Browse Topic: Steering systems

Items (2,153)
To address the rollover risk of six-axle semi-trailers due to their large mass, high center of gravity, and multi-axle articulation, a lateral force balance anti-rollover strategy based on the Ackermann steering principle is proposed. By establishing the wheel angle constraint equations for the full-wheel steering system of the six-axle semi-trailer, a rigid-body dynamic model considering the articulation characteristics is developed. The key control and observation parameters are included in the wheel angles, center of gravity lateral offset, yaw angular velocity, sideslip angle, and lateral load transfer rate. An SMC-PID joint controller is designed, in which the third axle steering angle of the tractor is optimized by the SMC controller, and the trailer’s three-axle steering angle tracking control is achieved by the PID controller. The nonlinear accumulation of centrifugal force and dynamic load transfer under high-speed emergency lane change conditions is suppressed by a
Zhang, QiyuanZhang, LeiLiao, ShengkunSun, JinxuHe, Jing
This paper presents a novel sensitivity analysis framework for differential braking as a backup steering solution in fail-operational Steer-by-Wire systems. The fault-tolerant design approach of Steer-by-Wire and steering systems for highly automated driving relies on the availability of road wheel actuators (RWA). Redundancies are therefore commonly used to ensure fail-operationality. Since its widespread implementation in production vehicles through electronic stability control, the use of differential braking as a cost-effective measure is desirable to increase functional diversity. However, feasible lateral accelerations through this backup solution are limited compared to conventional steering systems and lie close to ordinary driving scenarios. To address this limitation, this work investigates the influence of chassis parameters on differential braking performance. After defining characteristic values and a simulation test plan, a preliminary analysis using a linear single-track
Salzwedel, LeonIatropoulos, JannesHeise, CedricFrohn, ChristianHenze, Roman
Wheel-corner brake failures can significantly deteriorate vehicle stability and safety, since unbalanced braking forces may introduce an undesired yaw moment. This work investigates a fault-tolerant control strategy for Active Wheel-Corner Systems, exploiting Four-Wheel Independent Steering (4WIS) to mitigate such effects and preserve vehicle stability when brake actuator malfunctions occur. Unlike many existing approaches, the proposed framework does not require explicit fault detection or quantification as a prerequisite for corrective action, eliminating potential delays and uncertainties associated with fault-diagnosis schemes. A reference model for yaw rate and sideslip angle, incorporating combined longitudinal and lateral dynamics, is proposed, and a Weighted Pseudo-Inverse Control Allocation (WPCA) scheme is employed to distribute corrective actions among the four steering angles according to each tire’s capability, compensating for yaw moment imbalances caused by degraded
Sonnino, SamuelMelzi, StefanoCaresia, PietroManzoni, AlessandroVaini, Gianluca
In commercial vehicles, conventional engine-driven hydraulic steering systems result in continuous energy consumption, contributing to parasitic losses and reduced overall powertrain efficiency. This study introduces an Electric Powered Hydraulic Steering (EPHS) system that decouples steering actuation from the engine and operates only on demand, thereby optimizing energy usage. Field trials conducted under loaded conditions demonstrated a 3–6% improvement in fuel economy, confirming the system’s effectiveness in real-world applications. A MATLAB-based simulation model was developed to replicate dynamic steering loads and vehicle operating conditions, with results closely aligning with field data, thereby validating the model’s predictive accuracy. The reduction in fuel consumption directly translates to lower CO₂ emissions, supporting regulatory compliance and sustainability goals, particularly in the context of tightening emission norms for commercial fleets. These findings position
T, Aravind Muthu SuthanMani, KishoreAyyappan, RakshnaD, Senthil KumarS, Mathankumar
In commercial vehicles, Hydraulic Power Assisted Steering (HPAS) gear plays a crucial role in enhancing steering performance by providing hydraulic assistance. The HPAS gear comprises a Directional Control Valve (DCV) assembly, where the input shaft and recirculation units are integrated. The valve system which is known for the heart of the HPAS gear, operates under high-pressure conditions. In the DCV, the input shaft is equipped with bearings to support side loads exerted by the system, and a valve component is freely assembled to minimize friction caused by these side loads. The complexity of the floating valve design results in the less slot volume, leading to cavitation and vibrational noise. While this noise is typically suppressed in internal combustion (IC) engine-powered vehicles, its implementation in electric vehicles (EVs) has led to pronounced audible noise, dominating the system. Experimental vibration analysis of the steering gear reveals both low and high-frequency
Vijayenthran, PraveenAyyappan, RakshnaD, Senthil KumarN, Prabhakar
The design of advanced driver-assistance systems (ADAS) is essential to improve the safety and autonomy of rear wheel driven four-wheel vehicle in harsh conditions. This work introduces the design and development of a steering automation system for Lane Keep Assistance (LKA) in an rear wheel driven four-wheel vehicle with a parallel steering system. The system utilizes an ArduCam module to take real time images of the ground in front, and these are processed via machine learning techniques on a Raspberry Pi in order to identify lane edges with great precision. The corrective steering maneuvers are carried out by a motorized steering actuator based on the visual data after processing, and an encoder that is built into the actuator constantly tracks the steering angle and position. This closed-loop feedback affords accurate, real-time corrections to ensure lane discipline without driver intervention. Extensive calculations for steering effort, torque, and gear design confirm the system's
A R, ArundasSadique, AnwarRafeek, Aayisha
This study investigates noise, vibration, and harshness (NVH) characteristics of hydraulic steering systems in medium- and heavy-duty commercial vehicles due to hydraulic system design. Utilizing on-vehicle and lab environment testing, primarily a pressure sweep test and speed sweep test, to identify sources of NVH. Testing demonstrated a significant impact to perceptible noise and vibration through changes to system and component design. NVH mitigation is accomplished by reducing pressure pulsations, cavitation, and turbulence within the fluid by changing hydraulic plumbing diameter. Reduction in sound pressure level (SPL) averaged 30% with peak reduction of 75%. While optimizing hose diameter is an effective method for controlling NVH in commercial vehicle hydraulic steering systems, additional studies should be conducted in optimizing plumbing materials and routing.
Bari, Praful RajendraKintner, Jason
In class 8 semi-trucks, the hydraulic steering gear and torque overlay system are critical components affecting the steering feel design and vehicle control. Transitioning from traditional hydraulic gears to hydraulic gears with torque overlay steering (TOS) systems for increased enhancement of driver comfort is beneficial but has also resulted in drawbacks for on-center steer feel, especially at high vehicle speeds (60+ km/h). This article evaluates the impact of three design mechanisms within hydraulic steering gears of a TOS system that have shown improvement in on-center performance for traditional hydraulic gears. The study compares a standard assembly of TOS, i.e., baseline, and a design-optimized ideal prototype, to evaluate the effectiveness of the three design mechanisms: valve curve performance, on-center friction, and torsion bar stiffness. The two samples underwent high-speed vehicle testing to gather driver feedback and assess potential enhancements to the on-center
Bari, Praful RajendraChaudhuri, Nilankan
This SAE Recommended Practice describes a laboratory test procedure and requirements for evaluating the characteristics of heavy-truck steering control systems under simulated driver impact conditions, as well as driver entry/egress conditions. The test procedure employs a torso-shaped body block that is impacted against the steering wheel.
Truck Crashworthiness Committee
Objective: Previous studies have reported disparity in injuries between male and female drivers in the risk of certain types of injuries in frontal crashes that may be due to a myriad of sex-related differences, including body size, shape, anatomy, or sitting posture. The objectives of this study are 1) to use mesh-morphing methods to generate a diverse set of human body models (HBMs) representing a wide range of body sizes and shapes for both sexes, 2) conduct population-based frontal crash simulations, and 3) explore adaptive restraint design strategies that may lead to enhanced safety for the whole population while mitigating potential differences in injury risks between male and female drivers Method: A total of 200 HBMs with a wide range of body sizes and shapes were generated by morphing the THUMS v4.1 midsize male model into geometries predicted by the statistical human geometry models. Ten male and ten female HBMs were selected for population-based simulations. An existing
Sun, WenboHu, JingwenLin, Yang-ShenBoyle, KyleReed, MatthewSun, ZhaonanHallman, Jason
Elastomeric materials are essential in advanced automotive engineering for mobility, isolation, damping, fluid transfer (cooling, steering, fuel, and brake), and sealing because of their unique physio mechanical properties. Elastomers are commonly used in both static and dynamic components, such as hoses, mounts, bushes, and tires. Engine emission standards and weight optimization have caused higher temperature exposure conditions for automotive components. The steering system uses special purpose elastomers like Chlorinated Polyethylene that can deteriorate under abnormal conditions during vehicle operation or manufacturing process due to the high temperature exposure. Therefore, it is crucial to understand the causes and consequences of thermal degradation of elastomers. Thermal degradation is a significant phenomenon that changes the physiochemical properties of elastomers, which results in a product not meeting functional requirements. This study investigates the thermal
Thiruppathi, AnandhiMishra, NitishKrishnamoorthy, Kunju
In the initial stages of a vehicle development program, the sizing of various components is a critical deliverable. The steering system, in particular, requires a precise estimation of the rack load for the appropriate sizing of the rack and assists units. Accurately predicting the load on the system during the early stages of development is challenging, especially in the absence of benchmark or legacy data. Commonly used processes for estimating parking steering effort often employ simplistic approaches that may fail to account for parameters such as tire size, vertical stiffness, and steering geometry, leading to reduced accuracy. This paper introduces an advanced methodology for predicting steering rack loads, which incorporates considerations such as contact patch size and pressure variation, as well as the tire jacking effect. The methodology involves mathematical modeling of the contact patch using mesh-grids, utilizing common inputs available in the early stages of vehicle
Shirke, UmeshDabholkar, AniruddhBardia, VivekSrivastava, HarshitPrasad, Tej Pratap
The aim of this study is to develop a validated simulation method that accurately predicts vehicle behavior during a sudden loss of assist while cornering. The method also evaluates the steering effort required to return the vehicle to its intended path during failure scenarios, isolating the impact of uncertainties arising from driver performance. To illustrate the simulation methodology, the study involved testing various vehicles under conditions replicating sudden EPS assist loss during cornering. These tests captured the vehicle’s response, and the steering effort needed to correct its path. Different parameters affecting the vehicle behavior were studied and a validated method of simulation was developed.
Vishweshwara, ManasaVijay, VishnuNunes, RonaldoHubert, Robert
This paper presents the design and implementation of a Semi-Autonomous Light Commercial Vehicle (LCV) capable of following a person while performing obstacle avoidance in urban and controlled environments. The LCV leverages its onboard 360-degree view camera, RTK-GNSS, Ultrasonic sensors, and algorithms to independently navigate the environment, avoiding obstacles and maintaining a safe distance from the person it is following. The path planning algorithm described here generates a secondary lateral path originating from the primary driving path to navigate around static obstacles. A Behavior Planner is utilized to decide when to generate the path and avoid obstacles. The primary objective is to ensure safe navigation in environments where static obstacles are prevalent. The LCV's path tracking is achieved using a combination of Pure Pursuit and Proportional-Integral (PI) controllers. The Pure Pursuit controller is utilized as lateral control to follow the generated path, ensuring
Ayyappan, Vimal RajDhanopia, RashmiAli, AshpakN, RageshSato, Hiromitsu
To export India based SUVs to European markets, change in steering position is required to suit vehicle driving condition. Ideally, RHD and LHD variants of the same vehicle should have similar levels of ride and handling performance parameters. However, due to various packaging constraints and regulations, there is a possibility of minor change in Hard-points of steering or suspension system which may lead to different behavior in terms of body roll and steering response. While cornering or double lane change maneuvers, difference in steering phase angles or steering stiffness or suspension hardpoints results in different roll behavior as well as understeer characteristics of the vehicle. The present study shows key parameters and optimization methodology to maintain same level of ride and handling performance in both RHD and LHD variants. Objective measurements and physical kinematics and compliance tests were carried out with various configurations of RHD and LHD variants to
Hussain, Inzamam UlKamarthi, AshwinRewale, PratikNehal, S BRasal, ShraddheshNaidu, Kethireddi
In traditional commercial vehicles with leaf spring suspension and Recirculating Ball Joint (RCBT) steering systems often experience undesirable pulling due to unsymmetrical steering mechanism during braking, especially when the suspension and steering hardpoints are not properly tuned. This work analyzes the mechanisms responsible for pulling tendencies, primarily addressing brake steer and bump steer, which occur due to misalignments in the suspension and steering geometries. Brake steer occurs when braking forces create an imbalance in torque, resulting in the vehicle deviating to one side. On the other hand, bump steer refers to the unwanted changes in the wheel alignment when the suspension undergoes travel, leading to instability or unintended steering input. These two phenomena, if not controlled, can result in undesirable vehicle handling, especially under heavy braking conditions. This work focuses on evaluating these mechanisms and suggests strategies for minimizing their
Pandhare, Vinay RamakantM, Anantha PadmnabhanNizampatnam, BalaramakrishnaLondhe, AbhijitDoundkar, Vikas
Born Electric SUVs is gaining immense popularity due to enhanced ride and handling characteristics, advanced tech features elevating both performance and customer experience to an elite standard. Due to the platform constraints, the vehicle adopts a Front Wheel Drive (FWD) layout with a rear twist beam configuration, housing the electric motor at the front to deliver drive torque directly to the front wheels. Torque steer is a phenomenon often found in FWD cars, which is unsettling to driver where the steering wheel could be pulled hard to one side when there is aggressive throttle input potentially leading to deviation of the vehicle from its desired path. In contrast to internal combustion engines (ICEs), electric motors provide an instantaneous torque, something that can worsen torque steer if not well addressed. However, torque steer remains a key concern, with high torque output of electric motors especially for a front wheel drive vehicle. This paper introduces a methodology to
Prabhakara Rao, VageeshWankhade, KrishnaThakur, PragyeshRasal, ShraddheshAsthana, Shivam
Tyre rolling resistance is a fundamental parameter in automotive engineering, directly impacting vehicle fuel efficiency and overall performance. The Rolling Resistance Coefficient (RRC) is influenced by tyre construction, material properties, and operational conditions such as inflation pressure, vehicle speed, ambient temperature, and road surface roughness. This study investigates the influence of critical parameters—including test speed, inflation pressure, temperature on the rolling resistance of tyres of various sizes. While previous research has predominantly focused on radial tyres, this paper extends the analysis to include bias-ply tyres. The findings aim to offer valuable insights for policymakers and researchers by examining the behavior of bias tyres under real-world conditions. The results will be particularly beneficial for vehicle and steering system designers, offering data-driven insights to support future tyre and vehicle development. Additionally, the study presents
Joshi, AmolBelavadi Venkataramaiah, ShamsundaraKhairatkar, Vyankatesh
Modern automotive systems are becoming increasingly complex, comprising tightly integrated hardware and software components with varying safety implications. As the demand for ISO 26262 compliance grows, performing efficient and consistent Hazard Analysis and Risk Assessment (HARA) across these layers presents both methodological and practical challenges. Traditional approaches often involve performing HARA for an item (where item maybe a system or a combination of systems), which can lead to update of HARA for every new feature addition in an item, which in turn may lead to analysis of same functions in multiple HARAs leading to inconsistent risk categorization, redundancy, or even conflicting safety goals. Therefore, this paper proposes a unique HARA methodology which consolidates the list of functions from various systems and performs the HARA for the grouped functions (hereby referred to as Cluster HARAs). For example, Electrical power steering, Electric pump powered hydraulic
Somasundaram, ManickamVijayakumar, Melvin
The high-pressure steering hose in a hydraulic steering system carries pressurized hydraulic fluid from the power steering pump to the steering gear (or steering rack). Its main function is to transmit the force generated by the pump so that the hydraulic pressure assists the driver in turning the wheels more easily. The high-pressure hydraulic pipeline in the power steering system is a vital component for ensuring optimal performance. During warranty analysis, leakage incidents were observed at the customer end within the warranty period. The primary factors contributing to these failures include pipe material thickness, material composition, mechanical properties, and engine-induced vibrations. This study investigates fatigue-related failures through detailed material characterization and Computer-Aided Engineering (CAE) based on real world usage road load data collected. The objective is to identify the root causes by examining the influence of varying pipe thickness on fatigue life
Survade, LalitKoulage, Dasharath BaliramBiswas, Kaushik
In driving, steering serves as the input mechanism to control the vehicle's direction. The driver adjusts the steering input to guide the vehicle along the desired path. During manoeuvres such as parking or U-turns, the steering wheel is often turned fully from lock to lock and then released. It is expected that the steering wheel quickly returns to its original position. Steering returnability is defined as the ratio of the difference between the steering wheel position at lock to lock and the steering wheel angle after 3 seconds of release, to the steering wheel angle at the lock position, under steady-state cornering conditions at 10 km/h. Industry standards dictate that the steering system should achieve 75% returnability under these conditions within 3 seconds. Achieving proper steering returnability characteristics is a critical aspect of vehicle design. Vehicles equipped with Electric Power-Assisted Steering (EPS) systems can more easily meet returnability targets since the
Singh, Ram Krishnanahire, ManojJAIN, PRIYAVellandi, VikramanSUNDARAM, RAGHUPATHIPaua, Ketan
Road departures remain a major cause of fatal accidents in passenger vehicles, especially on highways, driving the demand for robust and affordable active safety technologies. Conventional Road Departure Mitigation Systems (RDMS) typically depend on camera- or LiDAR-based sensing, which can be cost-prohibitive and challenging to integrate across diverse vehicle platforms. The available RDMS technologies in the market focuses on road departure detection, and lacks the mitigation strategy. Although existing RDMS solutions have enhanced vehicle safety, their dependency on expensive, specialized sensors limits broader adoption, particularly in cost-sensitive market segments. This study introduces a sensor-less, cost-effective RDMS technology which has two parts, detection and mitigation. The technology utilizes existing vehicle sensors accessed through vehicle CAN channels. A decision tree based logic algorithm processes key parameters such as vehicle speed, steering angle, yaw rate, and
Iqbal, ShoaibAdsul, Sourabh
Path planning is a key element of autonomous vehicle navigation, allowing vehicles to calculate feasible paths in challenging environments for applications like automated parking and low speed autonomous driving. Algorithms such as Hybrid A*, Reeds-Shepp, and Dubins paths are widely used and can generate collision-free paths but tend to create curvature discontinuities. These discontinuities result in sudden steering transitions, which create control instabilities, higher mechanical stress, and lower passenger comfort. To overcome these issues, this paper suggests a path-smoothing technique based on the pure-pursuit algorithm to produce smoothed curve paths appropriate for real-world driving. This method utilizes the practical approach of the original path, but removes sudden transitions that destabilize control. By ensuring smooth curvature, the vehicle undergoes fewer jerky steering actions, improved energy efficiency, less actuator wear, and improved high-speed tracking. This paper
S, ShriniyathiA, JosanaEdwin J, Joel AntoT, AkshayaaM, Senthil VelKumar, Vimal
Nowadays, customers expect excellent cabin insulation and superior ride comfort in electric vehicles. OEMs focus on fine tuning the suspension system in electric vehicle to isolate the road induced shocks which finally offers superior ride quality. This paper focuses on enhancing the ride comfort by reducing the road excitation which originates mainly due to road inputs. Higher steering wheel vibration is perceived on the test vehicle on rough road surfaces. To determine the predominant force transfer path, Multi reference Transfer Path Analysis (MTPA) is performed on the front and rear suspension. Based on the finding from MTPA, various recommendations are explored and the effect of each modification is discussed. Apart from this, Operational Deflection Shape (ODS) analysis is used to determine the deflection shape on the entire steering system . Based on ODS findings, recommendations like dynamic stiffness improvements on the steering column and steering wheel are explored and the
S, Nataraja MoorthyRao, ManchiSelvam, EbinezerRaghavendran, Prasath
The road infrastructure in India has complex navigational challenges with most of the road unstructured especially in rural areas. Decision-making becomes a challenge for drivers in unpredictable environments such as narrow roads, flooded roads and heavy traffic. In this paper, an Augmented Reality based ML-Algorithm for Driver Assistance (ARMADA) has been proposed that improves awareness to safely maneuver in these conditions. The methodology for development and validation of this Augmented Reality (AR) based algorithm contains multiple steps. Firstly, extensive data collection is conducted using real time recording and benchmark datasets like Berkeley Deep Drive (BDD) and Indian Driving Dataset (IDD). Secondly, collected data are annotated and trained using an optimal machine learning (ML) model to accurately identify the complex scenario. In third step, an ARMADA algorithm is developed, integrating these models to estimate road widths, detect floods and provide seamless driver
Anandaraj, Prem RajSivakumar, VishnuThanikachalam, GaneshL, RadhakrishnanMotoki, YaginumaSelvam, Dinesh Kumar
Rack load estimation during the pre-design stages is critical for the calibration of steering systems, particularly in achieving the desired steering feel and optimizing assistance strategies in Electric Power Assisted Steering (EPAS). Conventional approaches often depend on physical vehicle testing or simplified empirical equations, which may be time-consuming or lacks the fidelity required for early-stage analysis. This paper presents a 1D simulation strategy to address limitations from conventional approaches. The proposed rack force estimation model is based on multi-physics analytical equations that calculate tire-road friction forces and the resulting moments about the steering axis, delivering a physics-based yet computationally efficient solution. The rack force estimation model is further extended into EPAS system model by incorporating Direct Current (DC) brushed motor model. The rack force estimation model is validated against physical test data which demonstrates a high
Adsul, SourabhIqbal, Shoaib
Vehicles with a high center of gravity (CG) and moderate wheel track, like compact Sport Utility Vehicles (SUVs), have a relatively low Static Stability Factor (SSF) and thus are inherently less stable and more susceptible to rollover crashes. Moreover, to be more maneuverable in highly populated urban areas, a smaller Turning Circle Diameter (TCD) is necessary. Here, Variable Gear Ratio (VGR) steering systems have major benefits over traditional Constant Gear Ratio (CGR) systems in terms of enhancing both roll stability and agility. To adapt VGR steering systems to a particular vehicle dynamic, Full Vehicle (FV) and Driver-in-the-Loop (DIL) simulations are utilized. Using this method, exact calibration is possible according to realistic driving conditions so that the VGR steering C-factor curve is properly tuned for optimal handling in on-center, off-centre, and transitional areas of the Steering Wheel Angle (SWA). Primary performance measures—e.g., SWA gradients at different lateral
Rewale, PratikKopiec, JakubKumar, DevaRasal, ShraddheshHussain, InzamamNehal, S B
Body-on-frame vehicles are well-regarded for their durability and off-road capabilities, but their structural design often makes them more vulnerable to noise, vibration, and harshness (NVH) issues. Vibrations originating from uneven roads are transmitted through the suspension and steering assemblies, sometimes resulting in rattles or other disturbances. These vibrations can be amplified by the inherent flexibility in the body-to-frame mounting system. In such vehicles, the steering system plays a critical role in driver comfort and is highly sensitive to vibrational inputs from the road surface, especially on coarse or uneven terrain. Occasionally, these inputs result in subtle rattle noises that are perceptible only to the driver and may not be detected under controlled testing environments. This poses a challenge for engineers trying to isolate and resolve such intermittent NVH phenomena. Identifying the source requires a combination of real-world driving evaluations, structural
Ramesh Chand, Karan KumarGopinathan, HaridossKabdal, Amit
Steering I-shaft with rubber coupling (or hardy disc) is an important part of complete steering system mainly in body on frame (BOF) vehicles. Hardy discs are used to dampen the vibrations that transmit to steering wheel through frame, steering gear and I-shaft. They also support to accommodate the variation between frame and BIW (Body in white) of body on frame vehicles. They are made up of rubber or other polymer composites, which have less torsional stiffness as compared to metals. The overall torsional stiffness of steering system reduces since the hardy disc is used in series in steering system, that impacts on the overall performance of steering system. So, during development of I shafts with different design, stiffness of hardy discs are used to optimize the steering and NVH performance of vehicle. Considering the development time and cost, each design of I-shaft cannot be validated at vehicle level. The torsional and axial force or displacement of hardy disc is measured at
Kabdal, Amit
This article presents a system to incorporate crash risk into navigation routing algorithms, enabling safety-aware path optimization for autonomous and human-driven vehicles alike. Current navigation systems optimize travel time or distance, while our approach adds crash probability as a routing criterion, allowing users to balance efficiency with safety. We transform disparate data sources, including traffic counts, crash reports, and road network data, into standardized risk metrics. Because traffic volume data only exist for a small subset of road segments, we develop a solution to project average daily traffic estimates to an entire road inventory using machine learning, achieving sufficient coverage for practical implementation. The framework computes exposure-normalized crash rates weighted by severity and integrates these metrics into routing cost functions compatible with existing navigation algorithms. The key strength of our solution is its scalability. In addition to the
Skaug, LarsNojoumian, Mehrdad
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