Demonstration of a novel smart structural system for pointing control of trusses

We designed and developed a novel smart structural system for pointing control of large-scale support structures, such as trusses. The system consists of a pointing control mechanism, an internal displacement-sensor, and a controller. Remarkable points of our system are (1) artificial thermal expansion of truss members is utilized as linear actuators, (2) elastic hinges are applied instead of boll joints, and (3) the internal displacement-sensor which does not need external jigs and has high measuring accuracy is applied. In this paper, we conducted the feasibility study and the experimental demonstration. As a result of the feasibility study, the proposed pointing control mechanism can produce several hundred arcseconds of the rotational displacements within three minutes, therefore it has potential for using in practical operations. As a result of the experimental demonstration, we confirmed that the hysteresis of the pointing control mechanism can be kept sufficiently small due to the absence of the sliding parts, and has high control accuracy and followability (the error RMS value for a circle of the radius of 500 μm is 3.6 %).