Browse Topic: Power steering
To reduce the harm caused by the failure of electronic and electrical system, the application of ISO 26262 functional safety standard in the automotive industry is more and more widespread. As a critical safety-related electronic and electrical system in automobile, electric power steering is very important and necessary to meet the requirements of functional safety. This paper introduces the main development activities of functional safety at software level. In order to realize the purpose of freedom from interference in memory, the safety mechanism of memory protection is proposed in software safety analysis. The memory protection is realized in AUTOSAR architecture by configuration
The flight area of drones and other unmanned aerial vehicles (UAVs) had been highly restricted but has been relaxing, including flights beyond the scope of sight. Deregulation without aircraft-reliability improvement increases the risk of accidents. However, demanding high reliability for all aircraft leads to an increase in the price of the aircraft. Therefore, if airspace restrictions are relaxed for more reliable aircraft, the cost of higher reliability and its benefits can be balanced. This will improve efficiency and optimize cost-effectiveness. The purpose of this proposal is to balance the cost of aircraft-reliability improvement (which allows flight to continue in the event of a failure) and its advantages. Specifically, the author proposes rules that apply more relaxed airspace restrictions to UAVs with higher FCLs (Flight Continuity Possibility Levels) and stricter airspace restrictions to those with lower FCLs. The FCL does not only refer to the distance or time that can be
This SAE Information Report relates to a special class of automotive adaptive equipment which consists of modifications to the power steering system provided as original equipment on personally licensed vehicles. These modifications are generically called “modified effort steering” or “reduced effort power steering.” The purpose of the modification is to alter the amount of driver effort required to steer the vehicle. Retention of reliability, ease of use for physically disabled drivers and maintainability are of primary concern. As an Information Report, the numerical values for performance measurements presented in this report and in the test procedure in the appendices, while based upon the best knowledge available at the time, have not been validated
If you accept that the oddball and odd-sized Journey never was a legit rival for the likes of the Honda CR-V, Toyota RAV4 and Ford Escape - and it wasn't - Stellantis' Dodge brand hasn't played in the compact SUV segment, one of the largest and most competitive in the U.S. That strategic gap is set to be filled by the 2023 Hornet, Dodge's performance-slanted attempt to peel out some sales volume from among the C-segment utilities that are typified by mundane and softly-tuned top-sellers. The Hornet's not just about having a little more engine power, either. Its platform is shared with the Alfa Romeo Tonale. Like Hornet, the Tonale slated to be in showrooms sometime in spring 2023 and incorporates chassis finery such as standard Koni-supplied Frequency Selective Damping (FSD) dampers. Specifically tuned, genuine by-wire braking (for the R/T trim) reduces curb weight by 9 lb. (4 kg) and improves steering feel via direct-action ratios from the electronic power steering; Stellantis claimed
The present article related to the investigation of fluid bore noise in the power steering pump which is the major source of noise generation in hydraulic power steering system due to the flow ripple and pressure pulsation. In this article, the different parameters (Pump operating speed, operating pressure, bypass hole dimensions and bypass hole orientation) has been investigated and its contribution to the fluid borne noise has been analyzed through Computational Fluid Dynamics (CFD) methods. The design optimization has been done on the power steering pump on the basis of CFD results and the physical sample was made for the same to validate the CFD results. The results show that the pump operating speed is more significant in the fluid borne noise generation followed by the operating pressure, bypass hole angle and diameter. The fluid borne noise increases as the operating speed and operating pressure increases. Conversely the fluid borne noise decreases as the bypass hole angle and
This SAE Standard defines the test conditions, procedures, and performance requirements for circuit breakers in ratings up to and including 200 A. The document includes automatic reset, modified reset, and manually reset types of circuit breakers for 12 VDC, 24 VDC, and 48 VDC electrical systems. Some circuit breakers may have dual voltage ratings (AC and DC); however, this document evaluates DC performance only
This SAE standard applies to self-propelled driver operated sweepers and scrubbers as defined in SAE J2130-1
The steering system is to provide the driver with the possibility of lateral vehicle guidance, i.e. to influence the lateral dynamics of the vehicle; moreover, it is crucial to promptly translate the steering input to have the vehicle in high-quality directional stability. An electrical power assisted steering (EPAS) system is the sophisticated variant to meet higher requirements for vehicle safety, ride comfort, and driver-assist. This research is to investigate if a CAE methodology could be innovated to better simulate the durability of a steering system under various working scenarios; figure out the critical features of the modeling; conduct a correct analysis procedure for validating the modeling and collecting data for evaluation. With step by step in modeling and analysis, a well-established example of CAE model of EPAS is enabled to highlight the novelty of steering vehicle level CAE methodology and therefore achieve the research goal
Hardware-in-the-loop (HIL) test benches are indispensable for the development of modern vehicle dynamics controllers (VDCs). They can be regarded as a standard methodology today, because of the extremely safety critical nature of the multi-sensor and multi-actuator systems used in vehicle dynamics control. The required high quality standards can only be ensured by systematic testing within a virtual HIL environment before going into a real car. The steering system is an important aspect of the automobile from operational safety and driver enjoyment perspectives. Current Problem/Opportunity is realistic subjective steering feel prediction before vehicle build. And upfront predict the handling characteristics more accurately with subjective feel before proto build. Current Issue is difficult to convert the objective data into subjective feel and difficult to incorporate the nonlinear steering characteristics with hysterics, friction and power assist curves using virtual simulation
Steering system is responsible for providing a precise directional control to the vehicle. The Hydraulic Power Assisted Steering (HPAS) 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 pressure assistance to rack and pinion or 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 operational induce frequency. As power train becomes 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 and quantify the moan noise and elaborate
The current simulation models of EV and ICE Vehicles are well known in industry for their use in estimating the fuel economy or Range benefits because of controller calibrations and component sizing. However, there is a gap in understanding the behavior of accessories such as HVAC, power steering and other such auxiliary loads and the energy losses associated with them. Impact of thermal behavior of electronics on vehicle range also needs to be studied in detail. These kinds of studies help OEM and tier 1 manufactures in improving their design concepts significantly with minimum cost and development time. Hence, the focus of this study is on building simulation models of thermal, electrical, traction and control circuits of a typical electric vehicle. These models are then integrated, and analysis is performed to understand vehicle system level performance metrics. Individual models have been built for HVAC and thermal circuit of on EV in AMESim, HV and LV electrical power distribution
In the current customer centric automotive market, NVH is one of the prime focus for the automotive industry. Almost all light commercial vehicles in the market are with hydraulic power steering system. Hydraulic power steering pump is heart of the steering system which circulates the hydraulic oil to steering gear for assisting the driver. One of the NVH problem which is inevitable with the hydraulic vane pump is humming noise and this is perceived as an irritant by end user. This paper describes a novel technique for reducing the humming noise which is perceived at driver ear level. Base vehicle level objective measurements is carried out to set the acceptance criteria. Existing design is optimized as per CAE iterations and vehicle updated with the multiple solutions and objective measurements are recorded. Driver ear level noise reduction upto 4 dB(A) perceived which meets acceptance criteria. This technique can be used for resolving all hydraulic power steering pump related noise
This paper is an application of ISO 26262 functional safety standards for fail-safe design, development and validation of Electric Power Assisted Steering (EPAS) System. As part of safety feature to save lives, prevent injuries and reduce economic loss due to accidents, many research institutes are working to ensure the safety and reliability of emerging safety-critical Electronic Control Systems in automobile applications. As, Advanced Driver Assistance Systems (ADAS) and other emerging technologies are introduced in the automobile application, the overall safety of these advanced electronic systems relies on the vehicle safety systems, such as steering systems. This paper outlines the approach of performing the Hazard Analysis & Risk Assessment (HARA) and developing a Functional Safety Concept. This approach incorporates several analysis methods, including Hazard and Operability study, Functional Failure Modes and Effects Analysis. This approach is then applied to the Electric Power
As the original engine sound is usually not enough to satisfy the driver’s desire for a sporty and fascinating sound, Active Noise Control (ANC) and Active Sound Design (ASD) have been great technologies in automobiles for a long time. However, these technologies which enhance the sound of vehicles using loud speakers or electromagnetic actuators etc. lead to the increase of cost and weight due to the use of external amplifiers or actuators. This paper presents a new technology for generating a target sound by the active control of a permanent magnet synchronous motor (PMSM) of a mass-production steering system. The existing steering hardware or motor is not changed, but only additional software is added. Firstly, an algorithm of this technology, called Active Sound Generation (ASG), is introduced which is compiled and included in the ECU target code. Then the high frequency noise issue and its countermeasures are presented. Afterwards, an ASG test bench is designed using a motor
In recent decades, research and development in the field of autonomous vehicles have rapidly increased throughout the world, and autonomous driving technologies have begun to be applied to mass production vehicles. Especially recently, even affordable mass production vehicles have begun to be equipped with some autonomous driving systems such as a Lane Keeping Assist (LKA) system. In general, mass-produced LKA systems use a lane detection camera as a means of keeping the lane. One of the common limitations of camera-based LKA systems is that the lane keeping performance significantly decreases when the camera cannot detect lane markings for various reasons such as snow coverage or blurred lane markings. To overcome this limitation, we have developed Global Navigation Satellite System (GNSS)-based LKA systems, which are not affected by the surrounding environment such as weather and the condition of lane markings. In our latest study, we applied Model Predictive Control (MPC) to our
Automatic Lane Change (ALC) function is an important step to promote the currently popular Advanced Driver Assistance Systems (ADAS) within a single lane. The key issue for ALC is accurate steering angle and trajectory tracking during the lane changing process. In this paper, an MPC controller with a receding horizon is designed to track the desired trajectory. During the tracking process, other objectives such as safety and smoothness are considered. Considering of the practical mechanism and parameter uncertainties, an SMC controller is designed to track the target steering angle. For validation, a Hardware-in-the-Loop (HIL) experiment platform is established, and experiments of different control algorithms under different conditions are carried out successively. Comparisons of the experiment results of MPC+SMC and PID+SMC schemes indicate that both the trajectory error and the steering angle error of the former combination are smaller. Specifically, the peak trajectory error in Y
Communicate the process of accurately measuring sound power levels of positive displacement hydraulic pumps commonly used in ground vehicle steering systems. This recommended practice defines the pump mounting (pulley, belt tension, isolation), operating conditions (fluid, speed, temperature, pressure), room acoustics, instrumentation, noise measurement technique and data acquisition setup to be used. Included are recommendations for test sample size, and format for data presentation/reporting
A major challenge in automotive NVH engineering is to approach complex structure-borne sound and vibration problems with sufficient accuracy but reasonable experimental effort. Typical issues encountered are poor correlation between objective component performance criteria tested for during bench validation and corresponding subjective targets evaluated during system validation in the actual vehicle. Additional challenges arise from the need to impose assumptions on sophisticated physical vibration problems to reduce the complexity to a level feasible for conventional experimental test methods. This paper addresses all mentioned issues by elaborating on a system NVH engineering approach employing Virtual Acoustic Prototyping (VAP) (related to what is now often called component Transfer Path Analysis) to synthesize time domain sound and vibration responses of vibrating machinery operated in a virtual vehicle environment. One crucial step of VAP is to characterize the strength of
This paper proposes a new evaluation method of analyzing stability and design of a controller for an electric power steering (EPS) system. The main purpose of the EPS system’s control design is to ensure a comfortable driving experience of drivers, which mainly depends on the assist torque map. However, the high level of assist gain and its nonlinearity may cause oscillation, divergence and instability to the steering systems. Therefore, an EPS system needs to have an extra stability controller to eliminate the side effect of assist gain on system stability and attenuate the unpleasant vibration. In this paper, an accurate theoretical model is built and the method for evaluating system quality are suggested. The bench tests and vehicle experiments are carried out to verify the theoretical analysis. The evaluation method proposed in this paper can not only guide the design of controller parameters, but also evaluate the control effect while the performance of several controllers are all
Recently, as the autonomous driving technology has been actively developed, the safety performance of EPS(Electric Power Steering) system of automobile is increasing more and more. Therefore, this paper propose a current sensorless control method that can continuously control the motor current even when the current sensor used for motor control in the EPS system fails. The current sensorless method proposed in this paper is a structure that preliminarily measures the output voltage required for motor current control and saves it as a table in SW, and it can be implemented easily without modeling of motor or parameter estimation The proposed method is implemented in EPS system of real vehicle and its performance is verified to be sufficient for steering assist
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