## 2 Principle of Servo Precision Press and Transmission Mechanism  
The explosion proof valve is a key component for the safe pressure relief of new energy power batteries. Its quality consistency and stability directly determine the safety of new energy vehicles and batteries because the burst value of the explosion-proof valve must be controlled within a certain tolerance range to ensure stable and reliable burst pressure, such as 0.8-0.9 Mpa. The stability and consistency of the blasting value depend on the tolerance value of the stamping residual thickness of the explosion-proof valve plate. The smaller the tolerance value, the higher the repeatability accuracy of the bottom dead center of the machine tool. The stamping accuracy of the explosion-proof valve is generally required to be within 0.01 mm. The precision of conventional press machines cannot meet these process requirements. For the precision extrusion and stretching compound stamping process of battery shells and covers with explosion-proof marks mentioned above, this paper proposes a new type of transmission mechanism. Figure 1 shows the schematic diagram of the transmission mechanism of the servo high-precision press, including 1--guide rail, 2--slider, 3--disk connecting rod, and 4--crank. Its working principle is as follows: when the crankshaft 4 rotates, it drives the disk connecting rod 3 to rotate in the slider 2, and when the disk connecting rod 3 rotates, it drives the slider 2 to move up and down in a reciprocating straight line along the slider motion center line. Under the premise of satisfying the geometric parameter relationship required for motion, different slider motion curves can be obtained according to different parameter designs, that is, different slider process motion characteristics. By reasonably changing the corresponding geometric parameters, the slider can achieve the process characteristics of slow stamping and pressure holding. An intelligent servo press is mainly composed of a mechanical system, servo drive system, control system, and feedback system, and can control the slider stroke through a direct drive crank connecting rod mechanism. Figure 2 shows the high-precision servo press developed in this project, which consists of servo motor drive system and disk connecting rod mechanism. The schematic diagram of the control system scheme is shown in Figure 3. The system adopts an MCX314 motion control card, PCL-818 control card, and other components to form a feedback control system. Figure 1: Schematic diagram of a new transmission mechanism; 1—guide rail, 2—slider, 3—disk connecting rod, 4—crank. As shown in Figure 4, from the perspective of the control system, the entire control system is a control system that tracks the position of the slider. The trajectory of the slider is usually determined by different trajectory requirements of the stamping process, which is the quantity that needs to be tracked. To truly achieve accurate positioning of the slider position, closed-loop control of the slider position is necessary. The so-called closed-loop control system refers to a system where the output (controlled quantity) of the controlled object is fed back to affect the output of the controller, forming one or more closed loops. A closed-loop control system has positive feedback and negative feedback. If the polarity of the signal given by the system is opposite to that of the feedback signal, it is called negative feedback. If the polarity is the same, it is called positive feedback [9; 10]. Generally, closed-loop control systems use negative feedback, also known as negative feedback control systems. In the position control of the servo press in this article, the controlled variable is obviously the position signal of the slider. At the same time, we use the actual position of the slider measured by the grating sensor as the feedback signal of the controlled variable, thus forming a closed-loop control system.