Development of the Control Strategy for an Innovative 4WD Device

Author(s):  
Federico Cheli ◽  
Paolo Dellacha` ◽  
Andrea Zorzutti

The potentialities shown by controlled differentials are making the automotive industry to explore this field. While VDC systems can only guarantee a safe behaviour at limit, a controlled differential can also increase the handling performance. The system derives from a rear wheel drive architecture with a semi-active differential, to which has been added a controlled wet clutch that directly connects the front axle and the engine crankshaft. This device allows distributing the drive torque between the two axles, according to the constraints due to kinematics and thermal problems. It can be easily understood that in this device the torque distribution doesn’t depend only from the central clutch action, but also from the engaged gear. Because of that the central clutch controller has to consider the gear position too. The control algorithms development was carried on using a vehicle model which can precisely simulate the handling response, the powertrain dynamic and the actuation system behaviour. A right powertrain response required the development of a customize library in Simulink. The approach chosen to carry on this research was the one used in automotive industry nowadays: an intensive simulation campaign was executed to realize an initial controller design and tuning.

Author(s):  
Gene Y. Liao ◽  
Trudy R. Weber ◽  
Shawn D. Sarbacker ◽  
Donald P. Pfaff

This paper describes four conceptual designs of strong hybrid vehicle powertrains. These concepts enable conversion of conventional powertrains into strong hybrid powertrains with minimal tear-up to the existing architecture. These concepts are configured as follows: (1) incorporates an electric machine attached to the front axle of a conventional rear-wheel-drive vehicle; (2) a Flywheel-Alternator-Starter (FAS) system with a motor placed between the torque converter and the transmission; (3) same as previous one but where the torque converter is replaced by a starting clutch; and (4) a dual mode Electric Variable Transmission (EVT). These concepts provide extensive hybrid functionality such as, electric motor-only drive; launch assist, braking energy recovery and regeneration. Simulation results indicate that the proposed strong hybrid concepts have the potential to provide fuel economy gains of 19% to 26% over conventional powertrains.


1971 ◽  
Vol 44 (4) ◽  
pp. 960-961 ◽  
Author(s):  
A. Kondo ◽  
F. C. Brenner

Abstract The total number of miles that could be expected for a tire was projected and compared from a test involving two vehicles, one with a front axle drive and one with a rear axle drive. On the front axle drive vehicle the tires when changed by forward-X pattern each 1000 miles wore at twice the rate on the front wheels as on the rear; on the other vehicle they wore at about the same rate on both sets of wheels. The projected mileages for the tires on the two vehicles were 22,400 and 22,500 miles which is not appreciably different.


Author(s):  
James A. D’Iorio ◽  
Joel Anstrom ◽  
Moustafa El-Gindy

A literature survey is conducted that compares the body of work written about dynamic yaw-moment control (DYC) systems implemented on vehicles with multiple electric motors. Four wheel drive, rear wheel drive, and front wheel drive vehicle architectures are compared with reference to advantages for DYC systems followed by a discussion on controller design. Advantages are weighed as to whether it is better to control vehicle yaw rate, body sideslip angle, or both. Next, methods for implementing the DYC system are evaluated. Sensors used, estimations made, and controller-type utilized are all discussed. Lastly, methods for simulation and testing are reviewed. The survey suggests that little progress has been made on front wheel drive vehicles. It was also determined that more work needs to be conducted on deciding desirable vehicle dynamics for handling. Investigations should be conducted to make these systems cost-effective and robust enough for production. Finally, future studies should include as much detailed simulation work and actual vehicle testing as possible as both are needed for a complete DYC investigation.


Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 394 ◽  
Author(s):  
Michele Vignati ◽  
Edoardo Sabbioni ◽  
Federico Cheli

When dealing with electric vehicles, different powertrain layouts can be exploited. Among them, the most interesting one in terms of vehicle lateral dynamics is represented by the one with independent electric motors: two or four electric motors. This allows torque-vectoring control strategies to be applied for increasing vehicle lateral performance and stability. In this paper, a novel control strategy based on torque-vectoring is used to design a drifting control that helps the driver in controlling the vehicle in such a condition. Drift is a particular cornering condition in which high values of sideslip angle are obtained and maintained during the turn. The controller is applied to a rear-wheel drive race car prototype with two independent electric motors on the rear axle. The controller relies only on lateral acceleration, yaw rate, and vehicle speed measurement. This makes it independent from state estimators, which can affect its performance and robustness.


Author(s):  
Federico Cheli ◽  
Leonidas Kakalis ◽  
Andrea Zorzutti

The most common automotive drivelines transmit the engine torque to the driven axle through the differential. Semi-active versions of such device ([10], [11], [12]) have been recently conceived to improve vehicle handling at limit and in particular maneuvers. All these differentials are based on the same structural hypothesis of the passive one but they try to manipulate the vehicle dynamics controlling a quantity which was fixed in the passive mechanisms. In this way it’s possible to control the amount of the stabilizing torque but it’s not possible to apply it in both directions. This fact is a great draw drawback of the semi-active differential because a complete yaw control can’t be developed. On the other hand, active differentials [17] can both apply the best yaw moment (in terms of amplitude) and do this with the right sign. Although classic active differentials are greatly versatile, they can’t (or hardly can) reproduce an extreme torque distribution as 0–100% when there is not a μ-split condition. That is because there is always a bias value due to the presence of a gear that has to be decreased by active clutch action. And these clutches are often not able to do that. The most innovative device presented in the last years is the Super Handling-All Wheel Drive (SH-AWD) by Honda ([2], [3], [4], [5]). It can freely distribute the drive torque to the desired wheel, maintaining one of them in free rolling condition, if this is necessary. This flexibility in the lateral torque distribution can hugely increase the vehicle manoeuvrability. Author has carried out a feasibility study to evaluate the handling improvement due to such a device on a high performance rear wheel drive vehicle normally equipped with a semi-active differential.


Author(s):  
Rami Y. Hindiyeh ◽  
J. Christian Gerdes

This paper presents the development of a controller for autonomous, steady-state cornering with rear tire saturation (“drifting”) of a rear wheel drive vehicle. The controller is designed using a three-state vehicle model intended to balance simplicity and sufficient model fidelity. The model has unstable “drift equilibria” with large rear drive forces that induce deep rear tire saturation. The rear tire saturation at drift equilibria reduces vehicle stability but enables “steering” of the rear tire force through friction circle coupling of rear tire forces. This unique stability–controllability tradeoff is reflected in the controller design, through novel usage of the rear drive force for lateral control. An analytical stability guarantee is provided for the controller through a physically insightful invariant set around a desired drift equilibrium when operating in closed-loop. When implemented on a by-wire testbed, the controller achieves robust drifts on a surface with highly varying friction, suggesting that steady cornering with rear tire saturation can prove quite effective for vehicle trajectory control under uncertain conditions.


2011 ◽  
Vol 86 ◽  
pp. 762-766
Author(s):  
Jian Jun Hu ◽  
Peng Ge ◽  
Zheng Bin He ◽  
Da Tong Qin

The dynamic models of whole rear-wheel drive vehicle, limited-slip differential, hydraulic control system and electronic throttle were established. Simulations of acceleration course on split-µ road, checkerboard-µ road, low-µ road and step-µ road were carried out combining electronic throttle PI controller and limited-slip differential fuzzy controller. The results show that the Anti-slip Regulation quickly works according to the road adhesion coefficient, effectively inhibits the slip of driving wheels on low adhesion coefficient road, the acceleration performance driving on bad roads was improved obviously, and show a good adaptability.


2021 ◽  
Author(s):  
Sandy Momoe Kawano ◽  
Richard W. Blob

Amphibious fishes and salamanders are valuable functional analogs for vertebrates that spanned the water-to-land transition. However, investigations of walking mechanics have focused on terrestrial salamanders and, thus, may better reflect the capabilities of stem tetrapods that were already terrestrial. The earliest tetrapods were aquatic, so salamanders that are not primarily terrestrial may yield more appropriate data for modelling the incipient stages of terrestrial locomotion. In the present study, locomotor biomechanics were quantified from semi-aquatic Pleurodeles waltl, a salamander that spends most of its adult life in water, and then compared to a primarily terrestrial salamander (Ambystoma tigrinum) and semi-aquatic fish (Periophthalmus barbarus) to evaluate whether walking mechanics show greater similarity between species with ecological versus phylogenetic similarities. Ground reaction forces (GRFs) from individual limbs or fins indicated that the pectoral appendages of each taxon had distinct patterns of force production, but hind limb forces were comparable between the salamanders. The rate of force development ('yank') was sometimes slower in P. waltl but generally comparable between the three species. Finally, medial inclination of the GRF in P. waltl was intermediate between semi-aquatic fish and terrestrial salamanders, potentially elevating bone stresses among more aquatic taxa as they move on land. These data provide a framework for modelling stem tetrapods using an earlier stage of quadrupedal locomotion that was powered primarily by the hind limbs (i.e., "rear-wheel drive"), and reveal mechanisms for appendages to generate propulsion in three locomotor strategies that are presumed to have occurred across the water-to-land transition in vertebrate evolution.


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