Rotational Angle Detection via Wiper Contact State Switching
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Solution Overview
Problem
Conventional rotational angle detecting devices using potentiometers can experience false detection due to slight contact between wipers and the resistor, leading to intermediate potential output and incorrect angle detection.
Innovation Solution
A rotational angle detecting device is designed with a rotary potentiometer, two wipers, and switching means controlled by a unit that switches the connection state of additional resistors to the power source, allowing for differentiation between valid and invalid contact states, thereby preventing false detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a potentiometer with two wipers is used to detect rotational angle, then the rotational angle can be detected from voltage change, but false detection occurs when a wiper is in slight contact with the resistor at dead band boundaries
Solution Approach 1:
The control unit performs preliminary evaluation of wiper contact states by analyzing voltage values before final angle detection. When a wiper is detected to be in slight contact (intermediate voltage state), the system preemptively identifies this as an invalid state and prevents false angle detection, thereby resolving the contradiction between measurement precision and reliability
Solution Approach 2:
The control unit acts as an intermediary between the potentiometer output and the angle detection system. It introduces an intermediate evaluation step that analyzes voltage values to determine valid vs. invalid wiper contact states, preventing false detection while maintaining accurate angle measurement when wipers are properly contacted
2Productivity
If angle detection is performed based on detection signals from last time and this time of sampling, then continuous angle tracking is achieved, but false detection continues when a wiper stays in slight contact and continuously outputs intermediate potential
Solution Approach 1:
The control unit implements feedback by continuously monitoring voltage values from both wipers and using this information to evaluate the validity of angle detection. When intermediate voltage indicates invalid contact, the feedback mechanism prevents using this data for angle calculation, thereby maintaining accuracy while preserving continuous tracking capability
Solution Approach 2:
Before performing angle detection based on sampling signals, the control unit preliminarily evaluates whether the wiper contact state is valid. This preliminary action prevents false detection from continuing even when a wiper remains in slight contact, while still allowing continuous angle tracking when contact is proper
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents false detection by changing the composite resistance value and output voltage, enabling accurate determination of the wiper positions and correct angle detection even when one wiper is in slight contact.
Implementation Method 1
two wipers in sliding contact with a surface of the resistor
Data Source
AI summary
A rotational angle detecting device includes a resistor of which one end is connected to the power source and the other end is grounded, a rotary potentiometer having two wipers which come into sliding contact with the surface of the resistor, a control unit which detects voltage applied to each of the wipers depending on the positions thereof upon the surface of the resistor, two resistors connected at one end to each of the two wipers, and switching means which switch the connection state between the other end of the two resistors and the power source under control of the control unit.