Variable damping device for seismic response controlled structure

In a variable damping device for a seismic response controlled structure, said structure having a frame main body and a variable stiffness elements to brace said frame main body, said variable damping device having a piston slidably mounted in

• a hydraulic cylinder, said piston being adapted to reciprocate therein, said cylinder being connected to said frame main body or to one of the variable stiffness elements;
• said piston being connected to one of said variable stiffness elements or to said frame main body;
• hydraulic chambers in said hydraulic cylinder being provided on opposite sides of said piston;
• a pair of outflow preventing check valves for preventing the outflow of hydraulic oil from said both hydraulic chambers;
• a pair of inflow preventing check valves for preventing the inflow of the hydraulic oil into said both hydraulic chambers;
• an inflow passage for connecting said both outflow preventing check valves with each other;
• an outflow passage for connecting said both inflow preventing check valves with each other;
• and
• a flow regulating valve provided on the connection position between said inflow passage and said outflow passage;
• the improvement comprising:
• control means for controlling the opening of said flow regulating valve, said control means including
• damping force judging means for judging a damping force to be generated by said device on the basis of the responses of said structure by the vibrational and external force and for generating the value corresponding to said damping force as a generated damping force command value S1;
• valve opening detection means for detecting the opening of said flow regulating valve and for generating the value corresponding to said opening as a detected valve opening value S5;
• pressure detection means for detecting the hydraulic pressure of said both hydraulic chambers and for the value corresponding to said hydraulic pressure as detected hydraulic pressure values S6 and S7, respectively;
• a subtraction circuit for generating the value corresponding to the difference between said both detected hydraulic pressure values S6 and S7 as a differential pressure value S8;
• command value judging circuit for judging the sign of said generated damping force command value S1 and that of said differential pressure value S8 and for generating the value corresponding to said generated damping force command value S1 as a pressure command value S2 when said signs are the same, while generating the value corresponding to the value where the opening of said flow regulating valve is fully opened as a valve opening command value S3 when said signs are different;
• a pressure controller circuit for feeding back said differential pressure value S8 with respect to said pressure command value S2 to make a correction and for generating the valve opening command value S3 corresponding to the correction value;
• a valve opening condition circuit for feeding back said detected valve opening value S5 with respect to said valve opening command value S4 to make a correction and for generating the valve opening control command value S4 corresponding to the correction value;
• and
• operating means for actuating said flow regulating valve on the basis of said valve opening control command value S4.

In a variable damping device for a seismic response controlled structure having a frame and variable stiffness members, including a hydraulic cylinder with opposite end portions;

• a piston slidably placed in said hydraulic cylinder to form first and second hydraulic chambers on opposite sides of said piston;
• said hydraulic cylinder being connected to said frame or to one of the variable stiffness members;
• said piston being connected to one of said variable stiffness members or to said frame;
• a hydraulic flow passage for interconnecting said first and second hydraulic chambers;
• and a flow regulating valve provided in association with said hydraulic flow passage, the improvement comprising:
• control means for controlling the functioning of said flow regulating valve, said control means including seismic force measuring means for determining the magnitude of the responsive damping force to be applied by said damping device to said structure, said seismic force measuring means including means to generating a first signal representing said damping force, flow regulating valve opening detection means for detecting the opening of said flow regulating valve and for generating a second signal proportionate to said flow regulating valve opening;
• pressure detection means for detecting the hydraulic pressures of said first and second hydraulic chambers and for generating third and fourth signals proportionate to said detected hydraulic pressures;
• a subtraction circuit for generating a fifth signal representing the difference between said third and fourth signals;
• circuit means for determining the sign of said first generated signal and that of said fifth signal and for transmitting said first signal as a valve controlling pressure command when the signs of said first and fifth signals are the same, and for transmitting a sixth signal as a valve opening command when the signs of said first and fifth signal are opposed;
• a pressure controller circuit for feeding back said differential pressure fifth signal responsive to said second signal pressure command to adjust and to transmit said sixth signal valve opening command;
• a valve opening controller circuit for generating and feeding back a detected valve opening seventh signal responsive to said sixth signal for correcting and for generating a valve opening control command eighth signal;
• and
• means for actuating said flow regulating valve responsive to said eighth signal.