Output Feedback Sliding Mode Control for Bending and Torsional Vibration Control of 6-story Flexible Structure

We discuss bending and torsional vibration control of a 6-story flexible structure. In the case in which the vibration control of high-rise buildings is considered, it is necessary to design a controller which shows good control performances, and which is simply designed so that personnel expenses are reduced. To this end, we have applied a sliding mode control theory, which is one of nonlinear robust control theories. By adopting this theory, the control system may easily be designed in a very short time. However, since it is in few cases that each story is provided with a sensor, this controller is generally designed as a state feedback controller, and is difficult to realize a state feedback. Therefore, the sliding mode controller should be designed as an output feedback controller. Accordingly, we have designed two output feedback sliding mode controllers by using minimum error excitation method. The first controller is constructed with only nonlinear control inputs, and the second controller is constructed with both linear and nonlinear inputs. We have investigated their performances by numerical simulations and experiments. In this paper, design methods, control system design constraints, and characteristics in flexible structural control will be explained.