the machine forward at operating element 17 causing the force action angle to be set flatter again if the vertical downward directed operator force decreases the force angle will likewise be set flatter again both measures will enable the machine to resume travel as long as the vibrating plate is not receiving any horizontal or vertical operator force signal it will reset the vibration exciter to a standard force angle of e g 45 u00b0 for special applications e g paving work other standard force angles can also be specified fig9 shows the control circuit of fig8 during backward travel of the vibrating plate operating element 17 was pivoted toward the rear by the operator in a known manner in order to control the vibration exciter in such a way as to produce a resultant force vector having a horizontal component in the backward direction here as well force measurement devices are again provided for acquiring the forces applied by the operator if during backward travel the vibrating plate moves onto a gradient the operator will intuitively try to lift operating element 17 as an extension of drawbar 16 upward toward the rear in order to lift the rear edge of soil contact plate 1 the force f d applied for this purpose is acquired by the force measuring device and is forwarded as force signal 18 to central computer 19 if the measured operator force exceeds the normal operator force this computer will set the force action angle to be steeper.