Velocity detector for detecting velocity from position detector outputting a pair of orthogonal signals

• US 5,012,188 A
• Filed: 11/08/1989
• Issued: 04/30/1991
• Est. Priority Date: 11/10/1988
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nagano, Hiroyuki, Kubo, Keishi, Kubota, Saburo
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US07/433,211
• Time in Patent Office: 538 Days
• Field of Search: 324/160, 324/161, 324/163, 324/165, 324/166, 364/565, 318/779, 318/799
• US Class Current: 324/160
• CPC Class Codes: G01P 3/44 for measuring angular speed G01P3/56 takes precedence

Abstract

A velocity signal is obtained by calculating both the selected signal of the differentiated signal of the position signal from a position detector and the selected signal of the sinusoidal wave signal according to position displacement, so that a velocity detection produces a smaller velocity detection error at a low velocity and generates no ripple component even when a high velocity is detected.

Claims

1. A velocity detector for obtaining the velocity based on first and second sinusoidal signals output from a position detector, said sinusoidal signals differing in phase by 90°

from each other according to position displacement, said velocity detector comprising;

first and second converters for respectively receiving and converting the first and second signals output from the position detector into first and second respective electrical signals;

first and second waveform shaping circuits for respectively receiving and waveform shaping said first and second electrical signals from said first and second converters and for providing respective outputs therefrom;

first and second differentiators for respectively receiving and differentiating said first and second electrical signal output from said first and second converters and for providing respective outputs therefrom;

first and second multipliers for obtaining the product of the signals from said first and second waveform shaping circuits and said first and second differentiators, said first multiplier multiplying said output of said first waveform shaping circuit and said second differentiator and said second multiplier multiplying the output of said first differentiator and second waveform shaping circuit;

a first adder for receiving outputs of said first and second multipliers and for providing an output corresponding to the sum thereof;

first and second absolute value detectors for respectively receiving said two signals output from said first and second converters and for providing respective outputs therefrom which correspond to the absolute value of the signals input thereto;

a second adder for receiving said outputs of said first and second absolute value detectors and for providing an output corresponding to the sum thereof;

a divider for receiving said output signals from said first and second adders and for providing an output corresponding to the quotient of said outputs of said first and second adders, said output corresponding to the detected velocity.