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Final drives and rear axles
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
A limited-slip differential is essentially a device that will allow normal differential action of the driving wheels for negotiating corners, but prevents loss of traction in the event of either driving wheel losing adhesion. Since the conventional differential always divides torque equally, it follows that if means can be found to increase the torque needed to turn the wheel having less grip, then the torque delivered to the wheel having more grip can be increased to maintain traction. Although it was in the field of motor racing that the need for some limitation on differential action first became imperative, because otherwise such cars would be virtually unmanageable when accelerating from a standing start or out of a slow corner, it was the ever-increasing power of American cars in the late 1950s that led to the development of the limited-slip or controlled-slip types of differential as we know them today.
Propeller Shaft, Differential and Rear Axles
Published in G. K. Awari, V. S. Kumbhar, R. B. Tirpude, Automotive Systems, 2021
G. K. Awari, V. S. Kumbhar, R. B. Tirpude
A limited slip differential (LSD) is very similar to the open differential model but has an additional component that prevents wheel spinning and loss of traction, the regular differential provides maximum torque to the wheel with minimum traction. The limited slip differential delivers maximum torque to the wheel with maximum traction, particularly in off-road vehicles.
Optimal control of a NASCAR – specification race car
Published in Vehicle System Dynamics, 2023
D. J. N. Limebeer, M. Bastin, E. Warren, H. G. Fensham
The inequality constraints include the maximum engine power constraint The limited-slip differential constraint is while the brake balance constraint is the wheel torques are given by The wheel radii are given by and so on. The minima in (55) ensure that the brake balance constraint only applies to braking torques. Constraints that ensure that the car remains on the track are in which is the (position-dependent) track width. The first two constraints ensure that no wheel touches the right-hand track boundary, while the second two constraints ensure the same for the left-hand boundary.
Dynamic characteristics and friction torque design method for bogies with friction coupling independently rotating wheelsets
Published in Vehicle System Dynamics, 2022
Yuanjin Ji, Youpei Huang, Han Leng, Lihui Ren, Jinsong Zhou, Dao Gong
Currently, a new type of coupled wheelset structure with independently rotating wheelsets is available, that is, the left and right wheels are coupled through a dry friction pair. friction coupling independently rotating wheelsets have a simple structure, low cost, and easy implementation and application. Bracciali et al. proposed the concept of partially independent wheelsets (partially independently rotating wheelsets) (Fig. 1a), comparatively analysed the dynamic performance of partially independent wheelsets and the rigid wheelset, and focused on the effect of a torque limiter on rolling contact fatigue (RCF). They indicated that setting an appropriate torque limiter could effectively decrease the rail RCF damage and the formation of rail corrugation on small-radius curves [12,13]. Shi et al. proposed a new type of lateral coupling structure for independent rotating wheels (IRW) (Fig. 1b), which used the friction pair instead of the gear pair to synchronise the rotation speed of the left and right wheels, so as to obtain the longitudinal creep rate [14]. Leng Han et al. established the mechanical model of the transverse friction coupling independently rotating wheelsets (TFCW) based on the structure of the friction limited-slip differential (Fig. 1c), studied the curve performance and critical speed of the friction coupling independently rotating wheelsets, and analysed the effect of friction torque on dynamic performance [15].
Real-time control for at-limit handling driving on a predefined path
Published in Vehicle System Dynamics, 2020
T. Novi, A. Liniger, R. Capitani, C. Annicchiarico
The first attempts to find the sequence of inputs that maximise vehicle performance were done with offline simulations for motorsport applications. The goal was to obtain the minimum lap time control input sequence and the optimal trajectory. The first lap time simulation was done by Mercedes Benz in the 1930s [9]. In the past decades, many different researchers have studied this topic in various ways. One approach is to simulate the Quasi-Steady-State (QSS) conditions. Brayshaw et al. [10] used the QSS method on a predefined path. The algorithm starts by calculating the vehicle's acceleration limits from a series of constrained nonlinear optimisation problems (NLPs). Then, peaks in the curvature data are identified as an apex of a corner and the maximum possible steady-state speed for each curve is found. The maximum acceleration and deceleration between apex pairs is then calculated and, finally, speed profiles are obtained together with the input sequence. Using the same method, Tremlett et al. [11] studied the influence of limited slip differential (LSD) on lap time simulation.