DE102022211991B3 - Method and control system for operating a self-propelled work machine - Google Patents

Abstract

The invention relates to a method for operating a self-propelled work machine (100), with the steps: detecting (S2) a pitch angle profile of the self-propelled work machine (100) with an inertial sensor (10), checking whether the detected pitch angle profile has a first threshold value for a critical pitch of the self-propelled work machine (100) in the direction of travel of the self-propelled work machine (100) to the front and a second threshold value for a critical pitching of the self-propelled work machine (100) in the direction of travel of the self-propelled work machine (100) to the rear is reached, determining that a critical pitching behavior of the self-propelled machine Work machine (100) is present if the testing step results in a test result that the detected pitch angle profile only reaches a threshold value, and outputting (S5) a control signal for controlling an operating device (20) of the self-propelled work machine (100) based on the determined critical nodding behavior. The invention also relates to a control system (200) for carrying out the method and a self-propelled work machine (100) with such a control system (200).

Description

Technical area

The present invention relates to a method and a control system for operating a self-propelled work machine. The present invention also relates to a self-propelled work machine with such a control system.

State of the art

It is known from the prior art to detect critical driving behavior of a self-propelled machine. Based on the recorded driving behavior, the operation of the self-propelled machine can be intervened in order to improve its driving behavior. However, a distinction between nodding behavior and hopping behavior of the self-propelled work machine cannot be directly derived from the recorded driving behavior, since both behaviors can be based on similar acceleration data of the self-propelled work machine. Depending on the existing behavior, however, various interventions in the operation of the self-propelled machine may be necessary in order to improve its driving behavior.

AT 17335 U1 discloses a dumper with a chassis, comprising a trough mounted on it in a tilt-adjustable manner, a travel drive and an electrical control device, to which sensors for driving state detection are assigned. In order to increase driving stability, it is proposed that the control device, depending on the trough position and the driving status, sends a danger signal when at least one vehicle-specific limit value stored in the control device and corresponding to the safety distance is exceeded, in order to maintain a safety distance from the tipping limit.

Out of DE 10 2020 213 674 A1 is a method for operating a self-propelled work machine with the steps: determining an operating size of a working device of the self-propelled work machine, determining a longitudinal dynamic driving size of the self-propelled working machine, checking whether a dangerous condition for the stability of the self-propelled machine based on the determined operating size and the specific longitudinal dynamic driving size Work machine can adjust, intervention in the longitudinal dynamics of the self-propelled work machine depending on a test result based on the testing step.

A work vehicle with a chassis, a ground intervention shield, a sensor assembly and a controller is out US 9,328,479 B1 known. The sign is connected to the chassis via a linkage arrangement that can be raised and lowered. The sensor assembly provides a chassis tilt signal indicating an angle of the chassis relative to the direction of gravity and a blade tilt signal indicating an angle of the blade relative to the chassis or the direction of gravity. The controller receives the signals, determines a target slope and distance error, and sends a command to move the blade toward the target slope based on the distance error.

Presentation of the invention

In one aspect, the present invention relates to a method for operating a self-propelled work machine. The method can be carried out while the self-propelled machine is traveling. The operation can be a front loading operation or a rear loading operation of the self-propelled work machine. The self-propelled work machine can be a work machine which can have a work device for carrying out work. The work equipment can be attached to the self-propelled work machine.

The self-propelled work machine can be, for example, a construction machine. If the self-propelled work machine is the construction machine, a work tool can be attached to it for carrying out work. The self-propelled work machine can be, for example, a wheel loader, which can be operated in front loading mode and to which a front loading shovel can be attached. The self-propelled work machine can also be a forklift, for example. If the self-propelled machine is a forklift, a lifting device for lifting a pallet can be attached to it. The self-propelled work machine can also be an agricultural machine, for example.

The method has, as one step, detecting a pitch angle profile of the self-propelled work machine with an inertial sensor arranged on the self-propelled work machine while the self-propelled work machine is traveling. The pitch angle curve can depict a dynamic pitching behavior of the self-propelled work machine while the self-propelled work machine is traveling. The pitch angle curve can be recorded continuously with the inertial sensor have the current pitch angle of the self-propelled machine. The pitch angle can represent a pitching of the self-propelled work machine about a transverse axis of the self-propelled work machine. A positive pitch angle or positive pitch angle components of the pitch angle curve can or can represent a pitching of the self-propelled work machine forward about the transverse axis in the direction of travel of the self-propelled work machine. A negative pitch angle or negative pitch angle components of the pitch angle curve can or can represent a pitching of the self-propelled work machine backwards about the transverse axis in the direction of travel of the self-propelled work machine. The inertial sensor can be or have an inertial measurement unit (IMU). According to one embodiment, the detected pitch angle profile is integrated over time and the further steps of the method are applied to the integrated pitch angle profile.

As a further step, the method includes checking whether the detected pitch angle profile reaches a first threshold value for a critical pitching of the self-propelled work machine forward in the direction of travel of the self-propelled work machine. The critical nodding can result from a critical change in position of a center of gravity of the self-propelled machine on the latter in the direction of travel. The critical change in position of the center of gravity can result from a load pickup in a front area of the self-propelled work machine with the work device in the direction of travel of the self-propelled work machine. The critical change in position of the center of gravity can result from a load redistribution on the self-propelled work machine in the direction of travel to the front of the self-propelled work machine. The critical pitching can lead to the self-propelled machine tipping over in the direction of travel. According to a further embodiment of the method, this can include, as a further step, deriving a change in position of a center of gravity of the self-propelled work machine while the self-propelled work machine is traveling and in a coordinate system tied to the self-propelled work machine.

The method has, as a further step, checking whether the detected pitch angle curve reaches a second threshold value for a critical pitching of the self-propelled work machine backwards in the direction of travel of the self-propelled work machine. The critical nodding can result from a critical change in position of a center of gravity of the self-propelled machine on the latter in the direction of travel to the rear. The critical change in position of the center of gravity can result from a load pickup in a rear area of the self-propelled work machine with the work equipment in the direction of travel of the self-propelled work machine. The critical change in position of the center of gravity can result from a load redistribution on the self-propelled work machine in the direction of travel to the rear of the self-propelled work machine. The critical pitch can lead to the self-propelled machine tipping over backwards in the direction of travel.

The method has, as a further step, determining that a critical pitching behavior of the self-propelled machine is present if the test result from one step of the two steps of testing is that the detected pitch angle curve reaches the corresponding threshold value, and if from the other step of the two Steps of testing as a test result results in that the detected pitch angle curve does not reach the corresponding threshold value. In the determination step, it can therefore be determined whether the detected pitch angle curve reaches exactly one of the two threshold values. In the determination step, it can also be determined that the detected pitch angle profile only or only reaches one of the two threshold values and thus a single one of the two threshold values.

As a further step, the method includes outputting a control signal for controlling an operating device of the self-propelled work machine based on the critical pitching behavior determined. The output step is carried out when the detected pitch angle curve reaches exactly one of the two threshold values. The operating device can be any component of a drive train or a steering system of the self-propelled machine. The operating device can be, for example, a transmission control unit of the self-propelled machine. The operating device can be a component for intervening in or influencing the driving dynamics of the self-propelled machine. The operating device can be a component for intervening in or influencing the transverse dynamics and/or the longitudinal dynamics of the self-propelled machine.

The operating equipment can also be the working equipment of the self-propelled machine. The control signal may be output to control the operating device such that the critical pitch can be stopped with controlling the operating device. Alternatively or in addition to stopping the critical pitch, the control signal can be output to control the operating device in such a way that the critical pitch is counteracted by controlling the operating device can be. According to one embodiment of the method, in the step of outputting the control signal, a control signal can be output to the operating device in order to control driving dynamics of the self-propelled work machine. The step of outputting the control signal can further be carried out based on the derived change in position of the center of gravity.

The operating device can be a steering system or a steering control device. According to one embodiment, the control signal is output to the steering or the steering control device in order to limit a steering angle of the self-propelled work machine. The operating device can be a longitudinal drive component or a drive control unit. According to one embodiment, the control signal is output to the longitudinal drive component or the drive control device in order to limit a travel speed or a longitudinal acceleration of the self-propelled work machine. The operating device can be a transmission or a transmission control unit. According to one embodiment, the control signal is output to the transmission or the transmission control unit in order to reduce deceleration of the transmission of the self-propelled work machine. The deceleration can be controlled when changing gears to a lower gear or changing the gear ratio of the transmission. The transmission can be a continuously variable power-split transmission. The operating device can be a warning device. According to one embodiment, the control signal is output to the warning device in order to warn an operator of the self-propelled work machine of a critical tipping of the self-propelled work machine.

With the invention, a distinction can be made between hopping and nodding of the self-propelled machine. The invention is based on the finding that hopping, that is, a translational movement of the self-propelled work machine up and down, can be detected if symmetrical pitching components to the front and back can be detected with an inertial sensor on the self-propelled work machine. The hopping can, for example, be stimulated by a natural frequency of the self-propelled machine or one of its components. The invention is further based on the finding that only if there is asymmetric pitching behavior forward or backward can a critical pitch be concluded and hopping can be ruled out. With the method, this is implemented efficiently by checking the two threshold values in stages. With the invention, tipping over of the self-propelled work machine can be reliably avoided without a critical change in position of the center of gravity of the self-propelled work machine itself having to be recognized or recorded. By issuing the control signal, critical tipping can be reliably counteracted. Critical tipping conditions, which can lead to the self-propelled machine tipping over, can thus be avoided with the method.

According to one embodiment of the method, in the step of detecting the pitch angle curve, the pitch angle curve can be detected based on accelerations and/or yaw rates of the self-propelled work machine, which are detected with at least one acceleration sensor and/or yaw rate sensor arranged on the self-propelled work machine. The inertial sensor or the inertial measuring unit can have at least one acceleration sensor and/or rotation rate sensor. The accelerations and/or yaw rates can have accelerations and/or yaw rates based on a coordinate system tied to the self-propelled work machine along at least one of the machine axes of the self-propelled work machine. The machine axes can have a transverse axis, a longitudinal axis and/or a vertical axis.

According to a further embodiment of the method, this can include, as a further step, determining a spatial change in orientation of a road surface on which the self-propelled work machine is traveling. The spatial change in orientation of the road surface can be determined with at least one inclination sensor. Alternatively or additionally, the spatial change in orientation of the road surface can be determined from measurement data from the inertial sensor or the inertial measuring unit. The spatial change in orientation of the road surface can be determined from measurement data from the acceleration sensor and/or the yaw rate sensor. According to a corresponding further embodiment of the method, in the step of determining the spatial change in orientation of the road surface, the spatial change in orientation can be determined based on measurement data which are recorded with the inertial sensor arranged on the self-propelled work machine.

As a further step, the method can include determining a pitch angle correction value based on the spatial change in orientation of the road surface for correcting a pitching of the self-propelled work machine caused by the spatial change in orientation of the road surface when the self-propelled work machine is traveling. The procedure can have, as a further step, attaching the specific pitch angle correction value to the detected pitch angle profile. Thus, an influence of a changing road inclination while the self-propelled machine is traveling on the pitch angle curve can be determined and taken into account in an advantageous manner.

According to a further embodiment of the method, this can include calibrating the inertial sensor as a further step. The calibration step can be carried out on a road surface with a predetermined spatial orientation, for example a horizontal orientation. The orientation of the gravitational acceleration component can thus be predetermined relative to the road surface. Calibrating the inertial sensor can be based on the predetermined orientation of the gravitational acceleration component. The calibration step can be carried out before the step of detecting the pitch angle profile. In the step of determining an existing critical pitching behavior, the influence of a road inclination can therefore be taken into account.

According to a further embodiment of the method, this can have, as a further step, a detection of a critical load-carrying state present when the self-propelled work machine is traveling based on the critical pitching behavior determined. The critical load carrying condition can cause the critical pitching behavior. The step of outputting the control signal may be performed based on the detected critical load receiving condition. The control signal can be output to the operating device in order to cause the operating device to stop or counteract the critical load-bearing condition. In this way, the operational safety of the self-propelled machine can be reliably maintained.

The present invention relates in a further aspect to a control system for operating a self-propelled work machine. The control system may be arranged to carry out the method according to the previous aspect. The control system may have at least one unit to carry out at least one step of the method.

The control system has an inertial sensor arranged on the self-propelled work machine, which is set up to detect a pitch angle profile of the self-propelled work machine while the self-propelled work machine is traveling. The control system also has an evaluation unit which is set up to check whether the detected pitch angle curve reaches a first threshold value for a critical pitching of the self-propelled work machine forward in the direction of travel of the self-propelled work machine and to check whether the detected pitch angle curve reaches a second threshold value for a critical pitching of the self-propelled work machine towards the rear in the direction of travel of the self-propelled work machine is achieved, the evaluation unit being set up to determine that a critical pitching behavior of the self-propelled work machine is present when the detected pitch angle profile reaches a threshold value of the two threshold values and when the detected pitch angle profile reaches the other threshold value Both threshold values are not reached. The evaluation unit is also set up to output a control signal for controlling an operating device of the self-propelled machine based on the critical pitching behavior determined.

The present invention relates in a further aspect to a self-propelled work machine. The self-propelled work machine has a control system according to the preceding aspect for operating the self-propelled work machine. Any embodiment of one aspect of the present invention may be or constitute a corresponding embodiment of another aspect of the present invention.

Short description of the characters

• 1 shows schematically a self-propelled work machine with a control system for operating the self-propelled work machine according to a respective embodiment of the invention.
• 2 shows a pitch angle curve of the self-propelled machine to explain the invention.
• 3 shows a flowchart with method steps of a method for operating the self-propelled machine according to an embodiment of the invention.

Detailed Description of Embodiments

1 shows a self-propelled work machine 100, on which an inertial sensor 10 for detecting a pitch angle profile of the self-propelled work machine 100 is arranged. The inertial sensor 10 has at least one acceleration sensor 12 for detecting the pitch angle profile. The pitch angle course has a course of continuously recorded pitch angles 3 of the self-propelled work machine 100 about a transverse axis 14 of the self-propelled work machine 100. The transverse axis 14 of the self-propelled work machine 100 is in one on the self-propelled Rending work machine 100 bound coordinate system 13 arranged.

The self-propelled work machine 100 travels on a road surface 102. The inclination of the self-propelled work machine 100 with respect to the road surface 102 is predetermined from measurement data from the inertial sensor 10. The self-propelled work machine 100 has a control system 200, which is set up to control an operating device 20 of the self-propelled work machine 100. The control system 200 is set up to control the operating device 20 depending on the detected pitch angle profile in order to prevent critical pitching of the self-propelled work machine 100 while the self-propelled work machine 100 is traveling. The operating device 20 is set up to control the driving dynamics of the self-propelled work machine 100 for this purpose.

In 2 a pitch angle curve 2 is shown, which was detected with the inertial sensor 10 while the self-propelled work machine 100 was traveling. The pitch angle profile 2 has positive and negative pitch angle components along a time axis 8 of the pitch angle profile 2. A first threshold value 4 for the positive pitch angle components and a second threshold value 6 for the negative pitch angle components are defined for the pitch angle 3. In 2 a critical pitch 5 of the self-propelled work machine 100 is determined, which is determined when either the positive pitch angle components or the negative pitch angle components exceed the respective threshold value 4, 6. In 2 It is shown that the positive pitch angle components exceed the first threshold value 4 for the positive pitch angle components, while the negative pitch angle components do not exceed the second threshold value 6 for the negative pitch angle components. Unilateral or asymmetrical overshooting is an overshooting in terms of amount. Since only one threshold value 4 of the two threshold values 4, 6 is exceeded by the pitch angle curve, the critical pitch 5 detected is a critical pitching behavior of the self-propelled work machine 100, which is not a hopping of the self-propelled work machine 100.

In 3 Method steps S0 to S5 of a method for operating the self-propelled work machine 100 are shown in a chronological sequence. In a first step S0, the inertial sensor 10 is calibrated, with the inertial sensor 10 being calibrated while the self-propelled machine 100 is at a standstill on a horizontal road surface 102 in order to attach the known orientation of the acceleration due to gravity to the measurement data of the inertial sensor 10. In a further step S1, correction values for a pitch angle curve 2 to be detected are determined. In step S1, a spatial change in orientation of the road surface 102 during a journey of the self-propelled work machine 100 is determined from measurement data from the inertial sensor 10. The spatial change in orientation of the road surface 102 is applied to the pitch angle profile 2 recorded in a subsequent step S2 in order to correct it.

In the subsequent step S2, the pitch angle curve 2 of the self-propelled work machine 100 is determined with the inertial sensor 10 while the self-propelled work machine 100 is traveling, as follows 2 described, recorded. In a further step S3 of the method, it is checked whether one of the two threshold values 4, 6 is exceeded by the pitch angle curve 2. In a first test step S3a, it is checked whether the detected pitch angle profile 2 with its positive pitch angle components reaches the first threshold value 4 for a critical pitch 5 of the self-propelled work machine 100 in the direction of travel of the self-propelled work machine 100 to the front. In a further test step S3b, it is checked whether the detected pitch angle curve 2 with its negative pitch angle components reaches the second threshold value 6 for a critical pitch 5 of the self-propelled work machine 100 in the direction of travel of the self-propelled work machine 100 to the rear.

In a further step S4, it is determined that a critical pitching behavior of the self-propelled machine 100 is present if only one of the two test steps S3a, S3b results in a test result that the detected pitch angle curve 2 reaches the corresponding threshold value 4, 6, and if from that Another test step of the two test steps S3a, S3b results in a test result that the detected pitch angle curve 2 does not reach the corresponding threshold value 4, 6. In a further step of the method S5, a control signal for controlling the operating device 20 of the self-propelled work machine 100 is output based on the determined critical pitching behavior in order to prevent the self-propelled work machine 100 from tipping over, which can result from the critical pitching behavior.

Reference symbols

2

Pitch angle progression

3

Pitch angle

4

first threshold

5

critical nod

6

second threshold

8th

Timeline

10

Inertial sensor

12

Accelerometer

13

Coordinate system

14

Transverse axis

20

Operating facility

100

self-propelled work machine

102

road surface

200

Tax system

50

Calibrate inertial sensor

S1

Determine pitch angle correction value

S2

Capture pitch angle progression

S3

Check thresholds

S3a

Check first threshold

S3b

Check second threshold

S4

Determine critical pitching behavior

S5

Output control signal

Claims (10)

Method for operating a self-propelled work machine (100), with the steps: detecting (S2) a pitch angle curve (2) of the self-propelled work machine (100) with an inertial sensor (10) arranged on the self-propelled work machine (100) while the self-propelled work machine is traveling ( 100), checking (S3a) whether the detected pitch angle progression (2) reaches a first threshold value (4) for a critical pitching (5) of the self-propelled work machine (100) forward in the direction of travel of the self-propelled work machine (100), checking (S3b) whether the detected pitch angle profile (2) reaches a second threshold value (6) for a critical pitching (5) of the self-propelled work machine (100) in the direction of travel of the self-propelled work machine (100) to the rear, determining (S4) that a critical pitching behavior of the self-propelled machine Work machine (100) exists if the test result from one step of the two steps of testing (S3a, S3b) is that the detected pitch angle curve (2) reaches the corresponding threshold value (4, 6), and if from the other step of the two Steps of testing (S3a, S3b) result in a test result that the detected pitch angle profile (2) does not reach the corresponding threshold value (4, 6), and outputting (S5) a control signal for controlling an operating device (20) of the self-propelled work machine (100 ) based on the critical pitching behavior identified. Procedure according to Claim 1 , wherein in the step of detecting (S2) the pitch angle curve (2), the pitch angle curve (2) is detected based on accelerations of the self-propelled work machine (100), which are detected with an acceleration sensor (12) arranged on the self-propelled work machine (100). Procedure according to Claim 1 or 2 , with the further steps: determining a spatial change in orientation of a road surface (102) on which the self-propelled work machine (100) is traveling, determining (S1) a pitch angle correction value based on the spatial change in orientation of the road surface (102) to correct a movement of the self-propelled machine Work machine (100) pitching of the self-propelled work machine (100) caused by the spatial change in orientation of the road surface (102), attaching the specific pitch angle correction value to the detected pitch angle profile (2). Procedure according to Claim 3 , wherein in the step of determining the spatial change in orientation of the road surface (102), the spatial change in orientation is determined based on measurement data which are recorded with the inertial sensor (10) arranged on the self-propelled work machine (100). Method according to one of the preceding claims, with the further step of calibrating (S0) of the inertial sensor (10), wherein the step of calibrating (S0) is carried out on a road surface (102) with a predetermined spatial orientation, and wherein the step of calibrating ( S0) is carried out before the step of detecting (S2) the pitch angle profile (2). Method according to one of the preceding claims, with the further step of detecting a critical load-carrying condition present when the self-propelled work machine (100) is traveling based on the determined critical pitching behavior, where the step of outputting (S5) the control signal is carried out based on the detected critical load-carrying condition becomes. Method according to one of the preceding claims, with the further step of deriving a change in position of a center of gravity of the self-propelled work machine (100) while the self-propelled work machine (100) is traveling and in a coordinate system (13) bound to the self-propelled work machine (100), where the Step of outputting (S5) the control signal is carried out based on the derived position change. Method according to one of the preceding claims, wherein in the step of outputting (S5) the control signal, a control signal is sent to the operating Device (20) of the self-propelled work machine (100) is output in order to control driving dynamics of the self-propelled work machine (100). Control system (200) for operating a self-propelled work machine (100), with an inertial sensor (10) arranged on the self-propelled work machine (100), which is set up to detect a pitch angle profile (2) of the self-propelled work machine (100) when the self-propelled work machine is traveling ( 100), and an evaluation unit (210), which is set up to check whether the detected pitch angle profile (2) has a first threshold value (4) for a critical pitch (5) of the self-propelled work machine (100) in the direction of travel of the self-propelled work machine (100) reaches the front and to check whether the detected pitch angle curve (2) reaches a second threshold value (6) for a critical pitch (5) of the self-propelled work machine (100) in the direction of travel of the self-propelled work machine (100) to the rear, whereby the Evaluation unit (210) is set up to determine that a critical pitching behavior of the self-propelled machine (100) is present when the detected pitch angle curve (2) reaches a threshold value of the two threshold values (4, 6) and when the detected pitch angle curve (2) reaches the other threshold value of the two threshold values (4, 6) are not reached, and wherein the evaluation unit (210) is set up to output a control signal for controlling an operating device (20) of the self-propelled work machine (100) based on the critical pitching behavior determined. Self-propelled work machine (100), which has a control system (200). Claim 9 for operating the self-propelled work machine (100).

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