Vibration based pavement roughness monitoring system using vehicle dynamics and smartphone with estimated vehicle parameters

Abstract

Due to the high cost associated with pavement roughness monitoring, researches are going on to develop new techniques of pavement monitoring which are cost effective, frequent and easily implementable. Conventionally, pavement monitoring is performed using road profilers consisting of laser and inertial sensors. Though these profilers provide measurements of high accuracy, the high operating cost of these devices makes it difficult to ensure regular pavement monitoring. With the development of technology, new researches are being performed for the development of low-cost pavement monitoring systems using ordinary vehicle and smartphones. However, in most of the studies, the effect of vehicle suspension system on pavement monitoring was not considered and also direct reconstruction of pavement profile was not performed to compute the International Roughness Index (IRI), widely used for pavement roughness monitoring system. Instead, some correlation based procedures have been followed for measurement of pavement roughness. In this paper, a vibration based method for monitoring of pavement condition is introduced using ordinary vehicle and smartphone as vibration sensors which includes calibration for vehicle suspension system. The whole process can be divided into two stages. The unknown dynamic parameters of the ordinary vehicle are identified first. The vehicle is driven over a speed bump of known dimension and vehicle vertical acceleration is recorded. State-space representation of the vehicle model with unknown parameters is performed and the parameters are estimated using Grey-Box model system identification technique. Secondly, a new pavement profile reconstruction technique is proposed based on inverse formulation of vehicle dynamics. The vertical acceleration of the vehicle with known parameters are collected by driving it over the pavement, the condition of which needs to be monitored. A new mathematical formulation of vehicle dynamics is developed and using the collected acceleration data, pavement profile is reconstructed. Further, International Roughness Index of the reconstructed pavement is calculated. Numerical simulations and field testing of the proposed method are performed for various pavement roughness conditions and vehicle speeds performed for determining its viability for pavement condition monitoring.