Abstract: A control mechanism for a simulator or stabilized platform comprising constant force spring device for supporting the weight of the platform and a plurality of impulsive force generating devices preferably in the form of electromagnetic linear rams although a rotary linkage driven by an electric motor would also work. The mechanism provides an agile arrangement at relatively low cost.

Abstract: An electromagnetic piston and cylinder device for producing linear motion has a cylinder provided with a plurality of magnetic devices along its length for producing radial magnetic fields of alternative polarity. The piston is also provided with at least one magnetic member producing a further radial field and there is control means for carrying piston radial field or the cylinder radial fields to alternate whereby to cause relative movement between the piston and cylinder. The piston and cylinder device is preferably sealed but connected to a fluid reservoir whereby the device operates as a combined spring and actuator.

Abstract: A simulator mechanism capable of operating in three degrees of freedom is described comprising a base (14) having a fixed plane, a simulator plane (12) and three independent extendible actuators (16, 18 and 20) capable of changing the simulator operating plane, three actuators (16, 18 and 20) being pivotally coupled with universal freedom at or around, a substantially single point (C), each actuator (16, 18 and 20) being pivotally coupled to points (J, E, and F) on the simulator plane (12), each point (J, E and F) being spaced apart from the other actuator coupling points on the same plane A restrainer means is provided to prevent motion in the yaw, surge and sway axes.

Abstract: An identification system comprises an interrogator which transmits an interrogation signal to a plurality of transponders, each of which is arranged automatically to reply by means of a first coded identification signal stored in the transponder and modulated onto a carrier wave transmitted by the transponder. The interrogator receives and checks the reply signal. In the event of there being a plurality of transponders within range and broadcasting reply signals simultaneously, the interrogator receives corrupted reply signals. The interrogator therefore retransmits the reply signals to the transponders and each transponder checks the retransmitted reply signal with its first coded identification signal. In the event of correspondence the transponder discontinues transmission and in the event of non-correspondence the transponder continues transmission.