Power Liftgate Sensor Zoning to Prevent False Obstacle Detection
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Solution Overview
Problem
Existing adjustment devices for vehicle parts, such as liftgates, often fail to differentiate between a user's body part and an obstacle, leading to incorrect obstacle detection and potential failure to close the vehicle part due to deactivation of sensor systems or collision risks.
Innovation Solution
An electronic control device is coupled to the drive, actuating element, and sensor, queuing the adjustment signal until the obstacle signal ceases, ensuring the user has left the monitoring region, and optionally using a delay or reduced speed to prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor device is completely deactivated for some time when an adjustment signal is triggered, then the user's body part no longer causes false obstacle detection, but the vehicle part may be adjusted although an actual obstacle is present in the adjustment path
Solution Approach 1:
The monitoring region is divided into two distinct zones: a first region containing the actuating element where the sensor is deactivated or obstacle signals are ignored, and a second region where normal obstacle detection continues. This segmentation allows the system to differentiate between the user's hand during actuation and actual obstacles in the adjustment path, resolving the contradiction between preventing false detection and maintaining safety.
Solution Approach 2:
The sensor device exhibits different operational characteristics in different spatial locations. In the first region (actuating element area), the sensor is either deactivated or its signals are ignored, while in the second region (adjustment path area), the sensor operates normally. This local differentiation in sensor behavior enables the system to tolerate the user's presence during actuation while still detecting actual obstacles.
2Reliability
If the sensor device remains active in the monitoring region, then actual obstacles can be detected, but the user's body part is incorrectly interpreted as an obstacle causing the adjustment to fail
Solution Approach 1:
The monitoring region is segmented into a first region with the actuating element and a second region along the adjustment path. The control device is configured to ignore obstacle signals from the first region while maintaining normal obstacle detection in the second region. This allows users to successfully actuate the vehicle part without false obstacle detection, while still maintaining safety through active monitoring of the adjustment path.
Solution Approach 2:
The control device acts as an intermediary that receives obstacle signals from the sensor device and selectively processes them based on their origin location. It mediates between the sensor's continuous monitoring function and the actuating element's need for unobstructed detection, allowing normal operation during actuation while maintaining safety monitoring elsewhere.
3Measurement precision
If the adjustment signal is queued until the obstacle signal ceases, then false obstacle detection by user body parts is avoided, but the adjustment operation is delayed
Solution Approach 1:
By segmenting the monitoring region and applying different processing rules to different zones, the system avoids unnecessary queuing delays. Obstacle signals from the first region (user's hand) are ignored rather than triggering queue delays, while signals from the second region (actual obstacles) properly trigger safety protocols. This eliminates unnecessary time loss while maintaining accurate obstacle detection.
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
Prevents false obstacle detection and ensures safe, reliable operation by ensuring the user has cleared the area before initiating the adjustment, reducing the risk of collisions and improving user interaction with power-operated vehicle parts.
Implementation Method 1
by means of which an obstacle in the adjustment path of the vehicle part can be detected in a contactless way and upon detection of an obstacle in the adjustment path of the vehicle part an obstacle signal is generated... The sensor device defines a monitoring region in the surroundings of the vehicle part to be adjusted in order to for example infer an obstacle from a changing capacitance in this monitoring region
Data Source
AI summary
It is provided an adjustment device for the power-operated adjustment of a vehicle part that is adjustable on a vehicle along an adjustment path between a closed position and at least one open position, comprising a sensor device by means of which an obstacle in the adjustment path of the vehicle part can be detected in a contactless way and upon detection of an obstacle in the adjustment path of the vehicle part an obstacle signal can be generated, and comprising an electronic control device coupled to at least one drive for the adjustment of the vehicle part, at least one actuating element for generating an adjustment signal and the sensor device, by means of which on the basis of the adjustment signal the at least one drive can be actuated for the power-operated adjustment of the vehicle part.