Actuator placement in structural control

The placement of force and torque actuators for structural control problems is considered. Objective functions are defined based on the elements of the actuator influence matrix, and optimization studies are conducted. The performance of the control is compared. The results indicate that a relatively even distribution of the actuators gives satisfactory results, whereas a close spacing of the actuators leads to excessive fuel and energy use. In all cases, several evenly spaced actuator distributions are found to be suitable. In addition, torque actuators are found to be less desirable than force actuators because they excite the higher modes to a greater degree. The efficiency of piecewise-continuous actuators is analyzed. Piecewise-continuous actuators are more realistic models than point actuators and they reduce stress levels. However, if their contact area is too large, they use more fuel.