Device for controlling speed

Claim 1

A device for controlling the speed of rotation of a DC electric motor to a nominal speed VM, comprising: (a) means for generating a measuring signal representative of the real speed vm of the motor; (b) an operating circuit for receiving the measuring signal and for generating and supplying said motor with a DC drive signal having an operating value EN, comprising: (i) means for storing a digital representative of a prepositioning value CN; (ii) a function generator responsive to said measuring signal and said prepositioning value CN for calculating said operating value EN as the sum of said prepositioning value CN and of a single-valued and monotonic function f of said real speed vm of the motor; and (iii) means, connected to the function generator for continuously calculating and modifying said prepositioning value CN as the difference between said operating value EN and a single-valued and monotonic function f of said nominal value VM; and (c) a circuit for receiving said operating value EN from the function generator and for driving the motor with a current directly proportional to said operating value, whereby said real motor speed is continuously maintained at said nominal value VM despite variations in loading of said motor.

Claim 2

A device for controlling the speed of rotation of a DC electric motor to a nominal speed VM, comprising: (a) means for generating a measuring signal representative of the real speed vm of the motor; (b) an operating circuit for receiving the measuring signal and for generating and supplying said motor with a DC drive signal having an operating value EN, comprising: (i) means for storing a digital representative of a prepositioning value CN; (ii) a function generator responsive to said measuring signal and said prepositioning value CN for calculating said operating value EN as the sum of said prepositioning value CN and of a single-valued and monotonic function f of said real speed vm of the motor; and (iii) means, connected to the function generator for continuously calculating and modifying said prepositioning value CN as the difference between said operating value EN and a single-valued and monotonic function f of said nominal value VM; and (c) a circuit for receiving said operating value EN from the function generator and for driving the motor with a current directly proportional to said operating value, whereby said real motor speed is continuously maintained at said nominal value VM despite variations in loading of said motor.

Claim 6

A device for controlling the speed of a tape, comprising: (a) means for driving said tape, said means including a DC electric drive motor; (b) means for generating a first measuring signal representative of the real instantaneous speed of the tape; (c) means for generating a pilot signal representative of a reference speed, which may vary over time, at which the tape is to be driven by said drive means; (d) a control circuit for receiving said first measurement signal and said pilot signal, comprising: (i) means for comparing said first measurement signal and said pilot signal and for generating error information representative of the deviation between the real and reference speeds of the tape; (ii) means for generating reference information from the pilot signal related to the reference speed; and (iii) corrector means for modifying the reference information as a function of the error information, the rate of variation of the reference information having a maximum value limited in absolute value; (e) means for generating a second measuring signal representative of the real speed vm of the motor; (f) an operating circuit for receiving said second measuring signal and said modified reference information and for generating and supplying said motor with a DC drive signal having an operating value EN corresponding to the reference speed, comprising: (i) means for storing a digital representation of a prepositioning value CN; (ii) a function generator responsive to said second measuring signal and said prepositioning value CN for calculating said operating value EN as the sum of said prepositioning value CN and of a single-valued and monotonic function f of said real speed vm of the motor; and (iii) means, connected to the function generator for continuously calculating and modifying said prepositioning value CN as the difference between said operating value EN and the reference information; and (g) a circuit for receiving said operating value EN from the function generator and for driving the tape drive motor with a current directly proportional to said operating value EN, whereby said tape speed is continuously maintained at said reference speed despite variations in loading of said motor and said tape.

Claim 7

A device for controlling the speed of a tape, comprising: (a) means for driving said tape, said means including a DC electric drive motor; (b) means for generating a first measuring signal representative of the real instantaneous speed of the tape; (c) means for generating a pilot signal representative of a reference speed, which may vary over time, at which the tape is to be driven by said drive means; (d) a control circuit for receiving said first measurement signal and said pilot signal, comprising: (i) means for comparing said first measurement signal and said pilot signal and for generating error information representative of the deviation between the real and reference speeds of the tape; (ii) means for generating reference information from the pilot signal related to the reference speed; and (iii) corrector means for modifying the reference information as a function of the error information, the rate of variation of the reference information having a maximum value limited in absolute value; (e) means for generating a second measuring signal representative of the real speed vm of the motor; (f) an operating circuit for receiving said second measuring signal and said modified reference information and for generating and supplying said motor with a DC drive signal having an operating value EN corresponding to the reference speed, comprising: (i) means for storing a digital representation of a prepositioning value CN; (ii) a function generator responsive to said second measuring signal and said prepositioning value CN for calculating said operating value EN as the sum of said prepositioning value CN and of a single-valued and monotonic function f of said real speed vm of the motor; and (iii) means, connected to the function generator for continuously calculating and modifying said prepositioning value CN as the difference between said operating value EN and the reference information; and (g) a circuit for receiving said operating value EN from the function generator and for driving the tape drive motor with a current directly proportional to said operating value EN, whereby said tape speed is continuously maintained at said reference speed despite variations in loading of said motor and said tape.