## 1 Introduction  
Robots were originally mainly used in industrial production such as for automobiles and household appliances. Germany, Japan, and other countries have actively developed industrial robot technology, which brings them higher efficiency, lower labor force requirements, and a strong economy. In the 21 st century, robotics has thrived in the rapid development of computers and control technology. Moreover, with the advancement of society, robots are not merely used to serve industrial production but also to handle more complex and diverse tasks. Therefore, with the advantage of strong adaptation to the environment, more and more mobile robots have been used in disaster relief, dangerous goods transportation, and other dangerous or difficult operations. In the 1980s, researchers proposed the application of mobile robots in disaster relief. However, such mobile robots were not invented until 1995. In 2001, rescue robots were used in the United States' \"9/11\" incident, attracting the attention of many researchers. Although the robots had performed well in this rescue operation, there were also many problems, such as instability, inferior waterproofing, limited vision, and so on [1]. After this incident, the scientific research institutions in the United States paid more attention to rescue robot research. Of these, iRobot's Packbot and the Warrior series of tracked rescue robots have been well used [2]. For example, the latter can be operated remotely; it is about 90 cm long, 80 cm wide, and 53 cm high and its total mass is 250 kg. Equipped with a mechanical arm, it can enter areas that are difficult to reach for human beings. In addition, unmanned aerial robots are also widely used in disaster relief. In addition to the military and commercial applications of drones, they are efficient in supporting emergency management [3]. The cameras and sensors carried by drones can also facilitate access to the environmental map of the disaster relief site, which can provide assistance in large area rescues [4]. The robots can adapt to the rescue site environment and can enable communication with the trapped casualties in real time, greatly improving the safety of personnel and the efficiency of rescue. This reduces casualties and secondary damage in the disaster area [5,6]. Though the research and development of mobile robots started relatively late in China, more and more universities and scientific research institutions have started to pay attention to this area. In recent years, China's research on mobile robots has also achieved some notable results. For example, in 2006, the China University of Mining and Technology developed a mobile robot, CUMT-1, for coal mine rescues. The robot, equipped with a camera, temperature sensor, gas sensor, and real-time voice communication system, could realize real-time monitoring for underground environments [7]. In 2008, Xidian University developed a six-track mobile robot with front and rear rocker arms [8]. The double rocker arms provided the mobile robot with a better obstacle-crossing ability, making it better suited for complex terrain. The University of Science and Technology of China developed a wheel-legged hybrid mobile robot called HyTR-I [9,10]. The wheels and legs of the robot are independent, and its wheeled motion mechanism can work alone on flat ground allowing it to move quickly. The Harbin Institute of Technology also developed a wheel-legged hybrid mobile robot called HIT-HYBTOR [11, 12, 13]. The wheels are installed at the ends of the legs, and the wheels at each end are independently driven. In recent years, clean energy such as photovoltaic power generation, wind power generation, and hydropower generation have developed rapidly. However, due to site and cost constraints, these clean energy sources have not been widely adopted. Therefore, the world is currently dominated by thermal power generation. In 2016, China's thermal power generation was 4,288.6 billion kWh, of which coal-fired power generation accounted for 91.1% [14].