Browse Topic: Four wheel drive
This project presents the development of an advanced Autonomous Mobile Robot (AMR) designed to autonomously lift and maneuver four-wheel drive vehicles into parking spaces without human intervention. By leveraging cutting-edge camera and sensor technologies, the AMR integrates LIDAR for precise distance measurements and obstacle detection, high-resolution cameras for capturing detailed images of the parking environment, and object recognition algorithms for accurately identifying and selecting available parking spaces. These integrated technologies enable the AMR to navigate complex parking lots, optimize space utilization, and provide seamless automated parking. The AMR autonomously detects free parking spaces, lifts the vehicle, and parks it with high precision, making the entire parking process autonomous and highly efficient. This project pushes the boundaries of autonomous vehicle technology, aiming to contribute significantly to smarter and more efficient urban mobility systems
After three years away from the U.S. market with its range-topping SUV, the Land Cruiser, Toyota unveiled the redesigned 2024 Land Cruiser in Salt Lake City on Aug. 1. The model, long known around the world for its durability and offroad credentials, arrives with the SUV competition hotter than ever. The company said the new model will start at around $55,000. The new Land Cruiser has just one engine option, the i-Force Max turbo 2.4-L four-cylinder hybrid that generates 326 hp and 465 lb-ft (630 Nm) that is routed through an 8-speed automatic transmission. All models are equipped with what Toyota classifies as a “full-time four-wheel-drive system” with a lockable center differential and an electronically controlled 2-speed transfer case to impart high- and low-range capability. Also standard is a lockable rear differential to apportion power in a 50/50 ratio across the rear axle
If a mid-20th century engineer could time travel and see Magna's electric off-road powertrains, they might ask “why is the rear differential so gigantic?” But that's no differential. It's a powerful electric motor fully integrated into each front and rear axle for full 4x4 traction. And Magna said the system will “very likely” be seen on a production vehicle within a few years. At its 2023 tech day presentation, held at a Michigan offroad park and Magna International HQ in Troy, Mich., SAE Media had the opportunity to drive prototype vehicles offroad and sample Magna's in-cabin safety features
This document will apply to the most common applications of electric motors, used for activating all-wheel drive (AWD) and four-wheel drive (4WD) disconnect systems as used in passenger (car and light truck) vehicles. The standard will provide consistent definition, terminology, tests, and reporting methods
CNH Industrial recently introduced what it says is the world's first autonomous-ready, battery-electric light utility tractor at its Tech Day in Phoenix, Arizona. The New Holland T4 Electric Power is another step in the company's vision for extensive electrification and autonomy across its lineup. The company said production would begin in late 2023 on the four-wheel-drive tractor. Its e-motor provides a continuous 75 hp (55 kW) and peaks at 120 hp (89 kW), with max torque of 236 lb-ft (440 Nm) and a top speed of 25 mph (40 km/h). All those performance figures - which are comparable to the many internal-combustion (IC) tractors in the light utility category - start with a 95-kWh battery pack. Engineers said the tractor's battery can power a full day of work for many mission profiles. That's largely because power is used on-demand and never at idle as with an IC-powered rig. If a mid-use charge is required, the battery can be charged to 100% capacity in about an hour with standard fast
With high integration, high efficiency and high flexibility, the front wheel independent Steer-by-Wire system (SbW) is a key link between autonomous vehicles and intelligent chassis technology, and is one of the current focused research in industry and academia. In this paper, a strategy for active control of steering geometry of the Steer-by Wire independent steering system is proposed based on the nonlinear three-step method and Ackermann geometry relationship with the control goal of improving the driving stability and handling performance of the vehicle. The control strategy takes the front wheel steering angle difference and yaw moment as the control variables, and tracks the expected side slip angle and yaw rate as the control objectives. A more accurate vehicle model, and a nonlinear tire model with a reference vehicle model, is used to design the three-step controller to improve the effectiveness of the steady-state control and reduce the system error. When designing the
An all-terrain vehicle (ATV) is capable of traveling on any kind of surface or terrain. It is built especially for extreme road conditions. High ground clearance and soft suspension springs are some of the characteristics of an ATV. The use of a four-wheel-drive (4WD) transmission in a light ATV is in high demand. Power on all four tires provides better traction and increases the off-roading capabilities of the ATV. The methodology described in the paper discusses the design and validation of a four-wheel driveline for a light ATV using various modeling and simulation software. Briggs and Stratton engine is coupled with a continuously variable transmission (CVT) to provide infinite ratios within its tuned range to deliver effortless shifting. A two-stage reduction gearbox is used to multiply the torque received from the CVT to provide sufficient traction to the tires. Power is transferred to the front differential via a propeller shaft. A shifting mechanism is installed for shifting
This paper investigates the application of torque weighting to vibration dose value. This is done as a means to enhance correlation of perceived drive comfort directly to driver pedal commands while rejecting uncorrelated inputs. Current industry standards for vehicle comfort are formulated and described by ISO2631, which is a culmination of research with single or multi-axis vibration of narrow or broadband excitation. The standard is capable of estimating passenger comfort to vibrations, however, it only accounts for reaction vibrations to controlled inputs and not perceived vibration request vs. response vibration. Metrics that account for torque inputs and the vibration response create actionable estimates of dosage due to driver torque requests without uncorrelated inputs. This reduces the need for additional accelerometers and special compensating algorithms when road or track testing. The use case for the proposed modified metric is during the powertrain calibration process
Pass-by/exterior noise of earth moving machines (EMM) and forestry machines is becoming a focus at early product development stages. ISO 6395 (2) or EC/2000/14 (1) standards defines exterior noise test procedure for EMM. However, these standards do not provide insights for diagnosing any noise issues which may arise. The analysis challenges are posed by the moving machine and acoustic sources with respect to the stationary hemisphere target microphone on the ground and changing operating condition of sources as function of time. There is need to develop a seamless methodology to identify acoustic sources, quantify respective source strengths and rank partial contributions from each source to the total target microphone response in order to overcome the aforementioned challenges. This paper demonstrates use of time and frequency domain Acoustic Source Quantification (ASQ) combined with time domain overall sound pressure level computation to mimic operational test conditions which
In this paper, in order to avoid the frequent switching of engine operating points and improve the fuel economy during driving, this paper proposes a control strategy for the 4-wheel drive (4WD) hybrid vehicle based on wavelet transform. First of all, the system configuration and the original control strategy of the 4WD hybrid vehicle were introduced and analyzed, which summarized the shortcomings of this control strategy. Then, based on the analyze of the original control strategy, the wavelet transform was used to overcome its weaknesses. By taking advantage over the superiority of the wavelet transform method in multi signal disposition, the demand power of vehicle was decomposed into the stable drive power and the instantaneous response power, which were distributed to engine and electric motor respectively. This process was carried out under different driving modes. The proposed control strategy not only ensured the dynamic property, but avoided the frequent switching of engine
A gray-box optimization procedure based on evolutionary algorithms for the initial design of a suspension concept for four wheel independently driven and steered vehicles is developed. With the presented optimization method, the energy consumption together with state of the art knowledge about the parametrization and design of vehicle suspension systems leads to an optimization setup closely to real world requirements while the vehicle’s topology is exploited. To this, the modelling presented in [1] is considered as a geometric suspension model. Furthermore, to take advantage of the potential of such vehicles, an autonomous closed-loop setup with integrated motion control is utilized. During the optimization, the chassis parameters with the most impact on energy consumption and driving dynamics, namely camber, caster, scrub radius and the steering axis inclination (SAI) depending on a varying caster angle and SAI in relation to the steering angle, will be focused. Therefore, the
This Aerospace Information Report (AIR) is presented in two parts. The first part is simply a summarization of design factors that must be considered in establishing vehicle specifications and design characteristics. The second part refers particularly to the performance characteristics of an aircraft tow tractor. Some definitions, formulas, data, and an example are provided mainly for assisting the specifying engineers of potential buyers and users of aircraft tow tractors in the evaluation and comparison of their requirements with the performance capabilities of the various tow tractors offered by the tow tractor manufacturers. Although the design engineers could also use the formulas and data in their calculations of the performance specifications of aircraft tow tractors, this AIR is not intended to provide the methods and all data necessary for detailed calculations and design of an aircraft tow tractor
All-wheel drive (AWD) and four-wheel drive (4WD) vehicles are becoming more prevalent in the market today. However, it is not well understood what the correct practice is when only one tire on the vehicle needs to be replaced. There are various recommendations and practices provided by tire dealers and car manufacturers to the consumer. The most common recommendation is to replace more than a single tire and match tread depths across all tires. The basis for this recommendation is the idea that tires with different tread depths will have a different number of revolutions per distance traveled due to differences in rolling radius. Mixing tires with different tread depths may cause extra wear or damage to the drivetrain components because, on a vehicle, the tires must rotate at different speeds to travel the same distance. In this study, the rolling radius of tires is measured on vehicle to understand the impact of tread depth, tire brand and model, and inflation pressure on the rolling
Based on the traditional heavy commercial vehicle, hydraulic hub-motor drive vehicle (HHMDV) is equipped with a hydraulic hub-motor auxiliary drive system, which makes the vehicle change from the rear-wheel drive to the four-wheel drive to improve the traction performance on low-adhesion road. In the typical operating mode of the vehicle, the leakage of the hydraulic system increases because of the oil temperature rising, this makes the control precision of the hydraulic system drop. Therefore, a temperature compensation control strategy for the assist mode is proposed in this paper. According to the principle of flow continuity, considering the loss of the system and the expected wheel speed, the control strategy of multifactor target pump displacement based on temperature compensation is derived. The control strategy is verified by the co-simulation platform of MATLAB/Simulink and AMESim. The simulation results show that the temperature compensation control strategy compensates the
A procedure for the initial design of a suspension concept with four independently driven and steered wheels is developed, whereby, steering angles above conventional values are considered. To fully exploit the potential of such vehicles, an autonomous closed-loop setup with integrated motion control is utilized. The goal is to obtain statements for an optimal suspension design and parametrization maintaining a general approach, while underlying black-box control and the vehicle configuration remains exchangeable. The investigation of the influence of the chassis parameters, with crucial impact on energy consumption, comfort and driving dynamics, namely camber, caster, scrub radius and the steering axis inclination (SAI) depending on a varying caster angle and SAI in relation to the steering angle will be focused. For this sensitivity analysis, an explicit behavioral-oriented model of the suspension is created. This behavior is evaluated with the resulting driving dynamics, specified
This SAE Standard applies to the usage of tires of the same nominal size and tread type, but with different outside diameter for articulated front-end loaders. Articulated four-wheel-drive front-end loader performance and component life can be affected by excessive differences in the tire outside circumference and/or diameter. The purpose is to provide specific guidelines for the usage of tires with different outside circumference and/or diameter on articulated front-end loaders
Almost all light trucks now are being manufactured with at least a driver side air bag and all will have dual air bags by 1998. The driving forces behind this feature are occupant safety, federal regulations, and competition in the industry. Along with the booming popularity of pickups and SUVs, they are commonly accessorized with a wide variety of products. Many accessories for four-wheel drives in particular are mounted on the front of the vehicle. These products include grille/brush guards, winches, snow plows, replacement bumpers, bicycle carriers, etc. Concerns have arisen over the compatibility of these accessories with the vehicle’s air bag system. The vehicle manufacturers are concerned because of their huge investment in design and crash test verification of the complete vehicle system and keen awareness of the federal regulations. The crushability of the front bumper and supporting structure are key elements in the system, so alterations to that area become logical concerns
The scope of this document is limited specifically to the following types of passenger vehicles: automobiles, light trucks, and sport/utility vehicles. This document addresses modifications as they apply to legal use of the vehicle, and examines suspension modification as it applies to stock (as manufactured) ride height, and changed (raised or lowered) ride height. Note that modifications of ride height are considered, exclusive of wheel and/or tire modifications, which can also have potentially serious side effects, and are outside the scope of this document
The four-wheel drive electric sport utility vehicle (SUV) requires high dynamic performance, and the front and rear axles are matched with a high-power motor. High-power motors operate under low-speed and low-torque conditions, with low efficiency and large power loss. To reduce the power loss under low-speed and low-load conditions, a hybrid system of front and rear dual motors and dual hydraulic pumps/motors is designed. A simulation model of a four-wheel drive SUV electrohydraulic hybrid system is constructed. Aiming at the optimal energy consumption, a dynamic programming algorithm is adopted to establish the driving control rules of the vehicle. Constrained by the Economic Commission for Europe Regulation No.13 (ECE R13), a braking-force distribution strategy for the front and rear axles is formulated. On the premise of satisfying the braking safety, regenerative braking is preferred, and the braking energy is recovered to the greatest extent possible. The optimal efficiency curve
Powertrain electrification could be a key enabler for compliance with future exhaust emission standards and carbon dioxide (CO2) emissions limits or a customer facing product differentiator. The main objective of this study was to assess the potential of electrified propulsion systems in achieving a substantial reduction in CO2 emissions when applied to a representative full-size heavy-duty (HD) truck compared to the baseline configuration. A representative full-size HD four-wheel drive (4WD) truck of adjusted loaded vehicle weight (ALVW) 4082 kg or 9000 lbs with a 6.6 L diesel engine was simulated with various electrified drive configurations over the combined US FTP-72 (Federal Test Procedure) cycle and the Highway Fuel Economy Test (HWFET). Every hybrid vehicle configuration used in the study was designed using representative battery pack and electric drive components. Stop-start (S/S) functionality with a belt alternator starter (BAS) system provided a 2.5% benefit in CO2 emissions
SAE J1362 presents graphical symbols for use on operator controls and other displays on off-road work machines as defined in SAE J1116 plus mobile cranes but excluding agricultural tractors. Symbols for agricultural tractors are covered by ASABE S304, ISO 3767-1, and ISO 3767-2
This SAE Aerospace Information Report (AIR) identifies and summarizes the various factors that must be considered and evaluated by the design or specifying engineer in establishing the specifications and design characteristics of battery-powered aircraft tow tractors. This AIR is presented in two parts. The first part is simply a summarization of design factors that must be considered in establishing vehicle specifications and design characteristics. The second part refers particularly to the performance characteristics of an aircraft tow tractor. Some definitions, formulas, data, and an example are provided mainly for assisting the specifying engineers of potential buyers and users of aircraft tow tractors in the evaluation and comparison of their requirements with the performance capabilities of the various tow tractors offered by the tow tractor manufacturers. Although the design engineers could also use the formulas and data in their calculations of the performance specifications
This document outlines the functional and design requirements for baggage/cargo tow tractors used for airline services
To reduce the fuel consumption of an intelligent four-wheel-drive (4WD) electric vehicle (EV), this paper presents a new method of speed trajectory planning. The proposed method can realize a fast real-time optimization of vehicle speed, aiming to achieve the minimum motor energy output according to the fuel consumption directly. In addition, the optimization method maintains the cruising speed within the deviation required to achieve a good control effect. First, the road slope information is considered, and then, a 4WD EV longitudinal dynamic prediction model and a fuel consumption function are established. Next, the state and control variables are chosen to establish the cost function; in this manner, the MPC optimization problem in each prediction horizon is transformed into quadratic form. Finally, the fast solving tool called GRAMPC is used to solve the MPC problem. The calculation results show that the average fuel consumption is reduced compared with that of normal driving, and
Lightweight of the structure is known as an effective approach to improve fuel economy and handling of the automobile. Moreover, the optimization for the powertrain increases the acceleration performance and reduces the energy consumption of driven components. In this paper, a popular powertrain of a Four-Wheel-Drive (4WD) vehicle is considered as a research object. The nonlinear hybrid mathematical model of optimization is created. The target function, whose value varies with continuous and discrete variables, is the combined moment of inertia consisting of transmission and sub-actuator. The constraints include the gear surface fatigue, gear bending fatigue, the belt tensile failure and so on. The design variable involves the sizes of gears and sheaves, the gear thickness, the numbers of sheaves and so on. Finally, some results based on the nonlinear programming principles are derived, and relative conclusions are drawn
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