Method of controlling operation of a vibratory roller

Abstract

The present invention relates to a method of controlling operation of a vibratory roller comprising a roller drum and a vibratory mechanism. The method comprises determining a temperature of a surface to be compacted by the vibratory roller, determining a desired phase angle based on said determined temperature and maintaining the phase angle at, or close to, said desired phase angle by controlling the vibration frequency of the vibratory mechanism.

1 . A method of controlling operation of a vibratory roller, said vibratory roller comprising a roller drum and a vibratory mechanism, said method comprising:
 determining a temperature of a surface to be compacted by the vibratory roller;   determining a desired phase angle as a function of said determined temperature, the phase angle being the difference in angular position between an eccentric force generated by the vibratory mechanism and the displacement of the roller drum and being determined based on signals from each of an accelerometer and an eccentric position sensor; and   maintaining the phase angle at, or close to, said desired phase angle by controlling the vibration frequency of the vibratory mechanism.   
     
     
         2 . A method according to  claim 1 , wherein the step of determining a temperature comprises measuring a temperature. 
     
     
         3 . A method according to  claim 1 , wherein said desired phase angle is determined continuously and preferably every 0.2 seconds. 
     
     
         4 . A method according to  claim 1 , wherein the temperature is measured using an infrared sensor. 
     
     
         5 . A method according to  claim 1 , wherein said vibratory roller has at least two amplitude settings. 
     
     
         6 . A method according to  claim 1 , further comprising the step of adjusting the speed at which the vibratory roller is operated based on said determined temperature. 
     
     
         7 . A method according to  claim 1 , wherein said vibratory roller comprises two roller drums and two vibratory mechanisms, and wherein the phase angle is maintained at, or close to, said desired phase angle by controlling the vibration frequency of each of the two vibratory mechanisms.