Yaw Motion Research Articles

ℒ1 adaptive controller of VEGA Launcher subject to flexible modes

Flexible launch vehicle modes contribute to the deterioration of its stability performance. For this reason, their influence must be considered when designing and validating appropriate solutions for its automatic control system. The first three bending modes are the most relevant for control system design and analysis. Next, considerations regarding the elastic modes of the Vega actuator, used in the simulations performed throughout this study, are presented. The IMU (Inertial Measurement Unit) measurements providing attitude angles and angular rates are strongly corrupted by the local elastic deformations resulting from structural flexibility. These measurements are fed back to the TVC (Thrust Vector Control) system which controls the pitch and the yaw motion of the vehicle. The design methodology for this control system is based on an ℒ1 adaptive technique incorporating a Butterworth filter guarantees good stability performances for wide variations of the launcher’s dynamics parameters.

The performance failure of yaw damper caused by air entering its inner tube and its impact on hunting instability of an intercity train

The yaw damper, employed to mitigate the relative yaw motions between the carbody and the bogie frame, is critical in ensuring the vehicle’s hunting stability. During a roller rig test, bogie hunting instability was observed in an intercity train, attributed to the performance failure of the yaw damper. To investigate this failure further, a physical parameter model, validated through static and dynamic test data, was established to capture the yaw damper performance under normal and faulty states. Then, the vehicle hunting stability was analyzed using the vehicle dynamic model, considering different numbers of faulty yaw dampers. The results indicate that the entry of free air into the inner tube, followed by its passage through the damper valve, induces the damping characteristics failure of the yaw damper. As the number of faulty yaw dampers increases, subcritical bifurcation and grazing bifurcation are observed at lower speeds, causing serious bogie hunting instability and further deteriorating the operational safety and ride comfort of the vehicle. The research offers theoretical support for structure improvement and performance optimization of the yaw damper to avoid the above failure.

Evaluation of aging characteristics in wind turbine performance based on yaw power loss

The yaw dynamics of wind turbines are crucial for ensuring their operational efficiency and maximizing wind energy capture. However, excessive yaw movements may precipitate premature aging of these turbines. Investigating how yaw behavior influences turbine performance can aid in refining yaw control strategies, thereby mitigating the rate of performance degradation. This paper analyzes five years of SCADA data from a wind farm, employs the DBSCAN algorithm to process anomalous data, and explores the correlation between state parameters and power output under varying operational conditions. The study leverages kernel density estimation and least squares approximation for univariate data processing and curve fitting. Furthermore, it introduces the concept of a yaw loss rate to assess power efficiency during yaw maneuvers quantitatively, calculates yaw-induced power losses under diverse conditions, and proposes a novel method to evaluate turbine performance by considering historical trends in power capture. The findings confirm that the proposed evaluation methodology is practical and effective, substantiated by analyzing five consecutive years of SCADA data from four turbines located in a mountainous wind farm in southern China.

A Numerical Method on Large Roll Motion in Beam Seas Under Intact and Damaged Conditions

The second-generation intact stability criteria, including five stability failure modes, were approved by the International Maritime Organization (IMO) in 2020, and it is an urgent task to develop the numerical method for the significant roll motion under dead conditions. Both intact and damaged stability focus on the large roll motion in beam seas. A unified numerical method is studied to predict the large roll motion in regular and irregular beam seas under intact and damaged conditions. Firstly, a sway–heave–pitch–roll–yaw coupled equation named 5-DOF and a sway-roll-yaw coupled motion with the roll-righting arm in still water named 3-DOF are used to predict the large roll motion in regular beam seas under the intact and damaged conditions. Secondly, the method is extended for the large roll motion in irregular beam seas, where the diffraction force in the roll direction and the sway and yaw motion under intact and damaged conditions are calculated by the subharmonic superposition method. Thirdly, the roll-righting arm in the calm water, roll-damping coefficients, and the roll natural roll period, under the intact and damaged conditions, are obtained by software and a free roll decay experiment, respectively. Finally, the numerical results of a patrol boat under intact and damaged conditions are compared to the experimental results. The results show that the sway-roll-yaw coupled motion with the roll-righting arm in still water named 3-DOF can predict the large roll motion in regular and irregular beam seas under intact and damaged conditions.

Structural optimization and performance investigation of power flow adaptive flow devices based on multi-body coupling

Through the multi-body coupling between the components in the numerical calculation, the self-adaptive yaw motion of the power flow turbine is realized. Specifically, the changes of launching dynamic performance in different yaw structure combinations (different rod length, different tail chord length, different tail limiting Angle and rotation axis position) are investigated. The results show that under the same operating conditions, the turbine efficiency of the optimized structure combination is increased by 1.05 % and the yaw speed is increased by 16.7 %. Then, the influences of different tip immersion depth and wave period on thrust coefficient and efficiency coefficient of turbine at free liquid surface are compared. The conclusion is that the turbine efficiency is increased by 0.8 % when the tip depth is 0.21D compared with that without free liquid surface. When the wave period is 1.3, the turbine efficiency is increased by 1.4 % compared with that without free liquid surface. The results show that the selection of appropriate structure combination and installation depth is of great help to turbine efficiency and yaw speed during the yaw process of turbine power flow unit.

Multi-Objective Optimization Design of a Mooring System Based on the Surrogate Model

As the development of floating offshore wind turbines (FOWTs) progresses from offshore to deeper sea, the demands on mooring systems to ensure the safety of the structure have become increasingly stringent, leading to a concomitant rise in costs. A parameter optimization method for the mooring system of FOWTs is proposed, with the mooring line length and anchor radial spacing as the optimization variables, and the minimization of surge, yaw, and nacelle acceleration as the objectives. A series of mooring system configuration samples are generated by the fully analytical factorial design method, and the open source program OpenFAST is employed to simulate the global responses in the time domain. To enhance the efficiency of the optimization process, a multi-objective evolutionary algorithm, Non-dominated Sorting Genetic Algorithm II (NSGA-II), is utilized to find the Pareto-optimal solutions, alongside a Kriging model, which serves as a surrogate model for the FOWTs. This approach was applied to an IEC 15MW FOWT to demonstrate the optimization procedure. The results indicate that the integration of the genetic algorithm and the surrogate model achieved rapid convergence and high accuracy. Through this optimization process, the longitudinal motion response of FOWTs is reduced by a maximum of 6.46%, the yaw motion by 2.87%, and the nacelle acceleration by 11.55%.

Electronic brake system-based hierarchical motion control of commercial vehicle for autonomous obstacle avoidance

As a high-level autonomous driving technology, efficient and safe automatic obstacle avoidance on highway is one of the critical and ongoing topics that requires in-depth research for commercial vehicles. Electronic control air pressure brake system, owing to its fast response and active braking ability, is an effective active-chassis technology to function path tracking and stability control in such condition. Yaw motion stability control problem of autonomous driving commercial vehicle based on active braking control with electronic air brake system for automatic obstacle avoidance is investigated. First, a hierarchical yaw motion dynamics control architecture is introduced after vehicle and brake system modeling. The quintic polynomial curve-based trajectory planning method and a Model Predictive Control based trajectory tracking control strategy are formulated. Second, to evade the possible stability losing issue in this circumstance, Cubature Kalman Filter (CKF) is utilized to estimate the vehicle motion states, and a fuzzy PID control-based differential brake stability control strategy is designed for the electronic brake system composed of front-and-rear two sets of dual-channel pressure regulator and ABS solenoid valve. Finally, the proposed hierarchical yaw stability control strategy for a commercial vehicle in typical obstacle avoidance conditions is comparatively verified based on the joint simulation tools. After the yaw stability control, the peak value of the lateral displacement error of trajectory tracking can be reduced by 44.7%. The yaw stability control strategy based on fuzzy PID control can reduce the yaw rate by 46%–57% and the sideslip angle by 60%–73% under different conditions. The results show that the proposed control strategy can effectively improve the yaw stability of the vehicle while avoiding obstacles at high speed.

Comparative Analysis of Machine Learning Models for Detecting Abnormal Driving Behaviour in Two-Wheeler Kinematics

Road accidents are a major global concern, particularly affecting vulnerable two-wheeler riders. This research investigates driving behaviour using time-series data from real-world scenarios to de- velop machine learning models for anomaly detection and risk as- sessment. The purpose of this study is to explore the performance of five predictive models—Long Short-Term Memory-Residual (LSTM- R), Gated Recurrent Unit (GRU), Adaboost, XGBoost, and a Mul- tilayer Perceptron (MLP) with Random Forest (RF) ensemble—are evaluated based on nine parameters: accelerometer (X, Y, Z), gyro rotation (X, Y, Z), motion yaw, pitch, and roll. A threshold rule-based approach using multi-output regression is employed for predictive modeling. The study makes three key contributions: First, it assesses the predictive accuracy of the five models, with the MLP-RF ensem- ble achieving a low MAE of 0.1157 on test data. Second, it identi- fies optimal hyperparameters for each model through systematic tuning. Third, it introduces a threshold-based anomaly detection method using residuals, which reduces overfitting and requires fewer instances of abnormal behaviour. The results indicate that these models, especially the MLP-RF ensemble and GRU, effectively predict and detect abnormal driving behaviours, enhancing safety for two-wheeler riders and contributing to sustainable urban devel- opment.

Modeling and dynamic performance of distributed force in high-temperature superconducting pinning magnetic levitation

High-temperature superconducting (HTS) pinning magnetic levitation (maglev) systems are highly promising for future applications in rail transportation. Through the interaction between onboard HTS bulks and the permanent magnet guideway (PMG), this system generates levitation and guidance forces, known as the HTS-PMG relationship. Under practical conditions, this interaction manifests itself as a distributed force. However, past models have only considered concentrated forces. This study aims to design experiments to investigate the HTS-PMG relationship and propose a more realistic discretized lateral-vertical coupling HTS-PMG relationship to accurately reflect torques in dynamic simulations. Based on this, a dynamic model is established to analyze the Sperling index and the five-degree-of-freedom dynamic response of the HTS pinning maglev vehicle system under different HTS-PMG relationship models. The results indicate that the proposed discretized lateral-vertical coupling HTS-PMG relationship accurately characterizes the torque generated by the HTS levitator, influencing lateral, roll, pitch, and yaw motions to some extent. Compared with the concentrated force model, the discrete force model exhibits superior dynamic performance, particularly in terms of lateral dynamics and the lateral Sperling index. This study provides valuable insights into the field of HTS maglev, particularly regarding investigating HTS-PMG relationships and their impact on HTS maglev system dynamic performance.

Anti-rollover Artificial Potential Field Motion Planning Method of an Autonomous Heavy Truck Optimised by Game Theory

Anti-rollover is a critical factor to consider when planning the motion of autonomous heavy trucks. This paper proposed a method for autonomous heavy trucks to generate a path that avoids collisions and minimizes rollover risk. The corresponding rollover index is deduced from a 5-DOF heavy truck dynamic model that includes longitudinal motion, lateral motion, yaw motion, sprung mass roll motion, unsprung mass roll motion, and an anti-rollover artificial potential field (APF) is proposed based on this. The motion planning method, which is based on model predictive control (MPC), combines trajectory tracking, anti-rollover APF, and the improved obstacle avoidance APF and considers the truck dynamics constraints, obstacle avoidance, and anti-rollover. Furthermore, by using game theory, the coefficients of the two APF functions are optimised, and an optimal path is planned. The effectiveness of the optimised motion planning method is demonstrated in a variety of scenarios. The results demonstrate that the optimised motion planning method can effectively and efficiently avoid collisions and prevent rollover.

Dynamic modelling and experimental validation of a dynamic track stabiliser vehicle–track spatially coupling dynamics system

A dynamic track stabiliser vehicle is an unconventional vehicle for maintaining the quality of ballasted tracks, and its dynamic performance has a significant impact on its working efficiency. For the first time, this paper proposes a comprehensive dynamic track stabiliser vehicle–track coupled vertical and lateral multi-body dynamics model based on classical vehicle–track coupling dynamics theory. In this model, detailed attention is given to the vertical, lateral, roll, yaw, and pitch motions of the components, including the vehicle body, bogies, wheelsets and stabilisers. The Shen–Hedrick–Elkins theory is employed to describe non-linear wheel–rail contact relationships between the bogie wheelsets and the rails, and three various methodologies are adopted to address complicated wheel–rail interaction problems between the stabiliser wheelsets and the rails. This comprehensive multi-body dynamics model enables a detailed investigation of the dynamic performance of the system under complex excitations, such as the lateral excitation of the stabilisers and vertical downward pressure exerted by hydraulic cylinders, especially the dynamic response of the stabilisers in the vibration environment of the complete vehicle. The dynamics model was fully validated by comparing its results with time- and frequency-domain data obtained from field tests. The results indicate that the model is capable of being used for analysis of the dynamic performance of dynamic track stabiliser vehicles.

Fixed-time controller for altitude/yaw control of mini-drone based on nonsingular terminal sliding mode: Real-time implementation with uncertainties

To obtain fixed-time stability and finite-time convergence of altitude and yaw motions of a mini-quadrotor subjected to perturbations, this paper proposes a new altitude/yaw motion finite-time tracking control. First, a nonsingular terminal sliding manifold is proposed for both subsystems whose states converge to their desired values in finite-time. To address the uncertainties of the system, a robust fixed-time switching controller is proposed whose stability is proposed and its settling-time depends only on control of the parameters and not the initial conditions. The validation of the proposed approach is presented based on a real mini-quadrotor.

Metaheuristic tuned decentralized PID controller based active suspension system for railway vehicle

AbstractA high‐speed railway system is one of the sustainable alternatives to other modes of transportation and may connect the most congested urban cities with minimum carbon emissions. However, the vibration intensity increases as the train's operating speed increases, resulting in deteriorated ride comfort and stability. Hence, this article investigates a 27‐degree‐of‐freedom (DOF) dynamic model of railway vehicles with an improved active suspension system. The decentralized control structure performs the controlling action with five optimized Proportional Integral Derivative (PID) controllers that suppress the vehicle body's vertical, lateral, pitch, roll, and yaw motions. Further, to optimize the PID parameters, three metaheuristic optimization techniques, Genetic algorithm (GA), Grey Wolf Optimization (GWO), and Flower Pollination Algorithm (FPA), are utilized, and their simulated results are compared with the passive system as well as other conventional tuning technique. Moreover, the performance of the proposed control strategy is evaluated in the frequency domain under random track irregularities, and the results are characterized in terms of power spectral densities (PSDs). The simulated results show that among the proposed metaheuristic algorithms, FPA outperforms with a significant reduction in vehicle vibration compared to other tuning methods. The percentage reduction of the vertical, lateral, pitch, rolls, and yaw accelerations is 71.4%, 35.1%, 52.8%, 48.1%, and 38.2%, respectively, ensuring enhanced vehicle ride comfort.

A hierarchical estimation of road grade based on tire force observation

Road grade is important for autonomous vehicles, but it is difficult to measure directly. To address this issue, a hierarchical estimation of road grade is suggested based on the observation of tire forces. First, a 7-degree-of-freedom (DOF) dynamics model, including vehicle longitudinal, lateral, and yaw motions together with wheel rotations, is developed while considering the road grade. Subsequently, a dual-layer road grade estimation strategy is proposed based on an unscented Kalman filter (UKF). The lower-layer UKF estimates the longitudinal and lateral tire forces for road grade observation, and the upper-layer UKF is employed to estimate the road grade by considering the vehicle’s lateral acceleration and yaw rate. Finally, CarSim and MATLAB joint simulations and road tests are performed under different conditions to validate the correctness and effectiveness of the proposed estimation method. The results show that the proposed tire force observation-based estimator exhibits a lower mean absolute error and root mean square error on sloping roads and combined curved and sloping roads, and presents a better overall estimation performance on road grade compared with the widely used kinematics and dynamics model-based estimators.

Visually induced vertical vergence as a motion processing biomarker associated with postural instability

The present study explored visually induced vertical vergence (VIVV) as non-specific motion processing response. Healthy participants (7 male, mean age 28.57 ± 2.30; 9 female, mean age 27.67 ± 3.65) were exposed to optokinetic stimuli in an HTC VIVE virtual reality headset while VIVV, pupil-size, and postural sway was recorded. The methodology was shown to produce VIVV in the roll plane at 30 deg/s. Subsequent trials consisted of 40 s optokinetic motion in yaw, pitch, and roll directions at 60 deg/s, and radial optic flow; optokinetic directions were inverted after 20 s of motion. Median VIVV amplitude changes were normalized to the clockwise roll rotation, analysed, and correlated with changes in pupil-size and body sway. VIVV, pupil-size, and body sway were all affected by changes in optokinetic direction. Post-hoc analyses showed significant VIVV responses during optokinetic yaw and pitch rotations, as well as during radial optic flow stimulations. VIVV magnitudes were universally correlated with pupil-size and body sway. In conclusion, VIVV was expressed in all tested dimensions and may consequently serve as a visual motion processing biomarker. Failing to support binocularity while responding to optokinetic directionality, VIVV may reflect an eye-movement response associated with increased postural instability and stress, similar to a dorsal light reflex.

Design and stability analysis of a new six-floater oscillating water column-based floating offshore wind turbine platform

The operational efficiency and lifespan of Floating Offshore Wind Turbines (FOWTs) are adversely impacted by the inherent platform motions and undesired vibrations induced by wind and wave loads. To effectively address these effects, the control of specific structural motions is of utmost importance, with platform pitch and yaw identified as the primary Degrees Of Freedom (DOF) that require attention. This study proposes a novel utilization of Oscillating Water Columns (OWCs) as a reliable and viable solution to mitigate platform pitch and yaw motions, thereby significantly enhancing the efficiency and reducing fatigue in wind turbines. This article aims to evaluate the impact resulting from integrating OWCs within each discrete floater of a Six-Floater platform. By considering different combinations of OWCs, a comprehensive analysis of the Response Amplitude Operators (RAOs) associated with pitch and yaw motions is presented. The primary objective is to identify the most efficient arrangements of OWCs and determine suitable combinations that effectively stabilize platform pitch and yaw motions. The empirical results substantiate that specific OWC configurations exhibit notable dampening effects on both pitch and yaw motions, particularly within specific wave frequency intervals. Consequently, it can be inferred that the integration and adequate operation of OWCs facilitate a substantial improvement in the stabilization of multi-floater platforms.

Harnessing the Propulsive Force of Microalgae with Microtrap to Drive Micromachines.

Microorganisms possess remarkable locomotion abilities, making them potential candidates for micromachine propulsion. Here, the use of Chlamydomonas Reinhardtii (CR) is explored, a motile green alga, as a micromotor by harnessing its propulsive force with microtraps. The objectives include developing the microtrap structure, evaluating trapping efficiency, and investigating the movement dynamics of biohybrid micromachines driven by CR. Experimental analysis demonstrates that trap design significantly influences trapping efficiency, with a specific trap configuration (multi-ring structure with diameters of 7µm - 10µm - 13µm) showing the highest effectiveness. The micromachine empowered with two CRs facing the same direction exhibits complex, random-like motion with yaw, pitch, and roll movements, while the micromachine with four CRs in a circular position each facing the tangential direction of the circle demonstrates controlled rotational motion. These findings highlight the degree of freedom and movement potential of biohybrid micromachines.

Fuzzy Logic Enhanced Second-Order Sliding Mode Controller Design for an Experimental Twin Rotor System Under External Disturbances

BackgroundThe twin rotor model is frequently studied by researchers because although it has a basic structure the coupled pitch and yaw motions are adequately represented. However, it is quite difficult to obtain an efficient controller due to external disturbances. Classical sliding mode controller (SMC), which is of first order, is recognized to be robust in case of parameter changes and external disturbances especially when the sliding motion takes place, but it possesses chattering in the control input which may damage the mechanical parts of the system.PurposeIn this study it was aimed to design a robust controller without chattering effect which will be used for the control of the twin rotor system in real time experiments.MethodsTo remedy the chattering issue, a novel fuzzy logic enhanced second-order sliding mode controller (FSOSMC) based on super twisting algorithm is proposed. This controller suppresses chattering while enhancing the robustness of the controller where the sliding surface slope parameter is updated online via a fuzzy logic unit. Then the proposed controller is implemented on an experimental twin-rotor system which has highly nonlinear and coupled dynamics.ResultsReal time experiments were performed on the twin rotor system using the proposed FSOSMC. For comparison purpose the SMC and second-order sliding mode controller (SOSMC) were also applied to the same system. The results have shown that the proposed controller increased the tracking performance without increasing the control effort while reducing the chattering.ConclusionsThe experimental results verified the success of the designed FSOSMC, therefore it may be recommended for the robust and precise control of aerial vehicles.Graphical

A rapid motion forecast strategy for ships in waves using seakeeping and maneuvering modules

This paper develops a new navigation assisted system for ships with time-varying wave disturbances. A new framework is presented using seakeeping and maneuvering modules to achieve the fast forecast of ship motions. S175 containership and KVLCC2 tanker are adopted to verify the seakeeping module. Based on the validated module, the heave, roll and pitch motions of a cruise ship in different conditions are calculated by using three-dimensional Rankine panel method. The horizontal surge, sway and yaw motions of ships can be rapidly evaluated by using MMG model considering the wave drift forces. Finally, the motion amplitudes of 6°-of-freedom can be forecasted rapidly by using seakeeping and maneuvering modules. The study provides the insight into the motions of ships in waves. It is of great engineering application value to evaluate the total ship motion amplitudes and to improve the safety of navigation of ships in waves.

Synthetic Optimization of Trafficability and Roll Stability for Off-Road Vehicles Based on Wheel-Hub Drive Motors and Semi-Active Suspension

Considering the requirements pertaining to the trafficability of off-road vehicles on rough roads, and since their roll stability deteriorates rapidly when turning violently or passing slant roads due to a high center of gravity (CG), an efficient anti-slip control (ASC) method with superior instantaneity and robustness, in conjunction with a rollover prevention algorithm, was proposed in this study. A nonlinear 14 DOF vehicle model was initially constructed in order to explain the dynamic coupling mechanism among the lateral motion, yaw motion and roll motion of vehicles. To acquire physical state changes and friction forces of the tires in real time, corrected LuGre tire models were utilized with the aid of resolvers and inertial sensors, and an adaptive sliding mode controller (ASMC) was designed to suppress each wheel’s slip ratio. In addition, a model predictive controller (MPC) was established to forecast rollover risk and roll moment in reaction to the change in the lateral forces as well as the different ground heights of the opposite wheels. During experimentation, the mutations of tire adhesion capacity were quickly discerned and the wheel-hub drive motors (WHDM) and ASC maintained the drive efficiency under different adhesion conditions. Finally, a hardware-in-the-loop (HIL) platform made up of the vehicle dynamic model in the dSPACE software, semi-active suspension (SAS), a vehicle control unit (VCU) and driver simulator was constructed, where the prediction and moving optimization of MPC was found to enhance roll stability effectively by reducing the length of roll arm when necessary.