Vehicle Obstacle Detection Adjusting Ultrasonic Directivity
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Solution Overview
Problem
Conventional obstacle detecting systems for vehicles experience a dead zone near the vehicle due to a longer masking period required to separate transmitting and receiving ultrasonic waves, limiting the detection range and increasing the dead zone width as the distance to the obstacle increases.
Innovation Solution
An obstacle detecting system with a directivity control section that adjusts the frequency of the transmitting wave based on the calculated distance to the obstacle, lowering directivity when close and increasing it when farther away, allowing for continuous obstacle detection without a dead zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the masking period is extended to separate transmitting and receiving waves, then the separation between transmitting and receiving waves is improved, but the dead zone width increases
Solution Approach 1:
The patent applies dynamics by making the directivity of the transmitting wave adjustable rather than fixed. The directivity control section dynamically changes the directivity based on detection needs, allowing the system to adapt between wide directivity (for near obstacles) and narrow directivity (for remote obstacles), thereby resolving the contradiction between wave separation and dead zone width
Solution Approach 2:
The patent changes the directivity parameter of the transmitting wave to resolve the contradiction. By adjusting directivity based on obstacle distance requirements, the system can use wide directivity with shorter masking periods for near obstacles and narrow directivity with longer masking periods for remote obstacles, eliminating the fixed trade-off
2Length of stationary object
If the transmitting wave is transmitted for a longer time period to detect remote obstacles, then the detection range is improved, but the masking period becomes longer
Solution Approach 1:
The system dynamically adjusts the directivity of the transmitting wave based on the desired detection range. For remote obstacles, narrow directivity concentrates energy over longer transmission periods, while for near obstacles, wide directivity provides sufficient coverage with shorter transmission periods, resolving the time-range contradiction
Solution Approach 2:
The patent changes the directivity parameter to optimize the balance between transmission time and detection range. By adjusting directivity according to obstacle distance requirements, the system achieves appropriate masking periods for different detection scenarios
3Use of energy by moving object
If the directivity of the transmitting wave is increased to detect remote obstacles, then the energy concentration is improved, but the detection of near obstacles is hindered
Solution Approach 1:
The patent applies dynamics by making directivity adjustable. The system uses wide directivity for detecting near obstacles to ensure comprehensive coverage, and switches to narrow directivity for remote obstacles to concentrate energy, thereby resolving the contradiction between energy concentration and near obstacle detection reliability
Solution Approach 2:
The system changes the directivity parameter based on obstacle distance. Wide directivity is used when near obstacles need detection, and narrow directivity is used when remote obstacles are the target, optimizing energy distribution for different detection scenarios
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
Enables reliable detection of obstacles at various distances by adjusting the directivity of the transmitting wave, reducing the dead zone and ensuring timely detection of both near and distant obstacles, while also generating an alarm for the driver when close proximity is detected.
Implementation Method 1
a clearance sonar sensor (3a to 3f) transmits an ultrasonic wave as a transmitting wave (TW) and receives an ultrasonic wave reflected by an obstacle (OB) as a receiving wave (RW)
Data Source
AI summary
An obstacle detecting system for a vehicle detects an obstacle by transmitting a transmitting wave and receiving a receiving wave, which is a reflection of the transmitting wave by the obstacle. The system calculates a distance to the obstacle. The system varies directivity of the transmitting wave in accordance with the calculated distance. The directivity is lowered when the calculated distance is less than a predetermined reference distance, than when the calculated distance is greater than the predetermined reference distance.