# Research on Fractional-Order Control of Anchor Drilling Machine Optimized by Intelligent Algorithms
## 2 Drilling and Bolting Robot Rig Structure and Workflow  
Currently, the common support process for anchor drilling rigs in China includes steps such as drilling, unloading drill rods, installing anchoring agents, installing anchor bolts, mixing anchoring agents, and pre-tensioning. To improve operational automation, this paper designs a new type of anchor drilling rig that integrates an anchor bolt magazine with automated support operations. It utilizes extended hollow self-drilling anchor bolts combined with liquid anchoring agents to achieve rapid support and simplify the construction process. As shown in Figure 1, the rig consists of a robotic arm, anchor bolt magazine, power head, anchor bolt clamping mechanism, and support structure (including top plate, bottom plate, and side plates). The anchor bolt magazine is located between the top and bottom plates and is divided into two layers, with five storage positions per layer. The interlayer movement of anchor bolts is achieved via a sprocket and chain mechanism, and the bolts are fixed by spring-loaded cassettes. The robotic arm moves along guiding columns and can extend vertically to perform grabbing actions, moving the anchor bolt to the power head for installation. The drilling mechanism is driven vertically by a chain and hydraulic cylinder, while the power head uses an externally meshed gear motor with hollow grouting capabilities. The top is equipped with an anchor bolt clamping mechanism for fixing the anchor bolt.  
As shown in Figure 2, the extended hollow self-drilling anchor consists of a hollow shaft with a drill bit at the upper end and a hollow anchor bolt at the lower end, equipped with a connector and fastening bolts. This design, in conjunction with the drilling rig, enables integrated drilling and grouting operations. The support process is as follows: after aligning the drilling rig with the target support area of the roadway, the robotic arm retrieves the upper self-drilling anchor and installs it onto the power head. Once the anchor reaches the predetermined depth, the clamping mechanism secures the anchor, allowing the power head to disengage. The robotic arm then grabs the lower anchor, connects it, and  
Figure 1: Structure of the intelligent drilling rig.  
continues drilling. Finally, the anchoring agent is injected through the hollow anchor bolt; after it solidifies, the anchor is clamped, and the nut is tightened to complete the support.  
Coupled with the proposed drilling-grouting equipment, a staged bolting strategy is implemented for high in situ stress, soft-rock conditions. The initial rapid-closure phase employs short self-drilling anchors to arrest early convergence, after which additional hollow anchor sections are joined at predetermined depths and times--selected on the basis of real-time deformation monitoring--to form a long, continuous bolt. This phased sequence limits bolt-rock relative displacement during installation, reduces axial stress concentration, and prevents the premature tensile failure occasionally encountered in one-step long bolt placement, thereby enhancing the durability and reliability of the overall support system.  
Although the intelligent drilling rig improves operational efficiency through its structural design and workflow, the limitations of traditional PID control methods remain significant, particularly in maintaining accuracy and response speed under complex working conditions. Consequently, the adoption of more flexible and robust controllers becomes critically important.