Pitch Control System Research Articles

Pitch angle and altitude control for unmanned helicopter based on new approximation-free control.

This article introduces an enhanced non-approximated control technique for the pitch and altitude control systems of unmanned helicopters. It takes into account unpredictable external disturbances and system dynamics. The integration of prescribed performance control into unmanned helicopter systems significantly improves the transient and steady-state response capabilities. This approach avoids the computational complexities often associated with neural networks and fuzzy control methods. By avoiding the need for function approximation, which can introduce inaccuracies and computational overhead, the controller design process is streamlined. This method's simplicity and ability to handle unknown disturbances make it highly suitable for real-world implementation, where robustness and efficiency are paramount. Finally, simulations are conducted to showcase the improved transient and steady-state response capabilities achieved by the proposed approach.

Independent Pitch Adaptive Control of Large Wind Turbines Using State Feedback and Disturbance Accommodating Control

Wind turbines experience significant unbalanced loads during operation, exacerbated by external disturbances that challenge the stability of the pitch control system and affect output power. This paper proposes an independent pitch adaptive control strategy integrating state feedback and disturbance accommodating control (DAC). Initially, nonlinear wind turbine dynamics are globally linearized, and DAC is applied to mitigate the impact of wind disturbances dynamically. Subsequently, the entire range of wind speeds is segmented, and controllers are individually designed to optimize gain settings according to specific control objectives at each wind speed interval. Scheduling parameters such as collective pitch angle and tower fore-aft displacement are identified and trained using Radial Basis Function Neural Networks (RBFNN). Finally, based on the output gain values determined by RBFNN, the full-state feedback controller group is adaptively adjusted, and the optimal controller is selected for the final output. Simulations conducted on the NREL 5MW reference wind turbine model using FAST and Simulink demonstrate that compared to the ROSCO controller, the proposed strategy ensures smoother output power and effectively reduces blade and tower loads, thereby extending the turbine’s operational lifespan.

RMSE POWER COEFFICIENT OF WIND TURBINES WITH INVERSE TOQUE-SPEED CONTROL

The Blade Element Momentum (BEM) method stands out among various turbine modelling techniques due to its integration of airfoil aerodynamics with momentum theory, allowing detailed force calculations on blade elements. While traditional methods like BEM and Wake Models are efficient for initial turbine design, advancements in computational power have enabled the use of Computational Fluid Dynamics (CFD) for more accurate simulations. Although these models are precise, they are computationally intensive, leading to the continued use of simpler empirical methods, such as the static power coefficient approach, in power system studies. Future research aims to validate and implement dynamic estimation models to account for wind variability and turbine control dynamics. Traditional constant torque-speed control strategies maintain a constant generator speed by using a fixed electromagnetic torque command and adjusting the pitch angle when wind speed exceeds the rated value. However, if the pitch control does not respond quickly enough, rotor acceleration can occur, leading to increased power beyond the generator’s rating. To mitigate this, the pitch control mechanism must react promptly to adjust the turbine's torque profile, ensuring convergence to the rated operating point and avoiding prolonged generator overload. To reduce the burden on the pitch-control system, an inverse torque-speed control approach is proposed, where the electromagnetic torque is dynamically adjusted based on real-time rotor speed data. This method aims to achieve rated power operation with improved responsiveness and reduced stress on the pitch-control mechanism.

Optimizing Aircraft Pitch Control Systems: A Novel Approach Integrating Artificial Rabbits Optimizer with PID-F Controller

The precise control of aircraft pitch angles is critical in aviation for maintaining specific attitudes during flight, including straight and level flight, ascents, and descents. Traditional control strategies face challenges due to the non-linear and uncertain dynamics of flight. To address these issues, this study introduces a novel approach employing the artificial rabbits optimizer (ARO) for tuning a PID controller with a filtering mechanism (PID-F) in aircraft pitch control systems. This combination aims to enhance the stability and performance of the aircraft pitch control system by effectively mitigating the kick effect through the incorporation of a filter coefficient in the derivative gain. The study employs a time-domain-based objective function to guide the optimization process. Simulation results validate the stability and consistency of the proposed ARO/PID-F approach. Comparative analysis with various optimization algorithm-based controllers from the literature demonstrates the effectiveness of the proposed technique. Specifically, the ARO/PID-F controller exhibits a rapid response, zero overshoot, minimal settling time, and precise control during critical phases. The obtained results position the proposed methodology as a promising and innovative solution for optimizing aircraft pitch control systems, offering improved performance and reliability.

Anti-Windup Pitch Angle Control for Wind Turbines Based on Bounded Uncertainty and Disturbance Estimator

Due to physical limitations and safety requirements, the rate and amplitude of change in wind turbines’ pitch angle are limited, which will bring integral saturation problems to the control system. This leads to the deterioration of the pitch control system’s performance or even an instability problem. This paper designs an anti-windup robust pitch angle control strategy to deal with pitch rate constraint issue to enhance the safety of the control system. First, to facilitate controller design, a filtered tracking-error technique is employed to transform the nonaffine form into an affine one. Subsequently, a feedback robust controller based on an uncertainty and disturbance estimator (UDE) is developed to handle the model’s uncertainty and external disturbances. To address the issue of integral saturation in the pitch system and guarantee its safety, an elliptical bounded constraint is integrated into the designed UDE strategy. This bounded UDE controller can improve the stability of power generation quality, reducing the mechanical loads on components. Finally, the effectiveness of the proposed scheme is verified on the Wind Turbine Blockset platform in Matlab/Simulink. It can achieve better performance than traditional methods.

A Proposed Controller for Pitch Angle of Wind Turbine

Wind turbines are complicated non-linear systems with certain random disruptions. The pitch control system is a commonly employed method for regulating the electricity generated by a wind turbine. Many researchers have observed developments in the pitch control field during the last few decades. Traditional PID controllers have the drawback of being slow or imprecise when wind and pitch angles suddenly change. These drawbacks can be solved with artificial intelligent algorithms. However, the algorithms' design and implementation are highly complex. A new pitch-regulated variable-speed control strategy for wind turbines to address their nonlinear properties is presented. To manage the pitch system's control mechanisms with disturbances, this research evolved a mathematical model that illustrates HAWT's pitch angle control system and applied a proposed Simple Optimal Intelligent PID Controller (SOI-PID). Under various operating conditions, the proposed SOI-PID controller was tested with the Traditional PID, Fuzzy Logic Controller (FLC), and Fuzzy-Adaptive-PID controller. For system simulation, the MATLAB/Simulink software was used. According to simulation results, compared to PID, FLC, and Fuzzy-Adaptive-PID controllers, the proposed SOI-PID controller responds faster and has a better rise and settling time. Other benefits of the SOI-PID controller are its simplicity of implementation and design, distinguishing it from other intelligent algorithms.

Optimization of the Powers Exchanged between a Cascaded Doubly Fed Induction Generator and the Grid with a Matrix Converter

The use of an electromagnetic converter of great reliability in wind energy, like the cascaded doubly fed induction generator (CDFIG), can solve several problems compared to the doubly fed induction generator (DFIG), among them the elimination of the brushes and copper rings. The work consists of studying the performance of a CDFIG-based wind system using a matrix converter and a variable pitch control system. The traditional PI is able to successfully solve a number of linear control problems. The fuzzy logic controller used can dramatically improve the system's performance. The active and reactive energy transferred between the CDFIG and the grid can be controlled by adjusting the machine inverter. The DC bus voltage has been kept stable by controlling the grid inverter. The pitch controller's objective is to maximise aerodynamic power while staying within the converter's power limits. Numerical simulation results implemented in the MATLAB/Simulink package will be provided in this study to show that the suggested control strategy is both possible and effective.

Experimental study of structural vibration control of 10-MW jacket offshore wind turbines using tuned mass damper under wind and wave loads

As slender structures, offshore wind turbines (OWTs) are prone to vibration and deformation under wind and waves. Tuned mass dampers (TMDs) have become among the most promising vibration-mitigation methods owing to their simplicity and practicability. To study the vibration control effect of a TMD on a jacket OWT under wind and wave conditions, we conducted a fully coupled dynamic model test of a 1/75 scale jacket OWT with and without a TMD. The physical model of the jacket OWT included scaled rotor-nacelle assembly (RNA) and support structure models. For the scaled RNA model, a redesigned blade model was used to ensure similarity of the aerodynamic thrust loads without modifying the scaled test winds. Drivetrain and pitch-control system models were designed to simulate the operating state of an actual OWT. The support structure model was established based on the hydro-structural elastic similarity. Furthermore, a TMD model was designed and manufactured based on the first mode of the scaled OWT. A fully coupled dynamic model test of a 10 MW jacket OWT with a TMD under wind and wave conditions was performed, and the vibration-mitigation performance of the designed TMD model on the structural responses of the scaled OWT model was evaluated.

Modeling of fault detection and isolation in pitch control of wind energy conversion systems via digital twins

There is a growing trend in renewable energies for wind harvesting and power generation. As new offers for the energy sector continue to rise up, the operation and maintenance team plays a vital role in increasing the availability and decreasing downtime of wind turbines subassemblies, based on conditional monitoring of their assets. This paper developed an approach for fault detection and isolation of the pitch control system on a direct drive permanent magnet synchronous generator using dynamic modeling and digital twins. The work presents two models of wind turbines, whose conditions were replicated in a multi-domain simulation software and the analyses were conducted under rotor constant speed. One concept represents a wind turbine model with a fault in pitch system, while the other is a healthy replica or a virtual model. Through the difference between three observable variables, namely: active power, angular speed and pitch angle, it was possible to isolate and classify each type of fault in the pitch system in wind turbines.

Fatigue Life Evaluation of Wind Turbine Tower Based on Measured Data

Fatigue life is a crucial design factor which dictates the safe operation of the wind turbines, but it is influenced by uncertain factors such as environmental loads, analytical models, material properties, and manufacturing methods. In this study, a 1.5 MW wind turbine was monitored in operation to understand the fatigue mechanism and enhance wind turbine design. The influence of different operating conditions on fatigue damage was analyzed by correlating strain monitoring data with supervisory control and data acquisition (SCADA) data. Furthermore, a fatigue evaluation method based on measured strain data was proposed. Fatigue damage increases with the increase of wind and rotation speed. More than 50% of the damage occurred at the rated rotation speed state, the corresponding wind speed was greater than the rated wind speed and the pitch control system was active. The findings of this study provide insights for investigating the real fatigue state of similar wind turbine towers and improving the return on investment by closely estimating their service life.

Reliability improvement of the large-scale wind turbines with actuator faults using a robust fault-tolerant synergetic pitch control

This study addresses the critical issue of enhancing the reliability of large-scale wind turbines in the presence of simultaneous pitch actuator faults. To do this, a fault-tolerant finite-time continuous nonsingular terminal synergetic control manifold is firstly designed and incorporated into the pitch control system to improve precision tracking performance and regulation of the pitch angle for stable power extraction under extreme wind conditions. Besides, the proposed scheme is model-independent, easily accessible, and features fast finite-time convergence. At the same time, the mismatched disturbance observer is designed to attenuate the time-varying perturbations of the wind turbine system (WTS) to achieve robustness and high tracking accuracy. Then, the proposed scheme’s stability conditions and finite-time convergence analysis are derived using the Lyapunov theory. Finally, the simulation and comparative studies are presented to signify the reliable performance of the proposed control method for both a 4.8 MW benchmark WTS and a large-scale 20 MW PMSG-based WTS to verify robustness against simultaneous pitch actuator faults and uncertainties.

PIDD2 Control of Large Wind Turbines’ Pitch Angle

The pitch control system has a profound impact on the development of wind energy, and yet a delay or non-minimum phase can weaken its performance. Thus, there is a strong incentive to enhance pitch control technology in order to counteract the negative effects of unidentified delays and non-minimum phase characteristics. To reduce the complexity of the parameter-tuning process and improve the performance of the system, in this paper, we propose a novel control method for wind turbine pitch angle with time delays. Specifically, the proposed control method is state-space PIDD2, which is based on internal model control (IMC) and the open-loop system step response. Then, considering the tracking, disturbance rejection and measurement noise, the proposed controller is verified through simulations. The simulation results demonstrate that the state-space PIDD2 (SS-PIDD2) can provide a trade-off between robustness, time domain performance and measurement noise attenuation and effectively improve pitch control performance in contrast to series PID and PI control methods.

Design of a pitch angle control system in wind turbines through an adaptive pi control by fuzzy logic

En el presente trabajo se llevó a cabo la investigación y el desarrollo de un sistema de control de ángulo de palas (pitch) en un aerogenerador. Dicho desarrollo se realizó utilizando el software Matlab, con las respectivas herramientas que posee. Se analizaron e implementaron modelos teóricos del rotor de un aerogenerador de eje horizontal de tres palas, de la transmisión mecánica y un sistema de control Proporcional-Integral adaptativo con ganancias variables cuyo valor se controló mediante controladores Fuzzy Logic, también se implementó un modelo estadístico del viento para analizar el comportamiento del aerogenerador en condiciones que simularían las condiciones meteorológicas naturales (turbulencias en el viento). Se realizó el modelado utilizando la herramienta Simulink y posteriormente se montó un modelo general ensamblando cada bloque. Se realizaron pruebas con cambios en la velocidad del viento dentro de los rangos que se pueden considerar normales y posteriormente se llevó el sistema al límite, elevando la velocidad del viento a velocidades superiores a las permitidas para realizar la prueba del frenado aerodinámico de emergencia. Se observó que el sistema; variando el pitch y las ganancias del controlador PI, rechazó las perturbaciones y cambios en la velocidad del viento, manteniendo la velocidad de rotación del rotor y la potencia mecánica, asimismo en la región de trabajo que excede los límites establecidos realizó el correspondiente frenado.

Aircraft pitch control design using LQG controller based on genetic algorithm

Designing a robust aircraft control system used to achieve a good tracking performance and stable dynamic behavior against working disturbances problem has attracted attention of control engineers. In this paper, a pitch angle control system for aircraft is designed utilizing liner quadratic Gaussian (LQG) optimal controller technique with a numerical tuning algorithm method in the longitudinal plane through cruising stage. Main design approach of LQG controller includes obtaining best weighting matrices values using trial and error method that consumes effort and takes more time, in addition, there is no guarantees to obtain optimum values for weighting matrices elements. In this research, genetic algorithm (GA) is used to optimize the state and control weighting matrices and determine best values for their elements. The proposed traditional and optimized LQG pitch controller schemes are implemented utilizing Matlab simulation tool and their performance are presented and compared based on transient and steady state performance parameters. The simulation results reveal the ability of the optimized GA_LQG controller to reject the effect of the noises in the aircraft system dynamic and achieve a good and stable tracking performance compared with that of the conventional LQG pitch control system.

Submarine control system using sliding mode controller with optimization algorithm

<span>The purpose of this paper is to design and implement the pitch and depth control system of an autonomous underwater vehicles (AUV). This control system will determine the best pitch angle as well as the depth automatically when there are changes in speed, weight, etc. In this paper, the kinematic and dynamic equations of motion for the AUV are derived to obtain the pitch angle and depth transfer functions. The control strategies applied here, are firstly, the sliding mode controller (SMC) driven by particle swarm optimization (PSO) algorithm. Secondly, the proportional integral derivative controller (PID) tuned by PSO algorithm as a standard controller. The PSO algorithm is used as an efficient algorithm to search for the optimal controllers’ parameters and hence improving the performance of the system. The findings show that the designed sliding mode control (SMC) could improve the stability and performance and provides more realistic behavior for the AUV compared to other classical controllers and according to pitch and the depth changes.</span>

Efficiency Optimization in Medium Power Wind Turbines: an Innovative Mechanical Pitch Control System

The paper illustrates the design of a new mechanical system for propeller blades pitch calibration in medium power wind turbines. The peculiarity of this system is its capacity of adjusting through a feedback control system, which allows the wind turbine to capture the maximum amount of energy from the wind. In this work an axial drive system was studied by means of racks capable of linearly adjusting the pitch of all wind turbine propeller blades in an intrinsically synchronous way, with an advantage over the traditional methods of propeller blades pitch calibration. For different wind speeds the system adjusts the blades angle of incidence in order to reduce the rotation speed and keep the system as close as possible to the pre-established design conditions generating maximum energy with a high efficiency. The manuscript examines the main analyses and simulations conducted during the design phase. These show that the proposed method allows to reach higher efficiencies with a greater intrinsic stability compared to the traditional pitch control mechanisms in medium power wind turbines. The experimental results on the first prototypes confirm the efficiency increase.

SystemXF: a novel approach for holistic system modeling in aircraft conceptual design

In aircraft conceptual design, systems are typically represented by historical regressions without considering system architecture. For novel technologies, this is no longer possible. Alternative approaches are either hard coded solutions for special system architectures or lack the analysis capabilities necessary for conceptual aircraft design. The novel SystemXF approach intends to close this gap by providing a framework for system modeling that is not technology specific and allows for the integration of different analysis disciplines within a single model. A central XML file is used for system specification which can be edited using a SysML interface. A mass estimation and a safety analysis tool are available. An example system which is inspired by a real pitch control system is used to illustrate the method and to show the applicability. This modeling example shows that the proposed model is capable to represent and analyze realistic systems in conceptual aircraft design. The analysis tools can be used for system studies and to provide inputs for a conceptual aircraft design process.

An innovative optical element for X-ray beam aperture, monitoring, and diagnostic at the CARNAÚBA beamline at SIRIUS/LNLS

The CARNAÚBA beamline is the tender-to-hard X-ray nanoprobe under commissioning for the new source Sirius at the Brazilian Synchrotron Light Laboratory (LNLS). The all-achromatic optics relies on horizontal deflection mirrors, a horizontal secondary source aperture (SSA), and Kirkpatrick–Baez (KB) mirrors to reach beam size down to ~30x30 nm2 at the sample position. To handle the highly focused power density of the pink beam and reach the desired stability for the horizontal secondary source, essential for the desired focusing and coherent properties at the sample position, we present here an SSA device based on a cryogenically cooled Si crystal in a channel-cut geometry. The crystal slabs define the channel aperture, which is controlled by a fine rotation. Simultaneously to the aperture function, the device plays the key role of beam position monitor and beam diagnostic. The scattered signal from the slabs is used to monitor the horizontal beam position during experiments and serves as a feedback input for the pitch control system of the upstream focusing mirror to stabilize the beam intensity and wavefront. The Bragg magnifier geometry of the device spreads the beam over the slabs, allowing the diffracted image of the beam to be collected by an area detector. The beam spread on the slabs also reduces the power density reaching the device, keeping it stable and under controlled temperatures.

A Review of Recent Aerodynamic Power Extraction Challenges in Coordinated Pitch, Yaw, and Torque Control of Large-Scale Wind Turbine Systems

As the impacts of environmental change become more severe, reliable and sustainable power generation and efficient aerodynamic power collection of onshore and offshore wind turbine systems present some of the associated key issues to address. Therefore, this review article aims to present current advances and challenges in the aerodynamic power extraction of wind turbines, associated supporting technologies in pitch, yaw, and torque control systems, and their advantages and implications in the renewable energy industry under environmental challenges. To do this, first, mathematical modeling of the environmental characteristics of the wind turbine system is presented. Next, the latest technological advances consider the environmental challenges presented in the literature, and merits and drawbacks are discussed. In addition, pioneering research works and state-of-the-art methodologies are categorized and evaluated according to pitch, yaw, and torque control objectives. Finally, simulation results are presented to demonstrate the impact of environmental issues, improvement claims, findings, and trade-offs of techniques found in the literature on super-large wind turbine systems. Thus, this study is expected to lay the groundwork for future intensive efforts to better understand the performance of large-scale wind turbine systems in addressing environmental issues.

Research on an All-Flow Velocity Control Strategy for a 120 kW Variable-Pitch Horizontal Axis Tidal Current Turbine

Horizontal-axis tidal current turbines have considerable potential to harvest renewable energy from ocean tides. The pitch control system is a critical part of variable-pitch tidal turbines. Existing control strategies for tidal turbines mainly rely on flow measurement devices to obtain tidal velocities, which are costly and subject to many limitations in practical applications, making them unsuitable for small off-grid tidal turbines. In this paper, we propose a pitch control strategy for a 120 kW horizontal-axis tidal current turbine based on the output power of the generator. The torque of the turbine was calculated based on the blade element momentum theory, and a dynamic model of the tidal turbine was established. The dynamic characteristics of the turbine and generator were studied under various flow rates and pitch angles. On the basis of the characteristic analysis, the generating efficiency of the unit was improved under a low flow rate, and the output power was limited to a rated value under high-current velocity by regulating the pitch angle. Furthermore, a novel protection and start up strategy is proposed to protect the unit and make full use of the tidal energy when the tidal current velocity exceeds the limit value. We performed simulations, the obtained results of which demonstrate the effectiveness and advantages of the designed control strategies.