Distance Sensor Calibration Using External Reference Objects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing calibration methods for in-vehicle distance sensors in work machines are limited by the requirement that a work tool must be present in the measurement area, which is not always feasible, especially when the sensor is positioned on a side surface or when the work machine lacks a work tool.
Innovation Solution
A calibration device and method that utilize a distance acquisition unit, position calculation unit, and calibration unit to calibrate the distance sensor by measuring first distance data from a reference object outside the work machine, calculating its position in a predetermined coordinate system, and establishing a positional relationship with a known reference object to determine calibration parameters, regardless of the presence of a work tool in the sensor's measurement area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance sensor is positioned on a side surface of the work machine, then the sensor can be installed in various locations, but the work tool is not present in the measurement area making calibration impossible
Solution Approach 1:
The patent introduces a reference object as an intermediary target for calibration. Instead of requiring the work tool to be in the measurement area, a reference object with known position and posture is placed in the area, serving as a mediator that enables calibration through its detectable features (code pattern, reflective markers, etc.)
Solution Approach 2:
The patent creates a virtual model (copy) of the reference object with known position and posture information. This digital twin is used to compare against actual sensor measurements, enabling calibration without requiring the physical work tool. The code pattern or markers on the reference object create a recognizable signature that can be matched to its known coordinates
2Measurement precision
If the calibration method requires work tool presence in measurement area, then calibration accuracy can be maintained, but the method cannot be applied when work tool is absent or sensor is on side surface
Solution Approach 1:
The patent makes the calibration system universal by replacing the work tool-specific calibration target with a general-purpose reference object. This reference object can serve multiple calibration scenarios regardless of sensor position (front, side, rear) or work machine type, enabling one calibration method to handle multiple installation configurations
Solution Approach 2:
The patent changes the calibration parameter from work tool position to reference object position. By using a reference object with known, pre-defined coordinates and detectable features, the calibration process transforms into comparing sensor measurements against these known parameters, maintaining accuracy while expanding applicability
Data Source
AI summary
A distance acquisition unit acquires first distance data that is distance data in an area in which a first reference object installed at an arbitrary position outside a work machine is present. The distance data is measured by an in-vehicle distance sensor. A position calculation unit calculates a position of the first reference object in a predetermined coordinate system based on the first distance data. A relationship acquisition unit acquires a positional relationship between the first reference object, and a second reference object of which a position in the coordinate system is known. A calibration unit calibrates, based on the first distance data and the positional relationship, a parameter to be used to measure a position in the coordinate system from the distance data of the in-vehicle distance sensor.