Search Content

The first part of this project conducted a detailed evaluation of the ability of a new friction measurement system to provide an accurate measure of road conditions. A system that records friction coefficient as a function of road location was developed using the same vehicle location measurement system as the current MDSS project. Studies conducted show that the friction measurement system provides a significantly more reliable measure of road surface conditions than does visual inspection. The second part of this project focused on a detailed evaluation of the performance of a closed-loop system that utilizes friction measurement for automatic applicator control. Experimental studies have shown that a friction measurement based zero velocity sander can adequately apply salt/chemicals to all slippery spots on a road at speeds up to 25 mph. The final part of this project focused on enhancement of the developed automatic applicator control system with utilization of real-time data from a geographical information system that provides information on upcoming geometric road alignment and known problematic segments of roadway. The developed friction measurement, data recording and applicator control system is compact, modular and can be used on both snowplows and pick-up trucks.

Real-time measurement of tire-road friction coefficient is extremely valuable for winter road maintenance operations and can be used to optimize the kind and quantity of the deicing and anti-icing chemicals applied to the roadway. In this project, a wheel based tire-road friction coefficient measurement system is first developed for snowplows. Unlike a traditional Norse meter, this system is based on measurement of lateral tire forces, has minimal moving parts and does not use any actuators. Hence, it is reliable and inexpensive. A key challenge is quickly detecting changes in estimated tire-road friction coefficient while rejecting the high levels of noise in measured force signals. Novel filtering and signal processing algorithms are developed to address this challenge including a biased quadratic mean filter and an accelerometer based vibration removal filter. Detailed experimental results are presented on the performance of the friction estimation system on different types of road surfaces. Experimental results show that the biased quadratic mean filter works very effectively to eliminate the influence of noise and quickly estimate changes in friction coefficient. Further, the use of accelerometers and an intelligent algorithm enables elimination of the influence of driver steering maneuvers, thus providing a robust friction measurement system. In the second part of the project, the developed friction measurement system is used for automated control of the chemical applicator on the snowplow. An electronic interface is established with the Force America applicator to enable real-time control. A feedback control system that utilizes the developed friction measurement sensor and a pavement temperature sensor is developed and implemented on the snowplow.