Browse Topic: Rack and pinion steering

Items (171)

Design and Development of Rack and pinion steering gear assembly for passenger car vehicle

2024-26-038501/16/2024

Cross-Helical gears are helical gears with non-parallel,non-intersecting axes and their helix angles are not equal and opposite. Profile shift gears are used to balance the strength of the rack and pinion, avoid undercut, and change the center distance as per the requirement of the vehicle. Passenger cars use these gears for maneuvering by converting the pinion rotary motion to rack translation and thereby turning the wheels. This paper discusses the design and development of Rack and pinion steering (RPS) gear assembly in terms of gear calculations, modeling, performance, and strength analysis over various load cases. Design calculations are being done for several parameters- Normal module, helix angle, No. of teeth as per steering gear ratio and shaft angle. A complete CAD geometry of the RPS gear assembly is made in CAD modeling software UG-NX as per vehicle requirements. BIW and its surrounding parts clearance from the RPS assembly are verified for packaging review. Performance

Rathore, Gopal Singh, chawla, Shubham

Analysis and Annihilation of Grunt Noise in Hydraulic Power Assisted Steering Systems

2024-26-021801/16/2024

Hydraulic steering systems employ pressurized fluid to alleviate the effort needed to steer the wheels of an automobile. Hydraulic Power Assisted Systems (HPAS) are cost-efficient, yet intricate. As customer trends lean towards reduced effort and improved handling, HPAS must intervene more in steering, leading to increased pressure requirements from the HPAS pump. Consequently, HPAS components must withstand higher pressure liquid and operate with closer tolerances, occasionally resulting in anomalous functioning. This paper delves into one anomaly with HPAS systems "Grunt Noise", a phenomenon caused by the resonance of the Torsion bar (T-bar) with fluid pressure pulsations. An extensive study was conducted to identify load conditions for grunt noise generation, examine transfer paths and analyze its frequency band. The study also explored the cascading process, reproducing the vehicle-level phenomenon at the rig-level for the Rack and Pinion and later at Pinion Valve assembly level

SETHI, AJITESH, Titave, Uttam, Vardhanan K, Aravindha Vishnu, Zalaki, Nitin, Naidu, Sudhakara

Optimized Variable Gear Ratio Steering System with Reduced EPAS Motor Size achieving Performance Targets

2022-01-106103/29/2022

In electric power assisted steering system (EPAS), the steering assistance torque is provided by the electric motor. The motor rating is decided based on rack force requirement which depends on the vehicle weight, steering gear ratio, wheel angles & turning circle diameter etc. The load on the EPAS motor varies with respect to the steered angles of the road wheels. The motor experiences higher load towards the road wheel lock position. Most of the steering systems used on passenger cars has rack and pinion gear with constant gear ratio (C-factor). The constant gear ratio is decided to create right balance between vehicle handling behavior and steering effort. The constant gear ratio exerts higher steering load which the EPAS motor is required to support up to road wheel lock angles and hence EPAS motor size increases. This paper presents variable gear ratio (VGR) steering system in which gear ratio varies from center towards end lock stroke of rack & pinion. The VGR is optimized in

Kulkarni, Parag Vijay, Salunkhe, Swapnil, Iqbal, Shoaib, Joshi, Nikhil, Shabadi, Nischalkumar

Experimental Analysis of Steering System Moan Noise

2021-26-030709/22/2021

Steering system is responsible for providing a precise directional control to the vehicle. The hydraulic power assisted steering system is commonly used in passenger cars and commercial vehicles due to low cost. Power Steering Pump develops and delivers required pressure to provide assistance while steering. It reduces the effort required to steer the vehicle. Steering pump (generally vane type) is a critical part providing hydraulic assistance pressure to rack and pinion/Gear Box. Basically the hydraulic pump noise can be classified as ‘Moan Noise’ and ‘Whine Noise’. The noise generated by power steering pump pressure pulsation is termed as moan and whine based on their frequency. As power train becomes quieter and quieter, it becomes more perceivable at typical engine operating speed range and gives impression of poor refinement and quality. This abstract describes the experimental measurement technique to investigate, analyze, quantify the moan noise and elaborates on design of

Shevate, Hemant Satish, Gosavi, Santosh, Chaskar, Mithun, Pingle, Gautam Ashok, Pawar, Hemant

Crank-Lever Electromagnetic Damper (CLEMD) Design for Automobile Suspension System

06-13-01-000202/04/2020

An effective damper is among the most important components of the suspension system. It ensures the right amount of damping force is acting on the suspension system to provide comfort to the passengers and proper road holding to tires. Unfortunately, the energy absorbed by the dampers from the suspension system gets wasted in the form of heat. In this article, it is proposed to use innovative electromagnetic damper (EMD) with a crank-lever mechanism to recover energy from the suspension system. The goal is to develop a lightweight design of EMD that can recover a high amount of power. For the design, an off-road vehicle is used since in off-road vehicles the amount of power wasted in the suspension system is high. Three different design approaches are used, which include single-stage gearbox type, two-stage gearbox type, and three-stage gearbox type of CLEMD. Out of them, the best design, i.e. three-stage gearbox type of CLEMD is selected because of minimum weight and inertia of the

Todmal, Prashant Eknath, Melzi, Stefano

Evaluation of a Robust Haptic Interface for Semi-Autonomous Vehicles

12-02-02-000705/15/2019

The advent of steer-by-wire technologies has changed the driving paradigm for drivers and vehicle autonomy. Such technologies integrate electric motors to actuate the tire-road plus human-machine interfaces. Steer-by-wire vehicles can benefit from haptic concepts through the provision of tunable force feedback, coupled with nonlinear control, to introduce lane keeping and pathway following technologies that minimize and possibly eliminate driver actions. In this article, two vehicle haptic interfaces, including a robotic grip and a joystick, both of which are accompanied by nonlinear sliding mode control, have been developed and studied on a steer-by-wire platform integrated with a virtual reality driving environment. An operator-in-the-loop evaluation that included 30 human test subjects investigated these haptic steering interfaces over a prescribed series of driving maneuvers through real-time data logging and post-test questionnaires. A conventional steering wheel with the robust

Wang, Chengshi, Wang, Yue, Wagner, John R.

Aircraft Nosewheel Steering/Centering Systems

AIR1752A (Current)04/17/2019

The intent of this AIR is twofold: (1) to present descriptive summary of aircraft nosewheel steering and centering systems, and (2) to provide a discussion of problems encountered and “lessons learned” by various airplane manufacturers and users. This document covers both military aircraft (land-based and ship-based) and commercial aircraft. It is intended that the document be continually updated as new aircraft and/or new “lessons learned” become available.

A-5B Gears, Struts and Couplings Committee

Kinematics and Compliance Analysis of a 3.5 Tonne Load Capacity Independent Front Suspension for LCV

2019-01-093504/02/2019

This paper deals with the development of a 3.5 tonne carrying double wishbone front suspension for a low floor LCV. It is a novelty in this class of vehicles. It has a track width of 1810 mm and it has a recirculating ball steering system. The steering mechanism has been arranged so that the steering angle could reach to 48° that is a very effective angle in that vehicle range. This results as a lower turning radius which indicates a better handling for the vehicle. The steering and the front suspension system here have been optimized in terms of comfort and handling by using DOE (design of experiments) based on sequential programming technique. In order to achieve better suspension and steering system geometry, this technique has been applied. The results have been compared with the benchmark vehicle.

Kuris, Salih, Gungor, Efe, Deniz, Ataman, Uysal, Gulsah, Aykent, Baris

Use of Cellphones as Alternative Driver Inputs in Passenger Vehicles

2019-01-123904/02/2019

Automotive drive-by-wire systems have enabled greater mobility options for individuals with physical disabilities. To further expand the driving paradigm, a need exists to consider an alternative vehicle steering mechanism to meet specific needs and constraints. In this study, a cellphone steering controller was investigated using a fixed-base driving simulator. The cellphone incorporated the direction control of the vehicle through roll motion, as well as the brake and throttle functionality through pitch motion, a design that can assist disabled drivers by excluding extensive arm and leg movements. Human test subjects evaluated the cellphone with conventional vehicle control strategy through a series of roadway maneuvers. Specifically, two distinctive driving situations were studied: a) obstacle avoidance test, and b) city road traveling test. A conventional steering wheel with self-centering force feedback tuning was used for all the driving events for comparison. Based on the lane

Wang, Chengshi, Alexander, Kim, Pidgeon, Philip, Wagner, John

Optimizing Steering Column Layout and UJ Phase Angle to Enhance Vehicle Dynamics Performance

2019-01-501002/05/2019

Vehicle dynamics is one of the most important vehicle attributes. It is classified into three domains, the longitudinal, vertical, and lateral dynamics. This paper focuses on optimizing the lateral vehicle dynamics which is driven by the straight ahead controllability and cornering controllability of the vehicle. One of the important parameters that dictates these sub-attributes is the steering ratio. Therefore, designing the right steering ratio is critical to meet the vehicle “specific” targets. Significant amount of work has been done by many researchers on variable steering ratio by implementing variable gear ratio (VGR) rack, active steering, and steer-by-wire systems. This paper discusses the methodology and considerations to optimize the steering ratio for a constant gear ratio rack by optimizing the steering column layout, viz., orientation and the phase angle in universal joints. A detailed analysis of steering system layout is done to optimize the steering ratio to enhance

Puvvula, Praneeth, Ravuri, Susheel, Dubal, Ajit, Salunkhe, Swapnil

Steering Control of the Off-Highway Vehicles

2019-26-010801/09/2019

Steering is integral system of any vehicle to achieve direction control. With driver’s inputs, as steering wheel is turned, the steering mechanism is operated to turn the road wheels to route the vehicle on desired path. This Paper studies the different steering architectures and the learning is applied to improve the off-highway vehicles’ steering control. Off-Highway vehicles have traditionally been using Hydrostatic Power Steering (HPS) mechanism with no feedback controls. This mechanism consists of inherent limitations to vehicle efficiency, reliability and control preciseness. In this paper, HPS is modeled using 1D simulation tools from the system parameters and derived equations. The results are plotted and discussed to acknowledge the merits and demerits of existing system which helped in proposing the alternate steering solution. Different steering architectures are evaluated and trade-off study performed to choose the Electro-Hydraulic Power Steering (EHPS) architecture. The

Joshi, Bharat, Sukumar, Srikant, Jawale, Vinit, Patil, Ojas

Optimization Control for 4WIS Electric Vehicle Based on the Coincidence Degree of Wheel Steering Centers

10-02-03-001107/24/2018

The steering centers of four wheels for passenger car do not coincide, which may result in tire wear and the unharmoniously movement of the vehicle. In this article, an optimization control method for Four Wheel Independent Steering (4WIS) electric vehicle based on the coincidence degree of steering centers is proposed, to improve the driving performance. The nonlinear vehicle model of the four-wheel independent steering vehicle is established, and the formula of the wheel steering center is derived. The coincidence degree of wheel steering centers is defined as the evaluation index, to describe and evaluate the performance of the coordination for wheels’ movement. Meanwhile, the structure design of 4WIS system and the establishment of Direct-Current (DC) steering motor model are carried out, and the Model Predictive Control (MPC) controller for steering actuator is designed. The coincidence degree and related performance index for 4WIS vehicle steering system are performed as the

Zheng, Hongyu, Yang, Shuo

Control of Steer by Wire System for Reference Steering Wheel Torque Tracking and Return-Ability

2018-01-056604/03/2018

This paper proposes a torque tracking algorithm via steer by wire to achieve the target steering feel and proposed a modified friction model to obtain return-ability. A three dimensional reference steering wheel torque map is designed using the measurement data of the steering characteristics of the target vehicle at a transition test and a weave test. In order to track the reference steering wheel torque, a sliding mode control is used in the tracking algorithm. In addition, to achieve return-ability, the modified friction model for steer by wire is used instead of the friction model defined in the reference steering wheel torque map. The modified friction model is composed of various models according to the angular velocity. The angular velocity and the angular acceleration used in the control algorithm are estimated using a kalman filter. A motor is used as the actuators to generate the targeted steering feel and the torque angle sensor (TAS) is used to measure the steering wheel

Lee, Jaepoong, kyongsu, Yi, Kim, Kwangil, Lee, Byungrim, Lee, Dongpil, Jang, Bongchoon, Chang, Sehyun

Multi-Objective Optimization to Improve SUV Ride Performances Using MSC.ADAMS and Mode Frontier

2018-01-057504/03/2018

Ride is an important attribute which must be accounted in the passenger segment vehicles. Excessive H point acceleration, Steering wheel acceleration, Pitch acceleration can reduce the comfort of the driver and the passengers during high frequency and low frequency rough road events. Excessive Understeer gradient, roll gradient, roll acceleration and Sprung mass lift could affect the Vehicle driver interaction during Steady state cornering, Braking and Step steer events. The concept architecture of the vehicle plays an important role in how comfort the vehicle will be. This paper discusses how to improve SUV ride performances by keeping handling performance attributes same or better than base vehicle. Multi Objective Optimization was carried out by keeping spring, bushing and damper characteristic as the design variables to avoid new system or component development time and cost. The first step in this process is DOE (Design of Experiments method) which allows to select critical or

Lenka, Visweswara Rao, Anthonysamy, Baskar, Londhe, Abhijit, Hatekar, Harshad

Steering Shaft Separation with a Collision Involved Heavy Duty Steering Gear

2018-01-052404/03/2018

A crash of a medium duty truck led to a study of the failure mechanism of the truck’s steering system. The truck, after being involved in a multi-vehicle vehicle collision, was found with its steering input shaft disconnected from the steering gear. The question arose whether the steering gear failure was a result of the collision, or causative to the collision. An in-depth investigation was conducted into whether forces on the vehicle due to the collision could cause the steering shaft to separate from the steering gear. Additionally, the performance of the steering gear with the adjuster nut progressively backed off was studied to determine the feedback a driver would receive if the steering gear came progressively apart. From the results of these studies, conclusions with regard to the crash causation were reached.

Larson, Robert, Retallack, Charles, Mikhailov, Michael

Design, Development and Application of Test Bench for Electrically Controlled Steering Systems

2018-01-070204/03/2018

This essay aims to develop an electrically controlled steering test bench and lay a solid foundation for the development of steering system. The first part mainly introduces the function, structure and working principle of the test bench. For the hardware system, it includes the steering system, fixture, sensors as well as a frameless disk motor for carrying out automatic motor input, and a dual linear motor system selected as the road resistance simulation actuator. As for the software, MATLAB/Simulink, CarSim, RTI and ControlDesk are used. Therefore, with the help of real-time simulation platform, researchers can not only build control strategy and dynamic model but also control the experiment and tune parameters in real-time. The second part of the essay aims to identify both electric and mechanical parameters of R-EPS system by carrying out tests on the proposed test bench. As parameters are successfully identified, the feasibility of the test bench is also verified. In the third

Wang, Junyang, Zheng, Hongyu, Zong, Changfu

Quantitative Evaluation of Steering System Rattle Noise

2017-28-195207/10/2017

Today’s automotive industry in the process of better fuel efficiency and aiming less carbon foot print is trying to incorporate energy saving and hybrid technologies in their products. One of the trends which has been followed by Original Equipment Manufacturers (OEMs) is the usage of Electric Power Steering (EPS) system. This has been an effective option to target fuel saving as compared to hydraulically assisted power steering system. EPS has been already tested successfully, not only on system level but also on vehicle level for endurance and performance by OEMs as per their norms and standards. Over the decade, NVH (noise, vibration & harshness) have become one of the touch points for customer perception about vehicle quality. This leads us to a commonly perceived problem in EPS or manual type steering system i.e. rattle noise. In this paper, a methodology has been highlighted for detection, identification and measurement of steering rattle noise and hence identifying the noise

Sharma, Utkarsh, Wilson, Simson T., Lalasure, Santosh, Rajakumar, K.

Adaptive Network Trained Controller for Automotive Steering Systems

2017-01-962604/11/2017

Electrical Power Assist Steering (EPAS) systems are currently eliminating the traditional hydraulic steering systems in vehicles. EPAS systems are nonlinear Multi Input Multi Output (MIMO) systems with multiple objectives, including fast response to the driver torque command, good driver feel, and attenuation of load disturbance and sensor noises. Optimal control method is employed to design EPAS system controllers for improved performance and robustness. But these controllers have showed acceptable performance for certain operating conditions and undesired steering feel for high steering gain. In this work, the neural networks are used which replace the optimal controllers of EPAS systems. A Euclidean adaptive resonance theory (EART) networks is trained according to the data collected from an H∞ optimal controller. The collected data represent the controller input and output signals. The said data are normalized and clustered into categories in the EART modules. The modules are

Chabaan, Rakaan, Alam, Mohammad Saad

Adaptive Network Trained Controller for Automotive Steering Systems

2017-01-9626-TEST-REC04/11/2017

Electrical Power Assist Steering (EPAS) systems are currently eliminating the traditional hydraulic steering systems in vehicles. EPAS systems are nonlinear Multi Input Multi Output (MIMO) systems with multiple objectives, including fast response to the driver torque command, good driver feel, and attenuation of load disturbance and sensor noises. Optimal control method is employed to design EPAS system controllers for improved performance and robustness. But these controllers have showed acceptable performance for certain operating conditions and undesired steering feel for high steering gain. In this work, the neural networks are used which replace the optimal controllers of EPAS systems. A Euclidean adaptive resonance theory (EART) networks is trained according to the data collected from an H∞ optimal controller. The collected data represent the controller input and output signals. The said data are normalized and clustered into categories in the EART modules. The modules are

Chabaan, Rakaan, Alam, Mohammad Saad

Steering Wheel Torque Control of Steer-by-Wire System for Steering Feel

2017-01-156703/28/2017

This paper proposes a reference steering wheel torque map and a torque tracking algorithm via steer-by-wire to achieve the targeted steering feel. The reference steering wheel torque map is designed using the measurement data of rack force and steering characteristic of a target performance of the vehicle at transition steering test. Since the target performance of the vehicle is only tested in nominal road condition, various road conditions such as disturbances and tire-road friction are not considered. Hence, the measurement data of the rack force that reflects the road conditions in the reference steering wheel torque map have been used. The rack force is the net force which consists of tire aligning moment, road friction force and normal force on the tire kingpin axis. A motor and a magnetorheological damper are used as actuators to generate the desired steering feel using the torque tracking algorithm. The torque tracking algorithm is composed of feedforward control and feedback

Lee, Jaepoong, Chang, Sehyun, Kim, Kwangil, Jang, Bongchoon, Lee, Dongpil, Lee, Byungrim, Yi, Kyongsu

Towards a Supermileage Autonomous Vehicle

2017-01-011403/28/2017

The project consists on the mechanical and electronic instrumentation of an existing vehicle (built at Universidad de Monterrey for the SAE Supermileage Competition) to be able to control its steering, braking and throttle systems “by wire”. Insight to the stages of turning the vehicle into an autonomous one is presented. This includes identification of the current mechanical properties, choosing adequate components and the use of a simulation to allow early work on the software involving cameras and motors to provide autonomy to the vehicle. Using software in the loop methodology mathematical models of the dynamics of the vehicle are run in Simulink and update the position and orientation of the 3D model of the vehicle in V-REP, a robot simulator.

Lozoya Santos, Jorge De-J., Tudon-Martinez, J. C.

Development of Road to Lab Steering Test Rig (ROLAST)

2017-26-031501/10/2017

The Steering system is one of the most safety critical systems in an automobile. With time the durability, reliability and the fine-tuning of the parameters involved in this subsystem have increased along with the competitiveness of the market. In a competitive market, accelerated testing is the key to shorter development cycles. It is observed that the majority of component manufacturers have a preference on vehicle level testing to achieve their development goals. The vehicle level trials are time consuming and lack the control and repeat-ability of a laboratory environment. This paper describes the development of a steering test rig designed to simulate the disturbances experienced on road within a controlled laboratory environment. The five axis steering rig would allow simulation of individual road wheel displacement along with steering wheel angle input and lateral steering rack displacements. The rig also is designed to be adaptable to a range of vehicle categories. The rig can

Kale, Jyoti, Kumar, Satish, Lavangare, Pravin, Subramaniam, Anand

A Novel Technique to Establish Various Important Characteristic to Analyze Complete Hydraulic Power Steering System using Model Based Design Approach

2017-26-025901/10/2017

Steering system deliver a precise directional control to the vehicle chassis and ensure the safe driving at all maneuvers. Hydraulic power assisted system (HPAS) helps drivers to steer by boosting steering assistance of the steering wheel while retaining the road feel. HPAS performance is associated with the design characteristics of rotary valve, steering, suspension, kinematics, brake, tire, vehicle speed and load transfer. Thus a detailed power steering system model is absolutely necessary to evaluate and optimize the performance characteristics. However, many components of HPAS system are proprietary in nature so it is very challenging to get component characteristic of each sub-system for the complete power steering system model. Hence, it is very important to establish a technique to extract all such influencing characteristics with available test facility. The present study shows a detailed vehicle level HPAS system dynamic model to predict various power steering system

Sawangikar, Sandeep V., Patil, Jeevan N., Palanivelu, Sivakumar, Kumar K, Arun

Steering System Noise Evaluation

2016-01-183206/15/2016

Intermediate shaft assembly is used to connect steering gear to the steering wheel. The primary function of the intermediate shaft is to transfer torsional loads. There is a high probability of noise propagating through the Intermediate shaft to the driver. The current standard for measuring the noise is by performing vehicle level subjective evaluations. If improperly clamped at either of the yokes, a sudden change in the direction of the torsional load on the Intermediate shaft can generate a displeasing noise. Noise can also be generated from the constant velocity joint. Intermediate shaft noise can be measured using a microphone or can be correlated to acceleration values. The benefit of measuring the acceleration over sound pressure level is the reduction of complexity of the test environment and test set up. The nature of the noise in question requires the filtering of low frequency data. This paper presents a new test procedure that has been developed by General Motors. The test

Kamath, Ramakrishna

Anti-Creep Mechanism Enables Ultra-Precise Motor Table Positioning

TBMG-2489406/01/2016

Motion control is essential for the digitization and automation of high-tech equipment, but bearings remain basic to frictionless movement. Bearing Engineers, a bearing distributor, recently changed its name to Motion Solutions (Aliso Viejo, CA) to better reflect their evolution into a custom designer of motion solutions for high-tech electromechanical systems. Developing custom solutions has lead to developing lines of proprietary products that the company manufactures in-house.

A Novel Electric-Power-Steering (EPS) Control Algorithm Development for the Reference Steering Feel Tracking

2016-01-154604/05/2016

This paper describes a reference steering feel tracking algorithm for Electric-Power-Steering (EPS) system. Development of the EPS system with intended steering feel has been time-consuming procedure, because the feedforward map-based method has been applied to the conventional EPS system. However, in this study, a three-dimensional reference steering feel surface, which is determined from current vehicle states, is proposed. In order to track the proposed reference steering feel surface, sliding mode approach is applied to second-order steering dynamics model considering a coulomb friction model. An adaptive technique is utilized for robustness against uncertainties. In order to validate the proposed EPS control algorithm, hardware-in-the-loop simulation (HILS) has been conducted with respect to a typical steering test. It is shown that the reference steering feel is realized well by the proposed EPS control algorithm.

Lee, Dongpil, Jang, Bongchoon, Yi, Kyongsu, Chang, Sehyun, Lee, Byungrim

Effect of Tie Rod Length Variation on Bump Steer

2016-28-020102/01/2016

Steering and suspension system has to be designed properly to achieve improved handling characteristics. Improper design of steering systems will result in steering errors such as bump steer and roll steer. These steering errors results in reduced steering performance. During the design of steering system the tie rod length has to be properly selected to reduce these steering errors. The purpose of the work is to analyze the effects of tie rod length variation on bump steer. Multi body dynamic model of the selected vehicle was created using MSC ADAMS Car software. Ideal design of steering system to achieve zero bump steer was created. The tie rod length was later varied up to 10% to study the effect of varying length on bump steer. Parallel wheel travel analysis was conducted to study the tie rod length variation on bump steer. Acceleration test was conducted on a flat road having bump to analyze the effect of changing tie rod length on steering performance of the vehicle. The test

Kulkarni, Upendra, Gowda, Monish M. H., Venna, Hima Kiran

Zero-Gravity Mobile Robot Using ON/OFF Adhesive Pads and Inchworm Mechanism

TBMG-2366201/01/2016

Inspection of the International Space Station and other manmade objects in space is difficult because of the microgravity environment. Robots are a promising approach to accomplish these inspection tasks and later repairs, but must be able to maneuver across the surfaces. Because there is no gravity, the robot is at high risk of floating away, necessitating grippers that can adhere to the surface and resist the forces and torques of inspecting and moving on the structure.

Custom System Rides the Rails at NASA Radar Range

10/01/2015

ADC USA, Inc. (Ithaca, NY) develops and supplies high-precision motion systems and instruments for large government laboratories and corporations around the world. ADC was contracted by NASA’s Langley Research Center (Hampton, VA) to design, build, and install the major components for a 40 × 40 × 40-foot indoor radar range. NASA’s goal was to refurbish and upgrade their old indoor radar range. They want to clear out what they had and replace it with newer, better-designed equipment. The goal was to put multiple targets inside the radar range without having to get a forklift to bring them in and out – not only things such as airplanes, but anything that is detected by radar.

Optimisation of Steering System Geometry of Longer FOH Commercial Vehicles

2015-01-272109/29/2015

Commercial vehicle industry is presently striving towards development of buses with enhanced passenger safety and comfort. This calls for additional components and aggregates that eventually lead to increase in the overall length and gross vehicle weight (GVW) of the bus for the same passenger capacity. Usually, steering system of longer front overhang (FOH) vehicles have multiple linkages such as bevel box arrangement or intermediate pivot arm arrangement instead of single direct draglink because of packaging and design constraints. In this work, an attempt has been made to design the steering system for one of the longer FOH bus with single direct draglink arrangement. Here, single draglink was packaged and designed with commercially available higher strength tube material. Design optimisation of steering geometry was carried such that the steering performance was atleast on par with existing performance. The MBD analysis has been carried out to compare the performance of existing

Lomada, Balaji, Jayaganthan, R., Vijaykumar, V.

Thermoplastic Racks Open Up New Motion Control Applications

06/01/2015

Rack and pinions are linear actuators that play a critical role in a wide range of linear motion control applications. While rack and pinions are commonly thought of as a timeless technology, several new developments have helped provide significant performance improvements in specific applications. One new approach, the Roller Pinion System, replaces the traditional rack and pinion with bearing-supported rollers, increasing positional accuracy, speed and durability.

An Innovative Design Concept of Four Wheel Steering Mechanism for an Automobile

2013-01-284511/27/2013

The main characteristic of vehicle moving on road is related to its response to the drivers command and to environmental factors affecting the direction of motion of vehicle. The two basic problems in handling the vehicle are control of vehicle along the desired path and stabilization of the direction of motion of vehicle against external disturbances. The vehicle with best handling characteristics is the vehicle which can always be controlled by the driver. While parking the vehicle and doing sharp turnings the vehicle with two wheel steering cannot be more significant. The two wheel steering system takes large radius of turning and requires more space to take turn. Hence four wheel steering is preferable than two wheel steering systems. A multi-function four wheel steering system could improve directional stability at high speeds, sharp turning performance at low speeds, and parking performance of a vehicle. Generally there are three types of steering systems which include front

Vanamala, Uma Maheshwar, koganti, Raja Rao

Steering Kickback Diminution on EHPS for Enhancing Vehicle Ride Comfort and Handling

2013-01-289311/27/2013

Electro-Hydraulic Power Steering (EHPS) system is used in modern vehicles to effect reduction in fuel consumption rate and steering effort. The mechanical linkages between the steering wheel and tire, transfers road shocks to steering wheel as high amplitude vibration. This high amplitude vibration causes the steering wheel to deviate from driver intended position. This phenomenon is called steering kickback. The initial objective is to reduce the steering kickback with minimum changes in the vehicle systems. Using check valve is one of the inexpensive and easy operational counter measures. Vehicle level tests were done to evaluate the countermeasure and it was found to have approximately 55 % reduction in kickback. Multi Body Dynamics (MBD) simulation is done using ADAMS/Car to establish the vehicle parameters involve in steering kickback. Full car model was simulated using the experimental conditions and validated. Finally from the simulation, optimized vehicle parameters are

Sundararajan, Rajeshkumar, Natarajasundaram, Balasubramanian, Ramamoorthy, Bhavanakumar, Subramaniam, Thirumalini

Implementation of Non-Contact Drives into a High-Rail, 7-Axis, AFP Motion Platform

2013-01-228809/17/2013

Traditionally, automated fiber placement (AFP) motion platforms use rack and pinion drive trains coupled through a gearbox to a rotary motor. Extensive use of non-contact linear motors on a new AFP motion platform produces a quiet, low-maintenance system without sacrificing precision. A high-rail gantry arrangement allows dynamic performance improvements to machine acceleration and speed, while lowering power consumption costs and capital expenses. The seventh axis incorporated into the machine arrangement effectively produces an effective “five sides of a cube” work envelope, permitting complex spar and panel fabrication.

Ehinger, Peter, Faubion, Guy, Hooks, Joshua, Seever, Luke

Target Cascading Optimization of the Kinematics of a Steering System Coupled to a Double Wishbone Suspension System of a Hybrid Off-Road Vehicle

2013-01-096704/08/2013

Target cascading methodology is applied to the optimization problem of the kinematics of a rack and pinion steering mechanism coupled to a double-wishbone suspension system of a hybrid off-road vehicle. This permits the partition of a complex problem into reduced order sub-problems in a hierarchical manner, leading to a more efficient design and optimization process. According to the nature of the problem, it is proposed a four level hierarchy organization. The uppermost level is the general vehicle design problem. The second level consists in various system-level design problems such as frame, powertrain and the set suspension-steering. The steering system design problem is proposed in a third hierarchical level. At the lowest level are the components design problems. The vehicle under study will work mainly under off-road condition at low speed. Hence, at the steering design problem, two main objectives are searched for optimization: steering performance according to the Ackerman

Blanco, Juan, Munoz, Luis

New Light Truck Platform Chassis

2013-01-037004/08/2013

The objectives of a new generation of light trucks required the development of a new platform chassis, using advances in packaging, manufacturing efficiency, mass reduction, fuel efficiency, noise and vibration toughness, and ride comfort, while maintaining the vehicle's fun-to-drive character. This paper outlines the chassis component and packaging integration, light weight material application with structural optimization, as well as technical concepts executed to improve performance. Key component focus points are axles and bearings, wheels, tires, suspensions, brakes, engine cradles and sub-frames, steering systems, mechanical controls, and fuel and exhaust systems.

Johnson, Joshua C.

Research on the Rig Tests for Evaluation of Steering Response of Electric Power Steering(EPS) Sub-System

2012-01-192009/24/2012

EPS has now become a compelling technology that nowadays rapidly replacing hydraulic power steering in world market because of its fuel efficiency, sophisticated assist control, additional safety and convenience features. There are various types of EPS such as Column assist type, Pinion assist type and Rack assist type. Small cars with less rack force are equipped with Column or Pinion assist type EPS but for full-sized vehicles with big rack power consumption need Rack assist EPS, what we call R-EPS. Each type of EPS has merits and demerits, but from the perspective of vehicle handling performance, R-EPS has some strong points. And this is why author started this study. Subjective handling evaluation has proven the superiority of R-EPS but objective evaluation was needed. So authors have tried to compare the on center handling characteristics of each EPS on the rig tests and proposed somewhat easy and reliable test method. And by using a design of experiment (DOE) approach, this study

Lee, Seongil, Roh, Eun Ho

Dynamic Research on Control Strategy of Electric Power Steering System

2012-01-021204/16/2012

The developing process of steering system has experienced four phases from the simple mechanical steering system (MS), hydraulic steering system (HPS) to electric-hydraulic steering system (EHPS), till the electric power steering system (EPS) with lower energy consumption and higher performance. EPS has been found of more and more applications in the rapid development of new energy electric vehicles. This paper aims at the dynamic research of the control strategy of EPS system. Through analyzing the simplified structure model of EPS system, the mathematical models of steering wheel-steering shaft, ECU-Assist motor and rack-pinion are established by Newton's second law. The design of curve-line assist curve is one of the main research points, especially the determination method for the function expression of all the segments in the curve-line assist curve. In order to adapt different operating conditions and reduce the side-effect of non-linear factors, three steering control modes and

He, Ziman, Gu, Mengyan

Research of the Impact of Power Steering System Parameters on the Vehicle Handling Stability

2012-01-025604/16/2012

The characteristic of steering system is extraordinary critical to vehicle handling and stability, and the coulomb friction, which consist of steering gear coulomb friction and kingpin coulomb friction, are usually neglected in the many previous steering system model. In the paper, the dynamic model of hydraulic power steering system (HPS) including 9 rotational degree-of-freedom (DOF) and 1 translational DOF is presented, taking into account coulomb friction of steering system, and the 2-DOF mathematical model is established based on the manipulation of dynamical theory. Then simulation of vehicle handling stability is developed using the model, a goal of investigation of effects of steering ration, stiffness coefficients and moment of inertia of parts on signs of handling and stability involving yaw rate, slip-angle of center of gravity and lateral acceleration. All the work lay good groundwork for designing and selecting of the parameters of steering system.

Liao, ShuHua, Yang, Caihong

AIRCRAFT NOSE WHEEL STEERING/CENTERING SYSTEMS

AIR1752 (Historical)08/10/2011

This document covers both military aircraft (land-based and ship-based) and commercial aircraft. It is intended that the document be continually updated as new aircraft and/or new "lessons learned" become available.

A-5B Gears, Struts and Couplings Committee

Transient Responses of a Hydraulic Power Assisted Vehicle Steering System

2011-01-098404/12/2011

This paper presents a comprehensive model of a hydraulic power steering system for predicting the transient responses under various steering inputs. The first principles of multi-body system dynamics and fluid mechanics are applied to model key nonlinear components and in particular, the rotary spool valve, piped fluid lines, the frictional coupling between multiple contacting surfaces with use of the empirical data. The system model, which integrates together all of lump masses, fluid line elements and hydraulic components, is formulated using the state space representation approach. It contains time-variant coefficient matrices resulting from the nonlinearities in the fluids systems. A numerical simulation scheme is developed to obtain the system transient responses and the results are compared with those measured from the tests. Large transient vibration (or judder) of multi-body subsystem, or pressure ripple in the hydraulic subsystem, are observed from both of simulation and tests

The Tri-Core Fault-Tolerant Control for Electronic Control Unit of Steer-By-Wire System

2011-01-100604/12/2011

In order to solve the reliability and security problems which are caused by the structural alteration of the traditional steering system, the fault-tolerant control method for the Electronic Control Unit of Steer-By-Wire system is studied in this paper. A hardware structure of SBW, with triple cores and dual motors is present. And one triple-loop control system and a triple-core control mechanism which is coordinated by distributed processing mechanism and voting mechanism are proposed too. The communication among steering feeling motor, steering motor and cores is achieved through FlexRay bus. The Hardware-in-loop Simulations test result shows that the reliability and safely of the Electronic Control Unit of Steer-By-Wire system is effectively improved.

He, Lei, Zong, Changfu, Chen, Shuang, Wang, Chang

Development of an Electrical Power Steering for Emergent Markets

2010-36-024310/06/2010

Development of an Electrical Power Steering (EPS) system for Emergent Markets, with emphasis on improved fuel economy and cost advantages to the customer. The EPS for Emergent Markets provides high steering wheel assistance on parking maneuvers and appropriate assistance on driving conditions similar to conventional EPS systems. The assistance levels decreases while vehicle speed increases providing better steering feel at high speed conditions (highway tracks). It also provides good tuning capability balanced with piece cost. In addition, this EPS enables an aftermarket bolt-on system for non-assisted steering vehicles (i.e., manual steering vehicles).

Ursolino, Davi Janini, Hage, Gustavo Matucci, Stachi, Sheldon Leonardo Erhardt, de Campos, Demerson Alves, Silva, Ricardo Pereira, Kelber, Christian Roberto, Lessa, Leonardo

Design Optimization of a Mini-Truck Hydraulic Power Steering System Based on Road Load Data (RLD)

2010-01-019804/12/2010

Today's automotive industry demands high quality component as well as system designs within very short period of time to provide more value added features to customers on one hand and to meet stringent safety standards on the other. To reconcile economy issues, design optimization has become a key issue. In the last few decades, many OEMs took to analytical tools like Computer-Aided-Engineering (CAE) tools in order to decrease the number of prototype builds and to speed up the time of development cycle. Although such analytical tools are relatively inexpensive to use and faster to implement as compared to the costly traditional design and testing processes: however, there are many variables that CAE tools cannot adequately consider, such as manufacturing processes, assembly, material anisotropy and residual stresses. Therefore, still smart measuring and testing techniques are required to substantiate the CAE results. In today's automotive scenario, though Electric power steering system

Babu, Hari Srinivas, Thakare, Prashant Anandrao, Shirguppe, Abhijeet

Characterization and Reduction of Power Steering Hiss noise for Passenger Car

2009-28-004912/13/2009

Passenger comfort has become one of the key areas to achieve success in the passenger car market segment. New upcoming products are rejected by customers not because of durability, but more by irritants like noise and vibrations. Hiss noise is one of the major irritants in passenger cars employing hydraulic power steering. This paper describes an attempt to evolve a structured methodology to identify and characterize power steering hiss noise from a rack and pinion type hydraulic power steering system. Extensive testing and detailed analysis of noise data was performed for characterization of power steering hiss noise, from which frequencies responsible for hiss noise were identified at vehicle level and component level. Subsequently several solutions were tried to reduce the hiss noise to an acceptable level considering the limitations of manufacturing and cost. Test results show the effectiveness of approach and methodology towards arriving at a solution for hiss noise. The most

Jagtap, Santosh, Madaswamy, Arunachalam, Winney, George

A New Tool for Design and Analysis of Optimized Rack and Pinion Steering Mechanisms

2009-01-167506/11/2009

Rack and Pinion steering systems are increasingly common in automobiles due to their superior performance characteristics. Because of differing vehicle parameters, even very similar vehicles must have different steering systems. Small changes in linkage dimensions, to accommodate space constraints, can result in significant changes in steering performance. Thus, each proposed design must be thoroughly analyzed and evaluated. A new, analytical engineering tool has been developed to help design engineers find optimum 2-D steering mechanisms quickly. It provides designers with the capability to input vehicle parameters, run a simple solver, and converge to an optimized steering system in seconds. Designers can also search through different possibilities quickly and find the best solutions for the constraints that are present. It also allows the design of leading or trailing systems, provides the ability to select the percentage of Ackermann steering desired, input estimated production

Leishman, Robert, Chase, Kenneth

Integrated Control of Active Steering and Electronic Differentials in Four Wheel Drive Vehicles

2009-01-044604/20/2009

In this paper the integrated control of front and rear active differentials with active front steering is investigated in order to improve dynamics, stability and to reduce the drawbacks of mechanical self-locking differentials. The proposed integrated centralized control feeds back both the yaw rate and the wheel speed measurements to the control inputs which are the front wheel steering angle and the torque transferred by the electronic differentials between the left and the right wheels of both vehicle's axles. The control of the electronic differentials is not only aimed at keeping the wheel speed differences at desired values but it is also integrated with the active steering control (a PI action from the yaw rate error) to produce a yaw moment (also depending on the yaw rate error) which improves handling and stability. Several simulations are carried out on a CarSim small SUV model to explore the robustness with respect to unmodelled dynamics such as pitch, roll and nonlinear

Marino, Riccardo, Scalzi, Stefano

Development of Methodology for Improvement in Steering Returnability

2008-01-049404/14/2008

An improvement in returnability of steering wheel, over and above meeting the regulatory norms, is required to have safe driving feel and maneuverability on turns. All the parts comprising of a steering system plays important roles in steering wheel returnability characteristics. All the parameters were studied in isolation and in combination also, to ascertain their effect on steering and various observations were made during experimentation on each parameter. This paper proposes a methodology of experimental testing used for finding influence of the frictional resistance in steering returnability. This methodology has facilitated to gain 40 % improvement in steering returnability without altering the design parameters e.g. steering geometry.

Avachat, Renuka, Mahajan, J. S., Gopalakrishna, K.

Steering Feedback Torque Definition and Generation in a Steer by Wire System

2008-01-049804/14/2008

Steer by wire (SbW) system is examined, considering the positive effects of the lack of direct mechanical connection between steering wheel and rack. SbW system's steering wheel has to generate a resistant torque which adds to the friction one. Such torque must be felt as natural by the average driver and carry information about vehicle dynamic condition. System prototype is obtained from a classical steering system. Steering wheel is linked to a brushless 12V DC current electric motor designed to develop resistance torque, after steering column is removed, triple stadium planetary gear is necessary to increase the torque output. A hardware in the loop test bench is realized in order to test feedback torque generation and steering wheel efficiency influence on vehicle behaviour. Steering wheel is fixed to the bench and its rotation acquired by an optic encoder. Steering wheel angle is used as input for a ten degrees of freedom vehicle model through an acquisition data board. The same

Morgando, Andrea, Velardocchia, Mauro

Sliding Mode Observer and Long Range Prediction Based Fault Tolerant Control of a Steer-by-Wire Equipped Vehicle

2008-01-090304/14/2008

This paper presents a nonlinear observer and long range prediction based analytical redundancy for a Steer-By-Wire (SBW) system. A Sliding Mode Observer was designed to estimate the vehicle steering angle by using the combined linear vehicle model, SBW system, and the yaw rate. The estimated steering angle along with the current input was used to predict the steering angle at various prediction horizons via a long range prediction method. This analytical redundancy methodology was utilized to reduce the total number of redundant road-wheel angle (RWA) sensors, while maintaining a high level of reliability. The Fault Detection, Isolation and Accommodation (FDIA) algorithm was developed using a majority voting scheme, which was then used to detect faulty sensor(s) in order to maintain safe drivability. The proposed observer-prediction based FDIA algorithms as well as the linearized vehicle model were modeled in MATLAB-SIMULINK. Three different fault types were used to evaluate the

Hasan, Mohammad Sharif-ul, Anwar, Sohel

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