Roll Stability Research Articles

Constrained Nonlinear MPC with Rudder-Roll Stabilization for Integrated Path Following and Collision Avoidance in Underactuated Surface Vessels

This study develops a constrained nonlinear model predictive control (NMPC) framework, integrating rudder roll stabilization to address coupled path-following and collision avoidance challenges for underactuated surface vessels (USVs). The compact state-space model integrates both navigational states and roll dynamics through augmentation, facilitating real-time optimization of the trade-off between safety margins for roll movements and path-following accuracy. Given that excessive roll movement during obstacle avoidance in the USV path following can readily lead to USV capsizing, the NMPC approach is employed to explicitly address multiple constraints, including obstacle avoidance constraint, roll movement safety, and control input rudder angle constraints, thereby achieving precise path following for the rudder-roll reduction control system. Different from traditional methods that adhere to a pre-planned obstacle avoidance path, the proposed NMPC approach formulates obstacle avoidance as a nonlinear inequality constraint, significantly enhancing the maneuverability of the USV during obstacle avoidance. To validate the effectiveness of the proposed algorithm, the stability and optimality of the rudder-roll reduction control system are analyzed. The advantages of the proposed algorithm are ultimately demonstrated through both theoretical analysis and simulation results.

A Semi-Trailer Path Planning Method Considering the Surrounding Traffic Conditions and Vehicle Roll Stability

Path planning for intelligent semi-trailers encounters numerous challenges in complex traffic conditions. Serious consequences, such as vehicle rollover, may occur when the traffic conditions change. Therefore, it is vital to consider both the surrounding dynamic traffic conditions and the vehicle’s roll stability during the lane-changing process of intelligent semi-trailers. We propose an innovative path-planning method tailored for intelligent semi-trailers. This path-planning method is designed for semi-trailers on straight-road alignments. Firstly, we employ a fuzzy inference system to process information about surrounding traffic, make lane-changing decisions, and determine the starting point. Secondly, the lane-changing path is generated using a B-spline curve. Subsequently, we apply a particle swarm optimization algorithm to enhance the B-spline curve. Thirdly, we utilize a Transformer model to analyze the nonlinear relationships among information about surrounding traffic, vehicle information, and the roll stability of the intelligent semi-trailer. We establish the roll stability boundary for the vehicle. Finally, we design a multi-objective cost function to select the optimal path. The simulation results demonstrate that the proposed method dynamically adapts the planned path to variations in driving parameters, ensuring trackability while reducing the steering angle, lateral acceleration, and yaw rate. This approach meets the roll stability requirements of intelligent semi-trailers, significantly enhances their stability during lane changing, and provides robust support for safe and efficient operation.

Effect of drum and disc brakes on roll stability of double-trailer trucks during braking-in-turn manoeuvers

This study compares the performance of drum and disc brakes in maintaining roll stability of long combination vehicles (LCV) using a multi-domain model intergrating pneumatic brake dynamics in Simulink® and truck dynamics in TruckSim®. The LCV consists of a Class 8 tractor, two 33-ft trailers, and an A-dolly. While the tractor and dolly’s brakes remain unchanged, the trailers’ brakes changed from drum (baseline) to disc brakes. The multi-domain model is validated using straight-line braking test data. The validated model is used to evaluate and compare the straight-ahead stopping distance and roll stability in J-turns at various speeds and timing for brake initiation (TBI). Results indicate that disc brakes better mitigate the lateral accelerations of both front and rear trailers during braking-in-turn manoeuvers, lowering rollover risks. The disc brakes’ faster response time and larger braking torques yield larger speed reduction when the vehicle enters a turn at speeds higher than the vehicle rollover threshold. At an entry speed of 40 mph or higher, the disc brakes result in a higher TBI, allowing more time for the driver to initiate braking to prevent a rollover. The improvement increases with increasing entry speeds.

Switched control strategy based on preview-based MPC for active suspension of heavy-duty vehicle to improve ride comfort and roll stability

Abstract This paper proposes a switched control system for heavy-duty vehicles, aiming to improve ride comfort and roll safety in unstructured road conditions. The realization of the comprehensive control target depends on the active suspension system: on the one hand, it can suppress the vibration caused by road excitation; on the other hand, it can dynamically adjust the output vertical force of the actuator to achieve the purpose of anti-roll. Focusing on the important influence of complex road conditions with road curvature and inclination on stability of heavy-duty vehicles, a vertical-lateral coupling nine-degree-of-freedom model is established. Then, a preview-based Model Predictive Control (MPC) switching controller is designed to make full use of road information, which allows the controller to be solved in advance, thereby improving the real-time performance. In addition, variable weight coefficients are used to realize the switched control of ride comfort and roll safety based on the preview road information. Finally, the simulation results given by Matlab/Simulink show that over the one without control, the proposed controller improves the ride comfort by about 53.2% and the roll safety by about 45.2%.

Numerical Mach Number Studies on a Multidelta Wing Configuration with Vertical Stabilizers

The presented investigations look at the vortical flow physics and aerodynamic performance of a generic, sharp leading-edge multidelta wing configuration with control surfaces. The work is part of a German Aerospace Center (DLR) project, looking at technologies and design requirements for next-generation fighter aircraft. The present paper deals with the aerodynamic task to integrate vertical stabilizers and to evaluate the effects of dihedral and rudder deflection angles, as well as the influence of the Mach number on the vortical flow, aerodynamic behavior, and stability. The work is based on a set of investigations looking at the roll stability at medium-to-high angles of attack of the configuration with strakes and wing leading-edge slats. The aim is to enhance the knowledge base regarding the integration of control surfaces for the next design stages within the DLR internal project.

Fully coupled dynamic analysis of novel floating dual-rotor wind turbines

This paper employs a fully coupled aero-hydro-servo-elastic approach to develop numerical models for the 10 MW floating single-rotor wind turbine (SRWT) and the 5 MW-5 MW floating dual-rotor wind turbine (DRWT). A series of numerical simulations was conducted to investigate the aerodynamic characteristics, wake characteristics, dynamic response, and tower base force characteristics of two types of wind turbines. The results under three conditions—wind only, wave only, and combined wind and wave were analyzed and compared. The results indicate that the rated wind speeds of the floating SRWT and DRWT are 11.4 and 14 m/s, respectively. Under wind-only conditions, the aerodynamic force of DRWT is greater than that of SRWT when the wind speed reaches the rated speed of DRWT. However, when the wind speed is below the rated speed of DRWT, the results are the opposite. Regarding aerodynamic wake recovery, the DRWT demonstrates greater advantages due to the mutual interaction and mixing of the wakes. In terms of platform motion and tower base forces, the DRWT not only exhibits greater stability in sway, heave, roll, and yaw degrees of freedom but also shows lower average values for both the force and bending moment at the tower base. Under combined wind and wave conditions, the DRWT exhibits more complex high-frequency response characteristics compared to the SRWT. This paper offers a comprehensive analysis of the floating DRWT in comparison with the floating SRWT and provides insight for future design optimizations of DRWTs.

Fatigue and recovery-related changes in postural and core stability in sedentary employees: a study protocol.

Prolonged sitting leads to a slumped posture, which indirectly influences spinal curvature and increases low back and hamstring stiffness. Active rather than passive recovery is an effective way to reduce the risks associated with such prolonged inactivity. However, it remains to be investigated which of the exercises frequently used for this purpose, the trunk stability and foam rolling exercise, is more beneficial. This protocol study will compare the effects of foam rolling exercises on the recovery of impaired core and postural stability induced by core muscle fatigue and hamstring muscle stiffness with those of trunk stabilization exercises in sedentary adults. Twenty sedentary adults ranging in age from 25 to 44years old, comprising 50% men and 50% women, will participate in a modified Abt's trunk muscle fatigue protocol, then proceed with (1) active recovery in the form of trunk stabilization exercises, (2) active recovery in the form of foam rolling exercises, and (3) passive recovery, entails lying on a bed, respectively. Pre-fatigue, post-fatigue, and after all three recovery modalities, core and postural stability, and back and hamstring muscle flexibility will be evaluated using an inertial sensor system, and a posturography system. Muscle-fatigue conditions will be determined using electromyogram signals. Although the effects of foam rolling and trunk stabilization exercises can be attributed to different physiological mechanisms, the former releasing myofascial to improve flexibility and reduce muscle tension, the latter strengthening core muscles to stabilize posture, we hypothesize that both are equivalently effective in reducing the consequences of prolonged sitting.

Rudder roll stabilisation control method of ship with input constraints

The effect of roll on the ship’s motion is most obvious because the ship’s transverse damping is small. To achieve roll reduction of the ship, a linear ship model is constructed, and a design method of rudder roll stabilisation controller based on linear matrix inequalities (LMIs) technology is studied. In this case, the rudder is used for simultaneous course keeping and roll reduction. Due to the rudder angle is constrained by a maximum angle and the rudder rate is constrained by a maximum rate, there is a problem of input constraints. Therefore, the solution conditions of the controller are derived based on the input constraints of rudder angle and rudder rate. These conditions are presented in the form of LMIs. The technology of rudder roll stabilisation does not need to add additional hardware, is relatively inexpensive, and can be applied to different ship types. Finally, the course keeping and roll reduction abilities of the rudder roll stabilisation controller is verified by simulation.

Hydrodynamic model of active fin stabilizers at zero advancing speed

Hydrodynamic model of active fin stabilizers at zero advancing speed

Rollover prevention by designing a new fuzzy set solution for automotive active stabilizer bars based on a complex dynamic model

In this paper, the author introduces using active stabilizer bars (hydraulic anti-roll bars) for automobiles to improve the stability of rolling over when an automobile is steering. The car rollover oscillation is described by a complex dynamic model, a combination of the Pacejka tire model, the motion model, and the full oscillation model. A new fuzzy solution has been developed in order to control the active stability bars. This algorithm has three inputs related to the car’s rollover factor. The fuzzy rule (with 125 situations) and membership function are determined based on views related to the car’s stability and the antiroll system’s responsiveness. Numerical calculations and simulation are performed with two cases corresponding to two kinds of steering angles. Three situations correspond to three velocity values: v1, v2, and v3, and four scenarios are simulated in each situation to facilitate the comparison of results. According to the research findings, output values such as roll angle, rollover index, and load change are drastically reduced when the new fuzzy solution is applied to the active anti-roll bars. In the last case, the rollover occurs when the automobile does not use any stability bars or uses regular mechanical bars. The roll angle peak values reach 8.79° and 10.79°, while the maximum value belonging to the Active with Fuzzy situation is 10.94° without rolling over (corresponding to a rollover index of 0.64). The results obtained from this paper are the basis for developing more complex solutions for stabilizer bars in the future.

Integrated Control of Intelligent Vehicle Driving Stability Using Three-Dimensional Phase Space

<div>To enhance vehicle dynamic stability during driving, we developed a three-dimensional phase space model that incorporates the sideslip angle of center of mass, yaw rate, and lateral load transfer rate. This model enabled real-time evaluation and active control of vehicle stability. First, longitudinal and lateral controllers were implemented to ensure precise vehicle trajectory. Second, a hierarchical control strategy was designed to actively manage the desired sideslip angle, yaw rate, and roll angle based on the vehicle’s destabilizing conditions, thereby maintaining the vehicle within a stable state space. We simulated and tested the stability analysis methods and integrated control strategies for both cars and trucks under DLC (double lane change) and CDC (circular driving condition) scenarios using joint simulations with CarSim/TruckSim and Simulink. The proposed integrated stability control strategy, which combined MPC-based trajectory tracking with direct yaw moment control and active suspension control, enhanced the vehicle’s directional and roll stability. This approach effectively mitigated vehicle instability under extreme conditions. Compared to the MPC lateral tracking control system, the performance of the integrated control system was significantly improved. In the DLC scenario, the maximum values of the sedan’s lateral deviation, sideslip angle, yaw rate, and vehicle roll angle decreased by 22.6%, 33.9%, 5.5%, and 1.2%, respectively. In the CDC scenario, the truck’s lateral acceleration, sideslip angle, yaw rate, and vehicle roll angle decreased by 7.5%, 46.8%, 8.2%, and 80%, respectively. Additionally, open-loop simulation tests were conducted under fishhook steering conditions for both passenger cars and trucks. The results further validated the effectiveness of the integrated control strategy, demonstrating its ability to significantly improve yaw rate and roll response, thereby enhancing overall vehicle stability under challenging driving conditions.</div>

Robust integrated control of autonomous vehicles path following with response performance improvement considering lateral stability

In this paper, a robust integrated control scheme is developed for autonomous vehicles path following considering both yaw stability and roll stability. First, a controller with H∞ and optimal guaranteed cost performances is presented, and the poles of the closed-loop system are configured in a given disk region to improve the state response performance. The controller outputs front and rear wheel angles for path following, as well as an external yaw moment and an external roll moment for lateral stability control. Secondly, the braking forces acted on four wheels are optimally distributed by means of quadratic programing. Besides, the steering angles of the four wheels conform to the Ackermann geometry relation. Finally, the proposed control scheme is verified by CarSim/Simulink co-simulation, the results show that the scheme has better performance on path following accuracy and stability of yaw and roll. Meanwhile, constraining the poles in a given disk region can improve the state response performance of the vehicle during operation.

Analysis of grease mechanical degradation in standard equipment

Analysis of grease mechanical degradation in standard equipment

Study on Cavity Filling Defects and Tensile Properties of L-Shaped Profiled Rings

Severe cavity filling defects and poor mechanical properties increase the difficulty in the integrated forming of L-shaped profiled rings due to its asymmetrical section geometry. A novel rolling method of a C-shaped ring was proposed in this study, and two symmetric L-shaped rings were prepared simultaneously. A numerical model of C-shaped ring rolling was established, and the cavity filling defects in different directions and the overall forming defect were defined for a qualitative analysis of the geometry’s accuracy. The effect of the rolling parameters on the forming defects and ring quality was investigated. The forming defects increased with an increase in the groove depth ratio as well as decreases in the groove angle and rolling ratio. The feeding strategy with a constant ring growth velocity led to the best geometric accuracy and strain uniformity of the C-shaped rings. Optimized rolling parameters can be acquired by the Box–Behnken optimization method with multi-objective optimization of the rolling stability and ring quality. An experiment of C-shaped ring rolling was successfully prepared, based on the optimized parameters. The hardness distribution on the cross-section was symmetric and uniform. The C-shaped ring showed obvious anisotropy of the tensile properties of the cast ring’s blank, and heat treatment had little effect on the improvement of the isotropy.

Research Progress on Rolling Forming of Tungsten Alloy.

Tungsten is a metal with many unique characteristics, such as a high melting point, high hardness, high chemical stability, etc. It is widely used in high-end manufacturing, new energy, the defense industry, and other fields. However, tungsten also has room-temperature brittleness, recrystallization brittleness, and other shortcomings due to the adjustment of the composition and organizational structure, such as the addition of alloying elements, adjusting the phase ratio, the use of heat treatment and deformation strengthening, etc. Its performance can be improved to meet the requirements for use in different fields. At present, the main production method of tungsten alloy is powder metallurgy. The use of a rolling open billet rotary forging-stretching process can improve production efficiency and product quality, but in actual production, due to the combined effects of various factors, such as elastic deformation of rolling elements, plastic deformation of the rolled material, etc., the mechanical properties of tungsten plates and bars are often difficult to control effectively, seriously affecting rolling stability and production efficiency. For this reason, researchers have conducted extensive and deep research and optimization on the rolling process of tungsten alloys, including establishing mathematical models, performing numerical simulations, optimizing process parameters, etc., providing important references for the rolling and forming of tungsten alloys. Meanwhile, the material properties are greatly influenced by the microstructure, and the evolution of the microstructure can be well quantified by some advanced characterization techniques, such as SEM, TEM, EBSD, etc., so that certain properties of tungsten can be obtained by controlling the texture evolution. In conclusion, this paper comprehensively summarizes the research progress of tungsten alloy roll forming and provides an important reference for further improving the processing performance and production efficiency of tungsten alloy.

Trajectory planning and tracking of dynamic lane change for autonomous buses considering vehicle stability in dynamic traffic scenarios

Trajectory planning and tracking of lane change are critical technologies for autonomous buses. Characteristics of the buses susceptible to stability problems resulting from the high height, large passenger capacity and long lengths, coupling the dynamic traffic with the dynamic changes in the states of adjacent vehicles and road adhesion coefficient, put forward great challenges in lane change for autonomous buses (ABs). To cope with the foregoing challenges, a framework is proposed to achieve the trajectory planning and tracking of dynamic lane change for ABs. For trajectory planning approach, the trajectory planning and replanning is optimized in the safe range of longitudinal length of the lane-changing trajectory to obtain the real-time reference trajectory, combining consideration of vehicle yaw, roll stability and lane-changing efficiency. The minimum longitudinal length of lane-changing trajectory determined by the yaw stability and roll stability of ABs, combined with the maximum length formed by the adjacent vehicles with dynamic states, form the real-time safe range for lane-changing trajectory planning. For trajectory tracking approach, a tracking approach using model predictive control based on multipoint preview is proposed to achieve the real-time planned trajectory tracking considering buses stability. The effectiveness of the proposed strategy is evaluated by simulating an experimentally validated Trucksim model in different dynamic traffic scenarios to demonstrate the capability of the strategy in trajectory planning and tracking, and guaranteeing vehicle stability for dynamic lane change of ABs.

Research on the Effect of Different Length–Diameter Ratios of the Cylindrical Tank on the Roll Stability of Tank Semi-Trailers

To investigate the effect of different length–diameter ratios of cylindrical tanks on the roll stability of tank semi-trailers, this paper uses an equivalent mechanical pendulum model to simulate liquid sloshing in the tank. The equation of motion for the equivalent mechanical pendulum model is derived, and the model is subsequently determined. The parameters are integrated with the Trucksim vehicle dynamics model to establish the roll stability model of the tank semi-trailer based on the dynamic characteristics, and joint simulation analysis is carried out under different working conditions. The results show that as the length–diameter ratio of the tank increases, the roll angle of the vehicle gradually increases, the rollover threshold of the vehicle continuously decreases, and the roll stability of the vehicle decreases. As the length–diameter ratio increases, the shock effect of the liquid also increases. This research will provide assistance in the design and development of tank trucks.

Controllable region analysis of active front steering and differential braking system stability control characterized by additional yaw moment

Active Front Steering (AFS) and Differential Braking System (DBS) are commonly used execution systems for vehicle anti-rollover or handling stability control. They regulate the vehicle’s yaw moment by adjusting the lateral tire force and longitudinal tire force, respectively. However, these two systems differ in terms of control capabilities and regulatory sensitivities. In emergency conditions, it becomes crucial to allocate and coordinate the tasks for the execution systems according to their yaw moment control capability and adjustment sensitivity. This paper proposes a method for calculating the controllable region represented by the additional yaw moment. This method allows for the computation of the control capability of AFS and DBS based on the current state. Additionally, the influence of different vehicle states on the controllable regions of the two execution systems is analyzed. Building upon this analysis, the yaw moment adjustment sensitivities of AFS and DBS systems under the current state are further investigated. Finally, a task coordinated strategy between AFS and DBS is developed based on the analysis of controllable regions and sensitivities of different execution systems. Simulink simulations are conducted on yaw stability and roll stability conditions to comprehensively analyze the working process of the proposed task coordination strategy.

Adaptive neuro-fuzzy inference control for active stabilizer bars based on multiple data sources.

In this research, we propose using active stabilizer bars to prevent rollover when steering. An intelligent control solution, the adaptive neuro-fuzzy inference system (ANFIS), is established in this article to control the performance of the active anti-roll systems. In contrast to the previously published studies, the intelligent algorithm designed in this research has many outstanding advantages, such as generating a large impact force, a fast response time, a small phase difference, and high convergence ability. The data used to train ANFIS are carefully selected and combined from the previous studies. The initial simulation observes that the roll angle decreases significantly from 8.15° to 6.87° when the ANFIS algorithm is applied to regulate the anti-roll bars. In contrast, the roll angles for the proportional-integral-derivative (PID) and passive (Mechanical) situations are respectively recorded at 7.08° and 7.80°. The reduction of the vertical force at wheels is also solved when the ANFIS algorithm is applied instead of other methods. This value increases sharply from 671.06 N (without bars) to 3030.40 N (ANFIS control), while it only reaches 2544.27 N (PID control) and 1428.83 N (mechanical bars), according to the research findings. If the vehicle does not have the anti-roll bars, a rollover occurs in the second case when the vehicle steers at v3 (80 km/h) and v4 (90 km/h). In contrast, the interaction between the wheels and the road is well maintained when the automobile is equipped with active bars controlled by the ANFIS solution. This is demonstrated by the minimum vertical force value in the rear wheel, which reaches 2687.33 and 2447.33 N, respectively, for the abovementioned conditions. In general, the vehicle's rolling stability can be well guaranteed in all moving situations when using the ANFIS controller for the anti-roll system in the vehicle.

Nonlinear Robust Stabilization of Ship Roll by Convex Optimization

For ship roll stabilization, this paper presents a nonlinear robust controller design method using the sum of squares (SOS) technique combined with the dual of Lyapunov's stability theorem. Varying ship speed and initial metacentric height are seen as uncertainties, sea waves are regarded as external disturbance, and then the robust nonlinear controller is also designed based on the suggested method. Simulations are performed by taking container ship model as an example. It is shown that the designed system guarantees robust performance with respect to the uncertainties and disturbance.