Pattern generator for the control of motion of a body movable over a predetermined path

Claim 2

Apparatus for generating an electrical control signal applicable to the control of a power unit for the movement of an object over a predetermined path, said apparatus comprising means for deriving two discrete series of electrical impulses, a first one of said series being produced by a high frequency source independent of movement of said body and having an impulse count indicative of a distance to be travelled by the body to reach a destination in said path, and a second one of said series being produced from a second source in response to travel by the body towards said destination and having an instantaneous impulse count indicative of the distance travelled by the body from its starting point, means for adding the impulses of said first series to obtain a total count and means for subtracting from said total count the impulses of said second series and, a digital to analogue converter responding to the instantaneous count in the counting means to provide at an output of the converter said control signal whose voltage is related to said distance to be travelled by the body.

Claim 3

Apparatus according to claim 1, wherein the means for deriving said series of electrical impulses is a control unit to which is connected said two sources of electrical impulses, said high frequency source being a static impulse generator, and said second source being an incremental encoder driven synchronously with movement of said body, said control unit controlling the relaying of impulses from said sources to the counting means.

Claim 4

Apparatus according to claim 2, including means for registering demands requiring travel of the body to a destination, and means for applying an input signal to the control unit when a demand is registered, said control unit responding to said input signal to send impulses from said first source to the counting means.

Claim 5

Apparatus according to claim 3, including a second counting means for impulses which also receives the impulses derived from the control unit, and comparitor means for comparing the distance represented by the count of impulses in the second counting means to a distance related to the registered demand, said comparitor means reacting to a predetermined relationship of said distances to each other to transmit an output signal to cause said control unit to cease relaying said impulses to both of said counting means, whereby the first mentioned counting means contains a count indicative of the distance thE body is required to travel to said destination.

Claim 6

Apparatus according to claim 4, wherein while the body is in motion impulses from said second source are relayed by said control unit to the first mentioned counting means to subtract from the count therein of impulses from said second source to produce a change in the voltage of the control signal and a resulting change in the speed of the object.

Claim 7

Apparatus according to claim 5, wherein said change in speed of the object is an increased speed so that an acceleration pattern of the object is represented by the voltage of the control signal as the object departs from a rest position towards said destination.

Claim 8

Apparatus according to claim 1, wherein said destination is a position in said path where the object is intended to come to rest, and means are provided for producing in the control signal a deceleration pattern to slow the travel of the object after it has passed a predetermined part of the total distance to be travelled to reach said destination.

Claim 9

Apparatus according to claim 1, wherein said dstination is a position in the path where the body would first attain a maximum speed in responding to said demand and including means responsive to a maximum count in the first mentioned counting means to cause the control unit to cease relaying the impulses from said second source to both said counting means and to cause impulses derived from said first source to be applied to add to the count in said first counting means, one of said output signals from the comparitor means causing the control unit to transfer impulses from said second source to said first mentioned counting means to subtract from the count therein.

Claim 10

An elevator system comprising at least one car movable along a shaft to service a plurality of landings, a hoist motor for effecting movement of said car, an electrical generator connected to supply power to the hoist motor, a power supply connected to energize at least part of the field of said generator, two sources of electrical impulses a first one of which is controlled by movement of the car to represent by the number of pulses produced a distance travelled by the car and a second one of which is of high frequency, two electrical impulse counters, a control unit for relaying the output of said sources to the counters, means for registering a demand for service by the car to instigate an input signal to the control unit to cause it to relay impulses from the second source to both said counters before the car commences to move, comparitor means for comparing the distance represented by the count in one of said counters with a distance related to the location of the destination of the car intended by the registered demand so as to transmit an output signal to said control unit when said distances bear a predetermined relationship to each other, said control unit responding to said output signal to cease relaying said impulses from the second source whereby the count in the other of said counters is then indicative of a distance to be travelled by the car, a digital to analogue converter responding to the count in said other counter to produce a control signal whose voltage is related to said distance, and means for modulating said power supply to the generator field under the control of the control signal, said control unit operating to apply to said other counter impulses originating from said first source to subtract from the count in said other counter and to change the voltage of the control signal thereby to produce an acceleration pattern for the hoist motor.

Claim 11

An elevator system comprising at least one car movable along a shaft to service a plurality of landings, a hoist motor for effecting movement of said car, an electrical generator connected to supply power to the hoist motor, a power supply connected to energize at least part of the field of said generator, two sources of electrical impulses a first one of which is controlled by movement of the car to represent by the number of pulses produced a distance travelled by the car and a second one of which is of high frequency, two electrical impulse counters, a control unit for relaying the output of said sources to the counters, means for registering a demand for service by the car to instigate an input signal to the control unit to cause it to relay impulses from the second source to both said counters before the car commences to move, comparitor means for comparing the distance represented by the count in one of said counters with a distance related to the location of the destination of the car intended by the registered demand so as to transmit an output signal to said control unit when said distances bear a predetermined relationship to each other, said control unit responding to said output signal to cease relaying said impulses from the second source whereby the count in the other of said counters is then indicative of a distance to be travelled by the car, a digital to analogue converter responding to the count in said other counter to produce a control signal whose voltage is related to said distance, and means for modulating said power supply to the generator field under the control of the control signal, said control unit operating to apply to said other counter impulses originating from said first source to subtract from the count in said other counter and to change the voltage of the control signal thereby to produce an acceleration pattern for the hoist motor.