SHAPE DETERMINATION AND ACTIVE CONTROL OF FLEXIBLE SPACE STRUCTURES

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Simulation and experimental studies have been done for the shape estimation and control of a simple structure. The problem of shape determination consists of estimating the deformed shape of a flexible structure from multi-point spatially distributed measurement of the structural deflections. The estimation and control designs are based on an infinite-dimensional approach that introduces the necessary finite element truncation and approximation after solving the estimation problem. The results of the numerical simulations showed the feasibility of the proposed estimation method.The optimal static control force is determined to give the minimum integrated restoration errors. The control design approach has been developed through the least squares estimation algorithm. It appears that the magnitude of the restoration errors largely depends on the number of available actuators and their locations.A prototype remote optical sensing device has been developed for the staic shape measurement. … More The main component of the optical sensing system consists of a laser scanner and retro-reflectors (corner cubes) mounted to the experiment structure. The measurement system determines the line of sight vector pointing the target corner cube. Since the laser beams scan all the corner cubes sequentially in each rotation cycle, the proposed method is fitted to the multi-point measurement in short time. The prototype measurement system has been tested for measuring the deflections of a simple beam.A tendon control system is under study for the vibration suppression of flexible space structures. A method of integrated structural and control design has proposed for preventing the reduced-order controller from being unstable due to spilover phenomina. This approach allows the designer to obtain an efficient and stable controller for the tendon control of highly flexible structures. The usefulness of the proposed design approach was validated through both numerical simulations and hardware experiments. Less