Multi-point Coordinated Static Loading Control System Based On LabVIEW

Structural static test is an important means of detection in the aerospace,automotive,ship and other fields.It can obtain the strain distribution,bearing capacity and stability of the structure under static loading,so as to reasonably evaluate the durability of the structure.For the structure with complex shapes and stress state,static test is even more important.In the case of complex forces,a single point of tension or compression test can not really simulate the actual conditions of the component,so it is necessary to study the multi-point loading control system.The development of the system mainly uses the virtual instrument technology.The data acquisition and control procedures are achieved by the development software LabVIEW and the electro-hydraulic servo actuator is controlled by the hardware platform of the virtual instrument.The control algorithm uses the PID control algorithm which is widely used in the control field.The control strategy uses the segmented control method.The control can be achieved by three steps: first calculate the loading speed of the current cycle,which divided by the control cycle to get the increment of the target location value.For each control cycle,the target location value equals the sum of previous control cycle target value and the incremental value calculated in this cycle.Finally the target value and the current position value input PID controller,which outputs control signal by calculating the target value and the current position value to complete a control.Through the cycle,repeat the above action to complete the entire control process.In addition,the real-time performance of the system is studied.The LabVIEW RT module extends the LabVIEW program execution environment,achieves the connection between upper and lower machine,and makes the real-time operating system as the code execution environment to improve the certainty of the system.The use of virtual instrument technology,greatly improves the efficiency of system development.The multi-point load control system based on the virtual instrument hardware and software system,has a friendly human-computer interaction interface,strong scalability and maintainability.After debugging operation,the system can meet the requirement at real-time performance and effectively carry out the load control.