A Torque Vectoring Control Logic for Active High Performance Vehicle Handling Improvement

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):  
Francesco Braghin ◽  
Edoardo Sabbioni ◽  
Gabriele Sironi ◽  
Michele Vignati

In last decades hybrid and electric vehicles have been one of the main object of study for automotive industry. Among the different layout of the electric power-train, four in-wheel motors appear to be one of the most attractive. This configuration in fact has several advantages in terms of inner room increase and mass distribution. Furthermore the possibility of independently distribute braking and driving torques on the wheels allows to generate a yaw moment able to improve vehicle handling (torque vectoring). In this paper a torque vectoring control strategy for an electric vehicle with four in-wheel motors is presented. The control strategy is constituted of a steady-state contribution to enhance vehicle handling performances and a transient contribution to increase vehicle lateral stability during limit manoeuvres. Performances of the control logic are evaluated by means of numerical simulations of open and closed loop manoeuvres. Robustness to friction coefficient changes is analysed.


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):  
Federico Cheli ◽  
Stefano Melzi ◽  
Edoardo Sabbioni ◽  
Michele Vignati

In recent years the interest towards electric vehicles has increased. Among the different layout of the electric powertrain, four in-wheel motors appear to be one of the most attractive. This configuration in fact allows to re-design inner spaces of the vehicle and presents, as an embedded feature, the possibility of independently distributed braking and driving torques on the wheels in order to generate a yaw moment able to improve vehicle handling (torque vectoring). The present paper presents and compares two different torque vectoring control strategies for an electric vehicle with four in-wheel motors. Performances of the control strategies are evaluated by means of numerical simulations of open and closed loop maneuvers, also taking into account their energetic efficiency.


Author(s):  
A J Cartwright

Current rear suspension designs for rear-wheel drive high performance luxury vehicles are compromised by the conflicting requirements of handling, stability and passenger comfort. This paper describes the philosophy and development behind the new Jaguar XJ40 independent rear suspension systems and shows that by simple design these compromises can be significantly reduced.


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.


Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 122
Author(s):  
Dejun Yin ◽  
Junjie Wang ◽  
Jinjian Du ◽  
Gang Chen ◽  
Jia-Sheng Hu

Torque distribution control is a key technique for four-wheel independent-drive electric vehicles because it significantly affects vehicle stability and handling performance, especially under extreme driving conditions. This paper, which focuses on the global yaw moment generated by both the longitudinal and the lateral tire forces, proposes a new distribution control to allocate driving torques to four-wheel motors. The proposed objective function not only minimizes the longitudinal tire usage, but also make increased use of each tire to generate yaw moment and achieve a quicker yaw response. By analysis and a comparison with prior torque distribution control, the proposed control approach is shown to have better control performance in hardware-in-the-loop simulations.


Author(s):  
David Moreno Giner ◽  
Claudio Brenna ◽  
Ioannis Symeonidis ◽  
Gueven Kavadarlic

Multibody dynamics simulation technology can provide a great help to understand and analyze motorcycle dynamics. In fact, its application in this field has grown very fast in the last years. However, apart from the mathematical model of the vehicle, a virtual rider is essential in order to properly simulate a motorcycle. This is due to the unstable nature of two-wheeled vehicles, which makes them very difficult to simulate by using open-loop maneuvers. The problem of developing a virtual rider for motorcycles has already been covered in literature but most of the proposed control algorithms achieved their purpose without considering the physiological limits of the rider. The objective of the research activities presented here are the preliminary development of a realistic virtual rider based on an experimental campaign and its subsequent simulation together with a detailed multibody model of a motorcycle. Special emphasis was put on making the rider model as simple as possible to facilitate the posterior design of the controller. Real rider movements were measured under laboratory conditions by means of the Motion Analysis technique. Several volunteers with different riding experiences, gender and anthropometry were involved in the experiments in order to provide a valid dataset for the analysis. For the present research, the virtual rider controls the direction of the motorcycle by means of both a torque on the handlebars and the movement of his body. The upper part of the rider’s body was modeled as an inverted pendulum. With regard to the longitudinal dynamics, the motorcycle is controlled by means of the brake torques and by the engine torque, which is transmitted to the rear wheel by means of a simplified model of the chain. First results of the developed virtual rider are presented at the end of this paper.


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