# Design Optimization of Underground Mining Vehicles Based on Regenerative Braking Energy Recovery
## 1 Introduction  
Coal mining is a crucial industry in China, with more than 90% of coal production occurring underground. Consequently, the use of underground mine cars is widespread, driven by various factors [1, 2]. One significant advantage of underground mine cars is their ability to transport materials within mining sites. These mine cars facilitate the quick and efficient transportation of essential mineral products such as ore, coal, and slag, resulting in time and labor savings. Another benefit is that underground mine cars enable the continuous transportation of large-scale ore, enhancing production efficiency. By utilizing automatic or semi-automatic systems, mine cars can transport ore continuously on the mining face, thereby reducing manual labor, labor intensity, and production time. Additionally, the use of underground mine cars allows for the transportation of miners, thereby reducing the time required for miners to reach their workforce. This not only improves production efficiency but also minimizes the time spent by miners in hazardous underground environments, consequently reducing the risk of accidents. Furthermore, underground mine cars contribute to mitigating the adverse environmental impacts of underground mining. With reduced mechanical excavation and ore processing activities, emissions of noise, vibration, and dust are decreased, thereby protecting surrounding ecosystems and minimizing surface environmental damage caused by mines [3]. Clearly, underground mine cars play a crucial role in mining operations. They enhance productionefficiency, ensure miner safety, optimize resource management, and diminish adverse environmental impacts. Consequently, they have become an indispensable tool in modern underground mining practices [4; 5]. There is currently a significant issue of energy waste during the traction process of underground mine cars. Given the unique characteristics of underground coal mining environments, these mine cars frequently operate on uphill and downhill sections. Unfortunately, during the downhill process, the mine cars generate a substantial amount of potential energy that is dissipated as inertial energy consumption during braking. Presently, this energy is primarily wasted in the form of heat, resulting in a notable electricity waste. Not only does this lead to the squandering of energy resources, but it also increases coal mining production costs. Currently, there is limited research on the optimization and improvement of underground mine cars conducted by scholars worldwide. Most studies have focused on track stability and mine car maintenance effectiveness. For instance, [PERSON] investigated the external causes of mine car transport damage, such as track damage and vehicle vibration. Using computer simulation technology, they simulated the effects of wheel-rail interaction forces on the pitching and vertical vibration of mine cars during underground transport. They identified internal factors influencing smooth operation and proposed a control strategy involving the installation of metal rubber [6]. Similarly, [PERSON] aimed to enhance the maintenance efficiency of underground mine cars and improve overall coal mining safety. Through the implementation of various management measures to enhance maintenance effectiveness, they analyzed maintenance methods for underground mine cars and how to promote maintenance efficiency [7]. Lastly, [PERSON] focused on ensuring the safe and smooth operation of underground electric locomotives in coal mines to avoid derailment. Drawing on practical experience, they discussed the design and application of automatic re-railers for underground mine cars, offering rational suggestions [8]. However, these existing studies mainly revolve around maintenance efficiency and track stability, resulting in only marginal improvements in the working efficiency of mine cars as they do not involve designing and optimizing their structure. In contrast, significant advancements have been made in energy recovery technologies for electric vehicles globally.