Method and apparatus for determining angular velocity from two signals which are a function of the angle of rotation

• US 4,814,701 A
• Filed: 11/06/1987
• Issued: 03/21/1989
• Est. Priority Date: 11/10/1986
• Status: Expired due to Fees

• Current Assignee: VDO Adolf Schindling AG (Vodafone Group PLC)
• Original Assignee: VDO Adolf Schindling AG (Vodafone Group PLC)
• Inventors: Wallrafen, Werner
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/118,182
• Time in Patent Office: 501 Days
• Field of Search: 324/160, 324/163, 324/165, 324/166, 324/168
• US Class Current: 324/160
• CPC Class Codes: G01P 3/44 for measuring angular speed G01P3/56 takes precedence

Abstract

A method and an apparatus for determining angular velocity from two voltage signals which are produced by an angle transmitter (1) having a sinusoidal function with respect to the angle of rotation of a rotatable member and are shifted in phase by 90 angular degrees. The amount and sign of the angular velocity (ω) are determined by the division of the derivative of a first voltage signal with respect to time by the second voltage signal when said second voltage is above zero. In that signal range in which the second voltage signal passes below zero, the derivative of the second voltage signal with respect to time is divided by the first voltage signal. Alternatively, the amount of the angular velocity (ω) is determined from the vector sum of the derivatives of the two voltage signals with respect to time. The sign of the angular velocity is determined from the two voltage signals and their derivatives.

Claims

1. A method for determining the amount and sign of angular velocity from two voltage signals produced by an angle transmitter, which signals have a sinusoidal course with respect to an angle of rotation of a rotatable body and are shifted 90 degrees in phase with respect to each other, comprising

obtaining derivatives, with respect to time, of said first and said second voltage signals said derivatives being obtained by applying said signals to differentiating means connecting dividing means to the differentiating means and, by said dividing means;

dividing the derivative with respect to time of the first voltage signal by the second voltage signal when said second voltage signal is above zero; and

within a signal region in which the second voltage signal passes below zero, dividing the derivative with respect to time of the second voltage signal by the first voltage signal by said dividing means; and

employing an inverter for inverting the resulting dividend.

2. A system for determining the amount and sign of angular velocity from two voltage signals produced by an angle transmitter, which signals have a sinusoidal course with respect to an angle of rotation of a rotatable body and are shifted 90 degrees in phase with respect to each other, comprising

differentiator means;

divider means having a dividend input connected to an output of said differentiator means;

jointly actuatable switches coupled to an input terminal of said differentiator means and to a divisor input terminal of said divider means;

an inverter connected to an output quotient terminal of said divider means;

zero voltage comparator for controlling said jointly actuable switches and a further switch;

wherein

said switches are operable to conduct the first voltage signal, in the region of passages above zero of the second voltage signal, to said differentiator means, and to conduct the second voltage signal to the divider input of said divider means; and

in the region of the passages below zero of the second voltage signal, said switches are operable to interchange the applications of the first and second voltage signals to said differentiator and said divider means, said further switch being operable with said inverter to provide a phase correction during said signal interchange.

3. A system according to claim 2, wherein

said differentator means, said divider means, said jointly actuatable switches and said further switches comprise circuits of analog operation for a high signal processing speed.