In the 1990s, the world's first parallel machine tool was born, and its structure is quite different from traditional machine tools. As shown in the parallel machine tool structure model, such machine tools have the advantages of simple structure, high rigidity and precision, fast response speed and good dynamic characteristics to obtain the end of the machine tool (depending on the specific structure). If any of the above conditions are not met, the test is in error, indicating that the leg length data file formed by the trajectory planning does not meet the requirements, and the trajectory planning needs to be performed again. 2 program design and implementation In the data verification program design, generally read the leg length data file formed after the trajectory planning, and then the data file is tested line by line until the end of the file according to the above requirements. If both meet the requirements, the display verification is correct and the program ends. Otherwise, it indicates that the leg length data file does not meet the requirements, and the trajectory planning needs to be performed again, and then the data is verified until the data meets the requirements. The whole data verification program flow is based on this, and the paper also issued a data security verification software module (moving platform and tool system) pose, and its operation speed is slow. In this paper, a preliminary rough safety test is carried out on the data formed after the trajectory planning, and the corresponding data verification security software is developed to ensure the safety of the machine tool to a certain extent. 1 Data inspection mechanism Before parallel machining, parallel machine tools need to be trajectory planning according to the geometric parameters of the parts to generate discretized tool position data files. Subsequently, each discrete point is inversely solved to obtain a discrete leg length data file. This data can be used by the control system of the parallel machine to control the machine action. Therefore, whether the leg length data file is correct will directly affect the correctness of the machine tool trajectory and the safety of the machine tool. Therefore, it is generally necessary to carry out processing after being verified. Under normal circumstances, at least the leg length data file has the following requirements: () the absolute value of the difference between the adjacent two rows of data should not exceed a certain range (depending on the accuracy requirements) () the expansion and contraction of any one axis is not It should exceed the telescopic range of the test bench to measure the performance parameters of the system. It is worth noting that since the servo control system itself has a dead zone (ie, an insensitive zone), the size of the dead zone must also be measured during the test. 2.3 The inner and outer loops of the servo control system are open loop. When the inner and outer loops of the servo control system are open loop, the whole system no longer has feedback signals, that is, the system does not have the characteristics of the servo control system. When the system inputs a fixed forward step signal U, the specific working process is as follows: (1) The servo valve opens the oil distribution valve in the servo valve under the action of current ic, and the small piston of the steering gear is extended forward. The integrated rocker arm mechanism opens the flat valve to extend the piston of the actuator forward; () because there is no feedback signal, the servo valve is always controlled by the forward current ic, and the flat valve is always in the forward open position, always giving Actuator pressure. When the piston of the actuator is in the maximum extended position, the system reaches equilibrium, and the small piston is also in the maximum extended position. If a negative step signal is input, the basic working principle is exactly the same, except that the final system balance position is: the small piston of the steering gear is in the reverse maximum position, and the piston of the actuator is also in the reverse maximum position. It can be seen from the above analysis that the typical characteristic of the fault is that the entire servo control system has no feedback control, as long as the control signal Ur is not, no matter how large, the small piston and the piston of the actuator are both in the positive direction (or vice To) the maximum position. 3 Conclusion Through the specific analysis of the typical fault of a single-channel servo control system of a four-duuge servo, the working principle and the essence of the fault are further understood, which lays a solid foundation for the intelligent fault diagnosis of this type of steering gear. By collecting actual troubleshooting data, summarizing, summarizing, analyzing typical fault instances, and statistically reporting fault symptoms and fault causes, it is possible to construct a fault diagnosis expert system for this type of four-duration servo. (Finish) Ningbo Sunhon International Co., Ltd. , https://www.scooterelectricadult.com