Brushed DC Motor Pulse Timing for Accurate Angular Displacement
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Solution Overview
Problem
Existing methods for determining the angular displacement of a brushed DC electromotor are not accurate due to manufacturing imperfections and variations in energy supply, leading to errors in counting pulses and determining rotational displacement.
Innovation Solution
A method that monitors the supply current to adjust pulse counting by subtracting or adding pulses based on deviations from expected time periods, using indicators like supply current, voltage, and ambient temperature to correct for errors and improve accuracy in determining angular displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pulse counting is used to determine angular displacement, then the measurement method is simple, but manufacturing imperfections cause additional pulses that reduce measurement precision
Solution Approach 1:
The system monitors the time intervals between consecutive pulses and compares them against expected values. When deviations are detected (indicating manufacturing defects), the system automatically compensates by adjusting the pulse count, thereby maintaining measurement precision without increasing hardware complexity
Solution Approach 2:
The invention changes the parameter being monitored from simply counting pulses to measuring the time intervals between pulses. By using time interval information, the system can identify and correct for manufacturing imperfections, improving measurement precision while keeping the device simple
2Ease of operation
If pulse counting is used to determine angular displacement, then the implementation is straightforward, but variations in energy supply cause pulse detection errors that reduce reliability
Solution Approach 1:
The system continuously monitors time intervals between pulses and uses this feedback to detect variations caused by energy supply fluctuations. When abnormal intervals are detected, the system compensates for the errors, maintaining reliable measurements without complicating the implementation
3Quantity of substance
If additional pulses from manufacturing defects are counted, then the pulse count increases, but the angular displacement measurement becomes inaccurate
Solution Approach 1:
The system extracts and identifies the spurious pulses caused by manufacturing defects by analyzing time intervals between consecutive pulses. When a pulse occurs at an unexpected time interval, it is excluded from the counting, thereby improving measurement precision while maintaining accurate pulse quantity measurement
Data Source
AI summary
Driving an electromotor and a brushed electromotor in particular results in ripples in the supply current. The amount of pulses is proportional to the amount of revolutions of the rotor of the electromotor. With a flawless motor, the amount of pulses is the same with each revolution. Flaws of the electromotor, in brushes, rotor, windings and/or other components, results in fluctuations of pulses in the supply current per revolution of the rotor. By comparing an expected amount of pulses to counted pulses and using various physical parameters of the electromotor, various methods may be employed to correct a counted amount of pulses or otherwise provide an appropriate value representing displacement of the rotor of the electromotor. The time between counted pulses may also be used for determining slip of a slip coupling comprised by a drive train to which the electromotor may be coupled.