Forage harvester comprising a monitoring mechanism for shear bar and cutting drum

A forage harvester including a frame, a cutting arrangement and a plurality of displacement mechanisms. The cutting arrangement includes a cutting drum that is rotatable about a rotation axis with respect to the frame, and a shear bar holder configured to receive a shear bar attached thereto. Each of the displacement mechanisms including an actuator for displacing the shear bar with respect to the cutting drum and the frame. The displacement mechanisms include a sensor arrangement to measure one or more values representative of a force exerted on the shear bar and the shear bar holder when the cutting drum is rotating and cutting crops supplied to an area between the cutting drum and the shear bar.