Method for determining the driving state of a preferably single-track vehicle

Abstract

The invention relates to a method for determining the driving condition of a preferably single-track vehicle, in particular an e-bike, wherein the vehicle has at least one air pressure sensor, comprising the steps: - Measuring air pressure using the air pressure sensor in at least one wheel of the vehicle at several times, - Comparing the air pressures measured within the several time points, and - Determining the vehicle's driving condition based on measured air pressures and / or comparison of air pressures.

Description

[0001] The invention relates to a method for determining a driving state of a preferably single-track vehicle, in particular an eBike, wherein the vehicle has at least one air pressure sensor.

[0002] Furthermore, the invention relates to a method for controlling a drive unit of a preferably single-track vehicle, in particular an eBike.

[0003] The invention further relates to a vehicle, preferably a single-track vehicle, in particular an eBike, comprising at least one air pressure sensor.

[0004] Although generally applicable to vehicles, the following invention is explained using eBikes. State of the art

[0005] Vehicles like bicycles require traction between their tires and the ground to ride safely. In difficult terrain or on slippery surfaces, such as gravel, mud, or wet conditions, the wheels can slip or slide. E-bikes, in particular, which provide high torque due to their motor assistance, can be difficult to control if slippage suddenly occurs or suddenly disappears.

[0006] To detect wheel slip, it has become common practice to use a sudden drop in wheel speed as an indicator of slip. This method is time-consuming and inaccurate. Disclosure of the invention

[0007] In one embodiment, the present invention provides a method for determining a driving state of a preferably single-track vehicle, in particular an eBike, comprising the steps: - measuring an air pressure by means of an air pressure sensor in at least one wheel of the vehicle at several times, - comparing the air pressures measured at several points in time, and - Determining the driving condition of the vehicle based on the measured air pressures and / or the comparison of the air pressures.

[0008] In one embodiment, the present invention provides a method for controlling a drive unit of a preferably single-track vehicle, in particular an eBike, comprising the steps: - Determining a driving state of the vehicle by means of a method according to one of claims 1-9, and - Changing a drive power, a drive speed and / or a drive torque of the drive unit and / or changing a braking power of a brake of the vehicle depending on the determined driving condition.

[0009] In one embodiment, the present invention provides a vehicle, preferably a single-track vehicle, in particular an eBike, comprising at least one air pressure sensor, as well as: - A measuring unit designed to measure an air pressure by means of the air pressure sensor in at least one wheel of the single-track vehicle at several times, - A comparison unit designed to compare the air pressures measured within the plurality of time points, and - A determination unit designed to determine a driving state of the preferably single-track vehicle based on the measured air pressures and / or the comparison of the air pressures.

[0010] One of the advantages achieved is that wheel slip can be reliably detected. Another advantage is that safety-relevant driving conditions of the vehicle, such as rear wheel lift or a jump, can be determined. Another advantage is that the vehicle's drive power can be adjusted to the detected driving conditions, for example, to give the driver better control of the vehicle.

[0011] Further features, advantages and further embodiments of the invention are described below or will become apparent thereby.

[0012] According to an advantageous development of the invention, the air pressure in a rear wheel and / or a front wheel of the vehicle is measured. Preferably, the pressure in the rear wheel of the vehicle is measured, since, especially in bicycles, the rear wheel is the driven wheel and is therefore more likely to exhibit slippage. It is also possible to measure the air pressure of the front and rear wheels and, for example, compare the measured air pressures. One advantage of this is that vehicle slippage can be reliably detected.

[0013] According to an advantageous development of the invention, the driving state comprises traction of at least one wheel, lifting of a rear wheel of the vehicle from a ground, lifting of a front wheel of the vehicle from a ground, lifting of all wheels of the vehicle from a ground, driving with a heavy load, driving without a driver, and / or driving along an incline. A heavy load can in particular be a weight on the vehicle of at least 60 kg, preferably at least 80 kg, in particular at least 100 kg. It is also conceivable that a driver's weight can be detected and / or stored. In this case, a heavy load can be an additional weight on the vehicle without the driver's weight of 10 kg, preferably 20 kg, in particular 30 kg. For example, lifting of the rear wheel can be detected by the air pressure in the rear wheel dropping and possibly increasing in the front wheel.Conversely, front wheel lift can be detected if the air pressure in the front wheel drops and the rear wheel rises. A drop in air pressure in both wheels can be indicative of a vehicle jump. High air pressure on both sides, higher than a predetermined value, can be an indicator that the vehicle is loaded. This can be used, for example, to detect whether a rider is sitting on the vehicle. Furthermore, a change in air pressure in the front and rear wheels can indicate driving along an incline. Another driving condition can be driving against an obstacle. This manifests itself in a sudden increase in air pressure. One advantage of this is that various driving conditions can be determined.

[0014] According to an advantageous development of the invention, comparing the air pressures measured at multiple points in time includes determining the time derivative of the measured air pressures, comparing the measured air pressures with an average air pressure, and / or determining a period of time during which the measured air pressure differs from the average air pressure. Various indicators can be used to determine the driving situations. For example, the air pressure of a wheel can be measured at multiple points in time, and the measured values ​​can be compared with the previous value. It is also conceivable to determine the time derivative of the measured air pressures.A high value of the time derivative at a point in time, i.e. a high rate of change in air pressure, can be an indicator that the vehicle has hit an obstacle, whereas a low time derivative is indicative of a continuous event, such as driving along a path with an increasing gradient. It is also conceivable that the air pressures of the front and rear wheels are compared. In addition, it is possible to determine reference pressures. These reference pressures could, for example, be determined using a moving average, so that a qualitative statement can be made about the course of the wheel air pressure. In particular, it is possible to determine the length of time during which measured air pressures deviate from an average value. For example, an initially high air pressure followed by a longer period of low pressure can indicate a jump.One advantage of this is that different driving conditions can be reliably detected.

[0015] According to an advantageous development of the invention, the driving condition is determined based on the vehicle's speed. For example, when driving against an obstacle, the air pressure in the wheel rises sharply. The rate of increase in the air pressure depends on the speed. Thus, the speed can be used to reliably detect a corresponding event. One advantage of this is that driving conditions can be recognized more reliably.

[0016] According to an advantageous development of the invention, the driving state is determined based on the acceleration of the vehicle. For example, when driving against an object, the vehicle experiences a high negative acceleration. This can be used as an additional indicator to detect a corresponding driving state. It is also conceivable that uphill driving can be detected more precisely using the accelerations. This makes it possible to differentiate certain driving states from other possible driving states. In particular, it is possible for the driving state to be determined based on a combination of one or more of the following measured variables: air pressure, acceleration, wheel speed, rate of change of the wheel speed, vehicle speed and / or pitch angle of the vehicle. The acceleration can be determined, for example, using an inertial measurement unit (IMU), so that the accelerations can be measured in several directions.One advantage of this is that certain driving conditions can be detected even more precisely.

[0017] According to an advantageous development of the invention, the driving condition is determined based on a temporal progression of extremes of the measured air pressures. Based on the temporal progression of the extremes of the measured air pressures, the vibration behavior within a wheel can be determined. The vibration behavior of the air pressure can be used, for example, to detect a vehicle jump, since characteristic vibrations propagate within the wheel after the jump. In particular, regularly occurring maxima or minima of the air pressure can be detected. Furthermore, the difference between the absolute values ​​of the measured extreme values ​​can be used to determine the vehicle load, since the fluctuations in the air pressure, i.e. the difference between the maxima and minima of the air pressures, are greater with a higher vehicle load. One advantage of this is that different driving conditions can be determined.

[0018] According to an advantageous development of the invention, the driving condition is determined by comparing the air pressures of the front and rear wheels. By comparing the air pressures of the front and rear wheels, driving conditions that place different loads on the front and rear wheels can be determined, for example, driving on the rear wheel, an impending rollover of the vehicle, or a one-sided slip in which only one wheel slips. One advantage of this is that these driving situations can be determined quickly and easily.

[0019] According to an advantageous development of the invention, a normal force of the vehicle is determined to determine the driving condition, wherein the determination of the normal force is based on the air pressures measured at multiple points in time and / or the comparison of the air pressures measured at multiple points in time. Using the air pressure, a currently acting normal force between the wheels and a surface can be deduced. The normal force correlates with the vehicle's adhesion to the surface. For example, a wheel lift can be detected based on a decreasing normal force. This can be used in particular to adapt the drive power of a vehicle's drive unit according to the normal force. This can prevent a wheel subject to a low normal force from being strongly accelerated by the drive unit, thus making the vehicle difficult to control.One advantage of this is that driving conditions that are difficult to control are prevented.

[0020] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures.

[0021] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0022] Preferred embodiments and embodiments of the present invention are illustrated in the drawings and are explained in more detail in the following description. It shows in schematic form Fig. 1 Steps of a method according to an embodiment of the present invention; Fig. 2 steps of a method according to an embodiment of the present invention; and Fig. 3 A vehicle according to an embodiment of the present invention.

[0023] Fig. 1 shows in schematic form steps of a method according to an embodiment of the present invention.

[0024] By means of the Fig. 1, a driving state of a preferably single-track vehicle, for example an eBike, can be detected.

[0025] For this purpose, in a step S1, the air pressure in at least one wheel of the vehicle is measured at several points in time. In particular, the air pressure in both the front wheel and the rear wheel is measured at the several points in time. It is possible that at some points in time the air pressure is only measured in one of the two wheels. The air pressure is measured using an air pressure sensor. For this purpose, a direct sensor can be used that directly measures the air pressure of the wheel, or an indirect sensor that, for example, measures the compression of the wheel and derives the air pressure from this. The air pressure sensor can be resolved such that it can sense a pressure difference of 60 mbar, preferably 10 mbar, in particular 1 mbar at an operating pressure between 1 bar and 10 bar.

[0026] In a subsequent step S2, the air pressures measured at the multiple time points are compared. In particular, comparing the air pressures can include the following steps alone or in combination: - Comparing air pressures with previously measured air pressures, with a moving average of previous air pressures and / or with a predetermined threshold, - Determine a function that describes the air pressures measured at several points in time, - Determine a derivative of the determined function, - Comparison of the values ​​of the derivative at different times with a threshold value, - Calculating normal forces depending on the measured air pressures at different times, - Determining a rate of change of the normal force and comparing the rate of change of the normal force with a threshold value, - Determining a period of time during which the measured air pressures differ from an average value and / or a predetermined threshold value, - Determining extreme values ​​in the determined function, - comparing the maxima and minima of the determined extreme values, - Determining the oscillation behavior of air pressures, - Comparing the vibration behavior of the air pressure with a natural frequency of the wheel, - Comparing the air pressures and / or derivatives and / or rates of change of the front and rear wheels.

[0027] In a further step S3, the vehicle's driving state is determined based on the measured air pressures and a comparison of the air pressures. Additional sensors, such as acceleration sensors, can be used to identify or validate individual driving states.

[0028] For example, the following driving situations can be detected: A rapid increase in front wheel pressure and high acceleration can indicate that the vehicle has hit an obstacle. A drop in air pressure followed by a persistently low pressure can be an indication that the vehicle is jumping. If the normal force or air pressure drops, and in particular if the acceleration does not change, this is a sign of wheel slip. Fluctuations in air pressure with pronounced extreme values ​​that differ from the mean by more than a limit value can indicate that the vehicle is jumping. If the front wheel pressure is high and, in particular, the rear wheel pressure is low at the same time, the vehicle could roll over. In contrast, low front wheel pressure and, in particular, high rear wheel pressure at the same time is a sign of driving on the rear wheel, i.e. a wheelie.If the air pressure in both wheels rises, the rider may be about to jump. A pressure difference between the front and rear wheels may indicate riding uphill. Furthermore, persistently high air pressure, and especially significant fluctuations in air pressure at the same time, may indicate a heavy vehicle load.

[0029] Fig. 2 shows in schematic form steps of a method according to an embodiment of the present invention.

[0030] The procedure according to Fig. 2 is particularly suitable for controlling a drive unit of a preferably single-track vehicle such as an eBike.

[0031] In a step S4, a driving state of the vehicle is detected by means of a method according to one of claims 1-9. In particular, the driving state is determined using a method according to steps S1 to S3 according to Fig. 1 detected.

[0032] In a further step S5, a drive power, a drive speed and / or a drive torque of the drive unit is changed and / or a braking power of a brake of the vehicle is changed, depending on the determined driving condition.

[0033] In particular, a drive torque and / or drive power of the drive unit can be reduced if it is detected that the rear wheel of the vehicle is slipping. For example, the determined normal force can be calculated using the formula F Haft = µ Haft * F normalthe adhesion force can be determined. If this adhesion force decreases, the drive power can be reduced. This prevents the rear wheel from being accelerated too sharply by the drive unit. It also prevents a driver from experiencing excessive pushing of the vehicle when the normal force increases again. The adhesion force can also be learned using a machine learning algorithm. For this purpose, the adhesion force is determined based on further sensor data and the current air pressure is measured at the same time. From this data, a model can be developed that determines the corresponding adhesion force for specific air pressures. In this way, the adhesion force can be calculated even more precisely. A drop in adhesion force can also be validated using further sensor signals. For example, an increase in wheel speed is an indicator of a wheel slipping or lifting and therefore of a reduced adhesion force.The power of the drive unit can be adjusted according to the determined adhesion force. This allows for active anti-skid control.

[0034] Using an acceleration sensor, it's also possible to calibrate the air pressure sensor. If no acceleration is detected during a ride, meaning the ride is performed without incline or acceleration, this pressure can be used as a reference for calibration.

[0035] It is also possible for the drive power to be reduced if a jump or rollover of the vehicle is detected. It is conceivable that the drive power could be reduced or the drive unit deactivated if it is detected that the vehicle's load is low, for example, because no driver is sitting on it. This can prevent the vehicle from being snatched from a user. Conversely, if the vehicle is heavily loaded, the drive power could be increased to make driving easier for the driver.

[0036] If a collision with an object is detected, such as hitting a step, the drive power can be reduced to ensure that the driver has greater control over the vehicle.

[0037] Furthermore, it is conceivable that the sampling rate of the air pressure sensor could be reduced in certain driving situations. For example, if straight-ahead driving is detected, the sampling rate can be reduced because the drive unit's power is not changed. Upon detection of a new driving situation, for example, via the acceleration sensor and / or the air pressure sensor, the sampling rate can be increased again.

[0038] Fig. 3 shows in schematic form a vehicle according to an embodiment of the present invention.

[0039] The vehicle 1, here in the form of an eBike, has a drive unit 2 and two air pressure sensors 3a, 3b, wherein the air pressure sensor 3a is arranged in the rear wheel 4a and the air pressure sensor 3b is arranged in the front wheel 4b.

[0040] In addition, vehicle 1 has: - A measuring unit 5, designed to measure an air pressure by means of the air pressure sensor 3a, 3b in at least one wheel 4a, 4b of the single-track vehicle 1 at several times by means of the air pressure sensor 3a, 3b, - A comparison unit 6, designed to compare the air pressures measured within the several points in time, and - A determination unit 7, designed to determine a driving state of the preferably single-track vehicle 1 based on the measured air pressures and / or the comparison of the air pressures.

[0041] The vehicle 1 is particularly designed to carry out steps S1 to S3 according to Fig. 1, as well as steps S3 and S5 according to Fig. 2 to be carried out.

[0042] In particular, further sensors, for example an acceleration sensor 8 and a speed sensor 9, can also be arranged, which can additionally be used to determine and / or validate the driving state.

[0043] In addition, a brake 10 is arranged, which here is designed as an engine brake in the drive unit 2. If a new driving condition is detected that requires a change in the drive power, either the drive power of the drive unit 2 can be changed directly, or the braking power of the brake 10 can be changed. It is also conceivable for the brake 10 to be arranged on one or both wheels 4a, 4b, so that the wheels are braked directly.

[0044] In summary, the present invention has at least one of the following advantages and / or provides the following features: - Fast detection of wheel slip, - Detection of driving conditions relevant to driving safety, - Active control of the drive unit for improved control of the vehicle.

[0045] Although the present invention has been described using preferred embodiments, it is not limited thereto but can be modified in many ways.

Claims

[1] Method for determining a driving state of a preferably single-track vehicle (1), in particular an eBike, comprising the steps: - measuring (S1) an air pressure by means of an air pressure sensor (3a, 3b) in at least one wheel (4a, 4b) of the vehicle (1) at several times, - comparing (S2) the air pressures measured within the several time points, and - Determining (S3) a driving state of the vehicle (1) based on the measured air pressures and / or the comparison of the air pressures. [2] Method according to claim 1, wherein the air pressure in a rear wheel (4a) and / or a front wheel (4b) of the vehicle (1) is measured. [3] Method according to one of claims 1 or 2, wherein the driving state comprises traction of the at least one wheel (4a, 4b), lifting of a rear wheel (4a) of the vehicle (1) from a ground, lifting of a front wheel (4b) of the vehicle (1) from a ground, lifting of all wheels (4a, 4b) of the vehicle (1) from a ground, driving with a high load, driving without a driver and / or driving along an incline. [4] Method according to one of claims 1-3, wherein comparing the air pressures measured within the plurality of times comprises determining the time derivative of the measured air pressures, comparing the measured air pressures with an air pressure mean value and / or determining a time period in which the measured air pressure differs from the air pressure mean value. [5] Method according to one of claims 1-4, wherein the driving state is determined based on a speed of the vehicle (1). [6] Method according to one of claims 1-5, wherein the driving state is determined based on an acceleration of the vehicle (1). [7] Method according to one of claims 1-6, wherein the driving state is determined based on a temporal course of extremes of the measured air pressures. [8] Method according to one of claims 2-7, wherein the driving condition is determined by comparing the air pressures of the front and rear wheels (4a, 4b). [9] Method according to one of claims 1-8, wherein a normal force of the vehicle (1) is determined to determine the driving state, wherein the determination of the normal force is based on the air pressures measured at the plurality of times and / or the comparison of the air pressures measured at the plurality of times. [10] Method for controlling a drive unit of a preferably single-track vehicle (1), in particular an eBike, comprising the steps: - determining (S4) a driving state of the vehicle (1) by means of a method according to one of claims 1-9, and - Changing (S5) a drive power, a drive speed and / or a drive torque of the drive unit (2) and / or changing a braking power of a brake (10) of the vehicle (1) depending on the determined driving condition. [11] Vehicle (1), preferably single-track vehicle (1), in particular eBike, comprising at least one air pressure sensor, and: - A measuring unit designed to measure an air pressure by means of the air pressure sensor (3a, 3b) in at least one wheel (4a, 4b) of the single-track vehicle (1) at several times, - A comparison unit designed to compare the air pressures measured within the plurality of time points, and - A determination unit designed to determine a driving state of the preferably single-track vehicle (1) based on the measured air pressures and / or the comparison of the air pressures.

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