## 1 Introduction  
High-pressure subsea pipelines are crucial for oil and gas transportation. With the increase in service time, pipeline failure accidents have frequently occurred due to corrosion [1; 2]. At present, the plugging technology of opening holes is relatively mature for pipeline maintenance. However, this technology requires making holes and much operation time [3], which can cause secondary damage to the pipeline and reduce the pipeline life. The location of opening holes is easily affected by the terrain, and the plugging distance and oil discharge can increase. Moreover, the opening holes method consumes a huge amount of human resources, and the high cost is beneficial for large-scale pipeline maintenance operations. In recent years, subsea pipeline maintenance technology based on pipeline intelligent plugging robots (PIPR) has become an effective way for high-pressure intelligent plugging. The PIPR does not require reducing pipeline pressure and opening holes, which can ensure pipeline reliability and transportation efficiency. During the high-pressureplugging operation, the coupling vibration between the flow field and PIPR aggravates the deterioration damage of PIPR [4]. Therefore, it is of great significance to study the vibration characteristics and vortex-induced vibration suppression methods of PIPR under turbulent flow field excitation, thereby improving the plugging stability and preventing pipeline failure accidents. Pipeline intelligent isolation plugging technology is widely used for the maintenance operation of high-pressure subsea pipelines. PIPR is a core part of the pipeline plugging operation. Plugging Specialists International (PSI) designed a high-pressure PIPR; the maximum plugging pressure can reach 25 MPa. The fixed-point plugging technology under the remote control of the pressure pipeline was developed by American T. D. Williamson (TDW) company, and the high-pressure plugging operation was completed under 35 MPa [5]. Oil States Hydro Tech is a company specializing in plugging and repairing subsea oil and gas pipelines [6]. This company can perform plugging operations at 1651 m below sea level. [PERSON] et al. [7] proposed a spherical PIPR with trajectory control algorithms for adjusting the rotation angle and vertical displacement. [PERSON] et al. [8] designed a novel PIPR with airbag plugging, which consisted of a drive unit, a connection unit, and a blocking unit. [PERSON] et al. [9] developed an energy-saving PIPR, where an impeller was introduced for energy conservation, and the fuzzy proportional integral derivative (PID) controller was used for velocity-tracking control. [PERSON] et al. [10] innovatively designed a PIPR with an autonomous plugging hydraulic control system, and the changes in hydraulic cylinder parameters and axial displacement of rubber cylinders were studied. [PERSON] et al. [11] proposed a modular composite-driven PIPR; the dynamic model and nonlinear controller were established for motion adjustment under deformation excitation. [PERSON] et al. [12] used neural network methods to establish the relationship between PIPR's slip parameters, and the functional relationship was optimized to obtain the optimal structural parameters for the maximum slip anchoring force. [PERSON] et al. [13] developed two differential equations to obtain in-pipe transient compressible fluid properties. The differential motion equation of the PIPR's speed regulation module was solved to obtain the speed and position. [PERSON] et al. [14] designed a speed control system with a brake unit for PIPR, which could achieve active speed control for PIPR. [PERSON] et al. [15] established a dynamic analytical model to describe the mechanical behaviors of PIPR's speed regulation module and proposed a quantitative assessment method. The plugging-induced vibration of the PIPR is the result of a multi-physics field. The vibration produced by external fluid pulsation is called external-induced excitation [16].