DEVELOPMENT OF HIGH FLOW, HIGH PERFORMANCE HYDRAULIC SERVO VALVES AND CONTROL METHODOLOGIES IN SUPPORT OF FUTURE SUPER LARGE SCALE SHAKING TABLE FACILITIES

摘要

The earthquake engineering research community has had to wrestle with the uncertainties created by shaking table (dynamic) experiments conducted on less than full scale models due to limitations in shaking table size and payload capacity. The potential value of being able to study the failure mechanisms of full size structures under realistic earthquake motions in a controlled laboratory setting has long been recognized. A shake table having this capability would have a surface area of approximately 15x20 meter. Accelerating a table of such size with a specimen greater than 1000 ton would require a large number of high force hydraulic actuators with precise servovalve control. MTS Systems Corporation has completed development of a new class of high flow, high performance hydraulic servovalves to support super large scale shaking table facilities. This paper will describe the design of a new 4 stage hydraulic servovalve and present performance data from bench top flow testing conducted on a small production quantity of these valves. The digital control methods utilized for real time control of a 6x6 meter prototype table driven with (8) 500 ton force hydraulic actuators will also be presented with table performance data demonstrating the effectiveness of these methods. The data contained in this paper support the conclusion that high fidelity seismic simulations using full scale structures is now possible. The previous limitation of precise control of large hydraulic actuators in a dynamic mode has been eliminated through advanced servovalve design and application of digital control methodologies.