SPACE STRUCTURE CONTROL DESIGN BY VARIANCE ASSIGNMENT

The performance requirements of spacecraft missions are usually specified in terms of root-mean-squared (rms) values on both the input and output variables. The rms contribution of each input or output in the overall system performance metric is called the 'input' or 'output' cost. A technique is derived that allows a linear controller to assign each of the multi-input or output costs. The procedure is illustrated by the design and shape control for NASA's 64-m Hoop-Column Antenna subject to power-limited actuators. By assigning only the output costs rather than the input costs, the procedure serves to determine the power required of the actuators (required input costs) to achieve the mission requirements (specified output costs). This determination of actuator sizing (and location) for the control of flexible structures is an important feature of the method.