Method and device for controlling the driving speed of an agricultural machine

Abstract

Methods for controlling a vehicle speed (v F ) an agricultural machine (10) which is equipped at a driver's seat with at least one accelerator pedal (32) and one brake pedal (34) for foot operation and with at least one hand lever (20), which pedals (32, 34) and hand lever (20) are each used to influence the driving speed (v F ) by means of corresponding driving commands from the machine operator, characterized in that the last actuation of one of the foot pedals (32, 34) or of the hand lever (20) by the machine operator is associated with a change request for the driving speed (v F) defines the active actuation mode for hand or foot control and suppresses a connection between the travel speed control (22) and the other actuation mode at least until the machine operator makes a change request by actuating one of the foot pedals (32, 34) or the hand lever (20), and wherein actuating one of the foot pedals (32, 34) or the hand lever (20) with a simultaneously occurring defined change in position is interpreted as a change request which triggers a priority control (36) of the respective actuated pedal (32, 34) or hand lever (20).

Description

[0001] The present invention relates to a method and a device for controlling the driving speed of an agricultural machine.

[0002] Common agricultural tractors, such as tractors, or self-propelled agricultural machinery like sprayers, harvesters, etc., often feature continuously variable transmissions (CVTs), which in turn necessitate the use of continuously variable transmissions. These CVTs are frequently designed as hydrostatic or hydraulically continuously variable drives.

[0003] The operator of such a machine typically has access to the familiar accelerator pedals, which include at least an accelerator pedal (i.e., a pedal for speed control) and a brake pedal. The accelerator pedal provides a control link to an engine and / or transmission control system, while the brake pedal interacts with at least a hydraulic braking system, and possibly with other service or continuous braking devices. In addition to these familiar foot pedals, there are other operating devices for driving and / or braking control, which can be described as joysticks.This is a hand lever that can swivel in several directions and / or rotate through a defined angle, allowing the machine to be controlled with just one hand. This means that virtually all manual control inputs related to the machine's basic driving function—namely, speed control and braking—can be performed using the hand lever or the joystick. The machines are generally designed with both a drive pedal and a joystick, the latter of which can have many different functions.

[0004] A preferred joystick design allows the vehicle to be accelerated or decelerated by moving the joystick forward or backward (in the direction of travel). In conventional vehicle control systems, acceleration or deceleration is achieved using the accelerator pedal. When the pedal is pressed, the vehicle accelerates; when it is released (swiped), the vehicle coasts until it comes to a stop; however, no active deceleration (braking) occurs.

[0005] Many machines already feature a system where the operator can choose between speed control via joystick or accelerator pedal. However, this requires the operator to manually select the desired speed control mode, for example, using an additional switch. This manual switching is cumbersome and detrimental to operator comfort. Furthermore, it can lead to operating errors, especially when the operator is distracted.

[0006] German patent DE 60 2005 002 867 T2 discloses a control system for vehicles such as tractors equipped with foot pedal controls. An additional hand control device can be overridden by other control elements. US patent 2010 / 0 313 693 A1 further discloses a vehicle with a hand control system that allows acceleration and braking of the vehicle by hand. The hand controls are electronically connected to vehicle control units that electronically control the drive and braking systems. The control unit can determine an accelerator pedal position when an accelerator pedal position signal is received and a brake pedal position when a brake pedal position signal is received.

[0007] A primary objective of the invention is therefore to create a reliable and safe actuation concept for controlling the driving functions of an agricultural machine, which is prepared for both manual and alternative foot operation. Both types of actuation should be equally possible, particularly depending on the actuation method preferred by the operator.

[0008] This objective of the invention is achieved by the subject matter of the independent claims. Features of advantageous embodiments of the invention are described in the respective dependent claims. To achieve this objective, the invention proposes a method for controlling the travel speed of an agricultural machine, the method being particularly suitable for controlling the travel speed of an agricultural tractor or a self-propelled work machine, and optionally also of construction machinery and other self-propelled work machines. The agricultural machine to which the method according to the invention relates is equipped at a driver's seat with at least one accelerator pedal and one brake pedal for foot operation, as well as with at least one hand lever. The at least two foot pedals and the hand lever each serve to influence the travel speed by corresponding driving commands from the machine operator.Depressing the accelerator pedal normally increases the vehicle speed, while releasing the pedal reduces the speed by switching the agricultural machine's drive motor into overrun or towing mode, also known as engine braking. Depressing the brake pedal actively reduces the vehicle speed by activating the wheel brakes and / or other active braking systems, such as a continuous braking system. The hand lever, which can also be called a joystick due to its resemblance to one, can be pushed forward to increase the vehicle speed and pulled towards the driver to decrease it. This reduction in speed can be achieved either solely through engine braking or also through additional activation of the service brakes.which may be due to the vehicle's wheel brakes.

[0009] The method according to the invention provides that the last actuation of one of the foot pedals or the hand lever by the operator, requesting a change in driving speed, defines a priority control and suppresses the connection between the driving speed control and the other actuation method at least until the operator makes a change request by actuating one of the foot pedals or the hand lever accordingly. The agricultural vehicle is equipped so that it can be driven either with the accelerator pedal or with the joystick. Switching between modes occurs without the additional actuation of a separate switch or the like, but primarily based on an evaluation of the operator's actions. Restrictions may be provided, the variations of which are explained in more detail below.

[0010] In this context, the term "priority control" refers to the selection of the currently "active" operating elements; that is, the priority control defines, based on the driver's actions, whether driving commands are issued and executed via the hand lever or the foot pedals. If the driver operates the hand lever, it remains decisive or "active" for further vehicle control until the driver later operates one of the foot pedals. In this case, the priority control switches over, so that driving commands issued via the foot pedals remain decisive for further vehicle control, meaning they are initially "active" while the hand lever is deactivated. Conversely, if the hand lever is activated and the priority control is activated accordingly, the foot pedals are deactivated or "inactive."

[0011] The procedure stipulates that the activation of one of the foot pedals or the hand lever, accompanied by a defined change in position, is interpreted as a change request, triggering the priority control of the respective pedal or hand lever. The detected change in position, resulting from the driver's activation, should not fall below a defined minimum value to avoid overly sensitive control characteristics. Instead, it is advisable to provide a minimum travel distance of, for example, two to four millimeters at the hand lever and a corresponding minimum travel distance of a few millimeters at the foot pedals, which are interpreted as activation and trigger the corresponding priority control. This prevents any mechanical pedal play or free play in the hand lever from being overlooked and potentially leading to unfavorable control behavior.

[0012] An alternative priority control method can also employ a time-dependent control system, so that after a definable period of, for example, three, four, or five seconds following the activation of one of the control elements, the other is deactivated. For example, if the foot pedals are activated and the hand lever is inactive, its activation can be monitored, and after a defined period of, for example, five seconds after the hand lever is activated, the foot pedals are deactivated until they are activated again by the driver.

[0013] Another variation of the method can provide an additional selector switch for setting a direction of travel for the agricultural machine, which, with regard to priority control over the hand lever, is assigned to at least two foot pedals. In this context, it can be advantageous if the foot pedals are given priority over the hand lever after the operator has actuated the selector switch, so that the foot pedals retain priority until the hand lever is actuated for the first time after the selector switch has been actuated. As soon as this occurs, it takes priority over the other operating devices.

[0014] In the method according to the invention, it is advantageous to first divide the generally available control options into so-called "driving strategies". Thus, there is a "joystick driving strategy" and a "pedal driving strategy". There can also be a third "cruise control driving strategy", which, however, does not require any separate measures.

[0015] The following control units are assigned to the accelerator pedal driving strategy: the direction switch (preselection option, forward / reverse driving), the accelerator pedal (speed change, speed change) and the brake pedal (deceleration).

[0016] The driving strategy joystick is only assigned to the joystick.

[0017] Furthermore, the agricultural machine can be equipped with a control computer that controls and regulates the machine. By touching a control unit or joystick, the control computer assigns the machine to the appropriate driving strategy. Speed ​​changes are then achieved using the control unit assigned to that driving strategy. The operator does not need to operate any additional switches or similar devices; a single touch of a control or operating unit is sufficient.

[0018] Optionally, it can also be provided that a distinction is made between road travel and field travel by means of a preselection via a control program and / or by exceeding a definable speed limit, which is simultaneously linked to a modified priority control. In this variant of the method, the machine control via hand lever is preferably deactivated during road travel and / or when the defined speed limit is exceeded and replaced by machine control via foot pedals in order to comply in particular with legal requirements that require speed control and braking of the machine via foot pedals.

[0019] Furthermore, to achieve the aforementioned goal, the invention proposes an agricultural machine, in particular an agricultural tractor or self-propelled work machine, which is equipped at a driver's seat with at least one accelerator pedal and one brake pedal for foot operation, as well as with at least one hand lever. The pedals and the hand lever each serve to influence the driving speed through corresponding driving commands from the operator. In addition, the foot pedals and the hand lever are linked to a control device that provides priority control by the foot pedals or the hand lever based on the operator's most recent actuation of one of the foot pedals or the hand lever with a request to change the driving speed.Furthermore, the agricultural machine may have a pre-selection switch for setting a direction of travel of the agricultural machine, which is assigned to at least two foot pedals with regard to priority control over the hand lever.

[0020] Furthermore, the control system of the agricultural machine can take into account a preset and / or a definable speed limit to distinguish between road travel and field travel. It is therefore advisable to suppress manual lever controls during road travel and / or when traveling at a speed above the defined speed limit.

[0021] Furthermore, it should be mentioned that the agricultural machine does not necessarily have to have a continuously variable transmission. To realize the invention, it is sufficient if the machine can be controlled with a joystick or a pedal.

[0022] The agricultural vehicle described and defined by the present invention is equipped in such a way that it can be driven either with the accelerator and brake pedals or with the joystick or hand lever. Switching between modes is achieved without the need for an additional separate switch or the like, but primarily based on an evaluation of the operator's actions. This is accomplished by interposing a priority control unit, whose output signal is used to generate a target speed signal in the control unit. This unit, in turn, generates a suitable engine control signal and, if necessary, a brake signal to control the drive motor and, if applicable, the vehicle's service brakes accordingly.The present invention thus provides a method and a set of actuating devices for an agricultural machine or tractor, in which the respective actuation of the foot pedal set or the hand lever, by means of the priority control, defines which of these different actuating elements – the pedals or the hand lever – are activated and which are deactivated. The decision to activate one of the actuating elements (for foot or hand operation) and the simultaneous deactivation of the other actuating element (for hand or foot operation) is essentially made based on the last actuating intervention by the machine operator, whereby additional restrictions may be superimposed, such as the driving speed and / or an actuated direction switch.

[0023] The following exemplary embodiments of the invention and its advantages will be explained in more detail with reference to the accompanying figures. The relative sizes of the individual elements in the figures do not always correspond to the actual relative sizes, as some shapes are simplified and others are enlarged for better illustration. Fig. Figure 1 shows a schematic representation of an agricultural tractor with input devices for controlling a driving speed. Fig. Figure 2 shows an interior view of the cab of an agricultural tractor, as it appears to a driver.

[0024] Identical or equivalently functioning elements of the invention are designated by the same reference numerals. Furthermore, for the sake of clarity, only those reference numerals necessary for describing the respective figure are shown in the individual figures. The illustrated embodiments merely represent examples of how the device or method according to the invention may be configured and do not constitute an exhaustive limitation.

[0025] The schematic representation of the Fig. Figure 1 illustrates an embodiment of an agricultural machine 10, here an agricultural tractor 12 with an attached trailer 14. The agricultural tractor 12 has a driver's cab 16 with a seat and command post for a machine operator, the basic design of which is known per se, but can also be seen from the schematic representation of the Fig. 2 results. In the driver's cab 16 and within reach of the seated driver or machine operator, there is a foot pedal set 18 and a hand lever 20, which can be designed like a joystick. The foot pedal set 18 and the hand lever 20 are signal-connected to a control unit 22, which derives a target signal v from the actuation commands of the foot pedals 18 and / or the hand lever 20. F(soll) for a driving speed v F formed by the tractor unit 12. From this target speed signal v F(soll) In the control unit 22, a drive control signal 24 is generated and transmitted to a control unit of the drive motor 26 of the tractor 12. The drive control signal 24 can, for example, act as a motor control signal in the area of ​​the drive motor 26, similar to a so-called cruise control system, with which the speed v is controlled. FThe drive control signal 24 can be kept constant or changed according to the control specifications of the input devices 18 and 20. However, the drive control signal 24 can optionally also include a transmission control signal, so that, depending on requirements and structural conditions, the drive control can be used to influence the motor speed and / or a change in the transmission ratio.

[0026] The schematic representation of the Fig. Figure 2 shows an interior view of the cab 16 of the agricultural tractor 12, as it appears to the driver looking through a windshield 28. The essential controls for steering the vehicle are a steering wheel 30, the foot pedal assembly 18 for operation by the driver, which includes at least an accelerator pedal 32 and a brake pedal 34. In addition, within the driver's reach is the hand lever 20, which may resemble a joystick and can accelerate or decelerate the vehicle by pivoting it forwards and backwards.

[0027] Ideally, the hand lever 20 is located within easy reach of the driver, e.g. near the steering wheel 30.

[0028] By pressing down the accelerator pedal 32, the so-called gas pedal, the driving speed can be increased, whereas the driving speed can be reduced by releasing the pedal 32, thereby slowing down the drive motor 26 of the agricultural machine 12 (cf. Fig. 1) transitions to a coasting or towing mode (engine brake). By pressing the brake pedal 34, the vehicle speed can be actively reduced by activating the wheel brakes and / or active braking devices of the vehicle, e.g., a continuous braking system. The hand lever 20 can be pushed forward to increase the vehicle speed and pulled towards the driver to reduce it, whereby this reduction in vehicle speed can optionally be based solely on an activated engine brake or also on additional activation of the service brakes or the wheel brakes of the vehicle.

[0029] As it is Fig. As indicated in Figure 2, a priority control system 36 first determines which of the two input alternatives – foot operation via the pedal set 18 or hand operation via the hand lever 20 – the driver has used to request a change in speed. This ensures that the operator's most recent actuation of one of the foot pedals 32 or 34 or of the hand lever 20 results in a request to change the driving speed v. F is primarily accepted as input, while at the same time a connection of the travel speed control 22 to the other type of actuation is suppressed at least until a changed request is made by the machine operator by actuating one of the foot pedals 32 or 34 or the hand lever 20 accordingly.

[0030] The agricultural vehicle 10 is equipped so that it can be driven either with the accelerator pedal 32 and the brake pedal 34 or with the joystick or hand lever 20. Switching between modes occurs without the need to operate a separate switch or the like, but primarily based on an evaluation of the operator's actions, namely by interposing the priority control 36, whose output signal is used to generate the target speed signal v. F(soll) is used in the control unit, which in turn is used according to Fig. 1 generates a motor control signal 24 (and possibly a brake signal; not shown) to control the drive machine 26 (and possibly service brakes not shown here) accordingly.

[0031] The present invention thus provides a method and a set of actuating devices for an agricultural machine 10 or tractor 12, in which the respective actuation of the foot pedal set 18 or the hand lever 20, by means of the priority control 36, defines which of these different actuating elements – the pedals 18 or the hand lever 20 – are activated and which are deactivated. The decision to activate one of the actuating elements (for foot or hand operation) and to simultaneously deactivate the other actuating element (for hand or foot operation) is essentially based on the last actuating action performed by the machine operator, whereby additional restrictions may be superimposed, such as the driving speed and / or an actuated direction switch.

[0032] The invention has been described with reference to a preferred embodiment. However, it is conceivable to a person skilled in the art that modifications or alterations of the invention can be made without departing from the scope of protection of the following claims. Naturally, the invention, in all its forms and principles, is applicable to various self-propelled machines of all kinds. Reference symbol list: 10 agricultural machines 12 agricultural tractor 14 trailers 16 Driver's cab 18 foot pedals, foot pedal set 20 hand levers 22 Control unit 24 Drive control signal 26 Drive machine, drive motor 28 Windscreen 30 steering wheel 32 Accelerator pedal, gas pedal 34 Brake pedal 36 Priority control

Claims

[1] Method for controlling a driving speed (v F ) of an agricultural machine (10) which is equipped at a driver's position with at least one accelerator pedal (32) and one brake pedal (34) for foot actuation and with at least one hand lever (20), which pedals (32, 34) and hand lever (20) are each used to influence the driving speed (v F ) by appropriate driving commands from the machine operator, characterized by that the last actuation of one of the foot pedals (32, 34) or the hand lever (20) by the machine operator is accompanied by a request to change the driving speed (v F) defines the respectively active actuation type for hand or foot control and suppresses a connection of the travel speed control (22) to the respective other actuation type at least until a changed request is made by the machine operator by correspondingly actuating one of the foot pedals (32, 34) or the hand lever (20), and wherein an actuation of one of the foot pedals (32, 34) or the hand lever (20) with a simultaneously occurring defined change in position is interpreted as a change request which triggers a priority control (36) of the respectively actuated pedal (32, 34) or the hand lever (20). [2] Method according to claim 1, in which an actuation of one of the foot pedals (32, 34) or the hand lever (20) with a simultaneous defined change in position is interpreted as a change request which determines whether the foot pedals (32, 34) or the hand lever (20) form the respectively active actuating element. [3] Method according to one of claims 1 or 2, in which the foot pedals (32, 34) are given priority over the hand lever (20) after actuation of a pre-selection switch by the machine operator. [4] Method according to one of claims 1 to 3, in which a distinction is made between road travel and field travel by means of a preselection by a control program and / or by exceeding a definable limit speed, which is simultaneously linked to a changed priority control (36). [5] Method according to claim 4, wherein during road travel and / or when the defined limit speed is exceeded, the machine control is deactivated by means of the hand lever (20) and replaced by the machine control by means of foot pedals (32, 34). [6] Method according to one of the preceding claims, wherein the agricultural machine (10) is an agricultural tractor (12) or self-propelled work machine. [7] Agricultural machine (10) which is equipped at a driver's position with at least one accelerator pedal (32) and one brake pedal (34) for foot actuation and with at least one hand lever (20), which pedals (32, 34) and hand lever (20) are each used to influence the driving speed (v F ) by corresponding travel commands of the machine operator, wherein the foot pedals (32, 34) and the hand lever (20) are linked to a control device (22) which has an implemented priority control (36), wherein the priority control (36) carries out an analysis on the basis of the most recent actuation of one of the foot pedals (32, 34) or the hand lever (20) by the machine operator with a change request of the travel speed (v F), and wherein an actuation of one of the foot pedals (32, 34) or of the hand lever (20) with a simultaneous defined change in position is interpreted as a change request which triggers a priority control (36) of the respectively actuated pedal (32, 34) or of the hand lever (20). [8] Agricultural machine according to claim 7, wherein the control device (22) takes into account a preselection and / or a definable limit speed for distinguishing between road travel and field travel. [9] Agricultural machine according to claim 8, wherein hand lever control is suppressed during road travel and / or when traveling at a speed above the defined limit speed. [10] Agricultural machine according to one of claims 7 to 9, wherein the agricultural machine (10) is an agricultural tractor or self-propelled working machine.

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