Agricultural working vehicle comprising an air-suspended driver's cab and a GPS track guidance system
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ZF FRIEDRICHSHAFEN AG
- Filing Date
- 2026-01-20
- Publication Date
- 2026-07-30
Smart Images
Figure EP2026051307_30072026_PF_FP_ABST
Abstract
Description
[0001] ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0002] Agricultural work vehicle with air-suspended driver's cab and GPS guidance system
[0003] The invention relates to an agricultural work vehicle with a driver's cab and a chassis and with a GPS sensor, which in operation has a driving position on the ground which is determined at least on the basis of the GPS sensor.
[0004] From EP 2 135498 A1, a method is known for navigating an agricultural vehicle equipped with a 3D imaging device for mapping the vehicle's surroundings and an image processing device, comprising: obtaining individual images from the 3D imaging device, which depict at least part of the vehicle's surroundings at different times while the vehicle is moving, thus providing a temporal sequence of individual images; analyzing the individual images; and detecting a change in the vehicle's position using the results of the analysis of at least two temporally different individual images. Additionally, a GPS sensor is used as a further navigation sensor.
[0005] The object of the invention is to propose improvements with regard to the GPS navigation of an agricultural work vehicle.
[0006] The problem is solved by a vehicle according to claim 1 in the form of an agricultural work vehicle. Preferred or advantageous embodiments of the invention, as well as of other categories of invention, will become apparent from the further claims, the following description, and the accompanying figures.
[0007] The vehicle contains a chassis that, during operation, typically travels on the ground on wheels. During operation, the chassis maintains a driving position on the ground. The driving position is therefore the current location of the chassis during operation. ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0008] The vehicle contains a driver's cab. The driver's cab is movably mounted on the chassis by means of at least one, and preferably several, air springs. In other words, the driver's cab is connected to the chassis via the air springs. In particular, the driver's cab is load-bearing (excluding other non-load-bearing connections) and is connected to the chassis exclusively via the air springs; in particular, the air springs thus form the sole load-bearing support of the driver's cab on the chassis. "Movable" means that the relative position between the driver's cab and the chassis can change.
[0009] Each air spring can be deflected along a certain travel distance to allow movement between the cab and the chassis. At any given time, the air spring has a current spring length, which corresponds to its deflection. This spring length is correlated with the relative position of the driver's cab to the chassis. The connection between the driver's cab and the chassis via the air springs is therefore designed such that the current relative position between the driver's cab and the chassis can be fully determined from knowledge of a specific number of current spring lengths (one, several, or all).
[0010] Each air spring contains a sensor. A corresponding sensor signal is provided by each sensor. The current spring length is represented by this sensor signal (its current value). The sensor signal is provided within the vehicle. This can be in the form of the original sensor signal or in a (pre-)processed form. The crucial point is that the current spring length can be derived from the sensor signal in some way.
[0011] The vehicle contains at least one GPS sensor (Global Positioning System), which is permanently mounted in the driver's cab. The GPS sensor determines the vehicle's current GPS position, which is then stored within the vehicle.
[0012] The vehicle is equipped with a lane guidance system. This system is designed to determine the current driving position of the chassis on the ground based on the current GPS position of the GPS sensor. This determination is carried out by [ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22].
[0013] The guidance system transforms the current GPS position (located at the GPS sensor on the driver's cab) into the current driving position of the chassis, taking into account the current relative position of the driver's cab to the chassis. This is achieved by using the current sensor signals to determine the current relative position.
[0014] According to the invention, the vehicle is equipped with air springs containing sensors to determine the relative position between the driver's cab and the chassis. Furthermore, this relative position is used to accurately transform the GPS position determined at the driver's cab onto the chassis, depending on the current relative position.
[0015] The invention is based on the understanding that the relative position between the driver's cab and the chassis can change noticeably with a comparatively long-stroke suspension. However, the GPS sensor is mounted on the driver's cab. The GPS position is always linked to the sensor and thus to the current position of the driver's cab. If, however, the relative position between the driver's cab and the chassis changes noticeably (in an unknown way), it is no longer possible to accurately determine the GPS driving position of the chassis (which is in an unknown relative position).
[0016] By utilizing the sensor signal according to the invention, the relative position between the driver's cab and the chassis can be determined, and thus the GPS position, originating from the driver's cab, can be correctly transformed onto the chassis. This is particularly advantageous here because an air suspension system is provided, which includes sensors and uses these sensors for the correct transformation of the GPS position from the cab to the chassis.
[0017] Air suspension and navigation enhancement can thus be used synergistically with added benefits, e.g., compared to sensorless air suspension and additional sensors external to the air springs for determining the relative position. ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0018] The accuracy of the chassis' driving position on the ground, determined based on the GPS location position, is thus improved.
[0019] In a preferred embodiment, the vehicle has a data bus. The sensor signal is then provided on the data bus. This makes the processing and distribution of the sensor signal in the vehicle particularly simple. Furthermore, such a bus is often already present in these types of vehicles, so that the invention allows the bus to be used synergistically for another purpose.
[0020] In a preferred embodiment of this system, the data bus is a CAN bus (Controller Area Network). Such a bus allows for particularly reliable transmission of the sensor signal within the work vehicle.
[0021] In a preferred embodiment, the spring travel of at least one, and in particular several or all, of the air springs is a straight line. By using straight spring travel, the relative position of the chassis and the driver's cab can be determined particularly easily. Air springs with straight spring travel are also particularly easy to implement.
[0022] In a preferred embodiment, at least one, and in particular several or all, of the air springs are electrically operated. The air spring is configured to use the sensor signal for its own operation. In other words, the air spring is electrically operated based on its sensor or its sensor signal. Therefore, a sensor does not need to be integrated into the air spring specifically for this invention, as it is already present within it. The same applies to the sensor signal, which is also already present within the vehicle. This signal simply needs to be made available to the vehicle, i.e., transmitted from the sensor / air spring to the outside. In other words, this also results in a synergistic dual use of the sensor and sensor signal, both internally for the air spring / suspension itself and for improving the accuracy of determining the chassis's driving position.ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22.
[0023] A corresponding air spring is known, for example, from DE 1020 15216956 A1. This discloses an air spring for a motor vehicle with a rolling diaphragm filled with pressurized gas, one end of which is connected to a cap-like load-bearing element and the other end of which is attached to a rolling piston. The load-bearing element and the rolling piston are movable relative to each other depending on a force acting on the load-bearing element towards the rolling piston and are equipped with a sensor device arranged within the rolling diaphragm, by which the distance between the load-bearing element and the rolling piston can be detected and a corresponding electrical signal can be generated.A pressure piece extending towards the rolling piston is arranged at the load-bearing point, through whose end region facing the rolling piston a sensor body can be driven directly or indirectly along a sensor path of the sensor device, wherein the sensor device generates an electrical signal corresponding to the position of the sensor body on the sensor path.
[0024] In particular, at least one such known air spring is integrated as an air spring in the agricultural work vehicle.
[0025] In a preferred embodiment, the driver's cab has a roof, and the GPS sensor is mounted on the roof of the cab. The cab roof is typically as far away from the chassis as possible, so that changes in the relative position between the cab and the chassis result in particularly large relative movements between the GPS sensor and the chassis, and thus the aforementioned inaccuracies. Therefore, in this case, incorporating the relative position into the determination of the driving position is particularly effective and leads to a significant improvement in the accuracy of determining the driving position based on the GPS position of the GPS sensor on the roof.
[0026] In a preferred embodiment, the vehicle is configured to adjust the relative position between the driver's cab and the chassis in a working position that deviates from a neutral position. The neutral position is one that the driver's cab assumes in an un-displaced state. In particular, it is one vertically above the vehicle when it is on a level horizontal surface. ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0027] The ground is stationary or at rest. The working position is, for example, a permanently horizontal orientation of the driver's cab during operation when the chassis is no longer horizontally aligned, for example, due to the vehicle driving on an inclined slope (mountain slope) or when driving with some of the wheels in a deeper furrow and other parts of the wheels on higher, unplowed ground. Such a vehicle then features, in particular, a cab mounting to decouple unwanted vibrations.
[0028] In a preferred embodiment, the vehicle is configured to adjust its working position based on at least one of the sensor signals. In this case, the sensor signals are also used for a dual purpose: firstly, to adjust the working position, and secondly, to improve the determination of the chassis' GPS driving position based on the GPS position of the GPS sensor.
[0029] The invention is based on the following findings, observations, and considerations and further comprises the following preferred embodiments. These embodiments are sometimes referred to simply as "the invention." The embodiments may also include parts or combinations of the embodiments mentioned above, or correspond to them, and / or may also include previously unmentioned embodiments.
[0030] According to the invention, in particular, the use of path signals from an air spring for correcting GPS driving data for tractor applications is possible.
[0031] In particular, this results in an extension of the track guidance calculation to include the offset of the static cabin tilt (deflection of the cabin from the neutral position).
[0032] The invention is based on the consideration that, due to requirements from the employers' liability insurance associations, tractors are increasingly being equipped with cab mounts to decouple unwanted vibrations. The requirements are growing. ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0033] and grow. For this reason, the aforementioned air springs (when integrated into such vehicles for the purpose of cabin mounting) will increasingly offer potential for improving this requirement.
[0034] With such air springs, it is possible to compensate for static tilts in the cab (e.g., driving uphill (including laterally) or plowing while driving in the plow track) to provide the driver with greater comfort. However, the coordinates of the GPS calculation (sensing on the cab roof) will then be subject to an offset.
[0035] The basic idea of the invention is therefore, in particular, to make the measured path signals (sensor signals) used for calculation and control in the air springs available on the vehicle CAN bus in order to be included in the calculation of the lane guidance based on the received GPS data.
[0036] Further features, effects, and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. These figures show, in each case in a schematic diagram:
[0037] Figure 1 shows an agricultural work vehicle in operation on a ground, Figure 2 shows the vehicle from Figure 1 in alternative configurations.
[0038] Figure 1 shows a vehicle 2 in the form of an agricultural work vehicle, here a tractor, during its operation B, namely the cultivation of soil 4, here grassland. The soil 4 has an inclination N (angle of inclination) relative to the horizontal H.
[0039] Vehicle 2 comprises a chassis 6 with a base body 8 and wheels 10, which rest on or drive on the ground 4. Vehicle 2, or rather its chassis 6, always maintains a current driving position FP, i.e., location (here in GPS coordinates) on the ground 4. ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0040] Vehicle 2 also includes a driver's cab 12 for a driver of vehicle 2 (not shown). The driver's cab 12 is movably mounted on the chassis 6. This means that the relative position R of the driver's cab 12 to the chassis 6 is changeable, or rather, the driver's cab 12 has a constantly changing relative position R to the chassis 6. In the simplified example presented here, the relative position R corresponds to an angle W between a central or vertical axis 18a of the chassis 6 and a central or vertical axis 18b of the driver's cab 12.
[0041] Figure 2 illustrates the mobility: The driver's cab 12 is shown roughly as a dashed line in a neutral position NS. In this position, the driver's cab 12 would be stationary if the vehicle 2 were performing the inclined driving maneuver shown in solid lines on the sloping ground 4 according to Figure 1. In reality, however, the driver's cab 12 is moved or displaced into a working position AS shown in solid lines.
[0042] The neutral position NS of the current vehicle 2 is one in which the driver's cab 12 is located vertically and horizontally directly above the vehicle 2, as if its chassis 6 were also resting horizontally on a horizontally running, level surface 4. This is also indicated by fine dashed lines in Figure 2.
[0043] In the present case, the working position AS is set up so that the driver's cab 12 - independent of the chassis 6 - always remains vertically aligned in order to increase the comfort of the driver of the vehicle 2.
[0044] Figure 1 further shows: To enable this mobility of the driver's cab 12 relative to the chassis 6, the driver's cab 12 is movably mounted on the chassis 2 solely by means of two air springs 14a,b. Each of the air springs 14a,b can be deflected along a spring travel 16a,b. The spring travel 16a,b is a straight line. In other words, the air springs 14a,b are telescopic along their spring travel 16a,b. ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0045] At any given time, each of the air springs 14a,b has a current spring length FLa,b along its respective spring travel 16a,b. The current spring lengths FLa,b are correlated with the relative position R of the driver's cab 12 to the chassis 6. In other words, the current relative position R (angle W) between the driver's cab 12 and the chassis 6 can be determined from the current spring lengths FLa,b at any given time.
[0046] Each of the air springs 14a, b contains an integrated sensor 20a, b. The respective current spring length FLa,b is represented by a corresponding sensor signal 22a, b from the respective sensor 20a, b. In other words, the current spring length FLa,b can be determined from the respective sensor signal 22a, b. The sensor signals 22a, b are provided in the vehicle 2.
[0047] The data is provided here on a data bus 24 of the vehicle 2, which is only symbolically represented in Figure 1 and is implemented here as a CAN bus.
[0048] The air springs 14a,b are designed here as electric or electrically active air springs, as described in the aforementioned DE 1020 15216956 A1. The sensors 20a,b and their sensor signals 22a,b of the air springs 14a,b are therefore used internally for their electrical operation and are thus also used internally within the air springs 14a,b.
[0049] Vehicle 2 is configured to adjust the above-described working position AS using the sensor signals 22a, b; in other words, to keep the driver's cab 12 vertically aligned with respect to its vertical axis 18b, regardless of the movement of the chassis 6. In this respect, the air springs 14a,b utilize the sensors 20a, b and their sensor signals 22a, b themselves.
[0050] Vehicle 2 contains a GPS sensor 26. This sensor is permanently attached to the driver's cab 12. The driver's cab 12 has a roof 28, on the roof, or rather on the upper surface of the driver's cab 12, the GPS sensor 26 is located. The GPS sensor 26 serves to determine a GPS position GO of the GPS sensor 26 itself. The GPS position GO is also recorded in the vehicle file ZF Friedrichshafen AG, file 214314, Friedrichshafen, January 22, 2025.
[0051] 2, also provided on data bus 24. Thus, the GPS sensor 26 rigidly follows every movement of the driver's cab 12. Based on the GPS position GO of the sensor, the GPS position of the entire driver's cab 12 is also known.
[0052] The vehicle 2 contains a guidance system 30. This is designed to determine the current driving position FP of the chassis 6 on the ground 4 based on the GPS location position GO.
[0053] Figure 2 illustrates what would happen if the guidance system 30 were to consider the rigid vehicle model (shown as a fine dashed line, with no change in the relative position R between the driver's cab 12 and the chassis 6). Starting with the GPS position GO, the guidance system 30 would correctly determine the position of the driver's cab 12 (shown as solid). However, it would then transform the GPS position GO to the chassis 6, which is in neutral position NS, resulting in the incorrect driving position FP'.
[0054] The determination of the driving position FP is therefore carried out taking into account the actual current relative position. This in turn is determined on the basis of the two sensor signals 22a, b. In this way, the GPS location position GO is transformed to the driving position FP of the chassis 6, taking into account the relative position R.
[0055] If the relative position R were not taken into account, the guidance system 30 would assume that chassis 6 and driver's cab 12 are in their neutral position NS, which would lead to an incorrect or inaccurate driving position FP' based on the correctly determined GPS position GO.
[0056] Figure 2 summarizes the following situations using two different line styles:
[0057] The situation is roughly depicted in dashed lines if the driver's cab 12 were in neutral position NS even when the vehicle 2 is traveling at an angle, and thus ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22
[0058] the vehicle would tilt to the side. Determining the driving position FP based on the GPS location position GO would then be correct if the fixed relative position R in the neutral position NS were always used for the transformation of the GPS location position GO to the driving position FP.
[0059] The finely dashed lines show the conditions when the vehicle with driver's cab 12 is in working position AS and the neutral position NS is incorrectly assumed. The changed relative position R would not be taken into account, and the driving position FP' would be incorrectly determined. ZF Friedrichshafen AG File 214314
[0060] Friedrichshafen 2025-01-22
[0061] Reference sign
[0062] 2 vehicles
[0063] 4 floors
[0064] 6 chassis
[0065] 8 basic shapes
[0066] 10 wheels
[0067] 12 Driver's cab
[0068] 14a,b Air spring
[0069] 16a,b Suspension travel
[0070] 18a,b Vertical axis
[0071] 20a, b Sensor
[0072] 22a, b Sensor signal
[0073] 24 data bus
[0074] 26 GPS sensors
[0075] 28 Roof
[0076] 30 Lane guidance system
[0077] B Operation
[0078] H Horizontal
[0079] N inclination
[0080] FP driving position
[0081] NS Neutral position
[0082] AS working position
[0083] FLa,b spring length
[0084] R Relative position
[0085] W angle
[0086] GO GPS location
Claims
ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22 Patent claims 1. Agricultural work vehicle (2), - with a chassis (6) which in operation (B) has a driving position (FP) on the ground (4), - with a driver's cab (12) which is movably mounted on the chassis (6) by means of at least one air spring (14a,b), - wherein each of the air springs (14a,b) can be deflected by a respective current spring length (FLa,b) along a spring travel (16a,b) and the spring length (FLa,b) is correlated with a relative position (R) between driver's cab (12) and chassis (6), - wherein the respective air spring (14a,b) contains a sensor (20a,b), and the spring length (FLa,b) is represented by its sensor signal (22a,b) and the sensor signal (22a,b) is provided in the vehicle (2), - with at least one GPS sensor (26) which is permanently attached to the driver's cab (12), wherein a GPS location position (GO) of the GPS sensor (26) determined with the GPS sensor (26) is provided in the vehicle (2), - with a guidance system (30) which is configured to determine the driving position (FP) on the basis of the GPS location position (GO) by transforming the GPS location position (GO) into the driving position (FP) of the chassis (6) taking into account the relative position (R) on the basis of at least one of the sensor signals (22a, b).
2. Vehicle (2) according to claim 1 , characterized by the fact that the vehicle (2) has a data bus (24) and at least one of the sensor signals (22a, b) is provided on the data bus (24).
3. Vehicle (2) according to claim 2, characterized by the fact that the data bus (24) is a CAN bus.
4. Vehicle (2) according to any one of the preceding claims, characterized by the fact that ZF Friedrichshafen AG File 214314 Friedrichshafen 2025-01-22 where at least one of the air springs (14a,b) has a straight line travel (16a,b).
5. Vehicle (2) according to any one of the preceding claims, characterized by the fact that at least one of the air springs (14a,b) is electrically designed and configured to use the sensor signal (22a, b) for its own operation 6. Vehicle (2) according to any one of the preceding claims, characterized by the fact that the driver's cab (12) has a roof (28) and the GPS sensor (26) is mounted on the roof (28).
7. Vehicle (2) according to any one of the preceding claims, characterized by the fact that the vehicle (2) is designed to adjust the relative position (R) between the driver's cab (12) and the chassis (6) in a working position (AS) that differs from a neutral position (NS).
8. Vehicle (2) according to claim 7, characterized by the fact that the vehicle (2) is equipped to adjust the working position (AS) using at least one of the sensor signals (22a, b).