## 2 Analysis of the Principles of the Temporary Support Robot  
### Overall Scheme of the Temporary Support System  
The 'excavation-backfill-retention' system of the section coal pillar is responsible for completing the integrated 'excavation-backfill-retention' mining of the section coal pillar, and its scheme is shown in Figure 1. The 'excavation-backfill-retention' system of the section coal pillar includes four subsystems: section coal pillar excavation and mining system, waste-filling system, transportation system, and ventilation dust removal system. Among them, the section coal pillar excavation and mining system includes a cutting robot [15], a scraper conveyor [16], a temporary support system, and platforms with drilling and anchoring equipment [17; 18], which are responsible for working face excavation and support. The waste-filling system completes the middle waste rock filling and the natural roadway formation on the left and right sides through the waste-filling robot. The transportation system can timely and smoothly load and transport the cut coal rock to the main transport system and transport the materials used for waste-filling to the designated position according to the requirements so as to provide an effective and reliable guarantee for the continuous work of the entire face section coal pillar excavation and mining and waste-filling. The loader and belt conveyor are essential in the mining face and belong to the transportation system. The loader transfers coal from the mining area to the main belt conveyor or storage, providing flexibility and improving efficiency. The belt conveyor enables continuous, stable transport of coal over long distances, reducing manual labor and enhancing safety. Together, they form the backbone of modern coal mining operations. The ventilation dust removal system is mainly responsible for supplying fresh air to the underground, diluting and discharging harmful gases and dust, providing a safe and healthy working environment for miners, preventing gas explosions and dust hazards, and ensuring the safe production of the mine. Each subsystem operates in parallel and collaboratively, which can realize the safety, high efficiency, and intelligence of the excavation and waste-filling process of the section coal pillar extraction system.  
The temporary support system is a part of the 'excavation-backfill-retention' system of section coal pillar extraction, mainly including the TSR and the end support robot. Considering that the end support robot needs to straddle the scraper conveyor and has a unique structure, this paper only focuses on the TSR. The face of the section coal pillar excavation and mining working face is divided into several sections. The cutting robot cuts a section from left to right for each section. Each section contains a group of two TSRs and a platform with drilling and anchoring equipment (as shown in Figure 1). The working process of each TSR group is as follows: two TSRs wait in the stable support situation for the cutting robot to complete the cutting action of the coal wall in the section. When the cutting work of the section is completed, and the cutting robot is traversed to the next section, the group of TSRs, according to the requirements of the scraper conveyor pushing in the comprehensive working face, and coordinates with the scraper conveyor pushing cylinder of the left TSR by controlling the extension of its scraper conveyor pushing cylinder to form an S-bend in the scraper conveyor pan. When the scraper conveyor pushing cylinder of the group of TSRs reaches the maximum stroke, the group of TSRs drives forward under pressure for a section from left to right in a push-pull sequence. When the group of TSRs completes the driving under pressure action, they jointly pull the platform with drilling and anchoring equipment located in the section forward for a section. All groups of TSRs in the temporary support system complete all the actions from left to right and then enter the next cycle.