Delta time measurement circuit for determining parameter derivatives of a rotational velocity sensor signal

• US 5,740,083 A
• Filed: 04/01/1996
• Issued: 04/14/1998
• Est. Priority Date: 04/01/1996
• Status: Expired due to Fees

• Current Assignee: Ford Motor Company, Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Ford Motor Company, Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Anderson, Robert Lee, Miller, Gary Lynn, Meyer, Marcella Evelyn
• Primary Examiner(s): Trammell, James P.
• Assistant Examiner(s): Shah, Kamini S.
• Application Number:
  US08/625,152
• Time in Patent Office: 743 Days
• Field of Search: 364/565, 364/426.1, 324/166, 324/160, 324/173, 377/19, 377/20, 74/866, 74/867
• US Class Current: 702/148
• CPC Class Codes: G01P 3/489 Digital circuits therefor

Abstract

An electronic circuit having control data registers (24-28) for receiving the output of a digital counter (20) that records clock pulses within a measured time that is determined by a rotary speed sensor (14) which produces a square wave pulse train signal and separate registers (30,32) for recording the time of each signal developed by the speed sensor and the time to produce a pulse train signal of predetermined length whereby the data in the data registers may be used to determine velocity and derivatives of that velocity for use in solving dynamic equations stored in memory thus effecting control system output functions.

Claims

1. A digital microprocessor for use in a control system that requires a variable that depends upon rotational speed of a rotary member and derivatives of that speed, said microprocessor comprising;

means for sensing rotational speed of said rotary member and creating electrical pulses having a frequency directly related to said rotational speed;

a first digital counter, means for pre-loading said first counter with a predetermined count value, means for transferring said electrical pulses to said first counter whereby said pulses are counted;

a second digital counter and an electronic timing clock adapted to record processor operating time in clock ticks;

control logic adapted during each background control loop of said microprocessor to record each instant said first counter counts said predetermined count value and to simultaneously clear said second counter and record the elapsed time for counting to said predetermined count value;

a stack of temporary data storage registers, means for transferring to a first of said storage registers the recorded number of said clock ticks as said second counter is cleared;

said stack of storage registers being adapted to shift clock tick counts from said first storage register to a second storage register and from said second storage register to a third storage register as clock ticks are stored in sequence in said first storage register during each background control loop;

means for addressing said storage registers during an elapsed measuring time to obtain clock tick values; and

means for computing rotational velocity and derivatives of said rotational velocity using said clock tick values in said storage registers and said elapsed time;

said first counter being a down counter adapted to count down from a pre-loaded constant count value to zero, said second counter being an up counter adapted to count the number of clock ticks following a clearing of said second counter by said control logic during each background control loop, the rotational velocity being determined using the equations;

##EQU3## where V₁, V₂ and V₃, respectively, are the recorded clock ticks in real time intervals Δ

t₁, Δ

t₂, and Δ

t₃ in said first, second and third storage registers.

2. A digital microprocessor for use in a control system that requires a variable that depends upon rotational speed of a rotary member and derivatives of that speed, said microprocessor comprising;

means for sensing rotational speed of said rotary member and creating electrical pulses having a frequency directly related to said rotational speed;

a first digital counter, means for pre-loading said first counter with a predetermined count value, means for transferring said electrical pulses to said first counter whereby said pulses are counted;

a second digital counter and an electronic timing clock adapted to record processor operating time in clock ticks;

control logic adapted during each background control loop of said microprocessor to record each instant said first counter counts said predetermined count value and to simultaneously clear said second counter and record the elapsed time for counting to said predetermined count value;

a stack of temporary data storage registers, means for transferring to a first of said storage registers the recorded number of said clock ticks as said second counter is cleared;

said stack of storage registers being adapted to shift clock tick counts from said first storage register to a second storage register and from said second storage register to a third storage register as clock ticks are stored in sequence in said first storage register during each background control loop;

means for addressing said storage registers during an elapsed measuring time to obtain clock tick values;

means for computing rotational velocity and derivatives of said rotational velocity using said clock tick values in said storage registers and said elapsed time;

first and second real time storage registers, means for capturing in a first of said real time storage registers the number of said clock ticks during each of said measuring times, said control logic being adapted to trigger a transfer of real time data from said first real time storage register to said second real time storage register when said first counter reaches a count equal to said pre-loaded count value, the rotational velocity being determined using the equations;

##EQU4## where V₁, V₂ and V₃, respectively, are the recorded clock ticks in real time intervals Δ

t₁, Δ

t₂ and Δ

t₃ in said first, second and third storage registers.

3. A digital microprocessor for use in a control system that requires a variable that depends upon rotational speed of a rotary member and derivatives of that speed, said microprocessor comprising;

means for sensing rotational speed of said rotary member and creating electrical pulses having a frequency directly related to said rotational speed;

a first digital counter, means for pre-loading said first counter with a predetermined count value, means for transferring said electrical pulses to said first counter whereby said pulses are counted;

a second digital counter and an electronic timing clock adapted to record processor operating time in clock ticks;

control logic adapted during each background control loop of said microprocessor to record each instant said first counter counts said predetermined count value and to simultaneously clear said second counter and record the elapsed time for counting to said predetermined count value;

a stack of temporary data storage registers, means for transferring to a first of said storage registers the recorded number of said clock ticks as said second counter is cleared;

said stack of storage registers being adapted to shift clock tick counts from said first storage register to a second storage register and from said second storage register to a third storage register as clock ticks are stored in sequence in said first storage register during each background control loop;

means for addressing said storage registers during an elapsed measuring time to obtain clock tick values;

means for computing rotational velocity and derivatives of said rotational velocity using said clock tick values in said storage registers and said elapsed time;

first and second real time storage registers, means for capturing in a first of said real time storage registers the number of clock ticks during each of said measuring times, said control logic being adapted to trigger a transfer of real time data from said first real time storage register to said second real time storage register when said first counter reaches a count equal to said pre-loaded count value, the rotational velocity being determined using the equations;

##EQU5## where V₁, V₂ and V₃, respectively, are the recorded clock ticks in real time interval Δ

t₁, Δ

t₂ and Δ

t₃ in said first, second and third storage registers, derivatives of said rotational velocity being determined using the equations;

##EQU6##