AGRICULTURAL APPLICATOR WITH AUTOMATIC CONTROL OF THE DAMPENING OF THE APPLICATOR BOOM

Abstract

An agricultural applicator includes a chassis supported on a ground surface and an applicator boom controllably movable with respect to the chassis about a pivot axis defined in a driving direction or suspended in a height-adjustable manner. An electronic control unit receives a sensor value regarding a current driving status of the chassis, and a dampening element is controlled by the electronic control unit based on the sensor value to dampen the movement of the applicator boom. The electronic control unit is programmed to calculate an expected driving status of the applicator based on the sensor value and variable physical parameters of the applicator, and to output a control signal to the dampening element based on an expected driving status of the applicator. The electronic control unit operably controls the dampening element to adjust dampening based upon a minimization of undesired movements of the applicator boom.

Claims

1. An agricultural applicator having a transport width and configured to move in a driving direction, comprising: a chassis supported on a ground surface; an applicator boom controllably movable with respect to the chassis about a pivot axis defined in the driving direction or suspended in a height-adjustable manner, the boom having a width measured transversely with respect to the driving direction and being greater than the transport width of the applicator; an electronic control unit configured to receive a sensor value regarding a current driving status of the chassis; and a dampening element for dampening the movement of the applicator boom, the dampening element being controllable by the electronic control unit based on the sensor value; wherein, the electronic control unit is programmed to calculate an expected driving status of the applicator based on the sensor value and variable physical parameters of the applicator and to output a control signal to the dampening element based on an expected driving status of the applicator; further wherein, the electronic control unit operably controls the dampening element to adjust dampening based upon a minimization of undesired movements of the applicator boom.

2. The applicator of claim 1, where the electronic control unit is programmed to take into account the effect of the current adjustable geometry of the applicator boom based on the expected driving status of the applicator when generating the control signal.

3. The applicator of claim 1, where the sensor value of the current driving status of the applicator or the expected driving status of the applicator is related to a lateral tilt of the chassis, a tilt of the chassis in a forward direction or vertical direction, a speed or acceleration of the chassis in at least one spatial direction, one orientation of the chassis about the vertical axis, lengthwise axis, or transverse axis, or a change of the orientation over time.

4. The applicator of claim 1, where the sensor value regarding the current driving status of the applicator is derived from measurement values of a vehicle suspension.

5. The applicator of claim 1, where the physical parameters of the applicator comprise its track width, total weight of the applicator, or fill level of a tank.

6. The applicator of claim 1, where the electronic control unit is programmed to receive data related to a topography of the ground surface to be traversed when calculating the expected driving status of the applicator.

7. The applicator of claim 1, where the electronic control unit is programmed to calculate the expected driving status by means of a mathematical model representing the physical behavior of the applicator or the applicator boom.

8. The applicator of claim 1, where the dampening element comprises a hydraulic cylinder.

9. The applicator of claim 8, where the hydraulic cylinder is simultaneously controllable by the control unit as an actuator for adjusting the applicator boom.

10. The applicator of claim 8, where the hydraulic cylinder is connected to a pneumatic pressure tank via a valve having an outlet opening, the outlet opening being operably controlled by the control unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above-mentioned aspects of the present disclosure and the manner of obtaining them will become more apparent and the disclosure itself will be better understood by reference to the following description of the embodiments of the disclosure, taken in conjunction with the accompanying drawing, wherein:

[0022] FIG. 1 shows a side view of an applicator designed as a self-propelled field sprayer,

[0023] FIG. 2 shows a rear view of the deployed applicator boom of the applicator of FIG. 1,

[0024] FIG. 3 shows an enlarged rear view of the middle part of the applicator boom of FIG. 2,

[0025] FIG. 4 shows a schematic of a sensor for registration of the current driving status of the chassis of the applicator,

[0026] FIG. 5 shows a schematic of the hydraulics for lift control of the applicator boom of the applicator,

[0027] FIG. 6 shows a schematic of the hydraulics for tilt control of the applicator, and

[0028] FIG. 7 shows a flow diagram according to which the control unit of the applicator operates.

DETAILED DESCRIPTION

[0029] FIG. 1 shows an applicator 10 for application of liquid products in the form of a self-propelled vehicle, which may be designed as an apparatus that is towed or mounted on a tractor, as an alternative to the self-propelled embodiment. The applicator 10 includes a chassis 12 with a frame 14, which is supported on the ground on front wheels 16 and rear wheels 18. The wheels 16, 18 can be steerable and powered. A tank 20 for the products and a cabin 22 are supported on the frame 14 and a motor compartment 24 is situated in front of the cabin. The driving direction V in operation goes to the right in FIG. 1. At the rear on frame 14 of the applicator 10, a tilt and height adjustable applicator boom 26 is mounted, which is further shown from the rear in FIGS. 2 and 3.

[0030] An adjustment frame 28, which can be adjusted in height via linked hydraulic cylinders 44, is mounted on frame 14. A pendulum arm 30 is mounted on the adjustment frame 28 so that it can rotate about an axis 34 that extends in the forward direction V. A central segment 36 of the applicator boom 26 is mounted on the pendulum arm 30 so that it can rotate about an axis 38 that extends in the forward direction V. Two boom wings 32 of the applicator boom 26 are mounted to the left and right on the central segment 36 and can be adjusted with respect to the central segment 36 about axes 42 that extend in the forward direction V by means of hydraulic cylinders 40. The central segment 36 and the two boom wings 32 together form the applicator boom 26, which is provided with nozzles for application of the products from the tank 20.

[0031] The pendulum arm 30 can be rotated with respect to the adjustment frame 28 about the axis 34 that extends in the forward direction V by means of two linked hydraulic cylinders 46. Moreover, the central segment 36 of the applicator boom 26 can be rotated with respect to the pendulum arm 30 about the axis 38 that extends in the forward direction, likewise by means of a hydraulic cylinder 48.

[0032] A control unit 50 is connected to the hydraulic cylinders 40, 44, 46, 48 via appropriate valves and can undertake the following adjustments for control and regulation of the applicator boom:

[0033] Height control: The height of the central segment 36 of the applicator boom 26 is adjusted by adjusting the frame 28 up and down with respect to the frame 14 via a parallel kinematic mechanism by means of the hydraulically actuated cylinders 44.

[0034] Tilt of the pendulum arm 30: The pendulum arm 30 is adjusted rotationally with respect to the adjustment frame 20 via the two hydraulically actuated cylinders 46. The axis of rotation 34 in this case runs parallel to the lengthwise axis of the vehicle and the forward direction V.

[0035] Offset of the applicator boom 26 with respect to the pendulum arm 30: The central segment 36 of the applicator boom 26 is rotationally adjusted with respect to the pendulum arm 30. The axis of rotation 38 in this case runs parallel to the longitudinal axis of the vehicle and the forward direction V.

[0036] Adjustment of the applicator boom geometry: The two boom wings 32 of the applicator boom 26 are tilted with respect to the central segment 36 of the applicator boom 26 by means of the hydraulic cylinders 40. The axis of rotation 42 in this case runs parallel to the longitudinal axis of the vehicle and the forward direction V

[0037] Not mentioned up to now are actuators (not shown) which are needed for the purpose of moving the applicator boom 26 between the working position and the folded transport position. In some cases, the actuators that have already been mentioned can be employed for moving the boom 26 between working and transport positions. For example, the hydraulic cylinders 44 are used to lower the applicator boom 26 into the transport locking mechanism after it has been folded up.

[0038] Measurements are made of the accelerations (in three directions) and rates of rotation (likewise in three directions) of the chassis 12 by means of a measurement unit 52, which is mounted on frame 14 and is shown in FIG. 4. The measurement unit may include a processor 54, a bus interface 56, a digital input and output interface 58, a plug connector 60 which is connected via a conductor 70 to the control unit 50, an acceleration sensor 62, which is designed as a microelectromechanical element (MEMS), a gyroscope 64, which is designed as a microelectromechanical element (MEMS), and a power supply 68. The signals are sent to the control unit 50 and processed by it in order to identify the expected driving status of the applicator 10 via an evaluation of the vehicle dynamics. In addition, measurements of the suspension travel (for example, via cable potentiometers or by means of rotary potentiometers actuated by the boom or direct remote measurement methods such as based on ultrasound) or pressure measurements in the suspension system of the wheels 16, 18 can be employed to calculate the expected driving status of the applicator 10.

[0039] By means of the signals from the measurement unit 52, the control unit 50 can recognize different movement profiles of the chassis 12 which include, for example, travel on slopes, travel on hilly terrain, transitions between flat land and slope, excitations due to potholes, rocks, or unevenness in the field, and curved travel. The type of curve in a turning maneuver can be recognized by means of operating data from elements of the applicator (see DE 10 2014 202 181 A1).

[0040] The control unit 50 enables an automatic adjustment of the dampening property of the applicator boom suspension to the relevant operating situation by utilizing the described hydraulic system that serves to adjust the applicator boom 26 along with the hydraulic cylinders 44 and 46 as an important dampening element. In this regard, and referring to FIGS. 5 and 6, the circuit of the hydraulic cylinders 44 for height control and the circuit of the hydraulic cylinders 46 for adjusting the tilt of the pendulum arm 30 are illustrated.

[0041] In the case of the height control according to FIG. 5, a switching valve 72 allows the hydraulic cylinders 44 for lifting or lowering to connect to a pump 74 or to a supply tank 76. To lift the frame 28, the piston chambers of the hydraulic cylinders 44 are filled via a check valve 92 and analogously the piston rod chambers of the hydraulic cylinders 44 are filled via a check valve 80 for lowering the frame 28. A pressure-controlled valve 90 is antiparallel-connected to the check valve 92 and an orifice 78 is parallel-connected to the check valve 80. Additional switching valves 82, 86 connect the piston chambers or the piston rod chambers of the parallel-connected hydraulic cylinders 44 to pressure tanks.

[0042] In the case of the tilt control according to FIG. 6, a switching valve 94 enables in each case one piston chamber of the hydraulic cylinders 46, the piston rod chambers of which are directly connected to each other via a line, to connect to a pump 98 or a supply tank 96 for adjustment of the tilt of the pendulum arm 30. To swivel the pendulum arm 30, the piston chambers of the hydraulic cylinders 46 are filled via check valves 100 or 102. In each case, pressure-controlled valves 104, 106 are antiparallel-connected to the check valves 100, 102. Additional switching valves 108, 110 connect the piston rod chambers of the hydraulic cylinders 46 to pressure tanks.

[0043] Accordingly, the control unit 50 can adjust on the one hand the height of the frame 28 and the tilt of the pendulum arm 30 in a substantially known way, based in particular on operator input via an operator interface (not shown) or sensors mounted on the applicator boom 26 (not shown) for registration of its height above the ground, and further connect the pressure tanks 84, 88, 112, 114 to the hydraulic cylinders 44, 46 via valves 82, 86, 108, and 110 in order to dampen the cylinders. Valves 82, 86, 108, and 110 can be designed as proportioning valves or can be controlled by pulse width modulation in order to be able to adjust the dampening in a continuously variable way. The current open cross section of the valves 82, 86, 108, and 110 and their geometry define the resistance to flow and thus the dampening characteristics of the hydraulic system. If the geometry of the valves 82, 86, 108, and 110 is designed as a throttle (i.e., the length of the taper is large by comparison with the cross section), the volume flow, in accordance with the flow principle, rises linearly with the pressure difference. If the geometry of the valves 82, 86, 108, and 110 is designed as an orifice (length of the taper small by comparison with the cross section), the pressure difference and volume flow behave nonlinearly. The dampening rate is also dependent on the hydraulic fluid temperature via the viscosity of the hydraulic oil. A temperature sensor in the hydraulic circuit can be used to compensate for this dependency. The pressure tanks 84, 88, 112, 114 act as spring elements via the preload generated by means of gas pressure. The gas pressure and thus the spring constant can usually not be actively adjusted or set during the operation of the machine.

[0044] The orifice 78 in FIG. 5 also causes a certain dampening of the hydraulic cylinders 44 and may have a variable orifice cross-section in order to adjust the dampening property by the control unit.

[0045] By means of the described identification of the movement profile, the hydraulic system can now be adjusted in terms of a semi-active dampening system to the usage profile of the applicator 10. Accordingly, the dampening of the hydraulic cylinders is actively regulated by the control unit on the basis of signals from the measurement unit 52 by means of the instantaneous tilt of the chassis 12, the instantaneous acceleration of the chassis 12, the instantaneous rate of rotation of the chassis 12, a predictive tilt of the chassis 12, a predictive acceleration of the chassis 12, and a predictive rate of rotation of the chassis 12.

[0046] The tilt, acceleration, and rate of rotation of the chassis 12 are predicted by the control unit 50 on the basis of variable physical parameters of the applicator 10. The parameters can be the setting of the variable track width of the applicator 10 (i.e., the lateral spacing of the wheels 16 and 18), the fill level of the tank 20, possibly the fill level of additional tanks (not shown), or data concerning the current geometry of the applicator boom 26 (for example, if one boom wing 32 is tilted with respect to the central segment 36 and the other boom wing 32 is tilted by means of a hydraulic cylinder 40). For this one can employ substantially known procedures, which calculate, by means of the measured values and the variable physical parameters, how the predicted values will look. Any mathematical model or an equation system derived therefrom, the parameters of which are matched to the current system of the applicator 10, as described, for example, in DE 10 2014 208 070 A1, can be used for the behavior of the applicator vehicle 10. The dampening of the hydraulic cylinders 44, 46 by the control unit 50 is determined in the manner described above with reference to FIGS. 5 and 6 by means of the predicted tilt, acceleration, and rate of rotation of the chassis 12 or the applicator 10. Thus, the dampening, and therefore the transfer function with which the hydraulics transmit possible variations of the applicator 10 to the applicator boom 26, is affected in a suitable way. For instance, the transfer function controlled by the control unit 50 on a side slope enables a good transfer of the movement of the chassis 12 of the applicator 10 to the applicator boom 26 (significant dampening), while in the case of potholes it will transmit the movement very little or not at all (no dampening).

[0047] The described procedure is further illustrated in the flow diagram of FIG. 7.

[0048] The dampening can be adaptively regulated on the basis of a position (for example, determined by means of a position determining system such as GPS) of the applicator 10 and stored data concerning the elevation profile of the field or the pneumatic pressure of a vehicle suspension of the applicator 10.

[0049] While embodiments incorporating the principles of the present disclosure have been described hereinabove, the present disclosure is not limited to the described embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains and which fall within the limits of the appended claims.