CPILS – New generation of compact pantograph inspection laser scanners

The project CPILS represents the international collaboration of the Danish Technical University, PantoInspect A/S, Z-LASER Optoelektronik GmbH and the Ferdinand-Braun-Institut within the framework of EuroStars, stimulating research and innovation projects that will be rapidly commercialized. In this project, a new eye-safe scanner for real-time automated analysis of pantographs (roof mounted current collectors) on light rail electrified rolling stocks will be developed.

Functional principle for a laser-based pantograph imaging in the project CPILS
Functional principle for a laser-based pantograph imaging in the project CPILS (http://www.pantoinspect.com)

In a worst case scenario, damaged pantographs, cause costly and dangerous overhead wire teardown, impacting passenger safety and operational punctuality. Pantograph inspection is today mostly done visually with vehicles periodically taken out of service. Commercial solutions for more efficient automatic control are currently only available for the heavy rail segment. Developing a lighter, more compact and technical robust system will enable to also target light rail and e-highways.

The working principle for the inspection is projecting laser lines onto the pantograph passing below the overhead wire and recording the illumination profiles with a camera to reconstruct a three-dimensional image. Applying 50 µs pulsed lasers with high output beam uniformity and high speed cameras enables to inspect pantographs with unprecedented accuracy and reliability at train speeds up to 180 km/h. Laser emission wavelengths specifically selected with respect to atmospheric absorption will further increase the signal-to-noise ratio of the measurements and enable light rail systems monitoring under city outdoor daylight and different weather conditions.

FBH and itsLaser Sensors Lab will develop two new tapered diode laser based light sources at 762 nm and 810 nm to be implemented into the scanners. While the latter is an established wavelength in pantograph inspection systems, the shorter wavelength range utilizes the enhanced absorption by oxygen for disturbing sunlight contributions. The superior high beam quality of the developed tapered lasers with respect to previously applied lasers enables uniform illumination along the pantograph and reduced output power of 1-3 W needed for inspection. External wavelength stabilization with volume Bragg gratings will reduce the laser emission bandwidth below 0.2 nm to implement optical filters into the imaging system for increased signal-to-noise ratio.

CPILS (duration 01.10.2017 - 29.02.2020)

Funding: BMBF grant number 01QE1756C