Control system for time sharing multiple stepper motors with a single controller

Claim 2

A motor control system for multiple stepper motors comprising a plurality of stepper motors each having a rotor movable by discrete steps upon being supplied with sets of drive pulses determining stator winding combinations to be energized sequentially, a single motor controller for generating said sets of drive pulses in repeating predetermined forward and reverse sequences representing the sequence of winding states for moving a desired motor to a commanded position, a memory unit for each motor for storing drive pulse data representative of said sets of drive pulses and corresponding to the actual motor winding state, means for selecting one motor and cycling said controller until the actual motor winding state stored in said memory unit and the controller winding state compare, and means for switching the selected motor for energization and successively triggering said controller to move the selected motor to the commanded position while enabling the respective memory unit for entry of drive pulse data.

Claim 3

The motor control system defined in claim 1 wherein said controller has a negative terminal and a plurality of output terminals for conducting said sets of drive pulses, said means for switching the selected motor comprises a switching network for effecting connection of the selected motor negative terminal to the negative terminal of said controller, and a distribution and isolation network including a rectifier in series between each output terminal and each stator winding to prevent unwanted interaction between designated stator windings of the selected motor.

Claim 4

A motor control system for multiple stepper motors comprising a plurality of stepper motors each having a rotor movable by discrete steps upon being supplied with sets of drive pulses determining stator winding combinations to be energized sequentially. a single motor controller for generating said sets of drive pulses in repeating predetermined forward and reverse sequences representing the sequence of winding states for moving a desired motor to a commanded position, a memory unit for each motor for storing drive pulse data representative of said sets of drive pulses and corresponding to the actual motor winding state, means for selecting one motor and for comparing the actual winding state of that motor stored in said memory unit with the controller winding state, and means for cycling said controller until the winding states compare, switching means for connecting the selected motor for energization, and means for generating motion control pulses for sequentially triggering said controller and moving the selected motor through one step per motion control pulse to the commanded position and for enabling the corresponding memory unit for entry of said drive pulse data.

Claim 5

A motor control system for multiple stepper motors comprising a plurality of stepper motors each having a rotor movable by discrete steps upon being supplied with sets of drive pulses determining stator winding combinations to be energized sequentially. a single motor controller for generating said sets of drive pulses in repeating predetermined forward and reverse sequences representing the sequence of winding states for moving a desired motor to a commanded position, a memory unit for each motor for storing drive pulse data representative of said sets of drive pulses and corresponding to the actual motor winding state, means for selecting one motor and for comparing the actual winding state of that motor stored in said memory unit with the controller winding state, and means for cycling said controller until the winding states compare, switching means for connecting the selected motor for energization, and means for generating motion control pulses for sequentially triggering said controller and moving the selected motor through one step per motion control pulse to the commanded position and for enabling the corresponding memory unit for entry of said drive pulse data.

Claim 6

The motor control system defined in claim 3 wherein said means for selecting one motor and comparing the winding states is comprised by a command unit for generating a motor selection signal, a multiplexer actuated by said motor selection signal for transmitting stored drive pulse data for the selected motor from the corresponding memory unit to one input of a comparator, the other input to said comparator being generated drive pulse data representative of the set of drive pulses then being generated by said controller, said comparator producing a non-compare output when the actual motor and controller winding states are different and a system ready signal when there is a compare.

Claim 7

The motor control system defined in claim 4 wherein said means for cycling said controller comprises an oscillator actuated by said non-compare output for producing at least one cycling pulse for triggering said controller.

Claim 8

The motor control circuit defined in claim 5 wherein said means for selecting one motor is further comprised by a motor select logic circuit for each motor which generates a switching output signal upon the coincidence at the inputs thereof of said motor selection and system ready signals.

Claim 9

The motor control system defined in claim 6 wherein each motor and said controller has a negative terminal, and said switching means comprises a switching network for effecting connection of the negative terminal of the selected motor to the negative terminal of said controller.

Claim 10

The motor control system defined in claim 7 wherein said controller has a plurality of output terminals for conducting said sets of drive pulses, and the control system further includes a distribution and isolation network including a diode in series between each output terminal and each stator winding of each motor that is selectively reverse biased to prevent unwanted interaction between designated stator windings of a selected energized motor.

Claim 11

The motor control system defined in claim 8 further including a dummy load resistor connected directly between the negative terminal of said controller and each controller output terminal.

Claim 12

The motor control system defined in claim 7 wherein said means for generating motion control pulses and enabling the corresponding memory unit comprises said command unit which is operative to generate the motion control pulses for sequentially triggering said controller after receiving said system ready signal, and further comprises a memory select logic circuit for each memory unit that produces a memory enabling signal upon the coincidence at the inputs thereof of said switching output signal and one of said motion control pulses.

Claim 13

The motor control system defined in claim 3 wherein said controller has a negative terminal and a plurality of output terminals for conducting said sets of drive pulses, said switching means comprises a switching network for effecting connection of the negative terminal of the selected motor to the negative terminal of said controller, and the control system further includes a distribution and isolation network including a rectifier in series between each output terminal and each stator winding that is selectively reverse biased to prevent unwanted interaction between designated stator windings of a selected energized motor.

Claim 14

The motor control system defined in claim 11 further including a dummy load resistor connected directly between the negative terminal of said controller and each controller output terminal to provide a partial load for the controller during operation of said switching means.