Development of active seismic base isolation system with mechanical controller (Proposal of the concept, demonstration experiment and parameter study)

Abstract

Many active seismic isolation systems and active seismic vibration control systems have now being produced to reduce earthquake damage as much as possible by suffering from recent frequent huge earthquakes. Existing active vibration isolation device systems are controlled by computers. They are driven by the commands given to actuator. Those commands are calculated as control inputs using movements of earthquake, building and actuator monitored with electric sensors. These systems have such advantage that the control characteristics can be changed easily by modifying the program algorithm. However, these electronic systems have some points of weakness. Computer itself and software should be updated to the latest model every several years. Small troubles like electrical disconnection, or electronic component parts aging deterioration or malfunction could cause total functional failure. In case the worst case takes place, it might go out of control. To solve this problem replacement of computer control instruction with highly reliable machinery mechanism using no electronic component is proposed in this study. The method of replacement of electronic control with machinery mechanism is as follows. Through link mechanism relative movement displacement between earthquake and building seismic vibration is transmitted to spool as command signal and direction of hydraulic pressure is changed to activate for seismic control