Method and system of servo control for speed control for vehicles

Claim 1

A system for speed control for vehicles, comprising means for producing d-c voltage proportional to the speed of a running vehicle, means for producing d-c voltage proportional to a desired pre-selected vehicle speed, said voltages being electrically connected with each other in mutually opposite polarity relationship, means to compare a difference in voltage between the two, a servo amplifier electrically coupled at its input end to said voltage comparison means, a servomotor electrically coupled by a driving circuit with the output end of said servo amplifier to drive said servomotor, said driving circuit being changed over by transistors operable depending upon the polarity of the output from said servo amplifier, a control clutch having a coil circuit operatively connected between the rotatable shaft of said servomotor and the rotatable shaft of a throttle valve for effecting the engagement and disengagement therebetween, the coil circuit of the control clutch being controlled by a relay circuit, said relay circuit including a normally closed contact adapted to be opened at the time of stepping on the brake of the vehicle, a normally opened contact adapted to be closed at the time of vehicle clutch engagement and a normally opened contact adapted to be closed at the time of the top-gear engagement of said vehicle when in motion, said contacts being connected in series, a diode positioned in said relay circuit and adapted to be rendered conductive by a reference voltage to drive said relay circuit whereby when a voltage substantially equal to the reference voltage is obtained, a relay is actuated to drive the control clutch and henceforth the forward and reverse rotation of the servomotor increases or decreases to the degree corresponding with the opening of the throttle valve to accelerate or decelerate the vehicle until the vehicle speed is equal to the desired speed, said system further including a comparison circuit operatively associated with the voltage producing means of the set vehicle speed and the voltage producing means of the vehicle running speed to compare the set vehicle speed and the running vehicle speed with each other and to produce a deviation voltage therebetween, comparing said deviation voltage with a changeover reference voltage, adjusting a minor feedback circuit on the basis of the result of such comparison so that when the speed difference therebetween is great, a speed feedback constant effective to increase the rotational speed of the servomotor is selected and when the speed difference is small, a speed feedback constant effective to decrease the rotational speed of the servomotor is selectEd.

Claim 2

A system for speed control for vehicles, comprising means for producing d-c voltage proportional to the speed of a running vehicle, means for producing d-c voltage proportional to a desired pre-selected vehicle speed, said voltages being electrically connected with each other in mutually opposite polarity relationship, means to compare a difference in voltage between the two, a servo amplifier electrically coupled at its input end to said voltage comparison means, a servomotor electrically coupled by a driving circuit with the output end of said servo amplifier to drive said servomotor, said driving circuit being changed over by transistors operable depending upon the polarity of the output from said servo amplifier, a control clutch having a coil circuit operatively connected between the rotatable shaft of said servomotor and the rotatable shaft of a throttle valve for effecting the engagement and disengagement therebetween, the coil circuit of the control clutch being controlled by a relay circuit, said relay circuit including a normally closed contact adapted to be opened at the time of stepping on the brake of the vehicle, a normally opened contact adapted to be closed at the time of vehicle clutch engagement and a normally opened contact adapted to be closed at the time of the top-gear engagement of said vehicle when in motion, said contacts being connected in series, a diode positioned in said relay circuit and adapted to be rendered conductive by a reference voltage to drive said relay circuit whereby when a voltage substantially equal to the reference voltage is obtained, a relay is actuated to drive the control clutch and henceforth the forward and reverse rotation of the servomotor increases or decreases to the degree corresponding with the opening of the throttle valve to accelerate or decelerate the vehicle until the vehicle speed is equal to the desired speed, said system further including a comparison circuit operatively associated with the voltage producing means of the set vehicle speed and the voltage producing means of the vehicle running speed to compare the set vehicle speed and the running vehicle speed with each other and to produce a deviation voltage therebetween, comparing said deviation voltage with a changeover reference voltage, adjusting a minor feedback circuit on the basis of the result of such comparison so that when the speed difference therebetween is great, a speed feedback constant effective to increase the rotational speed of the servomotor is selected and when the speed difference is small, a speed feedback constant effective to decrease the rotational speed of the servomotor is selectEd.

Claim 3

A system for speed control for vehicles, comprising means for producing d-c voltage proportional to the speed of a running vehicle, means for producing d-c voltage proportional to a desired pre-selected vehicle speed, reference voltage means for comparing the difference between said produced voltages, a servomotor electrically coupled by transistor means to said voltage comparing means whereby said transistor means are actuated and, depending upon whether said comparison is greater or less than the reference voltage, a relay contact of said servomotor will be actuated thereby to achieve forward or reverse rotation of said servomotor, a control clutch having a coil circuit operatively connected between the rotatable shaft of said servomotor and the rotatable shaft of a throttle valve for effecting the engagement and disengagement therebetween, the coil circuit of the control clutch being controlled by a relay circuit, said relay circuit including a normally closed contact adapted to be opened at the time of stepping on the brake of the vehicle, a normally opened contact adapted to be closed at the time of vehicle clutch engagement and a normally opened contact adapted to be closed at the time of the top-gear engagement of said vehicle when in motion, a relay for actuating a contact placed in the circuit for forward rotation of said servomotor, and a push-button switch for driving said coil circuit, whereby the emitter current of said transistor means for driving the circuit for reverse rotation of the servomotor will be led to a point between said push-button switch and a coil through the coil circuit of the control clutch, and upon closing the push-button switch when the contacts have been closed, the relay will be actuated and the control clutch will effect the engagement between the servomotor shaft and the throttle valve shaft and the driving of said relay will result in opening the contact of the circuit for forward rotation of the servomotor, and thereafter the circuits for forward and reverse rotation of the servomotor will be placed in an active state, thus rotating the servomotor in the forward or reverse direction in accordance with the amount of the differential voltage resulting from the comparison each time such comparison is made, thereby increasing or decreasing the degree of opening of the throttle valve of the vehicle engine to accelerate or decelerate the vehicle until the vehicle speed is equal to the desired speed; and upon opening the push-button switch, the emitter current of the transistor means will energize the servomotor reverse-rotation circuit only when the latter circuit is complete and will energize the control clutch and the reverse rotation of the servomotor will decrease to the degree of opening of the throttle valve of the engine to decelerate the vehicle until the vehicle speed is equal to the desired speed.

Claim 4

A system for speed control for vehicles, comprising means for producing d-c voltage proportional to the speed of a running vehicle, means for producing d-c voltage proportional to a desired pre-selected vehicle speed, reference voltage means for comparing the difference between said produced voltages, a servomotor electrically coupled by transistor means to said voltage comparing means whereby said transistor means are actuated and, depending upon whether said comparison is greater or less than the reference voltage, a relay contact of said servomotor will be actuated thereby to achieve forward or reverse rotation of said servomotor, a control clutch having a coil circuit operatively connected between the rotatable shaft of said servomotor and the rotatable shaft of a throttle valve for effecting the engagement and disengagement therebetween, the coil circuit of the control clutch being controlled by a relay circuit, said relay circuit including a normally closed contact adapted to be opened at the time of stepping on the brake of the vehicle, a normally opened contact adapted to be closed at the time of vehicle clutch engagement and a normally opened contact adapted to be closed at the time of the top-gear engagement of said vehicle when in motion, a relay for actuating a contact placed in the circuit for forward rotation of said servomotor, and a push-button switch for driving said coil circuit, whereby the emitter current of said transistor means for driving the circuit for reverse rotation of the servomotor will be led to a point between said push-button switch and a coil through the coil circuit of the control clutch, and upon closing the push-button switch when the contacts have been closed, the relay will be actuated and the control clutch will effect the engagement between the servomotor shaft and the throttle valve shaft and the driving of said relay will result in opening the contact of the circuit for forward rotation of the servomotor, and thereafter the circuits for forward and reverse rotation of the servomotor will be placed in an active state, thus rotating the servomotor in the forward or reverse direction in accordance with the amount of the differential voltage resulting from the comparison each time such comparison is made, thereby increasing or decreasing the degree of opening of the throttle valve of the vehicle engine to accelerate or decelerate the vehicle until the vehicle speed is equal to the desired speed; and upon opening the push-button switch, the emitter current of the transistor means will energize the servomotor reverse-rotation circuit only when the latter circuit is complete and will energize the control clutch and the reverse rotation of the servomotor will decrease to the degree of opening of the throttle valve of the engine to decelerate the vehicle until the vehicle speed is equal to the desired speed.