The University of British Columbia

Rudolf J Seethaler

Ian Yellowley

Gordon P McTaggart-Cowan

Ramin Ardekani

Bradley Reinholz

Devin Reinholz

Ashish Singh

There is a solenoid including a stator having a first stator tooth and a second stator tooth, and an armature having a first armature tooth and a second armature tooth. The armature is moveable with respect to the stator over a predetermined stroke. A coil is associated with one of the stator and the armature for conducting an electric current and generating magnetic flux that is guided by the stator and the armature. The stator or the armature acts as a ferromagnetic core for the coil. There is a first air-gap between the first stator tooth and the first armature tooth that has a first length, and a second air-gap between the second stator tooth and the second armature tooth that has a second length. The first and second lengths are constant to within a predetermined margin over the predetermined stroke when the first and second armature teeth overlap the first and second stator teeth respectively.

Solenoid apparatus and methods

A multi-operation control system is made up of a plurality of slave computers at least some of which are axis computers each monitoring its respective operation and receiving instructions broken down into plurality of discreet actions. The current state S.sub.c,N of each slave is determined and is compared with preset absolute maximum status for that slave S.sub.ab,N(max) and the maximum acceptable change in status .delta.S.sub.a,N(max) of each respective slave is determined and the corresponding appropriate state signal based on the maximum acceptable change to that slave is sent to all of the slaves in the system. Each axis slave then reads all state signals and determines the highest state signal acceptable to all slaves and each axis slave then carries out its correspond increment(s) of change in status .delta. S.sub.N based on the highest S.sub.a,N(max) acceptable to all slaves.

Multiple slave control

The desired path for each axis is predefined and converted to a first series of coarse position increments at time intervals. The coarse position increments are converted to a second series of spaced, (in time), fine position increments and expected values of velocity v. The latter parameters requiring splining and interpolation of values. The actual position of each axis is measured and compared with that required (by the fine series of position increments) to determine the resulting error E which is then compared with a calculated allowable error, e.sub.allowable calculated as a function of the then current planned velocity value v i.e. the planned value of velocity v corresponding to the current fine position increment and a signal is triggered when the actual error E exceeds the allowable error e.sub.allowable to prevent processing of the next increment in the second series of increments.

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Rudolf J Seethaler