# Individual Drive-Wheel Energy Management for Rear-Traction Electric Vehicles with In-Wheel Motors
## 1 Introduction  
As transport technology evolves, new opportunities arise. Formerly, the efficiency of energy usage in street vehicles was close to being maxed out, up to a point limited by the internal combustion engine's physical principles. With the renewed interest in electric vehicles (EVs) and the mass production of them, a vast new field for improvement has opened up for research engineers, physicists, and designers in many areas, including battery technology, charging stations, power train mechanics, and of course vehicle energy management [1]. This era of in-vehicle technology has seen the advent of two significant paradigm changes--the electrification of street vehicles and the implementation of higher levels of autonomous driving--thanks to the increased availability of high computational power onboard the vehicles and cloud computing connectivity [2]. The development of intelligent and connected vehicles and their integration with energy management technology in their power train can further increase energy efficiency [3, 4]. The integration of all the methods mentioned earlier comprises a synergy of great interest for studying, evaluating, and implementing, taking energy usage optimization to new high possibilities [5]. The transformation of ground transport to electromobility is an undeniable reality [6]. There is interest in increasing vehicle energy efficiency for environmental, technical, and economic reasons. In-wheel motor technology was first introduced to commercial vehicles by [PERSON] around the year 1900. With this technology, it is possible to eliminate extra components and simplify the power train system on hybrid and fully electric vehicles [7, 8]. One of the main characteristics of an IWMEV is the absence of a transmission combined with the wheel's differential, which has been essential in every four-wheeled vehicle sincethey were first developed more than one hundred years ago. The mechanical transmission has been improved over the years, aiming to maximize engine performance through its speed range. It is still being developed, and the possibility of its pertinency in electric vehicles is being researched [9]. On the other hand, the differential has been left alone as part of a specific and straightforward function. It is to maintain the freedom of spin of the rear axle wheels, allowing them to rotate at different speeds, one relatively against the other according to the car-specific requirements at any given time while still being capable of delivering a tractive effort to the ground to move the vehicle. The in-wheel motor technology does not allow a mechanical differential to be used in the vehicle [10]. However, the car still needs to control the wheel spin velocity during turning maneuvers. The development of an EDS presents the opportunity to solve this problem while also improving the vehicle's energy efficiency by addressing the energy management requirements of the IWMEV. The re-emerging in-wheel motor technology promises to expand the powertrain architecture possibilities for electric vehicles, addressing particularities like moving the motor's weight out of the car's suspended mass. At the same time, it increases the inertia of the wheels, which has undesired consequences that are out of the scope of this work. These differences bring new challenges like the one addressed in this work: the differentiation and power distribution in the individual motors of the IWMEV. This document explains the development, setup, and validation of the electric vehicle's onboard EDS with rear traction. The modeling was started using MATLAB(tm), and following this, tests were carried out on a chassis dynamometer and in real circuit driving experiments. The scope of this paper is to evaluate the performance of this EDS developed around vehicle geometry theory and dynamics equations to improve the handling behavior and energy control of an IWMEV.