Pinch Detection Using Relative Temperature Correction
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Solution Overview
Problem
Existing pinch detection apparatuses for opening-and-closing members, such as those in vehicles, face challenges in accurately detecting pinch conditions due to temperature variations affecting motor rotation speed and load relationships, leading to inconsistent detection thresholds and increased costs for high-accuracy temperature sensors, as well as reduced detection accuracy over time due to motor aging.
Innovation Solution
A pinch detection apparatus that calculates and stores reference load data and temperature data during a predetermined condition, then adjusts the detection threshold based on the relative temperature difference between the reference and actual temperatures during the closing operation, allowing for accurate pinch determination without the need for precise motor temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor with high accuracy is provided in vicinity of the motor to detect motor temperature for pinch detection, then pinch detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses environmental temperature as an intermediary parameter to represent motor temperature conditions. Instead of directly measuring motor temperature with a dedicated sensor, the system uses ambient temperature data combined with stored characteristic relationships to infer motor temperature effects on load, thereby achieving accurate pinch detection without requiring a high-precision motor-mounted temperature sensor
Solution Approach 2:
The patent creates a characteristic map that copies the relationship between motor temperature, rotation speed, and load under various conditions. This stored characteristic data allows the system to replicate motor temperature effects through calculation rather than direct measurement, eliminating the need for complex temperature sensing while maintaining detection accuracy
2Device complexity
If reference load data is calculated without considering environmental temperature, then calculation simplicity is improved, but pinch detection accuracy deteriorates due to temperature-induced relationship changes
Solution Approach 1:
The patent changes the parameters used in load calculation from simple rotation speed alone to a combination of rotation speed and environmental temperature. By incorporating temperature as an additional parameter and using stored characteristic data that accounts for temperature effects, the system maintains calculation simplicity while significantly improving pinch detection accuracy across varying environmental conditions
3Measurement precision
If an initial characteristic map is used for load estimation, then initial detection accuracy is improved, but detection accuracy deteriorates over time due to motor aging
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors actual motor behavior during operation and compares it against the characteristic map. When deviations occur due to motor aging, the system can update the characteristic data to reflect current motor conditions, thereby maintaining accurate pinch detection over the motor's lifetime rather than degrading from initial accuracy
Solution Approach 2:
The patent performs preliminary characterization of the motor's temperature-speed-load relationship and stores this data for future reference. This pre-established characteristic map serves as a baseline that can be updated over time to account for aging, allowing the system to maintain accuracy without requiring complex real-time adaptation mechanisms
Data Source
AI summary
A pinch detection apparatus for an opening-and-closing member actuated by a motor, the pinch detection apparatus includes a reference data storage portion calculating load data on the basis of a rotation speed of the motor and an environmental temperature, the reference data storage portion storing the load data and the environmental temperature as reference load data and reference temperature data, respectively, a drive load calculation portion calculating drive load data, and a pinch determination portion configured to determine an occurrence of pinch on the basis of a comparison result obtained by comparing a difference between the reference load data and the drive load data with a threshold, the pinch determination portion configured to correct a relative relation between the difference between the reference load data and the drive load data, and the threshold on the basis of a relative relation between a reference temperature and a drive temperature.