Browse Topic: Independent suspension
Optimization of the steering trapezoid mechanism parameter has great significance for improving vehicular handling performance and steering safety. The mathematical model of the current trapezoid mechanism design is oversimplified; Thus, the value of the optimum parameter is often not achievable. In this paper, a design model for the trapezoidal steering mechanism is proposed taking into consideration the size and kinematic constraints. Based on combining Ackerman's principle and spatial geometric relation, a multi-body dynamics design method is used to derive a nonlinear optimization model of the split steering trapezoid mechanism. In this investigation, a hybrid genetic algorithm is developed to minimize the steering error and the corresponding optimum design parameters. The selected design parameters are the bottom angle and the steering arm length of steering trapezoid mechanisms. The objective function of the structural optimization is a weighted summation of the relative error
Electronic Stop-Start (ESS) system automatically stops and restarts the engine to save energy, improve fuel economy and reduce emissions when the vehicle is stationary during traffic lights, traffic jams etc. The stop and start events cause unwanted vibrations at the seat track which induce discomfort to the driver and passengers in the vehicle. These events are very short duration events, usually taking less than a second. Time domain analysis can help in simulating this event but it is difficult to see modal interactions and root cause issues. Modal transient analysis also poses a limitation on defining frequency dependent stiffness and damping for multiple mounts. This leads to inaccuracy in capturing mount behavior at different frequencies. Most efficient way to simulate this event would be by frequency response analysis using modal superposition method. In order to do the same, there is a major hurdle which is due to the nature of the signal being highly transient and of short
The objective of this project is to analyze potential design changes that can improve the performance of helical spring in an independent suspension. The performance of the helical spring was based upon the result measure of maximum value of stress acting on it and the amount displacement caused when the spring undergoes loading. The design changes in the spring were limited to coil cross section, spring diameter (constant & variable), pitch and length of the spring. The project was divided into Stage I & Stage II. For Stage I, using all the possible combinations of these design parameters, linear stress analysis was performed on different spring designs and their Stress and displacement results were evaluated. Based on the results, the spring designs were classified as over designed or under designed springs. Then in Stage II, it was checked if the under designed springs can be optimized and classified according to a relevant application of the vehicles (racing cars or luxurious cars
Cadillac has unveiled the 2021 Escalade and will differentiate the full-size SUV from its Tahoe/Yukon platform-mates with a large dose of exclusive technologies including Super Cruise, audio systems from new partner AKG and the industry's slickest display-screen integration. Gaining similar mechanical benefits as its platform siblings, including wheelbase stretches and the new independent rear suspension (IRS) that should improve dynamics along with seating/cargo space, the all-new 2021 Escalade leverages the platform's new digital network architecture (see p.10) to raise the bar for integrated infotainment technology. The 2021 Cadillac Escalade makes use of GM's new GMT T1XX platform that began underpinning its pickup trucks in 2019, and serves as the basis of the upcoming MY2021 Chevy Tahoe/Suburban and GMC Yukon/Yukon XL full-size SUVs. In the fifth generation of Cadillac's longest-running nameplate, this equates to the same notable passenger space and interior volume gains for the
The present work aims to use complex tools for the calculation of vehicle dynamics, using optimization analysis. The study was applied to a single seat off-road prototype that has independent suspension, Double A or WishBones type, both on the front and rear axles and whose main objective will be the analysis of the prototype suspension arms fixing points. A multi-body model was created by MotionView software and straight-line acceleration and deceleration analyzes were applied to obtain better longitudinal load transfer ratios for the axes, besides the force measurements for the arm connections during these events. After the creation of the multi-body model, some studies using optimization tools, through HyperStudy software, were performed in order to obtain the new positions of the attachment points in the chassis, achieving a better dynamic suspension design. The new points change the longitudinal load transfer design and generate controlled alteration between predefined parameters
The high level of reliability of virtual analysis for suspension system development should not be thinking only for comfort and performance purpose, considering the `growing number of failures due to the touch between components in dynamic condition. The study establishes a simple and optimized methodology, able to predict more accurately the flexible brake hose path subject to the steering motion and associates with the independent suspension course, aiming the best route in order to achieve a low cost and robust design. In turn, the flexible brake hose non-linear model invalidates the multibody study to get the best route. However, with the aid of motion making use of NX9 [1] CAD [2] software was prepared dynamic movement that subjects front independent suspension system that establishes a Cartesian routine that maps 977 points, much higher than 9 points from previous studies, comprising a more accurate path performed by the hose. This data served as input to the IPS [3] software for
According to the U.S. National Highway Traffic Safety Administration, 743 pedal cyclists were killed and 48,000 were injured in motor vehicle crashes in 2013. As a novel active safety equipment to mitigate bicyclist crashes, bicyclist Pre-Collision Systems (PCSs) are being developed by many vehicle manufacturers. Therefore, developing equipment for evaluating bicyclist PCS is essential. This paper describes the development of a bicycle carrier for carrying the surrogate bicyclist in bicyclist PCS testing. An analysis on the United States national crash databases and videos from TASI 110 car naturalistic driving database was conducted to determine a set of most common crash scenarios, the motion speed and profile of bicycles. The bicycle carrier was designed to carry or pull the surrogate bicyclist for bicycle PCS evaluation. The carrier is a platform with a 4 wheel differential driving system. Each wheel is attached to an independent suspension system to protect motors, gears and
Suspension system is one of the most important systems in an automobile and the failure in the sub systems or parts would prove catastrophic. A semi-trailing arm (STA) suspension is an independent rear suspension system for automobiles where each wheel hub is located only by a large, roughly triangular arm that pivots at two points onto the chassis or the body. STA usually is subjected to three directional loads viz. vertical, longitudinal and lateral in service. The conventional methodology of validating the system is by applying multi-axial loads or by road load simulation consuming significant amount of time. In this paper an attempt is being made to validate the damper mounting pins by reproducing the damper loads locally instead of validating the entire system. STA was strain gauged at the critical locations and was mounted onto the vehicle. Accelerometer was mounted onto the wheel spindle and a displacement transducer (LVDT) was mounted parallel to the damper mounted to the body
Suspension plays an essential role in vehicle's handling stability and riding comfort. This paper discusses a novel suspension that has the capacity to trace a straight line in theory. Therefore it is called rectilinear suspension. So the alignment parameters are invariable during jounce and rebound if the elasticity of suspension components is ignored. According to the structure characteristics of the rectilinear suspension, it is suitable to mount on the rear axle. To evaluate its performance, the dynamics model is established through ADAMS. Moreover, a comparison of the rectilinear suspension with the twin-trapezoidal link suspension is carried out. Further, the K&C test results show that the alignment parameters of the rectilinear suspension are almost invariable compared with MacPherson suspension
The automotive industry commonly uses two definitions of the suspension roll center, the Kinematic Roll Center (KRC) - of interest in studying suspension geometry, and the Force-based Roll Center (FRC) - of interest in studying steady-state vehicle dynamics. This paper introduces a third definition, the Dynamic Roll Axis (DRA) - of interest in studying transient vehicle dynamics. The location of each one of these roll centers has a unique application to vehicle design and development. Although the physical meaning of each roll center is significantly different, the generic term “roll center” is often used without proper specification. This can lead to confusion about how roll centers influence vehicle behavior. This paper hopes to clarify some of this confusion and is organized into three parts: (1) Describes calculation methods for each of the three vehicle roll centers (for independent suspensions) as well as their relevance to vehicle dynamics; (2) Explains the relationship between
In this paper FR (Front Engine, Rear wheel Drive) based 4WD 5-link independent suspension systems are introduced which are developed for low friction road stability in the winter. The arrangement of the lower control arm of the newly developed suspensions has been changed in order to correspond to 4WD layout. And basic performance is satisfied due to the addition of the driveline. Also NVH (Noise, Vibration and Harshness) performance has improved, to enhance the comfort of the vehicle
This paper describes the design and the analysis of a stub axle front suspension developed to a rear-wheel drive of an automotive prototype. The automotive prototype is a vehicle developed for use on public roads with motor and transmission located at the rear and four-wheel independent suspension, with capacity for two occupants. By means of a finite element software, they were analyzed the efforts that acted on the steering and suspension components that interacted with the sleeve axis The stub axle is subjected to various loads in various ways, due to several conditions imposed by the motion that occur due to movement of the vehicle. They were analyzed three situations during the simulations: straight due to the movement of the vehicle, making a turn and during a braking situation. The analysis of the structure in those three situations allowed obtaining some characteristics, such as their strengths and critic regions where those efforts were higher. Based on the results obtained
The vehicle pull (sideways) is a complex outcome of many parameters in an automobile vehicle. This is mainly due to steering, suspension, brake, wheels and chassis parameters. The road conditions like road camber also plays an important role in vehicle pull behavior. All efforts are put in design and manufacturing processes to maintain controlled vehicle pull in normal driving condition. Even though normal vehicle pull seems to be in acceptance limit (subjectively), its intensity increases many folds at the time of harsh braking. In these kind of panic situations where driver firmly holds on the steering wheel, it is expected that the vehicle should stop without deviating too much sideways from its intended straight line path to avoid any kinds of accidents. This work is an outcome of systematic study carried out to understand the root cause of brake pull as a field complaint on current production vehicles and adopting best possible solutions to minimize the brake pull. This paper
The twist axle has highly complicated load paths because of its multiple functions of suspension components. This nature of the twist axle suspension makes the fixed reacted multi-axial suspension test more sophisticated than for other independent suspensions. GM has used Virtual Road Load Data Acquisition (vRLDA) for laboratory tests in the past, but this is the first application of vRLDA for a twist axle multi-axial suspension durability test. In order to utilize vRLDA data for the test input, a new approach to 8 channel multi-axial suspension durability test development was proposed for a twist axle rear suspension. vRLDA for a GM vehicle with twist axle rear suspension was performed and briefly discussed. Instead of using strain data from the twist axle for correlation channels, inboard channels such as shock tower vertical and trailing arm forces were used in the test development. Emphasis was placed on a high level of correlation for the inboard channels, while the correlation at
The articulated dump truck with independent suspensions is driven by six AC motors and each wheel is driven by one motor. Cooling system is configured in every electric wheel. The motor is the main heating source in the electric drive system. Hence, the cooling of the motor will affect the reliability and power-density of the whole electric drive system. According to the actual working conditions, the heating calculation about the cooling system has been carried out during the design process. The design concept of embedding spiral-shaped flow path in the shell of the stator has been drawn. The cooling water could pass through the path and accomplish cooling outside the stator. In this paper, the FLUENT has been used for the 3-D numerical simulation of the cooling system. The temperature field distributions of the cooling water and the shell are obtained. To analyze the influence of the shell structure on the cooling effect, the iSIGHT has been used to accomplish the structural and
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