## 1 Introduction
### Intelligent Control  
Regarding control, [PERSON] et al. [23] studied a novel photovoltaic panel cleaning system using FPGA and infrared sensors to identify the cleaning path and verified the effectiveness of the system through experiments. The power generation efficiency of the cleaned photovoltaic panel was increased by 35%. [PERSON] et al. [24] developed an automated monitoring and cleaning system for photovoltaic panel surfaces. The developed system is capable of evaluating the degree of dust accumulation by monitoring the color of the photovoltaic panel surface so that the robot can be driven to clean the dust accumulation area. [PERSON] et al. [25] developed a speed control strategy for the photovoltaic panel cleaning robot to increase the corresponding rapidity and stability. It was ensured that the swing arm can move up and down along the photovoltaic panel surface. [PERSON] et al. [26] adopted UAV to inspect and maintain photovoltaic power plants and proposed a strategy of segmentation and visual servo tracking of photovoltaic modules to monitor the dust accumulation on photovoltaic panels and elevate the intelligence level of photovoltaic power plants. [PERSON] et al. [27] developed a control system for unmanned aerial vehicles (UAVs) to clean photovoltaic panels which employed downward thrust during cruise to remove the dust on the panels. The effectiveness of the system was verified experimentally. [PERSON] et al. [28] proposed a self-cleaning photovoltaic sliding system which was validated experimentally to increase the efficiency of photovoltaic power generation and protect it from damage from the natural environment. With the continuous development of photovoltaic panel cleaning technology, the guide rail and panel self-cleaning technology cannot conform to the cleaning needs, and the cost is too high. The novel self-propelled photovoltaic panel cleaning robot will be more extensively employed. Due to the complexity of the road environment of photovoltaic power plants, the design of their vehicle chassis requires suspension and drive systems. The distance limitation of the photovoltaic panel array space enables the vehicle to have a steering system. As the end effector, the cleaning device needs a degree of freedom to control its working attitude. In order to place the cleaning device on the photovoltaic module, at least two degrees of freedom are needed to control at the plane level. In the non-working posture, the cleaning device needs to be retracted, and a rotational degree of freedom is needed to ensure its spatial activity; therefore, the boom mechanism adopts a four-degree-of-freedom series structure. Based on the requirements of cleaning the dust particles on the photovoltaic panel surface, this study proposes a novel self-propelled photovoltaic panel cleaning robot structure, establishes the kinematics model of the boom system, uses the optimized sparrow algorithm combined with the seventh order non-uniform B-spline curve to optimize the trajectory time of the boom, reduces the trajectory time of the boom, and improves the boom response speed and cleaning efficiency. Thus, the main contributions of this study can be summarized as follows:  
1. A novel self-propelled hydraulic driven photovoltaic panel cleaning robot was proposed in accordance with the environmental factors for photovoltaic power plants and the arrangement of photovoltaic panels. Tracked wheel drive was adopted to increase the contact surface with the ground and improve road adaptability, capable of completing walking functions under harsh environmental conditions. The three-point independent suspension design enabled the robot to level automatically during walking so that the stability of the upper frame mechanism during walking could be ensured. Independent rear-wheel steering is capable of increasing the turning radius of the robot, thus making its steering more flexible.