Method and control device for operating a two-wheeled vehicle

Abstract

The invention relates to a method for operating a two-wheeled vehicle, wherein, when cornering through a bend using a front-wheel drive (202) of the two-wheeled vehicle, a banking-position-increasing propulsion torque (100) is provided on the front wheel (200) of the two-wheeled vehicle when it is detected that the two-wheeled vehicle is driving out of the bend.

Description

[0001] Description

[0002] title

[0003] Method and control unit for operating a two-wheeler

[0004] Field of invention

[0005] The invention relates to a method for operating a two-wheeler, a corresponding control unit and a corresponding computer program product.

[0006] State of the art

[0007] A motorcyclist feels comfortable within a specific lean angle range. The size of this lean angle range depends on the rider's skill level. Generally, the maximum lean angle a rider achieves, often referred to as the "fear lean" angle, is less than the physically possible lean angle.

[0008] If a rider enters a curve at excessive speed, they will only lean the motorcycle into the curve to their individual "fear" lean angle, even if a greater lean angle would be necessary for that particular curve and speed. As a result, the rider and motorcycle will be forced to the outside of the curve, making it impossible to maintain their intended line and potentially leading to leaving the road or even entering oncoming traffic.

[0009] DE 10 2017 220 421 A1 describes a method and a driver assistance system for supporting stable cornering of a two-wheeler.

[0010] Disclosure of the Invention Against this background, the approach presented here comprises a method for operating a two-wheeler, a corresponding control unit, and a corresponding computer program product according to the independent claims. Advantageous further developments and improvements of the approach presented here will become apparent from the description and are partly described in the dependent claims.

[0011] Advantages of the invention

[0012] Since the contact point of a two-wheeler's front wheel shifts laterally relative to the point where the front wheel intersects the steering axis when the two-wheeler is leaning, a lever arm is created around the steering axis. A longitudinal force at the contact point thus generates a torque around the steering axis.

[0013] Braking force on the leaning front wheel creates a torque that increases the steering angle. This increased steering angle causes the front wheel to move under the motorcycle, reducing the lean angle. Therefore, the braking force causes the motorcycle to right itself unless the rider actively counteracts this torque.

[0014] An acceleration force at the leaning front wheel causes a torque that reduces the steering angle. Due to the reduced steering angle, the front wheel moves further out, increasing the lean angle.

[0015] The approach presented here extends the approach from DE 10 2017 220 421 A1 by adding another method for maintaining a intended lane while cornering. This involves applying additional drive torque to the front wheel of the two-wheeler to generate a steering torque, which causes the front wheel to drift and increases the lean angle of the two-wheeler. This increased lean angle allows for higher cornering speeds.

[0016] The approach presented here actively assists a rider of a two-wheeler using front-wheel drive to maintain a chosen line through a curve, even at otherwise excessive speeds. A method for operating a two-wheeler is proposed in which, during cornering, a lean-angle-increasing propulsive torque is applied to the front wheel of the two-wheeler when drifting out of the curve is detected.

[0017] Ideas for embodiments of the present invention can be considered to be based, among other things, on the thoughts and findings described below.

[0018] A two-wheeler can be a motorcycle, a scooter, or a bicycle. A two-wheeler requires front-wheel drive. This front-wheel drive can be, in particular, a hub motor located on or within the hub of the two-wheeler's front wheel. The front-wheel drive can, for example, be electric.

[0019] A motorcycle's sensors can detect when it drifts out of a curve. Without countermeasures, this can lead to a dangerous situation.

[0020] A propulsive torque can be described as a driving torque. This propulsive torque can generate a longitudinal force at a contact point of the front wheel. This longitudinal force, acting via a lever arm relative to the steering axis of the front wheel, produces a steering torque about the steering axis. This steering torque reduces the steering angle of the front wheel and thus increases the lean angle of the motorcycle.

[0021] The increased lean angle increases the possible cornering speed and thus increases the safety speed margin of the two-wheeler in the curve.

[0022] While the propulsive torque is being applied to the front wheel, a deceleration torque can be applied to the rear wheel of the two-wheeler. A deceleration torque can at least partially compensate for the propulsive torque. The deceleration torque can prevent or at least reduce an increase in speed. It can prevent the effect of a greater lean angle from being negated by an increase in speed. The deceleration torque can be implemented via the brakes as braking torque or via the engine at the rear wheel as drag torque, depending on the desired magnitude of the deceleration torque.

[0023] The deceleration torque can be equal in magnitude to the propulsion torque. This allows the speed of the two-wheeler to be kept at least constant. If the rider also brakes manually, a braking effect can be achieved.

[0024] The deceleration torque can be greater than the propulsive torque provided to reduce the speed of the two-wheeler. The two-wheeler can also be braked. By reducing the speed, a tighter turn can be negotiated at the same lean angle. By further increasing the lean angle, an even tighter turn can be negotiated.

[0025] The deceleration torque at the rear wheel can be provided by the rear-wheel drive of the two-wheeler and, alternatively or additionally, by the rear-wheel brake. The method of providing the deceleration torque is irrelevant. A rear-wheel drive can decelerate the two-wheeler powerfully when an acceleration demand is reduced. A rear-wheel brake allows for precise modulation of the deceleration torque. The rear-wheel brake can also modulate the deceleration torque.

[0026] The deceleration torque can be provided by a combination of reducing the drive torque of the rear-wheel drive and applying the rear-wheel brake. The reduction of the drive torque and the braking torque can be superimposed.

[0027] The available tractive torque can be determined depending on the current lean angle of the motorcycle and the current rotational speed of the front wheel. Dynamically determining the tractive torque prevents excessive torque from being applied, thus preventing front wheel slippage. The tractive torque can be reduced, in particular, as the lean angle of the motorcycle increases.

[0028] The available propulsive torque can be read from a stored map using the lean angle and rotational speed. A map can be pre-calculated specifically for the two-wheeler. The map can correspond to a multi-dimensional lookup table. For example, the map can depend on the dimensions and coefficients of the front tire.

[0029] The method is preferably computer-implemented and can be implemented, for example, in software or hardware or in a hybrid form of software and hardware, for example in a driver assistance system.

[0030] The approach presented here further creates a control unit in the form of a driver assistance system for a vehicle, wherein the driver assistance system is trained to carry out, control or implement the steps of a variant of the procedure presented here in appropriate facilities.

[0031] The control unit or driver assistance system can be an electrical device with at least one processing unit for processing signals or data, at least one storage unit for storing signals or data, and at least one interface and / or a communication interface for reading or outputting data embedded in a communication protocol. The processing unit can be, for example, a signal processor, a so-called system ASIC, or a microcontroller for processing sensor signals and outputting data signals depending on the sensor signals. The storage unit can be, for example, flash memory, an EPROM, or a magnetic storage device. The interface can be configured as a sensor interface for reading sensor signals from a sensor and / or as an actuator interface for outputting data signals and / or control signals to an actuator.The communication interface can be configured to read or output data wirelessly and / or via a wired connection. The interfaces can also be software modules, such as those found on a microcontroller alongside other software modules. A computer program product or computer program with program code is also advantageous. This code can be stored on a machine-readable medium such as semiconductor memory, hard disk storage, or optical storage and is used to execute, implement, and / or control the steps of the method according to one of the embodiments described above, particularly when the program product or program is executed on a computer or device.

[0032] It should be noted that some of the possible features and advantages of the invention are described herein with reference to different embodiments. A person skilled in the art will recognize that the features of the control unit and the method can be suitably combined, adapted, or exchanged to arrive at further embodiments of the invention.

[0033] Brief description of the drawings

[0034] Embodiments of the invention are described below with reference to the accompanying drawings, whereby neither the drawings nor the description are to be interpreted as limiting the invention.

[0035] Fig. 1 shows a flowchart of a procedure according to an implementation example;

[0036] Fig. 2 shows a representation of an intervention using a method according to an exemplary embodiment; and

[0037] Fig. 3 shows a representation of a characteristic map for a method according to an exemplary embodiment.

[0038] The figures are schematic only and not to scale. Identical reference symbols denote identical or equivalent features.

[0039] Embodiments of the invention

[0040] Fig. 1 shows a flowchart of a method for operating a two-wheeler with a front-wheel drive. When the two-wheeler is traveling around a curve and it is detected that it is in danger of drifting sideways out of the curve, a driving torque 100 is determined for the front-wheel drive to increase the lean angle 102 of the two-wheeler. The front-wheel drive is then controlled by a control signal 104 to provide this driving torque 100.

[0041] Fig. 2 shows an illustration of an engagement using a method according to an exemplary embodiment. The engagement is controlled using the method shown in Fig. 1. In this process, a front wheel 200 of a two-wheeler is driven with an (additional) drive torque 100 during cornering using a front-wheel drive 202 of the front wheel 200 in order to increase the lean angle 102 of the two-wheeler. This takes advantage of the fact that a contact point 204 with the ground of the front wheel 200 is arranged laterally offset from a steering axis 206 of the front wheel 200 due to the existing lean angle 102. The lateral offset of the contact point 204 results in a lever arm 208, via which a propulsive force 210 generated by the drive torque 100 at the front wheel 200 causes a torque 212 about the steering axis 206.

[0042] The propulsive force 210 is a longitudinal force directed in one direction of travel of the two-wheeler. The torque 212 caused by the forward-directed propulsive force 210 reduces the steering angle of the front wheel 200. Due to the reduced steering angle, the contact point 204 moves laterally away from the center of gravity of the two-wheeler, and the lean angle 102 is increased.

[0043] The increased lean angle of 102 allows the two-wheeler to travel through the curve at a higher speed without being blown sideways out of the curve.

[0044] In one embodiment, the propulsive torque 100 is determined using the current lean angle 102 and a rotational speed 106 of the front wheel 200.

[0045] Fig. 3 shows a representation of a characteristic map 300 for a method according to an exemplary embodiment. According to this embodiment, the characteristic map 300 is used to determine the propulsive torque using the inclination 102 and the rotational speed 106. The characteristic map 300 is shown in a three-dimensional diagram, which plots the inclination 102, the rotational speed 106, and a maximum adjustable indirect steering torque 302 on its axes. The steering torque 302 is converted into the propulsive torque 100 using the inclination 102.

[0046] In one embodiment, a drag torque 108 is applied to the rear wheel of the two-wheeler. This drag torque 108 essentially corresponds to the propulsive torque 100, but at the rear wheel it produces a braking force that opposes the propulsive force 210 at the front wheel 200. The braking force thus essentially compensates for the propulsive force 210. Therefore, the speed of the two-wheeler is not increased by the propulsive torque 100.

[0047] In one embodiment, a previously applied drive torque of a rear-wheel drive of the two-wheeler is reduced by the deceleration torque 108. If the drive torque was already negative, the negative drive torque is increased by the deceleration torque 108. If a maximum possible negative drive torque is less than the required deceleration torque 108, any remaining portion of the deceleration torque 108 is applied as a braking torque by a friction brake of the two-wheeler. Even if the rear-wheel drive cannot provide the deceleration torque, or cannot provide it completely, for any other reason, the deceleration torque 108 is applied in whole or in part by the friction brake.

[0048] In one embodiment, an additional deceleration torque 110 is applied to the rear wheel in addition to the deceleration torque 108. This reduces the speed 106 of the two-wheeler. As a result, a smaller lean angle 102 is required to prevent drifting in the curve. The effects of the increased lean angle and the reduced speed can thus complement each other. The previously applied drive torque at the rear wheel can be reduced by the drag torque 108 and the deceleration torque 110. The drag torque 108 and the deceleration torque 110 can also be distributed between the braking torque and the reduction of the drive torque.

[0049] Possible embodiments of the invention are summarized below or presented using slightly different wording. A method for providing an indirect steering torque to motorized two-wheelers to support safe cornering is presented.

[0050] German patent application DE 10 2017 220 421 A1 describes a method which, through active intervention, including in one embodiment active steering intervention, prevents a motorcyclist from drifting outwards in a curve and leaving the lane. DE 10 2017 220 421 A1 also describes an embodiment for detecting the impending drifting out of the lane and the components required for this detection.

[0051] Traditionally, two-wheelers are powered by internal combustion engines, central electric motors, and, for lower-powered motorcycles, by hub motors at the rear wheel. In India, there is discussion about banning internal combustion engine motorcycles from major cities to reduce air pollution. One way to continue using internal combustion engines and their greater range outside of cities is to equip motorcycles with a hub motor, even a lower-powered one, at the front wheel in addition to the internal combustion engine. This way, the motorcycle can be powered solely by the front hub motor in the city, while outside of cities it is driven by the internal combustion engine.

[0052] The patent application DE 10 2022 200 315 A1 describes a method in which a hub motor is controlled on the front wheel of a motorcycle to generate a steering torque and thus influence the yaw movement of the motorcycle, with the general aim of improving the maneuverability of the motorcycle.

[0053] In the approach presented here, when a two-wheeler is detected to be drifting out of the curve, a steering torque is indirectly generated by a brief drive torque applied to the hub motor at the front wheel. This momentarily increases the lean angle, thus assisting the motorcyclist in maintaining control of the curve without leaving the lane. Simultaneously, coordinated control of the rear-wheel drive and rear-wheel brake ensures that the rider's set speed is not increased or may even be reduced to further mitigate the situation. The detection of an impending drift from the lane to the outside of the curve is described in DE 10 2022 200 315 A1 and is assumed here.

[0054] The approach presented here allows an existing hub motor on the front wheel to be used not only to influence longitudinal dynamics, but also to influence lateral dynamics by indirectly applying a steering torque, in order to increase driving safety for the described application.

[0055] Steering torque is provided by a vehicle dynamics effect. As illustrated in Fig. 2 by the lever arm due to the lean angle, the tire-road contact patch is no longer in the vertical plane of the tire due to the tire width when leaning. This results in an indirect steering torque when a driving force is applied to the contact patch. Longitudinal forces transmitted by the tire to the road surface generate a resulting torque around the steering axis via the lever arm. On two-wheeled vehicles, steering torque is the primary parameter for controlling lateral dynamics. Braking forces (generated by a front-mounted engine or front-wheel brake) create a steering torque that increases the steering angle into the curve. This, in turn, causes the vehicle to stand upright (reduce the lean angle) because the front wheel moves below the overall center of gravity. The consequence of the reduced lean angle is a larger turning radius.Driving the hub motor at the front wheel produces the opposite effect.

[0056] Positive longitudinal forces produce a reduction in steering angle and thus a tighter curve radius, which is used in the approach presented here to prevent drifting out of the curve.

[0057] The relationship between the indirect steering torque M Len k and the drive torque at the front wheel M drive is approximately described by the following equation with the motorcycle's lean angle <p, dem Reifenradius r Re if en and the tire crown radius r c The magnitude of the indirect steering torque M Lenk is limited on the one hand by the motor-side drive torque limitation, which is speed-dependent, and on the other hand by the adhesion limit between tire and road surface. With large lean angles, a large part of the adhesion is already required for lateral guidance (lateral force), so that only lower longitudinal forces can be transmitted and therefore only lower drive torques can be set (keyword Kamm circle).

[0058] Fig. 3 shows the maximum adjustable indirect steering torque as a function of the engine speed and the motorcycle lean angle in a characteristic map.

[0059] If an impending drift out of the curve is detected, an indirect steering torque to the outside of the curve is briefly applied via the drive torque at the front wheel, according to the block diagram shown in Fig. 1, so that the motorcycle leans slightly more into the curve and the rider can follow the track.

[0060] Block 1 contains the logic determining the magnitude and duration of the indirect steering torque to be applied using the motorcycle's lean angle. <p und der Drehzahl des Hub Motors vorne bestimmt und sicherstellt, dass nur ein indirektes Lenkmoment, dass innerhalb des in Fig. 3 dargestellten Grenzkennfelds liegt, angefordert wird.

[0061] Block 2 is calculated using the motorcycle's lean angle. <p das für das indirekte Lenkmoment erforderliche Sollantriebsmoment für den Hub Motor am Vorderrad.

[0062] Since this drive torque should not increase speed, the value - M drive is simultaneously transferred as the required deceleration torque to the torque coordinator of the rear wheel (block 3), which determines and outputs a corresponding target motor drag torque and, if necessary, a corresponding target rear wheel brake pressure, depending on the drive state of the rear wheel drive.

[0063] The most common reason for leaving the lane to the outside of a curve is a so-called "lean angle fear" experienced by the rider, as described in DE 10 2017 220 421 A1. This means that motorcyclists typically have a certain individual lean angle limit, usually significantly below the physically possible limit, which they do not exceed. If a rider enters a tightening curve at a speed that is too high for their individual lean angle limit, they will be unable to stay in their lane and will leave it to the outside. Even if the lean angle is briefly increased via indirect steering, the rider will try to return to their individual lean angle limit, which, unless the curve radius has already increased, is insufficient to stay within the lane.

[0064] In one embodiment, represented by the switch in the block diagram, the rider receives optimal support. This is achieved by combining the above-described application of an indirect steering torque with an additional deceleration request (Mdeceleration) for the rear wheel. This reduces the speed in addition to briefly increasing the lean angle, allowing the rider to maintain their preferred lean angle through the curve at a reduced speed. The rear wheel torque coordinator sets the overall deceleration request.

[0065] ^Delay ^Drive UITI.

[0066] Finally, it should be noted that terms such as "comprising," "encompassing," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Reference numerals in the claims are not to be considered as limitations.

Claims

Claims 1. Method for operating a two-wheeler, wherein, during cornering through a curve using a front-wheel drive (202) of the two-wheeler, a lean-angle increasing driving torque (100) is provided at a front wheel (200) of the two-wheeler when drifting out of the curve is detected.

2. Method according to claim 1, wherein a deceleration torque (108) is provided at a rear wheel of the two-wheeler during the provision of the propulsion torque (100) at the front wheel (200).

3. Method according to claim 2, wherein the deceleration moment (108) is provided in an equal magnitude to the thrust moment (100).

4. Method according to claim 2, wherein the deceleration torque (108) is provided greater than the propulsion torque (100) to reduce the speed of the two-wheeler.

5. Method according to one of claims 2 to 4, wherein the deceleration torque (108) is provided at the rear wheel using a rear wheel drive and / or a rear wheel brake of the two-wheeler.

6. Method according to claim 5, wherein the deceleration torque (108) is provided by a combination of a reduction of a drive torque of the rear wheel drive and an actuation of the rear wheel brake.

7. Method according to one of the preceding claims, wherein the available propulsive torque (100) is determined as a function of a current lean angle (102) of the two-wheeler and a current rotational speed (106) of the front wheel (200).

8. Method according to claim 6, wherein the available propulsive torque (100) is read from a stored characteristic map (300) using the inclination (102) and the rotational speed (106).

9. Control unit, wherein the control unit is configured to execute, implement, and / or control the method according to any of the preceding claims in appropriate devices.

10. Computer program product configured to control a processor at To instruct the execution of the computer program product to execute, implement, and / or control the method according to any one of claims 1 to 8.

11. Machine-readable storage medium on which the computer program product according to claim 10 is stored.

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