CN118683494A - Pedal device for a drive-by-wire system of a vehicle - Google Patents

Abstract

A pedal device (10) for a drive-by-wire system of a vehicle (1), comprising at least one pedal (11), the pedal comprising an interior space (12) surrounded by a housing (14) having an elastic pedal pad (13), at least two sensors (16, 17) being arranged in the interior space, the sensors detecting an actuating force (F) currently acting on the elastic pedal pad (13) based on different measuring principles and outputting corresponding measuring signals to at least one evaluation and control unit (3, 18), a first sensor (16) of the at least two sensors (16, 17) being mechanically connected to the elastic pedal pad (13) and detecting elastic deformation of the pedal pad (13), the elastic deformation representing the currently acting actuating force (F), and a second sensor (17) of the at least two sensors (16, 17) detecting a pressure change in the interior space (12) without being mechanically connected to the elastic pedal pad (13), the pressure change representing the currently acting actuating force (F).

Description

Pedal device for a drive-by-wire system of a vehicle

Technical Field

The invention relates to a pedal device for a drive-by-wire system of a vehicle. The subject matter of the invention is also a vehicle having such a pedal device for a drive-by-wire system.

Background Art

Pedal units for vehicles known from the prior art are usually designed based on travel. In particular in vehicle brake systems, hydraulic pressure is built up in the brake system based on the pedal travel and mechanical intervention. This means that a corresponding driver brake request is assigned to a specific pedal travel. This pedal travel for pressure buildup, including an additional reserve travel for backup situations, defines the installation space available inside the vehicle for such a pedal unit.

In addition, so-called drive-by-wire systems are known from the prior art, which only forward the driver's commands electrically or electronically. Well-known examples of such drive-by-wire systems are electronic accelerator pedals for drive control, brake-by-wire systems for brake control or steering-by-wire systems for steering control. Drive-by-wire means that the vehicle is driven or controlled without mechanical force transmission from the vehicle's operating components (such as the accelerator pedal, brake pedal or steering wheel) to the corresponding control components of the vehicle (such as the throttle, brake and/or steering wheel of the vehicle). This means that in such a drive-by-wire system, the corresponding pedal unit is separated from the power flow and the mentioned functions are instead controlled by cables and servomotors or electromechanical actuators. The driver's actuation of the corresponding pedal unit can then be detected, for example, by a force-sensitive sensor surface and transmitted electrically to the corresponding vehicle system. By eliminating the mechanical connection, new pedal concepts can be realized, because the pedal travel is no longer required to achieve vehicle deceleration.

A method for operating a brake pedal unit of a vehicle and providing feedback to the driver is known from document DE 10 2017 217 578 A1. The brake pedal unit has a plurality of pressure-sensitive or force-sensitive sensors. In the method, output signals of the plurality of pressure-sensitive or force-sensitive sensors are detected; at least one position and/or direction of the operator's foot relative to the footrest is determined based on the detected output signals; a feedback signal characterizing the specific position and/or direction is output at an output unit of the vehicle.

From document DE 103 12 547 A1, a device for accelerating or decelerating a motor vehicle is known, wherein a first actuating part is used to accelerate the motor vehicle and a second actuating part is used to decelerate the motor vehicle, and the actuation thereof is performed by applying hand force or foot force. Here, the two actuating parts work essentially without stroke, and after the hand force or foot force has been removed from the first actuating part or the second actuating part (depending on whether hand force or foot force was last applied), the speed of the motor vehicle remains constant until the first actuating part or the second actuating part is further actuated.

From DE 102 39 913 A1, an actuating mechanism for influencing a device for braking, clutching or driving a motor vehicle is known. The actuating mechanism actuated by the driver is mechanically separated from the actuator of the device. For this purpose, the actuating mechanism is a sensor that specifically detects the driver's actuating force and generates a control signal, and the generation of the control signal is independent of the actuating stroke and does not have an actuating stroke. The actuating mechanism can be constructed as a force sensor, a strain gauge or a combination thereof of a piezoelectric ceramic. If it is necessary to detect the rotational force, a torque sensor can also be used instead of the force sensor. The actuating mechanism can be arranged in the driver's footwell or in the area of the steering wheel. For electrohydraulic brake devices that require a pedal, the actuating mechanism should be arranged on the foot pedal. The actuating mechanism can also be designed redundantly.

Summary of the invention

The pedal device for a drive-by-wire system for a vehicle having the features of independent claim 1 has the following advantages: The actuation force applied to the elastic pedal pad is detected by heterogeneous redundant measurements based on different measurement principles. The direct connection of the first sensor to the elastic pedal pad enables a more precise or more stable detection of the currently acting actuation force. Due to the lack of connection to the elastic pedal pad, pressure changes in the inner space of the pedal can be detected simply in order to easily check the plausibility of the measurement of the first sensor. Due to the elastic deformation of the elastic pedal pad, the volume of the inner space is compressed, which can be detected as a small pressure change.

An embodiment of the present invention provides a pedal device for a drive-by-wire system for a vehicle, the pedal device having at least one pedal. The pedal comprises an inner space surrounded by a housing having an elastic pedal pad, at least two sensors are arranged in the inner space, and the sensors detect the current actuation force acting on the elastic pedal pad based on different measurement principles, and output corresponding measurement signals to at least one evaluation and control unit. Here, the first sensor of the at least two sensors is mechanically connected to the elastic pedal pad and detects the elastic deformation of the pedal pad, which indicates the currently acting actuation force. The second sensor of the at least two sensors detects a pressure change in the inner space without being mechanically connected to the elastic pedal pad, and the pressure change indicates the currently acting actuation force.

Furthermore, a vehicle having such a pedal device is proposed.

In the present case, the evaluation and control unit may refer to an electrical device, such as a controller, in particular a brake controller or an engine controller, that processes or evaluates detected sensor signals. The evaluation and control unit may have at least one interface, which may be designed based on hardware and/or software. In a hardware-based design, these interfaces may, for example, be part of a so-called system ASIC that contains the various functions of the evaluation and control unit. But it is also feasible that the interface itself is an integrated circuit or at least partially consists of discrete components. In a software-based design, the interface may be a software module that exists, for example, on a microcontroller together with other software modules. A computer program product with a program code is also advantageous, which is stored on a machine-readable carrier such as a semiconductor memory, a hard disk memory or an optical memory, and is used to implement the evaluation when the program is executed by the evaluation and control unit.

In the present case, a sensor is understood to be a structural unit which comprises at least one sensor component which directly or indirectly detects a physical quantity or a change in a physical quantity and preferably converts it into an electrical sensor signal.

Plausibility checking refers to a method in which a result or a value of a determined physical variable is checked to see whether it is acceptable and/or plausible and/or understandable.

The measures and further developments listed in the dependent claims make possible advantageous developments of the pedal device for a drive-by-wire system for a vehicle as specified in independent claim 1 .

It is particularly advantageous if at least one evaluation and control unit is designed to determine the current actuation force as a function of at least one first measurement signal of at least two sensors and to perform a plausibility check on the at least one first measurement signal using at least one second measurement signal of at least two sensors. Thus, for example, the at least one first measurement signal can be output by a first sensor that is mechanically connected to the elastic pedal pad and detects elastic deformations of the pedal pad. The at least one second measurement signal for checking the plausibility of the first measurement signal can be output, for example, by a second sensor that detects pressure changes in the interior without being mechanically connected to the elastic pedal pad.

In an advantageous embodiment of the pedal device, the first sensor can be designed as a strain sensor with at least one strain gauge, or as a pressure sensor with at least one piezoelectric component, or as a linear travel sensor. This enables precise and stable detection of elastic deformations of the elastic pedal pad. The second sensor can preferably be designed as a gas pressure sensor. As a result, the volume compression of the interior of the pedal due to the elastic deformation of the pedal pad can be detected as a slight internal pressure change.

In another advantageous design of the pedal device, the interior space of at least one pedal can be closed in a fluid-tight manner. For this reason, the connection of the elastic pedal pad to the housing can be closed in a fluid-tight manner with silicone, for example.

In another advantageous embodiment of the pedal arrangement, at least one pedal can be a brake pedal for performing a braking function and for controlling a braking system. Alternatively, the at least one pedal can be an accelerator pedal for performing an acceleration function and for controlling a drive train. In vehicles with a manual transmission, at least one pedal can be a clutch pedal for performing a clutch function.

In another advantageous embodiment of the pedal device, the first evaluation and control unit can be arranged in the interior of at least one pedal. Additionally or alternatively, the second evaluation and control unit can be arranged outside of at least one pedal.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are shown in the drawings and explained in more detail in the following description.In the drawings, the same reference numerals represent components or parts that perform the same or similar functions.

FIG. 1 is a schematic diagram showing an embodiment of a pedal device for a drive-by-wire system for a vehicle according to the present invention.

DETAILED DESCRIPTION

As shown in FIG1 , the illustrated embodiment of a pedal device 10 for a drive-by-wire system of a vehicle 1 according to the present invention comprises at least one pedal 11, which comprises an interior space 12 surrounded by a housing 14 having an elastic pedal pad 13. At least two sensors 16, 17 are arranged in the interior space 12, which detect the actuation force F currently acting on the elastic pedal pad 13 based on different measurement principles and output corresponding measurement signals to at least one evaluation and control unit 3, 18. Here, the first sensor 16 of the at least two sensors 16, 17 is mechanically connected to the elastic pedal pad 13 and detects the elastic deformation of the pedal pad 13, which indicates the currently acting actuation force F. The second sensor 17 of the at least two sensors 16, 17 detects the pressure change in the interior space 12 without being mechanically connected to the elastic pedal pad 13, which indicates the currently acting actuation force F.

As further shown in FIG. 1 , the first sensor 16 is configured as a strain sensor 16A having at least one strain gauge, which is directly connected to the elastic pedal pad 13. In FIG. 1 , the solid line of the pedal pad 13 represents the static position of the elastic pedal pad 13 when no actuating force F is applied. The dashed line of the pedal pad 13 represents the elastic deformation of the elastic pedal pad 13 when the actuating force F is applied. The pedal device 10 is preferably arranged in the footwell of the vehicle 1. In the embodiment shown, the pedal 11 is configured as a brake pedal 11A for performing a braking function, wherein the actuating force F is applied by the driver's foot. The brake system of the vehicle 1 is controlled by the brake pedal 11. This means that the measurement signals of at least two sensors 16, 17 are evaluated by at least one evaluation and control unit 3, 18 to generate a control signal for an actuator of the brake system.

In addition to the brake pedal 11A, the pedal device 10 also includes another pedal 11, not shown, configured as an accelerator pedal, which is used to perform an acceleration function and to control the drive train, and which is configured similarly to the brake pedal 11 shown in order to redundantly detect the actuation of the pedal 11 configured as an accelerator pedal. In a vehicle 1 with a manual transmission, the pedal device 10 includes a third pedal 11 configured as a clutch pedal for performing a clutch function, which is also configured similarly to the brake pedal 11 shown in order to redundantly detect the actuation of the pedal 11 configured as a clutch pedal.

As further shown in FIG. 1 , a first evaluation and control unit 18 is arranged on a circuit board 15 in the interior space 12 of the pedal 11 and is electrically coupled to a first sensor 16. The first evaluation and control unit 18 generates a first measurement signal in conjunction with the first sensor 16 configured as a strain sensor 16A, which represents the current actuation force F and is preferably evaluated to generate a control signal. As further shown in FIG. 1 , due to the elastic deformation of the elastic pedal pad 13, the volume of the interior space 12 of the pedal 11 is compressed. In the illustrated embodiment, the second sensor 17 is configured as an air pressure sensor 17A and is integrated into an ASIC module (ASIC: Application Specific Integrated Circuit). The air pressure sensor 17A detects pressure changes in the interior space 12 of the pedal 11 caused by the volume compression of the interior space 12. The ASIC module of the air pressure sensor 17A is also arranged on the circuit board 15 and outputs a second measurement signal of the second sensor 17 configured as an air pressure sensor 17A, which redundantly represents the currently acting actuation force F and is evaluated to check the plausibility of the first measurement signal. In the event of a failure of first sensor 16 , the second measurement signal of second sensor 17 can be used to generate a control signal in an emergency operation of vehicle 1 .

In the illustrated embodiment, the interior 12 of at least one pedal 11 is closed in a fluid-tight manner. For this purpose, the connection of the elastic pedal pad 13 to the housing 14 is closed in a fluid-tight manner with silicone. The circuit board 15 is electrically connected to the external second evaluation and control unit 3 arranged outside the interior 11 via a connecting cable 5, which is guided from the interior 12 of the pedal 11 through a fluid-tight cable bushing 19. In the illustrated embodiment of the pedal device 10, the second evaluation and control unit 3 is designed as a brake controller for performing a braking function. This means that the second evaluation and control unit 3 receives a first measurement signal representing the currently acting actuating force F detected by the first sensor 16 from the first evaluation and control unit 18, and generates a control signal for the brake system actuator based on the currently acting actuating force F. The second evaluation and control unit 3 receives a second measurement signal redundantly representing the currently acting actuating force F from the ASIC module of the second sensor 17 designed as a gas pressure sensor 17A, and evaluates the second measurement signal in order to check the plausibility of the first measurement signal of the first sensor 16 before outputting the control signal for the brake system actuator.

In an alternative embodiment (not shown) of the pedal device 10 , the first sensor 16 is designed as a pressure sensor with at least one piezoelectric element or as a linear travel sensor in order to detect the elastic deformation of the elastic pedal pad 13 caused by the currently acting actuating force F.

Claims (10)

1. Pedal device (10) for a drive-by-wire system of a vehicle (1), comprising at least one pedal (11) having an interior space (12) surrounded by a housing (14) having an elastic pedal pad (13), in which interior space at least two sensors (16, 17) are provided, which sensors detect an actuation force (F) currently acting on the elastic pedal pad (13) on the basis of different measurement principles and output corresponding measurement signals to at least one evaluation and control unit (3, 18), wherein a first sensor (16) of the at least two sensors (16, 17) is mechanically connected to the elastic pedal pad (13) and detects an elastic deformation of the pedal pad (13), which elastic deformation represents a currently acting actuation force (F), wherein a second sensor (17) of the at least two sensors (16, 17) detects a change in pressure in the interior space (12) without being mechanically connected to the elastic pedal pad (13), which indicates a current change in the force (F).

2. Pedal device (10) according to claim 1, characterized in that the at least one evaluation and control unit (3, 18) determines the current actuation force from at least one first measurement signal of the at least two sensors (16, 17) and verifies the plausibility of the at least one first measurement signal with at least one second measurement signal of the at least two sensors (16, 17).

3. Pedal device (10) according to claim 1 or 2, characterized in that the first sensor (16) is configured as a strain sensor (16A) with at least one strain gauge, or as a pressure sensor with at least one piezo-element, or as a linear travel sensor.

4. A pedal device (10) according to any one of claims 1 to 3, characterized in that the second sensor (17) is configured as a barometric pressure sensor (17A).

5. Pedal device (10) according to any one of claims 1 to 4, characterized in that the inner space (12) of the at least one pedal (11) is closed in a fluid-tight manner.

6. Pedal device (10) according to any one of claims 1 to 5, characterized in that the at least one pedal (11) is a brake pedal for performing a braking function and for operating a brake system, or an accelerator pedal for performing an acceleration function and for operating a drive train, or a clutch pedal for performing a clutch function.

7. Pedal device (10) according to any one of claims 1 to 5, characterized in that a first evaluation and control unit (18) is arranged in the interior space (12) of the at least one pedal (11).

8. Pedal device (10) according to any one of claims 1 to 6, characterized in that the second evaluation and control unit (3) is arranged outside the at least one pedal (11).

9. A vehicle (1) having a pedal device (10) designed according to any one of claims 1 to 8.

10. The vehicle (1) according to claim 9, characterized in that the first pedal (11) is configured as a brake pedal (11A) and the second pedal (11) is configured as an accelerator pedal, wherein the third pedal (11) is configured as a clutch pedal if the vehicle comprises a manual transmission.