Patent Application
20200359563
This application claims priority under 35 USC 119 of German Application No. DE 10 2019 112 968.0, filed on May 16, 2019, German Application No. DE 10 2019 112 973.7, filed on May 16, 2019 and German Application No. DE 10 2019 112 965.6, filed on Jul. 1, 2019, the disclosure of which is herein incorporated by reference.
The invention is directed to a driver assistance system of an agricultural work machine constructed as forage harvester for monitoring the wear status of chopping knives.
A sensor arrangement which detects the revolving knives of a chopping drum arrangement by means of inductive sensors and derives a wear status of the chopping knives from the determined magnetic flux is known from DE 10 2017 103 537. Wear is determined from the induced voltage.
In addition, a similar cutting sharpness detection device is known, inter alia, from EP 1 522 214. In this case, optical sensors such as camera systems, lasers and near infrared sensors are used as detection devices.
Optical sensors have the problem that the cutting edge analysis is made more difficult by the high revolving speeds of the chopping knives, which often leads to poor-quality analysis results. On the other hand, the analysis of an induced voltage is influenced appreciably less by the high revolving speeds of the chopping knives to be detected. However, the evaluating process which is exclusively directed to the induced voltage does not always lead to a sufficiently accurate estimation of a wear status.
Further, a forage harvester outfitted with a driver assistance system is known from DE 10 2018 106 915.4. The work elements of the forage harvester are constructed as automatic adjusting means which are controllable by the driver assistance system in such a way that the work parameters of the forage harvester can be optimized without necessitating the involvement of the operator of the forage harvester in this process. This has the effect in particular that the operator need no longer personally monitor the work quality of the forage harvester. The drawback of this is that the known driver assistance system does not remove the operator of the agricultural work machine from the process of grinding the chopping knives.
Therefore, it is the object of the invention to avoid the disadvantages of the prior art described above and in particular to enable a driver assistance system to monitor the wear status of chopping knives.
This object is met according to the invention by an agricultural work machine constructed as forage harvester that comprises a monitoring device 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 and/or a change of position of the shear bar is to be activated or deactivated. In this way, it is ensured that a knife grinding process and a change of position of the shear bar is not dependent on monitoring by or judgment of the operator, which has the effect in particular that the knife grinding process is limited to the necessary extent.
In an advantageous configuration of the invention, the driver assistance system activates or deactivates the knife grinding process and/or the change of position of the shear bar automatically or generates a notification for an operator of the agricultural work machine to activate or deactivate the grinding process and/or the change of position of the shear bar so that the operator is completely relieved of monitoring tasks with regard to the cutting sharpness of the chopping knives. Further, the driver of the machine is notified about the state of the knives.
In an advantageous further development of the invention, it is ensured that the chopping knives are always kept in a sharp state which, in addition to high chopping quality, results in optimal fuel consumption in that the signals generated by the monitoring device which contain 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 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 the “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.
In order to limit the grinding process to the necessary extent, the signals which are generated by the monitoring device and which contain 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 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 the “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.
In order that crop-dependent effects on the wear of the chopping knives can be better taken into account, the “sharp knife” reference value and the reference distance values of the shear bar can be changed depending on the type of crop.
A high precision is achieved in the monitoring of cutting sharpness in that the monitoring device monitors the cutting sharpness and/or the wear status and/or the magnitude of the cutting gap for each chopping knife.
In view of the fact that an irregular product flow to the chopping drum to the chopping drum substantially influences the wear of the chopping knives, a radius of the chopping drum is determined from the distance signals generated by the monitoring device. This has the effect that an irregular wear and, therefore, an irregular product feed to the chopping drum can be inferred from the change of radius of the chopping drum. In this connection, it is also advantageous when a product feed-dependent wear status is inferred from the signals generated by the monitoring device, preferably the derived change of the radius of the chopping drum, and steps are derived which bring about a product feed that reduces wear. In the simplest case, the wear-reducing product feed can be brought about in that 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.
It is further ensured that the operator is substantially relieved from configuring effort in that the quantity of chopping knives positioned on a chopping drum is determined from the signals generated by the monitoring device, and the configuration of the chopping drum is brought about automatically in the driver assistance system.
It is ensured in a simple manner that the wear status of each chopping knife can be determined individually in that the detection arrangement for detecting a wear status of a chopping knife arrangement of a chopping device provided for processing a product flow is constructed as an inductive detection arrangement, and the voltage induced when a chopping knife arrangement passes over the sensor arrangement forms the measured magnetic value, and the detection arrangement determines the induced voltage and records it as a voltage signal, and an evaluating unit determines the wear status of the respective chopping knife from the at least one detected measured value.
In a further advantageous configuration of the invention, the detection of the wear status of chopping knives can be improved through simple measures in that the voltage signal is resolved into its frequency components in the evaluating unit by means of frequency analysis, and the frequency components are separated into frequency components of a fundamental oscillation and into frequency components of a superposed oscillation which cause signal distortion, and the separated frequency components of the superposed oscillation which cause a signal distortion are inverse-transformed in the time domain, and a measurement for the wear status and/or the cutting sharpness of a chopping knife is derived from the inverse-transformed frequency components of the superposed oscillation.
A sensor arrangement or the plurality of sensor arrangements are positioned at the circumference of the chopping drum such that every chopping knife of the chopping drum is detected by means of a sensor arrangement, it is ensured that each chopping knife positioned at the circumference of the chopping drum can be detected. This effect is also achieved in a further advantageous configuration in that 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.
A high-resolution and therefore very precise analysis of the wear status and knife sharpness is achieved in that a plurality of induction sensors, preferably five induction sensors, are associated with each sensor arrangement and each induction sensor generates a voltage signal, and each of the generated voltage signals is preferably analyzed separately and, further preferably, 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.
By means of Fourier analysis, the respective voltage signal is classified into frequency components of a fundamental oscillation and frequency components of a superposed oscillation which cause signal distortions, and the frequency components representing the fundamental oscillation are not taken into account in the derivation of the wear status and/or of the cutting sharpness of the respective chopping knife. In this way, it is ensured that only those frequency components which change significantly depending on the wear of the chopping knives and which are therefore suitable as indicators for qualifying wear or knife sharpness are taken into account. A particularly advantageous configuration results in this respect when the amplitude of the respective voltage signal of the frequency components causing a signal distortion is taken into account because this amplitude is a measurement for assessing the wear status and/or cutting sharpness of the respective chopping knife and can be determined in a simple manner.
A particularly efficient monitoring of the wear status or chopping knife sharpness, particularly with respect to different types of wear occurring on the chopping knives, is made possible when the assessment of the cutting sharpness is effected by means of evaluation criteria, and the evaluation criteria are one or more of the evaluation criteria comprising “grinding surface length of the respective chopping knife”, “roundness of the chopping knife tip”, “general knife wear” and/or “camber of the chopping knife” or “relative distance of the shear bar from the chopping knife”.
Further advantageous configurations are the subject of further subclaims and are described in the following with reference to an embodiment example shown in the figures. In the drawings:
According to
Details of the measuring device will now be described referring to
The respective voltage signal 38a . . . e is converted in the evaluating unit 36 into a voltage signal 49a . . . e which can be further processed. This voltage signal 49a . . . e which can be further processed is formed in such a way that the induced voltage 38, i.e., the reference value 38 of the induced voltage, is initially determined for a sharp, unworn chopping knife 8, the induction voltage 38a . . . e which changes contingent on wear is then determined during the operation of the chopping knife 8 and, lastly, the voltage signals 49a . . . e which can be further processed are determined from the difference of the wear-dependent change in induction voltage 38a . . . e minus the reference value 38 of the induced voltage of an unworn chopping knife 8.
The respective voltage signals 49a . . . e is then resolved into its frequency components 42, preferably oscillation period or phase 43 and amplitude 44, in the evaluating unit 36 in a manner known per se by means of frequency analysis 41, preferably by means of Fourier analysis 47. In doing so, the respective induced voltage signal 49a . . . e is separated into frequency components 42 of a fundamental oscillation 45 and into frequency components 42 of a superposed oscillation 46 which cause signal distortions. The separated frequency components 42 causing a signal distortion, i.e., the so-called superposed oscillation 46, are then inverse-transformed in the time domain 48 in a manner to be described more fully later and, lastly, a measurement for the cutting sharpness, i.e., the wear status 39, of a chopping knife 8 is derived from the inverse-transformed frequency components 42 in a manner which will likewise be described more fully later.
The frequency analysis 41 carried out according to the invention by the evaluating unit 36 is shown schematically in detail in
The voltage signal 49a . . . e shown at bottom right in
It will be noted that the described characteristic areas 51, 53, 55 induce voltages 49a . . . e of different levels. The area 51, 52 describing the roundness of the knife tip induces the highest total voltage 49a . . . e. It will be noted at the same time that the size of the air gap 33 has an influence on the induced voltage 49a,e. As expected, the value of the induced voltage 49a . . . e decreases as air gap 33 increases. The signal shape of the induced voltage 49a . . . e is acquired and separated for every knife. This means that a plurality of voltage signals 49a . . . e are available for each chopping knife 8 depending on the configuration of the sensor arrangement 23a . . . b. According to
Alternatively or additionally, the assessment of the wear status 39 or of the cutting sharpness 65 can also be coupled to evaluation criteria 72. Preferably, the evaluation criteria can be one or more of the evaluation criteria comprising “grinding surface length 54 of the respective chopping knife 8” 72a, “roundness of the chopping knife tip 52” 72b, “general knife wear 39” 72c and/or “camber of the chopping knife 8” 72d or “relative distance of the shear bar 11 from the chopping knife 8” 72e. Analogous to the preceding description, a reference value 73 can also be stored in the evaluating unit 36 or other data processing device, including an external data processing device, with respect to the evaluation criteria 72a . . . e. In the simplest case, this is a stored reference value 73 of the amplitude 44 of the induced voltage 38a . . . e, 49a . . . e. Depending on the selected evaluation criterion or individual stored evaluation criterion 72a . . . e, the stored reference value 73 is then either a measurement for the wear status 39 of the respective chopping knife 8 in total or for the sharpness of the cutting edge 24. If the value falls below the reference value 73, the grinding signal 67 described above is generated. This grinding signal 73 can then conceivably be generated in different ways. In the simplest case, the chopping knife or chopping knives 8 which have fallen below the reference value 73 can be displayed to an operator 68 on a display 69. In this case, the operator decides when a grinding process 70 of the chopping knives 8 is to be initiated. However, it is also conceivable that a control device 71 monitors the adherence to reference value 73 and automatically initiates the grinding process 70. The automatic initiation of the grinding process 70 is preferably defined such that a minimum number of chopping knives 8 must fall below the reference value 73 before a grinding process 70 is activated. It is also taken into account in a manner known per se that the forage harvester 2 is not in a working mode in that crop 5 is moved through the forage harvester 2.
Alternatively or additionally, when the value falls below the reference value 66 or reference value 73, replacement of a chopping knife 8 can be suggested, namely, when measurements fall below reference value 66, 73 to such an extent that it can be inferred that the respective chopping knife 8 is at the end of its usable range.
In view of the fact that the induced voltage 38a . . . e, i.e., the voltage signal 49a . . . e derived therefrom increases with increasing roundness 52 of the cutting edge 24 of the chopping knives 8, it is provided that the reference value 73 is an amplitude 44 of the determined voltage signal 49 when the “roundness of the chopping knife tip 52” evaluation criterion 72b is selected.
Since the oscillation period 43 of the induced voltage 38a . . . e increases with increasing grinding surface length 54 of the chopping knife 8, the reference value 73 is an oscillation period 43 of the derived voltage signal 49a . . . e when the “grinding surface length 54 of the respective chopping knife 8” evaluation criterion 72a is selected.
Due to the fact that the oscillation period 43 and the amplitude 44 of the induced voltage 39a . . . e both increase significantly with increasing general wear 39 of chopping knife 8, reference value 73 is an amplitude 44 and an oscillation period 43 of the determined voltage signal 49a . . . e when the “general knife wear” evaluation criterion 72c is selected.
The distance of the chopping knife 8 from the shear bar 11 increases and the amplitude 44 of the induced voltage 38a . . . e decreases significantly with increasing wear 39 of the chopping knife 8 so that when the “camber of the chopping knife 8” or “relative distance of the shear bar 11 from the chopping knife 8” evaluation criterion 72d, e is selected, reference value 73 is an amplitude of the determined voltage signal 49a . . . e.
The driver assistance system 80 according to the invention is shown in detail in
In a manner known per se, the shear bar 11 associated with the chopping drum 7 is swivelably movably guided in a bearing 86 associated with the underside of the shear bar 11 by a swiveling mechanism 85. The edge 87 of the shear bar 11 facing the chopping drum 7 is positioned so as to be spaced apart from the envelope curve 84 of the chopping drum 7 by a determined distance 88, the so-called cutting gap 89. Further, at least one actuating motor 90 which enables a change of position of the shear bar 11 and, therefore, a change in the cutting edge 89, is associated with the swiveling mechanism 85 likewise in a known manner. Further, the shear bar 11 receives one or more ping sensors 91 which are capable of determining the distance of the shear bar 11 from the envelope curve 84 of the chopping drum 7 by means of vibration analysis.
The driver assistance system 80 according to the invention further comprises a monitoring device 92. In a known manner, the monitoring device 92 receives the acoustic signals A generated by the ping sensors 91 and generates distance signals B therefrom which correspond to the distance 88 of the shear bar 11 from the envelope curve 84 of the chopping drum 7. Further, the monitoring device 92 is capable of generating actuating signals C for activating the actuating motor or actuating motors 90. Further, the monitoring device 92 is constituted such that it generates the knife grinding signal D which causes the knife grinding device 17 to be activated or deactivated so that the grinding stone 18 can be moved radially and tangentially relative to the respective cutting edge 24 of the chopping knives 8. The monitoring device 92 further comprises a module 93 which is constituted in such a way that it generates information I about the wear status 39 of every chopping knife 8. The module 93 is preferably formed by the above-described evaluating unit 36. Further, the “sharp knife” reference value 66 which has already been described and a reference distance value 94 for the distance 88 of the shear bar 11 from the envelope curve 84 of the chopping drum 7 are stored in the monitoring device 92.
The monitoring device 92 further comprises a comparison step 95 in which the information I concerning the wear status 39 of the chopping knives 8 and/or the distance signal B representing the distance 80 of the shear bar 11 from the envelope curve 84 of the chopping knives 8 are compared with the respective reference value, namely, the “sharp knife” reference value 66 and the reference distance value 94. According to the invention, the monitoring device 92 is integrated in the driver assistance system 80 in such a way that the driver assistance system 80 automatically detects when a knife grinding process 96 must be activated or deactivated and/or when a change of position 97 of the shear bar 11 must be activated or deactivated. In the simplest case, this is effected in such a way that it is determined in comparison step 95 whether the actual value lies below or above the respective reference values 66, 94. As soon as this is determined, the driver assistance system 80, in a manner to be described more fully, generates the actuating signal C for activating the actuating motor or actuating motors 90 of the shear bar 11 for the purpose of change of position 97 of the shear bar and/or generates the knife grinding signal D for activating or deactivating the grinding process 96. In this respect, the grinding process 96 is terminated when it is determined in comparison step 95 that the information I defining the wear status 39 of the chopping knives 8 has reached or again lies above the stored associated “sharp knife” reference value 66. Analogously, the change of position 97 of the shear bar 11 is deactivated when it is determined in comparison step 95 that the stored reference distance value 94 was reached. With respect to the process, known per se, of moving the shear bar 11 into the respective position, reference is made to EP 2 764 767, the disclosure of which is hereby incorporated by reference in its entirety herein.
Further, the driver assistance system 80 is constituted in such a way that the actuating signals C generated by it and the generated knife grinding signals D either start and stop the grinding process 96 directly or start or stop the change of position 97 of the shear bar 11. Alternatively or additionally, it also lies within the scope of the invention that the actuating signals C and/or the knife grinding signals D generate a notification to an operator 68 of the agricultural work machine 1 to activate or deactivate the grinding process 96 and/or the change of position 97 of the shear bar 11.
It further lies within the scope of the invention that the “sharp knife” reference value 66 and the reference distance value 94 of the shear bar 11 which are stored in the monitoring device 92 can be changed depending on the crop.
According to
The actual cutting sharpness value 98 is monitored during the activated grinding process 96. If the actual cutting sharpness value 98 reaches or lies above the “sharp knife” reference value 66 in comparison step 95′″, the grinding process 96 is deactivated. The respective chopping knife 8 is deemed sharp. On the other hand, if the actual distance value 99 reaches or lies below the stored reference distance value 94 in comparison step 95″, the change of position 97 of shear bar 11 is deactivated in one of the ways described above, since the shear bar 11 has reached its position stored in the monitoring device 92, i.e., the predefined cutting gap 89.
Accordingly, the monitoring device 92 is constituted in such a way that it monitors the cutting sharpness 65 and/or the wear status 39 and/or the magnitude of the cutting gap 89 for each chopping knife 8.
At the same time, the driver assistance system 80 is constituted in such a way that a radius R of the chopping drum 7 is determined from the distance signals B generated by the monitoring device 92. Due to the fact that the distance signal B describes the distance 88 of the shear bar 11, the edge 87 of the shear bar 11, from the envelope curve 84, the distance of the cutting edge 24 of a chopping knife 8 from the shear bar 11, a change in the radius AR of the chopping drum 7 can be inferred from this distance signal B.
Further, the driver assistance system 80 is adapted to infer the quantity 100 of chopping knives 8 positioned on a chopping drum 7 from the chopping knife-specific signals generated by the monitoring device 92, e.g., acoustic signals A and/or distance signals B and/or the information I with respect to the wear status 39. A configuration signal K which automatically configures the respective chopping drum 7 that is used in the driver assistance system 80 is then generated from the determined quantity 100 of chopping knives 8.
In a further advantageous configuration, a product feed-dependent wear status 102 can be inferred, for example, from the detected change in radius AR of the chopping drum 7 in a further evaluating step 101, and steps are derived for bringing about a product feed that reduces wear. In particular, the derived steps can comprise a change in one or more parameters of the header 3 and/or of the gathering and pre-compacting rollers 4 arranged downstream of the latter for picking up and conveying crop 5.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 112 968.0 | May 2019 | DE | national |
| 10 2019 112 973.7 | May 2019 | DE | national |
| 10 2019 112 965.6 | Jul 2019 | DE | national |
