Standard-wheel-based field calibration method for railway wheelset diameter online measuring system

Area of Science:

• Engineering
• Metrology
• Sensor Technology

Background:

• Laser displacement sensors (LDS) are crucial for non-contact, high-efficiency, and high-precision online wheel diameter measurement.
• Effective calibration is essential for obtaining accurate extrinsic sensor parameters in these systems.

Purpose of the Study:

• To propose a field-based, economical, and efficient calibration method for LDS-based wheel diameter online measuring systems.
• To simplify the calibration process using a single standard wheelset as a 3D calibration target.

Main Methods:

• Developed a calibration method using a single standard wheelset to create a 3D calibration target.
• Employed a multistart framework with a nonlinear programming solver to minimize the residual sum of squares for obtaining extrinsic sensor parameters.
• Analyzed the impact of standard wheelset placement and sensor noise on calibration accuracy.

Main Results:

• Successfully obtained extrinsic parameters for each LDS by minimizing the residual sum of squares.
• Validated the calibration method through field experiments, showing agreement with manual caliper measurements.
• Demonstrated the feasibility and correctness of the proposed calibration approach.

Conclusions:

• The proposed field-based calibration method is effective, economical, and easy to operate for LDS-based wheel diameter measurement systems.
• The method accurately determines sensor extrinsic parameters, crucial for reliable online measurements.
• Further analysis confirmed the influence of placement and noise on calibration errors, providing insights for practical implementation.