METHOD FOR TRACTION-RELATED SPEED CONTROL OF A WORKING MACHINE

Abstract

A method (A) for the traction-related control of a drive-train of a working machine (1) having a drive unit (2), a transmission (3), a control unit (10) and first and second vehicle axles (7, 9) each supporting wheels (6, 8). At least one of the vehicle axles (7, 9) being driven, and following the entry of a drive requirement relating to a driving speed, wheel slip is iteratively reduced by adapting a rotational speed of the wheels (6, 8) of the driven vehicle axle (7, 9).

Claims

1-7. (canceled)

8. A method (A) for traction-related control of a drive-train of a working machine (1) having a drive unit (2), a transmission (3), a control unit (10) and first and second vehicle axles (7, 9) with wheels (6, 8), the method comprising: driving at least one of the vehicle axles (7, 9), entering a drive requirement relating to a driving speed, and iteratively reducing a wheel slip by adapting a rotational speed of the wheels (6, 8) of the driven vehicle axle (7, 9).

9. The method (A) according to claim 8, further comprising reducing or increasing the rotational speed of the wheels (6, 8) depending on a difference between an actual driving speed and a target driving speed.

10. The method (A) according to claim 8, further comprising monitoring a change of the driving speed, in reaction to an adaptation of the rotational speed of the wheels (6, 8), and, if an expected change of the actual driving speed has not occurred, reversing the adaptation of the rotational speed of the wheels (6, 8).

11. The method (A) according to claim 8, further comprising in a first process step (A1), entering the drive requirement; in a second process step (A2), starting the working machine (1) off at a first driving speed and with a defined wheel slip; in a third process step (A3), measuring an actual driving speed of the working machine (1) and calculating a corresponding actual wheel slip; in a fourth process step (A4), comparing the actual driving speed with the target driving speed, and, if the actual driving speed is higher than or equal to the target driving speed, in a fifth process step (A5), reducing the rotational speed of the wheels (6, 8) and the method reverts to the third process step (A3), and, in a sixth process step (A6), increasing the rotational speed of the wheels (6, 8) if during the comparison during the fourth process step (A4) the actual driving speed is found to be lower than the target driving speed.

12. The method (A) according to claim 11, further comprising, in a seventh process step (A7), monitoring the actual driving speed, checking whether the actual driving speed has increased in reaction to the increase of the rotational speed of the rotational speed of the wheels (6, 8) in the sixth process step (A6), and then maintaining the increase of the rotational speed in accordance with a ninth process step (A9) and returning to the second process step (A2), whereas otherwise the increase of the rotational speed of the wheels (6, 8) is reversed in an eighth process step (A8) and a return to the second process step (A2) then occurs.

13. The method (A) according to claim 8, further comprising also entering a specification for the wheel slip besides a drive requirement.

14. A working machine (1) with a drive unit (2), a transmission (3) and a control unit (10), wherein drive power is passed to the transmission (3), by way of a drive input shaft (4), and resulting drive power is transmitted, by way of a drive output shaft (5), to wheels (6, 8) of at least one of a first and a second vehicle axle (7, 9), and the control unit (10) is suitable for and designed to carry out the method (A) of the invention according to claim 8.

Description

[0016] The invention will be explained in greater detail with reference to the attached figures, which show:

[0017] FIG. 1: A schematic representation of a working machine with an attachment;

[0018] FIG. 2: A schematic representation of a flow chart of the method for traction-related speed control of a working machine.

[0019] In a greatly simplified schematic representation, FIG. 1 shows a working machine 1 with an attachment 11. In the present case, the working machine 1 is in the form of a tractor or farming tractor, and comprises a drive unit 2, a transmission 3 and a control unit 10. The drive unit is connected by way of a drive input shaft 4 to an input of the transmission 3, whereas an output of the transmission 3 is connected by way of a drive output shaft 5 to a first vehicle axle 7 and the wheels 6 fitted thereto. The drive unit 2 delivers a drive input power, which by way of the driveshaft 4 is passed into the transmission 3 and, in accordance with the set gear ratio, is transmitted by the drive output shaft 5 to the first vehicle axle 7. In this case the working machine 1 has a second vehicle axle 9 to which wheels 8 are fitted. The second vehicle axle 9 can also be connected to the drive output shaft 5 or to the first vehicle axle 7, and in that case all the wheels 6, 8 of the working machine 1 will be driven wheels.

[0020] The control unit 10 is connected for signal exchange with the transmission 3 and/or the drive unit 2, as illustrated by the broken lines. Moreover, the control unit 10 comprises a sensor or measuring device (not shown) for detecting the driving speed of the working machine 1. Instead of being integrated in the control unit 10, the sensor can also be a separate component with a signal-transmitting connection.

[0021] The attachment 11 is in the present case in the form of a plow. In alternative embodiments it can also be any other agricultural attachment for working the soil or for crop harvesting. In the simplest version it can also be a trailer. By means of a lifting device 13 the height of the attachment 11 can be adjusted, in particular that of the plow. Depending on the lifting height of the attachment 11 set, a sinking depth into the ground 12 changes. In particular, the ground 12 is the surface of an agriculturally useful area. In alternative embodiments, however, the ground 12 can be a pathway or a street, and in such cases attachments 11 different from the plow in the present case are attached to the working machine 1. By virtue of the contact of the attachment 11 with the ground 12, the latter is broken or dug up, as indicated by a raised area 14 in the figure.

[0022] FIG. 2 shows a schematic representation of a flow chart of the method for the traction-related speed control of the working machine 1. When a drive requirement relating to a driving speed is entered, the wheel slip is reduced iteratively by adapting a rotational speed of the wheels 6, 8 of the driven vehicle axles 7, 9.

[0023] For this, in a first process step A1 the drive requirement is entered. In a second process step A2 the working machine 1 drives off at a first driving speed with a defined wheel slip. In a third process step A3, an actual driving speed of the working machine 1 is measured and a current wheel slip corresponding to it is calculated. In a fourth process step A4, the actual driving speed is compared with the target driving speed. In a fifth process step A5 the rotational speed of the wheels 6, 8 is reduced and a return to the third process step A3 is initiated if the actual driving speed is higher than or equal to the target driving speed. On the other hand, in a sixth process step A6 the rotational speed of the wheels 6, 8 is increased if, when compared in the fourth process step A4, the actual driving speed is found to be lower than the target driving speed.

[0024] The sixth process step A6 is followed by a seventh process step A7 in which the actual driving speed is monitored. During this it is checked whether the actual driving speed has increased in reaction to the increase of the rotational speed of the wheels 6, 8 in the sixth process step A6. If not, in an eighth process step A8 the increase of the rotational speed of the wheels 6, 8 is reversed and the process reverts to the second process step A2. Otherwise, in a ninth process step A9 the increase of the rotational speed of the wheels 6, 8 is maintained if it has been found in the seventh process step A7 that the actual driving speed has increased in reaction to the increase of the rotational speed of the wheels 6, 8 in the sixth process step A6. The ninth process step A9 is likewise followed by a return to the second process step A2.

INDEXES

[0025] 1 Working machine [0026] 2 Drive unit [0027] 3 Transmission [0028] 4 Drive input shaft [0029] 5 Drive output shaft [0030] 6 Wheel [0031] 7 First vehicle axle [0032] 8 Wheel [0033] 9 Second vehicle axle [0034] 10 Control unit [0035] 11 Attachment [0036] 12 Roadway [0037] 13 Lifting device [0038] 14 Raised area [0039] A Method [0040] A1-A8 Process steps