Servosystem

Claim 2

In a motor control system for accelerating the motor to a predetermined velocity and phase condition, said system including means for sensing the instantaneous velocity of the motor, means for comparing the sensed velocity with said predetermined velocity to derive an error signal, and means for applying said error signal to a control amplifier which accelerates the motor to said predetermined velocity, said error signal having a first value which causes the motor to accelerate rapidly and a second value at which the motor acceleration is relatively small, the improvement comprising means operative at the moment when said velocities are equal for providing a momentary auxiliary error signal and for combining said auxiliary error signal with said first mentioned error signal to provide a composite error signal which rapidly changes from said first value to said second value at the moment that said velocities are equal, said auxiliary error signal causing said composite error signal to change from said second value to approach a steady state value intermediate said first and second values at a predetermined rate, said auxiliary error signal serving to compensate for overshoot of said motor so as to cause said motor to stabilize at said predetermined velocity in a shorter time than would be required for such stabilization in the absence of said auxiliary error signal.

Claim 3

The combination with a servosystem having means for driving a load, means providing a first signal indicative of the velocity of said load, and means responsive to said first signal and a second signal representative of a reference velocity for providing to said driving means a velocity error signal; of fourth means coupled to said third means for providing an output indicative of a first condition wherein said load velocity is less than said reference velocity and of a second condition wherein said load velocity is greater than said reference velocity, fifth means coupled between said fourth means and said drive means and responsive to the output of said fourth means for causing maximum drive to be provided to said load during said first condition; and sixth means including signal shaping means coupled between said fourth means and said drive means and responsive to the output of said fourth means causing the drive to said load upon the occurrence of said second condition to be varied from a minimum value to a given intermediate value in accordance with the output of said signal shaping means.

Claim 4

The combination with a servosystem having means for driving a load, means providing a first signal indicative of the velocity of said load, and means responsive to said first signal and a second signal representative of a reference velocity for providing to said driving means a velocity error signal; of fourth means coupled to said third means for providing an output indicative of a first condition wherein said load velocity is less than said reference velocity and of a second condition wherein said load velocity is greater than said reference velocity, fifth means coupled between said fourth means and said drive means and responsive to the output of said fourth means for causing maximum drive to be provided to said load during said first condition; and sixth means including signal shaping means coupled between said fourth means and said drive means and responsive to the output of said fourth means causing the drive to said load upon the occurrence of said second condition to be varied from a minimum value to a given intermediate value in accordance with the output of said signal shaping means.

Claim 5

A servosystem for accelerating a load from a static condition to substantially constant reference velocity in minimum time, comprising: drive means coupled to said load; control means for providing to said drive means a controlled energizing signal in accordance with inputs to said control means; means for providing a first signal indicative of the velocity of said load; error detecting means responsive to said first signal and a second signal indicative of said constant reference velocity for providing a first input to said control means with a value in accordance with said velocity error, said detecting means including further means for providing an output signal having first and second conditions indicative of said load velocity being respectively less than and greater than said reference velocity; means coupled to said detecting means and responsive to the first condition of said output signal for clamping the amplitude of said first input to said control means to a value to cause sustained maximum energization of said drive means during said first condition of said output signal; and means coupled to said detector means output an operable in response to said second condition of said output for applying to said control means, a second input signal having a controlled amplitude variation from a value providing minimum drive of said load to said value of said first input, in a period sufficient to substantially reduce velocity overshoot of said load.

Claim 6

A servosystem for accelerating a load from a static condition to substantially constant reference velocity in minimum time, comprising: drive means coupled to said load; control means for providing to said drive means a controlled energizing signal in accordance with inputs to said control means; means for providing a first signal indicative of the velocity of said load; error detecting means responsive to said first signal and a second signal indicative of said constant reference velocity for providing a first input to said control means with a value in accordance with said velocity error, said detecting means including further means for providing an output signal having first and second conditions indicative of said load velocity being respectively less than and greater than said reference velocity; means coupled to said detecting means and responsive to the first condition of said output signal for clamping the amplitude of said first input to said control means to a value to cause sustained maximum energization of said drive means during said first condition of said output signal; and means coupled to said detector means output an operable in response to said second condition of said output for applying to said control means, a second input signal having a controlled amplitude variation from a value providing minimum drive of said load to said value of said first input, in a period sufficient to substantially reduce velocity overshoot of said load.

Claim 7

The invention according to claim 3, wherein said clamping means includes controlled signal conducting means and further said error detecting means includes means for providing respective levels to control said signal conducting means in response to said first and second velocity conditions.

Claim 8

The invention according to claim 3, wherein said detector means output provided rapid level transition between said first and second conditions, and said last mentioned means includes signal differentiating means including a timing network responsive to said detector output to provide controlled duration nonlinear amplitude variation of said second input signal.

Claim 9

The combination with a headwheel servo for providing from a stalled condition synchronized rotation of a transducer drive means with a first pulse train indicative of a reference velocity, wherein said servo includes means for providing a second pulse train indicative of the velocity of said drive means and a control amplifier for energizing said drive means, comprising: velocity error detecting means responsive to said first and second pulse trains for providing to the input of said control amplifier a third signal whose amplitude varies from a first value at said reference velocity in accordance with said error, fourth means coupled to said detecting means for providing an output signal level at the first value of said third signal when said drive means velocity is less than said reference velocity and a second level substantially greater than the second value of said third signal when said drive means velocity exceeds said reference velocity, unidirectional conducting means coupled between the output of said fourth means and said control amplifier input, second unidirectional conducting means coupled to said control amplifier input, and differentiating circuit means operable in response to a transition of said fourth means to said second level for providing through said second unidirectional conducting means a fourth signal to said control amplifier.

Claim 10

The combination with a headwheel servo for providing from a stalled condition synchronized rotation of a transducer drive means with a first pulse train indicative of a reference velocity, wherein said servo includes means for providing a second pulse train indicative of the velocity of said drive means and a control amplifier for energizing said drive means, comprising: velocity error detecting means responsive to said first and second pulse trains for providing to the input of said control amplifier a third signal whose amplitude varies from a first value at said reference velocity in accordance with said error, fourth means coupled to said detecting means for providing an output signal level at the first value of said third signal when said drive means velocity is less than said reference velocity and a second level substantially greater than the second value of said third signal when said drive means velocity exceeds said reference velocity, unidirectional conducting means coupled between the output of said fourth means and said control amplifier input, second unidirectional conducting means coupled to said control amplifier input, and differentiating circuit means operable in response to a transition of said fourth means to said second level for providing through said second unidirectional conducting means a fourth signal to said control amplifier.