Driver assistance system of a forage harvester

Abstract

A driver assistance system of an agricultural work machine constructed as forage harvester, wherein the agricultural work machine comprises a header for gathering crop, a chopping device having a chopping drum and chopping knives for comminuting the crop, and a monitoring device operable to generate a signal containing information about the wear status of the respective chopping knife and/or about the distance of the cutting edge of a chopping knife from a shear bar. This information is compared with a reference value, and the agricultural work machine has activation devices for activating and deactivating a knife grinding process and means for change of position of the shear bar. The monitoring device is integrated in the driver assistance system so that the driver assistance system automatically detects when a knife grinding process or a change of position of the shear bar must be activated or deactivated.

What is claimed is: 
     
         1 . A driver assistance system of an agricultural work machine constructed as forage harvester having a header for gathering crop and a chopping device comprising a chopping drum and chopping knives associated with the chopping drum for comminuting the crop, and activation devices for activating and deactivating a knife grinding process and for changing a position of the shear bar, the driver assistance system comprising:
 a monitoring device that is operable to generate a signal which contains information about a wear status of a respective one of the chopping knives or about a distance of a cutting edge of one of the chopping knives from a shear bar,   wherein the driver assistance system is configured to compare information about the wear status of the chopping knives or about the distance of the cutting edge from the shear bar with a reference value in each instance, and   wherein the monitoring device is integrated in the driver assistance system in such a way that the driver assistance system automatically detects when a knife grinding process must be activated or deactivated or a change of position of the shear bar is to be activated or deactivated.   
     
     
         2 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 1 , wherein the driver assistance system is configured to activate or deactivate the knife grinding process or the change of position of the shear bar, or generates a notification for an operator of the agricultural work machine to activate or deactivate the knife grinding process or the change of position of the shear bar. 
     
     
         3 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 1 , wherein the driver assistance system is configured such that signals generated by the monitoring device which contain information about the wear status of the respective chopping knife or about the distance of the cutting edge of a chopping knife from a shear bar are converted into an actual cutting sharpness value and an actual distance value of the shear bar, and the respective actual value is compared with the stored associated reference value, and when the respective actual value lies below a sharp knife reference value or above the reference distance value, the knife grinding process or the change of position of the shear bar is activated. 
     
     
         4 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 3 , wherein the driver assistance system is configured such that signals which are generated by the monitoring device and which contain information about the wear status of the respective chopping knife or about the distance of the cutting edge of a chopping knife from a shear bar are converted into an actual cutting sharpness value and an actual distance value of the shear bar, and the respective actual value is compared with the stored associated reference value, and when the actual value reaches or lies above a sharp knife reference value or when the actual value reaches or lies below the reference distance value, the knife grinding process or the change of position of the shear bar is deactivated. 
     
     
         5 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 3 , wherein the driver assistance system is configured such that the sharp knife reference value and the reference distance values of the shear bar can be changed depending on the type of crop. 
     
     
         6 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 1 , wherein the monitoring device monitors the cutting sharpness or the wear status or a magnitude of a cutting gap for each chopping knife. 
     
     
         7 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 1 , wherein the driver assistance system is configured to determine a radius of the chopping drum from distance signals generated by the monitoring device. 
     
     
         8 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 1 , wherein the driver assistance system is configured to determine a quantity of chopping knives positioned on a chopping drum from signals generated by the monitoring device, and a configuration of the chopping drum is brought about automatically in the driver assistance system. 
     
     
         9 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 1 , wherein the driver assistance system is configured such that a product feed-dependent wear status is inferred from signals generated by the monitoring device, and steps are derived which bring about a product feed that reduces wear. 
     
     
         10 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 9 , wherein the derived steps contain a change of one or more parameters of the header for receiving crop and/or gathering and pre-compacting rollers arranged downstream of the header. 
     
     
         11 . The driver assistance system of an agricultural work machine constructed as a forage harvester according to  claim 1 , wherein the monitoring device comprises a detection arrangement for detecting the wear status of a respective chopping knife of the chopping device, wherein the drum is a revolving chopping drum and wherein there is at least one shear bar which cooperates with the chopping knives, wherein the detection arrangement comprises at least one sensor arrangement which has a magnetic exciter arrangement and a flux conducting device magnetically coupled thereto, wherein the sensor arrangement provides a pole arrangement which forms at least one magnetic pole with a pole surface for conducting magnetic flux, wherein the sensor arrangement is positioned such that at least a portion of the chopping knives passes the pole arrangement during a rotation of the chopping drum, the chopping knife passing the pole arrangement forms an air gap arrangement with at least one air gap with respect to the pole arrangement, and at least one magnetic circuit excited by the exciter arrangement is accordingly closed via the respective chopping knife, wherein the detection arrangement has a measuring arrangement and an evaluating unit, wherein the measuring arrangement is configured to detect at least one measured magnetic value pertaining to the magnetic flux in at least one magnetic circuit excited by the exciter arrangement, and the evaluating unit is configured to determine the wear status of the respective chopping knife from the at least one detected measured value. 
     
     
         12 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 11 , wherein the voltage induced when the chopping knife arrangement passes the sensor arrangement forms the measured magnetic value, and the detection arrangement is configured to determine the induced voltage and record it as a voltage signal, the evaluating unit is configured to resolve the voltage signal into its frequency components by means of frequency analysis in which frequency components are separated into frequency components of a fundamental oscillation and into frequency components of a superposed oscillation which cause signal distortion, wherein the separated frequency components of the superposed oscillation which cause a signal distortion are inverse-transformed in a time domain, and a measurement for the wear status or cutting sharpness of one of the chopping knives is derived from the inverse-transformed frequency components of the superposed oscillation. 
     
     
         13 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 11 , wherein the at least one sensor arrangement is positioned at a circumference of the chopping drum such that every chopping knife of the chopping drum is detected by means of a sensor arrangement, wherein right-hand-side and left-hand-side chopping knife arrangements are associated with the chopping drum, and at least one sensor arrangement is associated with each of these chopping knife arrangements. 
     
     
         14 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 11 , wherein a plurality of induction sensors are associated with each sensor arrangement, and each induction sensor is configured to generate a voltage signal, wherein each of the generated voltage signals is analyzed separately, and wherein a plurality of voltage signals, or all of the voltage signals, of a detected chopping knife are combined to form one or more voltage signals prior to an analysis. 
     
     
         15 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 14 , wherein the frequency analysis of the voltage signal is carried out by means of Fourier analysis to classify the respective voltage signal into frequency components of a fundamental oscillation and frequency components of a superposed oscillation which cause signal distortions, and wherein the frequency components representing the fundamental oscillation are not taken into account in the derivation of the wear status or of the cutting sharpness of the respective chopping knife. 
     
     
         16 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 15 , wherein an amplitude of the respective voltage signal of the frequency components causing a signal distortion forms a measurement for assessing the wear status and/or the cutting sharpness of the respective chopping knife. 
     
     
         17 . The driver assistance system of an agricultural work machine constructed as forage harvester according to  claim 16 , wherein the assessment of the cutting sharpness or wear status is effected by means of evaluation criteria selected from the group consisting of grinding surface length of the respective chopping knife, roundness of a chopping knife tip, general knife wear, camber of the chopping knife and relative distance of the shear bar from the chopping knife.