Method and control device for operating a self-propelled work machine

Abstract

A method for operating a self-propelled work machine (100) is described, comprising the steps of determining an operating variable of a work equipment (10) of the self-propelled work machine (100), determining a longitudinal dynamic drive variable of the self-propelled work machine (100), checking, based on the determined operating variable and the determined longitudinal dynamic drive variable, whether a situation of a stability risk for the self-propelled work machine (100) is imminent, and intervening in a longitudinal dynamics of the self-propelled work machine (100) in dependence on a result of the checking based on the checking step. A control device (20) for operating a self-propelled work machine (100) and a self-propelled work machine (100) having a work equipment (10) and a control device (20) are also described.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method and a control device for operating a self-propelled work machine. The invention also relates to a self-propelled machine. BACKGROUND

[0002] For example, self-propelled work machines can be used for various tasks on a construction site. During the operation of a self-propelled work machine, for example in civil engineering, accidents can still occur due to the lack of stability of the self-propelled work machine, despite the safety measures that already exist. SUMMARY

[0003] In one aspect, the invention relates to a method for operating a self-propelled work machine. The self-propelled work machine can be a vehicle or a machine that can be designed to perform at least one work task. Thus, the self-propelled work machine can be a vehicle or a machine that is primarily used to perform at least one work task. Thus, the self-propelled work machine is not a vehicle or a machine that is primarily used to transport people. However, the self-propelled work machine can be designed to transport things. Thus, the method can also be performed for performing at least one work task with the work machine.

[0004] According to one embodiment, the self-propelled work machine can be a construction machine. The construction machine can have a tool for performing at least one work task. The self-propelled work machine can be, for example, a wheel loader. The tool can be, for example, a bucket. The work equipment of the machine can comprise the tool or the bucket.

[0005] The method has a step of determining an operating variable of a work equipment of the self-propelled work machine. The work equipment can be located on the self-propelled work machine. The work equipment can be located in front of or behind the self-propelled work machine. The work equipment can be operated under variable or fixed load. The work equipment can be fixedly or movably arranged on the work vehicle. The operating variable of the work equipment can describe a current operating parameter or a current operating state of the work equipment. The operating variable of the work equipment can be a static or dynamic operating variable of the work equipment. The operating variable can have a static operating state.

[0006] According to another embodiment, the step of determining the operating variable of the work equipment can be based on a detection of the operating variable by a sensor. The operating variable of the work equipment can be recorded directly by the sensor or determined based on a sensor-detected variable.

[0007] Another step of the method is to determine a longitudinal dynamic drive variable of the self-propelled work machine. The longitudinal dynamic drive variable can be a drive dynamic variable related to the longitudinal movement of the self-propelled work machine. The longitudinal dynamic drive variable or the drive dynamic variable can be, for example, a drive variable, an acceleration variable or a braking variable.

[0008] A further step of the method is to check, based on the determined operating variable and the determined longitudinal dynamic driving variable, whether a critical condition of the stability of the self-driving work machine occurs. Thus, a critical condition of the stability of the self-driving work machine can be detected.

[0009] The checking step can be based on determining information about the position of the center of gravity of the self-driving work machine. The critical condition of the stability of the self-driving work machine can be a current or future operating state of the self-driving work machine in which the self-driving work machine is tilted or will be tilted. Thus, the checking step can comprise a determination of a current critical condition of the stability of the self-driving work machine or a prediction of a future critical condition of the stability of the self-driving work machine. As a result of the checking step, a critical condition can thus exist or will exist.

[0010] According to a further embodiment, the checking step can comprise comparing the determined information about the position of the center of gravity of the self-driving work machine with at least one limit information about the position of the center of gravity of the self-driving work machine. If a limit value is exceeded, the test result that can be obtained is that, based on the determined information about the position of the center of gravity of the self-driving work machine, a critical condition of the stability of the self-driving work machine has occurred or will occur.

[0011] A further step of the method is to intervene in the longitudinal dynamics of the self-driving work machine depending on the checking result of the checking step. Thus, a further step that the method can comprise can be a braking or acceleration of the self-driving work machine in order to prevent or eliminate a critical condition of the stability of the self-driving work machine. Intervening in the longitudinal dynamics of the self-driving work machine can comprise controlling a driving motor for longitudinal dynamic driving of the self-driving work machine or controlling a drivetrain of the self-driving work machine. According to an embodiment, the intervention can thus comprise a minimization of the longitudinal dynamic or driving dynamic. The aggressiveness of the longitudinal dynamic or driving dynamic can thus be reduced, whereby a risk of instability can be avoided, for example when the self-driving work machine is reversing. According to an embodiment, the intervention can also be performed depending on a load acting on the work equipment.

[0012] The method can thus comprise a further step of monitoring a tilt of the self-driving work machine, wherein the monitoring step can comprise a continuous determination of the critical condition or the tilt condition.

[0013] According to a further embodiment, the step of determining an operating variable of the work equipment comprises determining a task hydraulic request requested by the driver for performing a task with the work equipment. The task hydraulic request can be requested directly or indirectly by the driver. The task hydraulic request can be a volumetric flow request to the work hydraulic device. The volumetric flow request can also be requested directly or indirectly by the driver. The step of determining an operating variable can comprise determining a maximum task hydraulic request requested by the driver or a task hydraulic request that exceeds a predetermined threshold value.

[0014] According to another embodiment, the step of determining an operating variable of the work equipment comprises determining a task hydraulic request communicated by the automated work system for automatically performing a task with the work equipment. Thus, the step of determining an operating variable can further comprise determining a maximum task hydraulic request or a task hydraulic request exceeding a predetermined threshold communicated by the automated work system. Moreover, the step of determining an operating variable of the work equipment can already comprise an inquiry about whether the automated work system is activated.

[0015] According to another embodiment, the step of determining an operating variable of the work equipment comprises determining a load acting on the work equipment. The load acting on the work equipment can be generated by a gravitational force acting on the work equipment. For example, the work equipment can carry an object or material, thereby resulting in a load acting on the work equipment. Alternatively or additionally, the load acting on the work equipment can be generated by the work equipment performing a work task, for example pulling or pushing with the work equipment. For example, if the work equipment has a bucket, a load state or a current load of the bucket can be determined in another step. Determining the load acting on the work equipment can be performed based on a determination of an output torque of an electric motor driving the work equipment. Alternatively or additionally, determining the load acting on the work equipment can be performed based on a determination of an adjustment angle of a hydraulic pump hydraulically driving the work equipment. The hydraulic pump can be designed as a variable displacement pump or a gear pump.

[0016] According to another embodiment, the step of determining an operating variable of the work equipment comprises determining a work pressure in a work hydraulic system of the work equipment. Determining the work pressure can also be performed based on determining the output torque of the electric motor or the adjustment angle of the hydraulic pump.

[0017] According to another embodiment, the step of determining an operating variable of the work equipment comprises determining spatial position information of the work equipment. The spatial position information can contain information about at least one of an alignment or an orientation and a position of the work equipment. If the work equipment has a bucket, determining the spatial position information can comprise determining a position of the bucket, for example a lifting height of the bucket. If the work equipment has a lifting arm, determining the spatial position information can comprise determining a position of the lifting arm, for example a lifting height of the bucket.

[0018] The work equipment can have a lifting frame. The lifting frame can have a lifting structure. The lifting frame or the lifting structure can have at least one lifting arm. According to another embodiment, the step of determining an operating variable of the work equipment can comprise determining a work variable of a lifting kinematics of the lifting frame or the lifting structure. The work variable of the lifting kinematics can comprise an angle in a lifting frame joint or a length of an extendable lifting frame component.

[0019] According to another embodiment of the method, this comprises a further step of determining a steering variable. The steering variable can comprise a steering angle or a hinge angle of the self-driving work machine. The checking step can be performed based on the determined steering information. Thus, the risk of instability of the work machine when accelerating can also be avoided when turning.

[0020] According to another embodiment, the step of determining a longitudinal dynamic driving variable comprises determining a driving request requested by the driver for longitudinal dynamic driving of the self-driving work machine. The driving request can be a speed request or an acceleration request. Further, the driving request can be any request for operating a driveline of the self-driving work machine, such as a request to start or deactivate a drive unit of the self-driving work machine, or a request to operate a gearbox of the self-driving work machine.

[0021] According to another embodiment, the step of determining a longitudinal dynamic driving variable comprises determining a travel direction change requested by the driver to change a travel direction of the self-driving work machine. Determining a travel direction change requested by the driver can comprise determining a reverse requested by the self-driving work machine.

[0022] According to another embodiment, the checking step comprises checking whether a tilting condition of the self-driving work machine is present. For example, it can be checked whether a current center of gravity of the self-driving work machine is within the limits of a tilting edge polygon, such as a stability triangle or a stability quadrangle formed in the self-driving work machine. Thus, as a result of the checking step, it can also be that a tilting condition is present or will be present.

[0023] According to another embodiment, the method comprises a further step of determining information about a spatial orientation of the self-driving work machine. Determining information about a spatial orientation of the self-driving work machine can comprise determining information about a tilt of the self-driving work machine, such as a longitudinal tilt or a lateral tilt of the self-driving work machine. The checking step can be performed based on the determined information. The checking step can comprise comparing the current spatial orientation or tilt with predetermined limit values for the spatial orientation or tilt. Then, the checking result can be that the predetermined limit values have been exceeded. The self-driving work machine can have a tilt sensor, wherein the step of determining information about a spatial orientation of the self-driving work machine can be performed based on measurement data of the tilt sensor.

[0024] According to another embodiment, the step of intervening in the longitudinal dynamics comprises limiting a driving request that the driver can request to drive the self-driving work machine. The step of intervening in the longitudinal dynamics can comprise limiting a speed request or an acceleration request. Thus, the longitudinal dynamic aggressiveness of the self-driving work machine that the operator can request can be limited to ensure the stability and safety of the self-driving work machine and to avoid tilting of the self-driving work machine.

[0025] According to another embodiment, the method comprises a further step of implementing a maximum task operating variable requested by the driver for performing a task with the work equipment. The implementation of the maximum task operating variable requested by the driver can be based on the fact that the maximum task operating variable that can be requested by the driver is not reduced or limited. The implementation of the maximum task operating variable requested by the driver can involve a control of a drive motor or a work hydraulic device of the self-driving work machine. The step of implementing the maximum task operating variable requested by the driver can be possible by intervening in the longitudinal dynamics or by limiting the driving requests that can be requested by the driver. Despite the implementation of the maximum task operating variable requested by the driver, the stability of the self-driving work machine can be ensured, so that a tilting of the self-driving work machine can be avoided.

[0026] According to another embodiment, the method comprises a further step of implementing a maximum braking of the self-driving work machine triggered by the driver to trigger an emergency braking process. The step of intervening in the longitudinal dynamics can be performed independently of maintaining a maximum braking of the self-driving work machine that can be triggered by the driver in order to trigger an emergency braking process. Thus, for example, an emergency braking during the operation of the self-driving work machine can be performed independently of a limitation of the driving requests that can be requested by the driver. In this way, the operating safety of the self-driving work machine can also be improved. According to another embodiment, the implementation of the maximum braking of the self-driving work machine triggered by the driver can be performed depending on a load acting on the work equipment. In this way, even during an emergency braking, the risk of a destabilization of the self-driving work machine can be avoided.

[0027] According to another embodiment, the method can be performed automatically, wherein the driver can trigger the execution of the method. The triggering can be based on a command from the driver, for example an input via an interface. The interface can be in the form of a display or a control element.

[0028] In another aspect, the invention relates to a control device for operating a self-driving work machine. The control device can be set up to perform the method according to the preceding aspect. The control device can comprise at least one unit or interface for performing at least one of the steps described for the method.

[0029] The control device comprises an evaluation unit for determining an operating variable of a work equipment of the self-driving work machine and for determining a longitudinal dynamic driving variable of the self-driving work machine. The control unit comprises a checking unit for checking whether a critical state of the stability of the self-driving work machine can arise based on the determined operating variable and the determined longitudinal dynamic driving variable. The checking unit is set up to provide a checking result based on the check. The control unit has an interface for outputting a control signal with which, depending on the checking result that can be provided by the checking unit, an intervention in the longitudinal dynamics of the self-driving work machine can be performed.

[0030] In another aspect, the present application relates to a self-propelled work machine having a work device and a control device for operating the self-propelled work machine according to the preceding aspect. The work device can be the work device described in the preceding aspect.

[0031] The self-propelled work machine can be an electrically propelled self-propelled work machine. The self-propelled work machine can comprise at least one of a battery powered drive system, a fuel cell powered drive system and a conventional drive system. According to one embodiment, the self-propelled work machine comprises a first drive system for driving the work device and a second drive system for longitudinal dynamic driving of the self-propelled work machine. The second drive system can be controlled by the control device independently of the first drive system. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A schematic diagram illustrating a self-propelled work machine according to one embodiment of the present application is shown, wherein the self-propelled work machine comprises a control device for operating the self-propelled work machine according to another embodiment of the present application.

[0033] Figure 2 A schematic flow chart illustrating steps of a method of operating a self-propelled work machine according to one embodiment of the present application is shown. DETAILED DESCRIPTION

[0034] Figure 1 A self-propelled work machine 100 according to one embodiment is shown, which has a control device 20 for operating the self-propelled work machine 100 according to another embodiment.

[0035] The self-propelled work machine 100 comprises a work device 10 for performing a task. The work device 10 is arranged on the self-propelled work machine 100. The self-propelled work machine 100 further comprises a drivetrain 30 for driving the self-propelled work machine 100. The self-propelled work machine 100 comprises a first drive system 12 for driving the work device 10 and a second drive system 32 for driving the drivetrain 30. According to one embodiment, both drive systems 12, 32 are electric drive systems, which are powered by at least one battery (not shown).

[0036] The control device 20 is arranged to control both drive systems 12, 32. Thus, the control device 20 is further arranged to control the work device 10 and the drivetrain 30 by both drive systems 12, 32.

[0037] The control device 20 comprises an evaluation unit 22 which is set up to determine an operating variable of the work device 10. According to an embodiment, the evaluation unit 22 is set up to determine a position of the work device 10 relative to a frame (not shown) of the self-propelled work machine 100 based on the measured variables which have been read out. The evaluation unit 22 is further set up to determine a longitudinal dynamic drive variable of the self-propelled work machine 100. According to an embodiment, the evaluation unit 22 is set up to determine an acceleration request of the driver based on the acceleration signals which have been read out.

[0038] The control device 20 comprises a checking unit 24 which is set up to check, based on the operating variable determined by the evaluation unit 22 and the longitudinal dynamic drive variable also determined by the evaluation unit 22, whether a critical state of the stability of the self-propelled work machine 100 will occur. According to an embodiment, the checking unit 24 is set up to check, based on the relative position of the work device 10 and the acceleration request of the driver, whether a tilting state of the self-propelled work machine 100 will occur when the self-propelled work machine 100 is accelerated. The checking unit 24 is further set up to provide a checking result based on the check, wherein the checking result according to an embodiment is the presence or absence of the tilting state during the acceleration of the self-propelled work machine 100 requested by the driver.

[0039] The control device 20 comprises an interface 26 for outputting a control signal. With the control signal, an intervention into the longitudinal dynamics of the self-propelled work machine 100 is carried out depending on the checking result which can be provided by the checking unit 24. According to an embodiment, in the case of the presence of the tilting state, an intervention into the drive train 30 of the self-propelled work machine 100 is carried out so that, regardless of the acceleration requested by the driver, only a reduced acceleration of the self-propelled work machine 100 is allowed and implemented in order to avoid a tilting of the self-propelled work machine 100.

[0040] Figure 2 A flow chart of the steps Sla to S4b of the method for operating Figure 1 the self-propelled work machine 100 which is schematically shown in Fig. 1.

[0041] In a step Sla, an operating variable determination is carried out. Here, an operating variable of the work device 10 of the self-propelled work machine 100 is determined. As described, the step Sla is carried out by the control device 20. In a further step Sib, a drive variable determination is carried out in parallel to the step Sla. Here, a longitudinal dynamic drive variable of the self-propelled work machine 100 is determined. As described, the step Sib is carried out by the control device 20.

[0042] In an optional step S1c, determining the orientation of the self-driving machine 100 is also performed in parallel with steps S1a and S1b. Here, the current orientation of the self-driving machine 100 is determined by the control device 20. Step S1c is performed by the control device 20 based on information already read about the tilt angle of the self-driving machine 100. This information pertains to the longitudinal tilt angle of the self-driving machine 100. Alternatively or additionally, it pertains to the lateral tilt angle of the self-driving machine 100.

[0043] In another step S2, a stability check is performed. Here, the checking unit 24 of the control device 20 checks whether a dangerous state of stability of the self-driven machine 100 may occur, based on the operating variables determined in step S1a and the longitudinal dynamic drive variables determined in step S1b. Optionally, step S2 is also performed based on the orientation determination performed in step S1c. As described, step S2 is also performed by the control device 20.

[0044] In another step S3, longitudinal dynamic intervention is performed. This is performed in the longitudinal dynamics of the self-driven operating machinery 100 based on the inspection results of step S2 (which have the form described above).

[0045] Following step S3, the task operation variables are implemented. Here, the maximum task operation variable requested by the driver for performing the task using the work equipment 10 is implemented. Based on step S3, the implementation of the maximum task operation variable is only possible without compromising the stability of the self-propelled work machinery 100. According to one embodiment, the position of the work equipment 10 can be changed at maximum speed; for example, the work equipment 10 can be raised at maximum speed. However, based on step S3, the self-propelled work machinery 100 can only accelerate with reduced aggression, or according to another embodiment, it can be reversed.

[0046] According to another optional step S4b, braking is performed. Here, the maximum braking of the self-driving work machinery 100, triggered by the driver, is implemented to trigger the emergency braking process independently of step S3. Therefore, the operational safety of the self-driving work machinery 100 can be guaranteed independently of step S3.

[0047] Figure Labels

[0048] 10 working equipment

[0049] 12 First Drive System

[0050] 20 control devices

[0051] 22 assessment units

[0052] 24 inspection units

[0053] 26-interface

[0054] 30 Transmission System

[0055] 32 Second Drive System

[0056] 100 self-driving operating machinery

[0057] S1a Operation Variable Determination

[0058] S1b driving variable determination

[0059] S1c orientation determined

[0060] S2 stability check

[0061] S3 longitudinal dynamic intervention

[0062] Implementation of S4a task operation variables

[0063] Implementation of S4b braking.

Claims

1. A method for operating a self-propelled work machine (100), comprising the following steps: The step of determining (S1a) the operating variables of the working equipment (10) of the self-driven working machine (100) includes determining whether a task hydraulic request transmitted by the automatic working system for automatically performing a task using the working equipment exceeds a predetermined threshold transmitted by the automatic working system and an inquiry about whether the automatic working system is activated. Determine (S1b) the longitudinal dynamic drive variables of the self-driven operating machinery (100); Determine (S1c) information regarding the spatial orientation of the self-driving machine (100); Based on the determined operating variables, the determined longitudinal dynamic drive variables, and the determined information about the spatial orientation, check (S2) whether a dangerous state affecting the stability of the self-driven operating machinery (100) could occur. Based on the inspection results of the inspection step (S2), the longitudinal dynamics of the self-driven operating machinery (100) are intervened (S3).

2. The method according to claim 1, wherein, The step of determining (S1a) the operating variables of the work equipment (10) includes: determining the task hydraulic request requested by the driver for performing a task using the work equipment (10).

3. The method according to claim 1 or 2, wherein, The step of determining (S1a) the operating variables of the working equipment (10) includes: determining the load acting on the working equipment (10).

4. The method according to claim 1 or 2, wherein, The step of determining (S1a) the operational variables of the working equipment (10) involves determining the spatial location information of the working equipment (10).

5. The method according to claim 1 or 2, wherein, The working equipment (10) includes a lifting frame, and The step of determining the operational variables of the working equipment (10) (S1a) involves: determining the operational variables of the lifting kinematics of the lifting frame.

6. The method according to claim 1 or 2, wherein, The step of determining (S1b) the longitudinal dynamic drive variable includes: determining the drive request requested by the driver for longitudinal dynamic drive of the self-driven work machinery (100).

7. The method according to claim 1 or 2, wherein, The step of determining (S1b) the longitudinal dynamic drive variable includes: determining the change of driving direction requested by the driver to change the driving direction of the self-driven operating machinery (100).

8. The method according to claim 1 or 2, wherein, The inspection step (S2) includes checking whether the self-driven operating machinery (100) can be tilted.

9. The method according to claim 1 or 2, wherein, The steps of intervening (S3) in the longitudinal dynamics include: limiting the drive requests that can be requested by the driver to drive the self-driven work machinery (100).

10. The method according to claim 1 or 2, with an additional step: implementing (S4a) the maximum task operation variable requested by the driver for using the work equipment (10) to perform the task.

11. The method according to claim 1 or 2, with an additional step: implementing (S4b) maximum braking of the self-driving work machinery (100) triggered by the driver to initiate an emergency braking process.

12. A control device (20) for operating a self-propelled work machine (100), comprising: Evaluation unit (22), the evaluation unit (22) is used to determine the operating variables of the working equipment (10) of the self-driven operating machinery (100), to determine the longitudinal dynamic drive variables of the self-driven operating machinery (100), and to determine information about the spatial orientation of the self-driven operating machinery (100), wherein, Determining the operating variables of the working equipment (10) of the self-driven operating machinery (100) includes determining whether the task hydraulic request transmitted by the automatic operating system for automatically performing a task using the working equipment exceeds a predetermined threshold transmitted by the automatic operating system and inquiring about whether the automatic operating system is activated; Inspection unit (24) is used to check whether a dangerous state affecting the stability of the self-driven working machine (100) can occur based on the determined operating variables, the determined longitudinal dynamic drive variables and the determined information about the spatial orientation, wherein the inspection unit (24) is configured to provide inspection results based on the inspection. as well as Interface (26) is used to output a control signal, which, based on the inspection results provided by the inspection unit (24), enables longitudinal dynamic intervention of the self-driven operating machinery (100).

13. A self-propelled operating machine (100), comprising: Operating equipment (10), and The control device (20) for operating a self-driven work machine (100) according to claim 12.

14. The self-propelled operating machine (100) according to claim 13, comprising: The first drive system (12) for driving the working equipment (10), and The second drive system (32) is used for longitudinal dynamic driving of the self-driven operating machinery (100). The second drive system (32) can be controlled independently of the first drive system (12) using the control device (20).

Images