, but having a richer spectral composition, were produced by having the target follow the same path but at a constant speed (CS), and by combining the horizontal SS velocity with the vertical CS velocity and vice versa. Several different quantitative models were evaluated. The predictive contribution to the eye tracking command signal could be modeled as a low-pass filtered target acceleration signal with a time delay. This predictive signal, when combined with retinal image velocity at the same time delay, as in classical models for the initiation of pursuit, gave a good fit to the data. The weighting of the predictive acceleration component was different in different experimental conditions, being largest when target motion was simplest, following the SS velocity profiles.

Stabilising intervalwise receding horizon H∞ tracking controls for continuous time-varying systems

A stabilising intervalwise receding horizon H∞ tracking control (IHTC) for continuous time-varying systems that has a flexible computation time and guarantees a H∞ norm bound is proposed. We also propose a stabilising IHTC with an integral control action for time-invariant systems that makes the tracking error approach zero asymptotically for a constant tracking command as well as satisfying a H∞ norm bound. We illustrate the proposed results via simulation studies.