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.