Bidirectional speed control system

Claim 2

A bidirectional speed regulation system for a d.c. motor, comprising: a transducer device for supplying pulses having a frequency related to the motor speed; circuit means for comparing the period of said pulses with a reference period and for supplying periodic pulses whose duration is equal to the difference between said reference period and said period related to the motor speed; a constant current generator fed by a voltage source, said generator having two independent output leads for providing a current of the same polarity on each lead; circuit means for supplying a short control pulse in coincidence with each of said periodic pulses; a pair of capacitors, each connected to one of said independent output leads; a switching device controlled by said periodic pulses, for controlling the charge on said pair of capacitors, during the duration of said periodic pulses; a pair of switching devices for short circuiting said pair of capacitors for the whole duration of said control pulses; a conditioning logic circuit, controlled by external signals for selectively controlling said pair of switching devices and for selectively short circuiting, for the whole duration of said external signals, either one of said pair of capacitors; and an operational amplifier for driving said motor, said amplifier including an inverting and a non-inverting input lead, an output lead connected to said motor and coupled through a feedback path to said inverting input lead, each of said input leads being connected to one of said pair of capacitors through a separate resistor so as to be coupled to ground through its resistor whenever the corresponding capacitor is short circuited.

Claim 3

In a bidirectional speed regulation system for a d.c. motor which includes transducer means for producing output pulses at a frequency related to motor speed, pulse generating means connected to said transducer means for producing error pulses of a duration proportional to the difference between actual motor speed and desired motor speed, capacitor means connected to said pulse generating means for producing an error voltage proportional to said difference, and operational amplifier means connected to said capacitor means for driving the motor, said operational amplifier means having an inverting input terminal and a non-inverting input terminal; the improvement comprising: first switching means for connecting said error voltage which may be present during rotation of the motor in one direction to said inverting input terminal of the operational amplifier means whereby to regulate motor speed in said one direction; second switching means for connecting said error voltage which may be present during rotation of the motor in the opposite direction to said non-inverting input terminal of the operational amplifier means whereby to regulate motor speed in said opposite direction; said operational amplifier means further including a feedback path of resistance Rf connected to said inverting input terminal, whereby the gain a' of said amplifier means is ##EQU5## when said error voltage from said capacitor means is applied to said inverting input terminal with Ra being the input impedance, and wherein said inverting input terminal is referenced to ground through a resistance of value Rb when said error voltage from said capacitor means is applied to said non-inverting input terminal, whereby the gain a" of said amplifier means in response to such input to the non-inverting terminal is ##EQU6## and wherein |a'| = |a"|.

Claim 4

In a bidirectional speed regulation system for a d.c. motor which includes transducer means for producing output pulses at a frequency related to motor speed, pulse generating means connected to said transducer means for producing error pulses of a duration proportional to the difference between actual motor speed and desired motor speed, capacitor means connected to said pulse generating means for producing an error voltage proportional to said difference, and operational amplifier means connected to said capacitor means for driving the motor, said operational amplifier means having an inverting input terminal and a non-inverting input terminal; the improvement comprising: first switching means for connecting said error voltage which may be present during rotation of the motor in one direction to said inverting input terminal of the operational amplifier means whereby to regulate motor speed in said one direction; second switching means for connecting said error voltage which may be present during rotation of the motor in the opposite direction to said non-inverting input terminal of the operational amplifier means whereby to regulate motor speed in said opposite direction; said operational amplifier means further including a feedback path of resistance Rf connected to said inverting input terminal, whereby the gain a' of said amplifier means is ##EQU5## when said error voltage from said capacitor means is applied to said inverting input terminal with Ra being the input impedance, and wherein said inverting input terminal is referenced to ground through a resistance of value Rb when said error voltage from said capacitor means is applied to said non-inverting input terminal, whereby the gain a" of said amplifier means in response to such input to the non-inverting terminal is ##EQU6## and wherein |a'| = |a"|.

Claim 5

A bidirectional speed regulation system for a d.c. motor which comprises, in combination: transducer means for producing a pulse train of a frequency related to rotational speed of an associated motor to be regulated; wave shaping means connected to the output of said transducer means for converting said pulse train to a second pulse train of corresponding frequency with each pulse of said second pulse train having a selected duration T o which is substantially equal to the period of that pulse train produced by said transducer means when the associated motor is rotating at the desired regulated speed; inverter means connected to said wave shaping means to produce an error signal which is constituted of pulses of duration T-T o where T is the period of the rotational frequency of the associated motor, whereby the pulses of said error signal are of decreasing duration as the motor speed approaches said desired regulated speed; a constant current source, capacitor means for charging from said current source, and a switching device between the current source and said capacitor means for controlling the duration of charging of the latter; said error signal being connected to said switching device for closing same during the durations T-T o , and means for rapidly discharging said capacitor means at the beginning of each of said pulse of the error signal, whereby said capacitor means charges to decreasing voltage levels as the motor approaches said desired regulated speed; an operational amplifier having an inverting input terminal and a non-inverting input terminal; and switching means for connecting the output voltage derived from said capacitor means selectively to said inverting input terminal and said non-inverting input terminal.

Claim 6

A bidirectional speed regulation system for a d.c. motor which comprises, in combination: transducer means for producing a pulse train of a frequency related to rotational speed of an associated motor to be regulated; wave shaping means connected to the output of said transducer means for converting said pulse train to a second pulse train of corresponding frequency with each pulse of said second pulse train having a selected duration T o which is substantially equal to the period of that pulse train produced by said transducer means when the associated motor is rotating at the desired regulated speed; inverter means connected to said wave shaping means to produce an error signal which is constituted of pulses of duration T-T o where T is the period of the rotational frequency of the associated motor, whereby the pulses of said error signal are of decreasing duration as the motor speed approaches said desired regulated speed; a constant current source, capacitor means for charging from said current source, and a switching device between the current source and said capacitor means for controlling the duration of charging of the latter; said error signal being connected to said switching device for closing same during the durations T-T o , and means for rapidly discharging said capacitor means at the beginning of each of said pulse of the error signal, whereby said capacitor means charges to decreasing voltage levels as the motor approaches said desired regulated speed; an operational amplifier having an inverting input terminal and a non-inverting input terminal; and switching means for connecting the output voltage derived from said capacitor means selectively to said inverting input terminal and said non-inverting input terminal.

Claim 7

A bidirectional speed regulation system as defined in claim 3 wherein said switching means includes a pair of input terminals adapted to receive external control signals selectively to apply said output voltage from said capacitor means to said inverting input terminal during rotation of the associated motor in one direction and to said non-inverting input terminal during rotation of the motor in the opposite direction.

Claim 8

A bidirectional speed regulation system as defined in claim 4 including circuit elements connected to said inverting and non-inverting input terminals such that |a'| = |a"| where a' is the gain of said amplifier in response to input to its inverting input terminal and a" is the gain of said amplifier in response to input to its non-inverting input terminal.

Claim 9

A bidirectional speed regulation system as defined in claim 3 including circuit elements connected to said inverting and non-inverting input terminals such that |a'| = |a"| where a' is the gain of said amplifier in response to input to its inverting input terminal and a" is the gain of said amplifier in response to input to its non-inverting input terminal.

Claim 10

A bidirectional speed regulation system for a d.c. motor, comprising in combination: means for producing a train of error pulses of frequency related to rotational speed of an associated motor to be regulated and of durations which decrease as the regulated speed approaches a desired value; capacitor means receiving said error pulses for producing an error voltage signal proportional to the difference between actual motor speed and said desired value; an operational amplifier for regulating the speed of the associated motor, said operational amplifier having conventional input terminals which respectively are inverting and non-inverting input terminals; and switching means for selectively connecting said error voltage signal to said inverting input terminal to regulate motor speed in one direction of motor rotation and connecting said error voltage signal to said non-inverting input terminal to regulate motor speed in the opposite direction of motor rotation, said switching means including a pair of input terminals adapted to receive external control signals to selectively apply said error voltage signal from said capacitor means to said inverting input terminal during rotation of the associated motor in said one direction and to said non-inverting input terminal during rotation of the motor in said opposite direction.

Claim 11

A bidirectional speed regulation system for a d.c. motor, comprising in combination: means for producing a train of error pulses of frequency related to rotational speed of an associated motor to be regulated and of durations which decrease as the regulated speed approaches a desired value; capacitor means receiving said error pulses for producing an error voltage signal proportional to the difference between actual motor speed and said desired value; an operational amplifier for regulating the speed of the associated motor, said operational amplifier having conventional input terminals which respectively are inverting and non-inverting input terminals; and switching means for selectively connecting said error voltage signal to said inverting input terminal to regulate motor speed in one direction of motor rotation and connecting said error voltage signal to said non-inverting input terminal to regulate motor speed in the opposite direction of motor rotation, said switching means including a pair of input terminals adapted to receive external control signals to selectively apply said error voltage signal from said capacitor means to said inverting input terminal during rotation of the associated motor in said one direction and to said non-inverting input terminal during rotation of the motor in said opposite direction.

Claim 12

A bidirectional speed regulation system as defined in claim 7 including circuit elements connected to said inverting and non-inverting input terminals such that |a'| = |a"| where a' is the gain of said amplifier in response to input to its inverting input terminal and a" is the gain of said amplifier in response to input to its non-inverting input terminal.

Claim 13

A bidirectional speed regulation system as defined in claim 7 including circuit elements connected to said inverting and non-inverting input terminals such that |a'| = |a"| where a' is the gain of said amplifier in response to input to its inverting input terminal and a" is the gain of said amplifier in response to input to its non-inverting input terminal.

Claim 14

In a speed regulation system as defined in claim 7 wherein said operational amplifier means includes a feedback path of resistance Rf connected to said inverting input terminal whereby the gain a' of said amplifier means is ##EQU7## when said error voltage signal from said capacitor means is applied to said inverting input terminal with Ra being the input impedance, and wherein said inverting input terminal is referenced to ground through a resistance of value Rb when said error voltage signal from said capacitor means is applied to said non-inverting input terminal, whereby the gain a" of said amplifier means in response to such input to the non-inverting terminal is ##EQU8## and wherein |a'| = |a"|.

Claim 15

Bidirectional speed regulation system for a d.c. motor comprising: a transducer device for supplying pulses having a frequency related to the motor speed; circuit means for comparing the period of said pulses with a reference period and for supplying periodic pulses, whose duration is equal to the difference between said reference period and said period related to the motor speed; a constant current generator fed by a voltage source; circuit means for supplying a short control pulse, in coincidence to said periodic pulses; a capacitor connected to the output lead of said constant current generator; a first switching means controlled by said control pulses for short circuiting said capacitor; a second switching means, controlled by said periodical pulses, for connecting said capacitor to said constant current generator during the duration of said periodical pulses; an operational amplifier provided with two input leads, respectively inverting and not inverting for driving said motor; and capacitor switching means for applying the charge voltage of said capacitor, through a resistor, to either input lead selectively, according to the required direction of motion.

Claim 16

Bidirectional speed regulation system for a d.c. motor comprising: a transducer device for supplying pulses having a frequency related to the motor speed; circuit means for comparing the period of said pulses with a reference period and for supplying periodic pulses, whose duration is equal to the difference between said reference period and said period related to the motor speed; a constant current generator fed by a voltage source; circuit means for supplying a short control pulse, in coincidence to said periodic pulses; a capacitor connected to the output lead of said constant current generator; a first switching means controlled by said control pulses for short circuiting said capacitor; a second switching means, controlled by said periodical pulses, for connecting said capacitor to said constant current generator during the duration of said periodical pulses; an operational amplifier provided with two input leads, respectively inverting and not inverting for driving said motor; and capacitor switching means for applying the charge voltage of said capacitor, through a resistor, to either input lead selectively, according to the required direction of motion.

Claim 17

The regulation system of claim 11, wherein said capacitor switching means comprises two field-effect transistors, each being series connected to the said either input lead.

Claim 18

The regulation system of claim 11, wherein said capacitor switching means comprises in addition two transistors for selectively grounding said either input lead.