Sensor Unit Calibration for Industrial Trucks
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Solution Overview
Problem
Existing calibration methods for sensor units on industrial trucks are time-consuming, error-prone, and require specific surroundings, limiting their precision and flexibility, especially when recalibrating in different environments.
Innovation Solution
A method involving the displacement of the sensor unit along predetermined directions to measure its spatial arrangement relative to a stationary object, using at least two positions and solving equations with the least linear square method to determine extrinsic parameters such as mounting position and angles, allowing for precise calibration without the need for optical markers or specific surroundings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual arrangement of the sensor unit on the load-bearing device is used, then the spatial position can be determined, but the process is time-consuming and error-prone
Solution Approach 1:
The sensor unit performs self-calibration by automatically determining its own spatial arrangement relative to the load-bearing device through image processing and coordinate transformation, eliminating the need for manual arrangement and measurement
Solution Approach 2:
The manual mechanical arrangement process is replaced by an automated computational method using image data processing, coordinate system transformations, and algorithmic calculation of spatial parameters
2Measurement precision
If optical markers and specific surroundings are used for calibration, then the sensor signal can be evaluated, but the method is complex and requires specific calibration surroundings
Solution Approach 1:
The calibration method extracts and uses only the necessary elements (sensor unit, load-bearing device, and object images) while eliminating unnecessary components such as optical markers and specialized calibration surroundings
Solution Approach 2:
The calibration method can be performed in any environment where the sensor can capture images of objects, making it universally applicable without requiring specific calibration surroundings or specialized equipment
3Measurement precision
If the sensor unit is arranged on the load fork with a reference object, then positioning can be achieved, but the reference object restricts the field of vision and may interfere or become damaged during operation
Solution Approach 1:
The reference object that causes field of vision restriction and damage risk is completely removed from the system. Instead, the load-bearing device itself serves as the reference frame for calibration
Solution Approach 2:
Images of objects captured by the sensor unit serve as intermediaries to establish the spatial relationship between the sensor and the load-bearing device, eliminating the need for physical reference objects that could interfere with operation
Data Source
AI summary
A method for calibrating a sensor unit disposed on a load-bearing device of an industrial truck includes the steps of: determining a first position of the sensor unit relative to an object located remotely from the industrial truck, displacing the sensor relative to the object in a first direction by a first distance, determining a second position of the sensor unit relative to the object, determining the spatial position or arrangement of the sensor unit relative to the load-bearing device based on the first and second positions, the direction of movement, and the distance between the first and second positions.