The Measurement And Control System Of Earthquake Simulation Test Bench With 6 Degrees Of Freedom Based On The EtherCAT Bus

The earthquake simulation test bench simulates intense jitter,shaking and other forms of movement of the earth's crust based on the seismic wave motion mechanism.It is one of important experimental equipments that studies the design of earthquake-resistant structures and improves people's escaping skills when earthquake occurred.Above all,this paper studies the kinematics,position,inverse solution and working space of the seismic simulation test bed based on the theoretical foundations of the parallel mechanism.Firstly,a method of trajectory planning for earthquake simulation test bench is proposed based on the similarity relationship between joints space and work space among the earthquake simulation test bench and the manual simulation platform.The relationship is derived through calculating the inverse position model.Secondly,the driven cylinder's equation of motion of 6-Do F earthquake simulation test bench is obtained by the similarity method.The manual simulation platform motion process is acquired as well.Moreover,the similarity relationship between the characteristic curves of the joint and working spaces for the manual and earthquake simulation platforms is also verified by establishing corresponding models in ADAMS.In the next place,the research of the control system for the 6-DoF earthquake simulation platform,which plays a key role in our study,is also conducted in this paper.The PC together with the Beckhoff motion controller based on EtherCAT is adopted as the control architecture to establish an open and scalable control and measurement system.The corresponding software in the host and slave computers is programmed in visual studio and TwinCAT.Finally,based on the control system of 6-DoF earthquake simulation test bench,control functions related experiments are carried out,such as the ADS communications between PC and PLC,the reliability test of the platform protection system,and the simultaneous coupling control and acquisition experiments with vibration seismic waves for multicylinder.The results show that the earthquake simulation test bench has advantages of smooth operation,low noise,high reliability and high flexibility,and verifies the feasibility and applicability of this test bench in simulating seismic motion and reproducing earthquake scene.