# Experimental Research on Braking Feedback and Taxing Feedback System of New Energy Vehicles
## 1 Introduction  
Due to the oil crisis and growing environmental awareness that continues to improve, the arrival of the era of new energy vehicles is highly valued by the society. However, their short driving range and insufficient endurance have become the main problems in the development of new energy vehicles [1; 2].  
According to current research, improving the short-distance driving ability and range of new energy vehicles is divided into the following three ways, one is to improve the quality of the battery [3], the second is to change the charging method of new energy vehicles so that the vehicle can be charged while it is running [4; 5; 6; 7], and the third is the new energy recovery system [8].  
The energy recovery system of new energy vehicles is divided into braking energy recovery and coasting energy recovery. In the braking process, the energy consumed by friction braking accounts for approximately 50% of the total driving energy of the car. Under urban operating conditions of more frequent braking and starting, effective recovery of braking energy can reduce the energy consumption of electric vehicles by approximately 15%, which can extend the driving distance of electric vehicles by 10% to 30% [9].  
The braking feedback and coasting feedback are some of the most important technologies to extend its driving range and energy efficiency [10; 11; 12]. According to the literature, through braking feedback and coasting feedback system, vehicle economy can be improved by 15% [13; 14; 15]. Braking feedback technology is to recycle the energy lost during braking to improve the cruising range and driving performance of new energy vehicles [16]. Coasting feedback is the energy recovery achieved by releasing the throttle. At present, in-depth research has been conducted on braking energy recovery and conclusions have been drawn.  
However, it is difficult to apply it in practice due to the lack of clear research on pure electric buses and hybrid buses. The research purpose of this article was to conduct an actual vehicle test to analyze the difference between superposition's and coordinated vehicle braking's energy recovery economic contribution rates and the difference in the economic contribution rates of the whole vehicle with or without the recovery of coasting energy.  
At present, researchers, automobile manufacturers and component manufacturers all over the world have conducted research and development on the control and design of brake energy recovery systems [17]. In the research by [PERSON], [PERSON], [PERSON], and others, a new type of sliding mode control based on high-precision hydraulic feedback modulation was proposed. An open-loop load pressure control based on the linear relationship between the pressure drop and the coil current under the critical opening equilibrium state of the valve was proposed [18]. In [19], an electro-hydraulic brake system developed by Toyota was successfully applied to hybrid vehicles. In [20], in order to promote the realization of transient fault prevention and the detection and mitigation at the node and system levels, a new transient fault tolerance method for BBW systems was proposed. In [21], the position pressure map estimation algorithm was introduced to study the vehicle brake by wire, and the control of the electro-hydraulic brake by wire system was proposed. In [22], the economic contribution rate of the brake energy recovery of the proportional relay valve pneumatic control module was slightly higher than that of the proportional relay valve. In [23], the feasibility of using bidirectional half-bridge DC converters as chargers and brush-reduced DC (BLDC) motors provided actual data on the components in a power scale of 10:1.  
In summary, although the research on braking energy recovery energy management strategies has been extensive and in depth, further system analyses will be necessary for the integration and application of braking energy recovery systems on pure electric buses and hybrid buses.