Semiactive control of civil engineering structures

Structural control can be used to mitigate dynamic structural response and prevent structures from reaching their limit states. Typical active vibration systems utilize large electric motors, and expensive hydraulic pumping equipment to provide force inputs to a structure during a dynamic event. This paper explores the effectiveness of low power, inexpensive semiactive control hardware to provide vibration attenuation, for structures. While there are a number of electro-mechanical devices that might provide semiactive (SA) control forces, our investigation analyzes the use of an automatically adjustable hydraulic actuator. The variation in damping characteristics is accomplished by using variable orificing. While semiactive hydraulic actuators are a relatively cheap means of providing smart damping for a structure, the development of effective closed loop control strategies for these devices is not a completely resolved issue. We developed a dynamic model of a semiactive actuator. A heuristic control approach is used to demonstrate the effectiveness of the proposed design. Experimental results are also discussed.