## 4 Simulation Result Analysis  
Figure 8a shows the required closing time for the elastic pressure-holding controller to close at different azimuth angles under the influence of gravity and the flip angle curve of the valve cover during the entire closing process, as calculated by numerical simulation with ADAMS software. According to the continuous flow of position response that ADAMS/Solver can provide, the time it takes to use its sensor to capture the angular displacement of the bonnet up to 90\({}^{\circ}\) is the closing time. Summarizing the closing time law at different azimuth angles determined that, when the horizontal core operation was performed and the hinge of the pressure-holding controller was at the lowest position, the spring bonnet overcame the bonnet's own gravity to work the most, the closing time was the longest, and the bonnet was closed. The shortest and longest times were 0.077 and 0.158 s, respectively. In Figure 8b, simulation models at three typical azimuth angles are shown, located at points A, B, and C in Figure 8a. Figure 7: Mechanism model of trigger mechanism under ADAMS/View. When the viscous resistance encountered by the sleeve is as described in Section 3.1, the corer uses several springs with different stiffness levels in the range of 0.075-0.11 N/mm to the same initial elastic force at 4 azimuth angles from 0 to 90 degrees. The required time to drive the sleeve to rebound is shown in Figure 9. The figure shows that the smaller the spring stiffness is, the longer the rebound time because spring force decreases with increasing rebound distance, and stiffness likewise decreases. The larger the spring force is, the greater the elastic potential energy and the kinetic energy after dissipation are. To ensure that the sleeve falls back after the valve cover is closed during the coring operation at various angles, it is necessary to select a stiffness value whose rebound time is greater than 0.158 s at each inclination angle, so the selected stiffness was 0.08 N/mm. Figure 8: (**a**) Distribution law of valve cover closing time for pressure-holding controller under different azimuth deflection angles. (**b**) Closing simulation model of pressure-holding controller at three typical azimuth angles of A, B, and C (Figure 6a). The plane motion trajectory of points A, B, and C on the contact pin member in Figure 4 is shown in Figure 10, where point A is located at the center of rotation, and its displacement was pulling along the core barrel. Displacement in the direction of the \(x\) axis was extremely small and could be ignored. The motion trajectories of the centers of contact arc surfaces B and C showed that the mutual intrusion between contact surfaces was within a reasonable range. Additionally, the corresponding ADAMS simulation showed that there was no serious jumping phenomenon in the trajectory curve [37], which could be used as a basis for judging the reasonableness of the simulation, that is,  
\[r_{i}-d_{max}\leq d_{i}\leq r_{i}\,i=1,2 \tag{19}\]  
where \(d_{i}\) is the real-time normal distance between points B and C from the contact surface during the movement of the component, and \(r_{i}\) is the curvature radius of the two contact surfaces. As shown in Figure 11, when angle \(\gamma\) of the stylus, flip angle \(\theta\) of the stylus, and simulation parameters are the same, when three different angle combination schemes are used for simulation, the trigger mechanism can complete the action from locking to unlocking, but the flipping angular velocity of the stylus and contact positive pressure \(F_{N1}\) and \(F_{N2}\) had different trends with time. scheme 2 took the shortest time to complete the action, so its action performance was better. When different schemes are adopted, stable  
Figure 10: Motion trajectory of typical points A, B, and C on control pin mechanism. Figure 9: Springback time law for different stiffness levels corresponding to sleeves under several inclination angles.