Active suspension design for a Large Space Structure ground test facility

For ground testing of controlled flexible space structures an active suspension design is proposed to eliminate dynamic reaction forces from the suspension cables. Thus, supporting only the constant weight forces at the hinges, an approximative dynamic g-compensation is achieved. The principle suspension actuator design is based upon apassive spring bias weight support, augmented by an electrodynamic actuator which eliminates the spring restraint forces about equilibrium. Moving mass reaction forces are compensated for by feedback of a hinge mounted dynamic force sensor output. The salient feature of the voice-coil type actuator is the on- line compensation of the inherent non-linear force-displacement characteristic by a high-speed signal processor. Due to the simple mechanical design the actuator can be easily adapted with respect to range and output force level. Moreover the overall cost is considerably reduced by elimination of complex mechanical adjustment and calibration procedures and by utilization of respective software control instead.