DE102019115312B3 - Device for speed control and manipulation detection for an electric bike - Google Patents

Abstract

Method and device for regulating and detecting manipulation of an electric bicycle driven by an electric motor. An engine speed and a wheel speed are detected and an actual transmission ratio is formed from them. This is compared with a target transmission ratio. If the actual gear ratio deviates from the target gear ratio, an error counter is incremented and if the error counter exceeds a threshold value, an electric motor output of the electric motor is limited. Furthermore, the electric motor output is limited on the basis of a valid transmission ratio that is determined from the actual transmission ratio. An evaluation of the actual transmission ratio, such as the counting up of the error counter, is activated or deactivated on the basis of a force-fit detection.

Description

The technical field of the present description relates to the regulation of electric bicycles.

Since the EU regulation 168/2013 came into force, a second speed limit has been prescribed for newly registered S-Pedelecs. This is intended to make manipulations that override the speed limitation more difficult. It is stipulated that if a curtailment fails, for example due to manipulation, support is not provided at higher speeds than without the curtailment failing. Furthermore, the chainring and the sprocket set are part of a type approval on an S-Pedelec and may not be changed afterwards.

Methods for reducing the speed of electric bicycles are already known.

For example, the DE 10 2016 209 570 B3 a control method for controlling a pushing aid of an electric bicycle, wherein an electric motor is controlled as a function of a maximum speed of the pushing aid for generating a speed of the electric bicycle.

The control method has a determination of the gear ratio of the gear shift as a function of the detected engine speed and the detected speed, the electric motor being regulated as a function of the determined gear ratio and the maximum speed of the pushing aid to adapt the speed so that the maximum speed is not
is exceeded.

The EP 2 829 466 A1 discloses an engine control system having a vehicle speed detection unit and a wheel speed detection unit and a motor drive control unit, the motor drive control unit receiving values detected by the vehicle speed detection unit and the wheel speed detection unit to determine a chain transmission ratio for driving a motor drive .

The WO 2012 086 460 A1 discloses a motor drive control apparatus comprising a speed processing unit that generates a value by converting an actual speed into a duty cycle, a torque processing unit generating another value by converting a target torque into the duty cycle, and a drive unit that controls a switch by an average duty cycle, which corresponds to a sum of the value and the further value in order to drive a motor.

The object of the invention is therefore to provide an improved device and an improved method for regulating an electric bicycle. This object is achieved by the subject matter of the independent claims.

Advantageous developments result from the dependent claims.

In a first aspect, the present description discloses a computer-implemented method for regulating an electric bike driven by an electric motor, wherein the electric bike can in particular also be an electric bike with two or more wheels, and wherein the electric bike can in particular be an electric bike in which a pedal drive of a rider is supported by a motor, as with a Pedelec or S-Pedelec.

Here, the regulation or regulation of the motor relates in particular to a regulation that is carried out in addition to an existing regulation of the motor, and in particular to a regulation or regulation, whereby a power and / or rotational speed of a motor is reduced, limited or regulated becomes. Furthermore, the regulation also relates to manipulation detection. Accordingly, a suspension of the regulation refers to a suspension of this additional regulation or regulation or manipulation detection, the existing motor regulation still remaining active.

Here and in the following, method steps that are carried out by an electronic component such as a control unit or a microcontroller are described as a process for the sake of brevity, without explicit reference being made to this component.

According to the method, a motor speed of rotation of the electric motor is continuously detected, with continuous detection referring to detection at regular short time intervals, for example with a cycle duration in fractions of seconds or in the millisecond range. The motor speed is detected on the basis of an output from a detection device, for example by sensor signals from a sensor that is arranged on a motor shaft or on a component driven off it, or even without sensors by evaluating currents and / or voltages that are applied to the motor. The engine rotational speed is also referred to as engine speed or engine shaft rotational speed

Furthermore, the method includes a simultaneous detection of a wheel speed of a wheel of the electric bicycle driven by the motor, wherein the detection of the wheel speed can also relate to a detection of wheel rotations or of wheel rotation angles. The wheel speed is detected on the basis of an output from a wheel speed detection device, for example on the basis of the sensor signals from a wheel speed sensor which is arranged in the area of the driven wheel.

The "simultaneous detection" refers to the fact that the wheel speed is measured while the engine speed is measured, whereby the measurement of the wheel speed can take place in larger time intervals and the measurement times do not have to be exactly the same.

An actual transmission ratio is formed from the engine rotational speed and the wheel rotational speed, which indicates a ratio of engine rotational speed to wheel rotational speed or of motor rotational angle to wheel rotational angle. The actual gear ratio is compared with one or more specified target gear ratios, which are also referred to as “valid” gear ratios.

If the actual gear ratio deviates from the specified target gear ratio, an error counter is increased. The error counter is a value which is stored in a readable and writable computer memory and which is changed by increasing it. For example, the error counter can be increased by one or by another fixed amount each time the discrepancy is detected.

The check as to whether the actual transmission ratio deviates from the target transmission ratio takes place at regular intervals, for example as part of a program loop. The deviation between the target transmission ratio and the actual transmission ratio relates to a specified tolerance. The target gear ratio or the target gear ratios can in particular be stored in a computer memory and called up from the computer memory for comparison with the actual gear ratio.

If the error counter exceeds a predetermined threshold value, an electrical motor output of the electric motor is reduced, wherein a reduction can in particular relate to a limitation of a motor output and / or a motor speed, which is thereby reduced compared to a non-regulated case. In particular, in this case the control can switch to an emergency run through which the engine output is permanently reduced until a trip is ended and the engine is restarted. The emergency operation can in particular be designed in such a way that an engine speed is limited in such a way that a predetermined wheel speed is not exceeded even in a top gear.

Increasing the error counter is also intended to relate to increasing an amount of the error counter. That is to say, a case which is symmetrical for increasing, in which an error counter is instead decreased and in which the threshold value is a negative value, should also be included.

The error counter is set to an initial value at an initialization time, for example at the start of the journey, it being possible for the initial value of the error counter to be zero, for example. According to one embodiment, the error counter is counted up from an initial value of zero to a threshold value of 1000. The threshold value is selected to be sufficiently large, so that it can be ensured that the engine output is not unnecessarily reduced, which is particularly advantageous in the case of emergency operation the functionality of the e-bike is permanently restricted. The threshold value can, for example, be specified or predetermined in that it is stored as a fixed value in a memory element.

The above-mentioned method is particularly suitable for automatically detecting a manipulation or a malfunction, for example in the case of a bicycle gearbox and / or a wheel speed sensor of the electric bicycle, and then regulating the electric bicycle by reducing the motor power so that a specified maximum speed is not exceeded, if the manipulation or the functional failure is detected.

By using an error counter that is counted up to a threshold, an unnecessary or premature reduction in engine power can be avoided. Furthermore, it can be avoided that a false alarm or a manipulation detection is triggered by revving the engine, for example when starting, or by invalid gear ratios when shifting.

Furthermore, if the actual gear ratio does not or no longer deviates from the predefined target gear ratio, the error counter can be reduced, a non-deviation referring to a sufficiently small deviation that lies within a predefined tolerance range.

By reducing the error counter, it can be avoided, for example, that the predefined threshold value of the error counter is already reached when there is no defect or no manipulation. For example, the error counter can be increased during a gear shift if there is a discrepancy between the target gear ratio and the actual gear ratio, but can be reduced again after the gear shift when there is no longer any discrepancy between the actual gear ratio and the target gear ratio, so that the unnecessary increases are compensated.

In particular, the error counter can also be reduced if the error counter has already exceeded the threshold value and the engine output can be increased again when the error counter falls below the threshold value, whereby an increase in the motor output can refer to the fact that the electric bike is supported again by the motor or that full motor support is available again.

According to one embodiment, the error counter is only counted down to a minimum value and no further, for example to a minimum value of zero. This avoids that the error counter is continuously counted down and the threshold value is not reached or is reached too late by increasing the error counter.

Likewise, according to one exemplary embodiment, the error counter can remain at the threshold value when the threshold value is reached and cannot be incremented any further. In this case, the error counter is only reset by initialization, for example at the start of a journey. In this way it can be ensured, for example, that if manipulation or a functional failure is detected, the motor power remains permanently reduced until initialization.

Furthermore, the method can include retrieving a list of several target gear ratios from a computer memory, such as a firmware memory, an EPROM or the like, and selecting the target gear ratio from the list of target gear ratios, with the target gear ratio in particular can be selected that has the smallest distance from the actual transmission ratio.

In particular, the selection of the target gear ratio from the list of target gear ratios can have the following steps. Determining the smallest deviation of the actual gear ratio from the target gear ratios in the list, for example by forming the amount of the difference between the gear ratios, and selecting the target gear ratio with the smallest deviation, or the least one from the actual gear ratio deviates.

By using the list of target gear ratios, it can be achieved that the deviation from the actual gear ratio and the target gear ratio is correctly determined for the selected gear. This is possible without a “gear sensor” or gear shift sensor having to be provided that recognizes the selected gear. In addition, the regulation is then not of it depends on whether the gear shift sensor is functional. A gear shift sensor can also be provided, for example to reduce the engine output when shifting.

In particular, the detection of the engine speed of rotation can include a detection of an angle of rotation of the motor, the angle of rotation of the motor being able to be detected in such a way that no absolute position of the motor shaft is required for this.

Furthermore, the detection of the wheel speed of rotation can include detection of a wheel rotation angle. In particular, the wheel rotation angle can be obtained in a simple manner, for example, by a sensor signal from a spoke sensor. The actual transmission ratio can be formed by forming the actual transmission ratio from the motor rotation angle and the wheel rotation angle, in particular by calculating a quotient of the angle values. To form the actual gear ratio, the wheel rotation angle is recorded during the same period as the engine rotation angle.

The acquisition of an angle of rotation for the acquisition of the rotational speed of the motor and rotational speed of the wheel can be advantageous, inter alia, because an averaged speed can thereby be formed which has fewer fluctuations than an instantaneous rotational speed. If a wheel speed sensor is used, which determines the wheel revolutions and thus the wheel rotation angle, the wheel rotation angle obtained in this way can moreover be efficiently compared with the motor rotation angle. For this reason, among other things, an efficient calculation of a transmission ratio can be achieved by forming a rotation angle.

Furthermore, the detection of the motor rotation angle can comprise a detection of motor rotation part angles within a cycle time, the motor rotation angle being formed by adding up the motor rotation part angles. This summation can take place in particular when the wheel rotation angle is equal to a predetermined wheel rotation angle or after a predetermined period of time. In the case of a spoke magnet, entire wheel revolutions are usually measured, which corresponds to a multiple of 360 degrees.

By forming partial rotation angles, for example, the efficiency of the angle calculation can be improved or the accuracy of the angle calculation can be increased.

In particular, the wheel speed can be determined by one or more spoke magnets and a Hall sensor attached to a frame of the electric bicycle. This device provides a robust and technically simple determination of a wheel speed. However, the wheel speed can also be measured by another sensor system.

Furthermore, forming the actual gear ratio can include forming the actual gear ratio based on a current engine speed, a current wheel speed, an engine speed detected at an earlier point in time and a wheel speed detected at an earlier point in time. Among other things, this can be used to smooth the measured values or to ignore outliers and thus avoid unnecessarily increasing the error counter.

In particular, the formation of the actual gear ratio can include filtering the current engine speed, the current wheel speed, the previous engine speed and / or the previous wheel speed, the filtering being provided, for example, by a smoothing filter such as a simple mean value filter, a low-pass filter, an exponential low-pass filter or the like can be. It is also possible to use a complex filter to be calculated with non-constant coefficients such as a Kalman filter.

The previously determined actual transmission ratio can also be used to regulate the engine speed or to reduce the engine power in order to avoid exceeding the speed. Compared to a “rigid” curtailment that does not take an actual transmission ratio into account, this curtailment can be designed flexibly, and in particular also so that it only intervenes when a first curtailment does not work.

For this purpose, a maximum motor rotational speed is determined, which can take place on the basis of a maximum permissible speed or control speed, a wheel circumference of a rear wheel and the previously formed actual gear ratio, with the speed and the wheel circumference or a value calculated therefrom being stored in a computer memory of the control system . In particular, too the determination of the target gear ratio from a list of gear ratios which is closest to the actual gear ratio can be used.

The detected engine speed is compared with the previously determined maximum engine speed. If the detected motor rotational speed exceeds the maximum motor rotational speed, an electric motor output of the electric motor is reduced, wherein the decrease can relate in particular to a limitation of the motor output and / or the motor speed. In particular, the engine power can be reduced in such a way that the maximum engine speed is no longer exceeded, for which purpose a control loop can be used.

Furthermore, the method can include detecting an existing frictional connection of the electric motor. The traction detection takes place on the basis of the output of a traction detection device. For example, the frictional connection detection device can have a sensor which measures a phase current with which the motor is supplied, and the motor speed detection device. The detection of the frictional connection can take place on the basis of the phase current and the previously determined motor speed, for example by comparing the phase current and the motor speed with predetermined or predetermined values.

If, according to the previous detection of the frictional connection, it is determined that there is no frictional connection, the increase in the error counter is suspended or deactivated, with the suspension in particular being able to take place temporarily over a period of time that is determined by the duration of the non-existent frictional connection. As a result of the suspension, the above-mentioned step of increasing the error counter is not carried out, as a result of which an unnecessary incrementing of the error counter, for example during a switching process, can be avoided. In the more general sense, a change, i.e. an increase or decrease in the error counter, is suspended.

The further features of the method according to the second aspect and of the method according to the third aspect, which are mentioned below, can also be combined with the method according to the first aspect.

In a second aspect, the present application discloses a further computer-implemented method for controlling an electric bicycle driven by an electric motor.

According to this method, a motor rotation speed of the electric motor is detected. At the same time, a wheel rotation speed of a wheel of the electric bicycle driven by the motor is detected and an actual gear ratio is formed from the motor rotation speed and the wheel rotation speed. A maximum engine rotational speed is formed from a maximum permissible speed, a wheel circumference of a rear wheel and the previously established actual gear ratio.

When calculating the maximum engine speed, in particular a target gear ratio from a list of target gear ratios can be used which comes closest to the actual gear ratio.

This detected engine speed is compared with the previously determined maximum engine speed. If the detected motor rotational speed exceeds the maximum motor rotational speed, an electric motor output of the electric motor is reduced, wherein, as already explained above, the decrease can relate to a limitation of the motor output and / or the motor speed.

The reduction or limitation of the engine output can also take place depending on whether the actual transmission ratio was previously recognized as valid, that is to say does not deviate from the target transmission ratio by more than a predetermined tolerance. Furthermore, the reduction in the engine power can take place as a function of whether an evaluation of the actual gear ratio is activated when a frictional connection of the motor has been detected or is deactivated when it has been detected that the motor is not frictional.

The motor curtailment mentioned in the previous paragraph can in particular be designed to be harder than an existing curtailment. For this purpose, in particular a failure of a first governing mechanism that limits an engine speed can be detected, the detection also relating to a Detecting a speed, power or other characteristic that is not achieved when the first curtailment is functional.

In this case, the downward regulation takes place to the extent that the reduction in the electrical motor power takes place at a higher motor speed and / or over a smaller motor speed range than the limitation of the motor speed. For example, this can be done in that the maximum speed of the motor at which the motor is governed is selected to be greater than that of the first governing mechanism.

This method is particularly suitable for the abovementioned downward regulation based on the actual gear ratio, and it can advantageously be used in addition to an already existing method for downward regulation of the motor or the motor speed.

The above remarks apply mutatis mutandis to the features that have already been mentioned in the method according to the first aspect. The features of the method according to the first aspect and the features of the method mentioned below according to the third aspect, which relates to traction detection, can also be used for this method. For example, the features can advantageously be used which relate to the determination of the actual transmission ratio, such as the determination of angles of rotation or partial rotation angles or the filtering of the measured values.

In a third aspect, the present description discloses a further computer-implemented method for controlling an electric bicycle driven by an electric motor.

According to this method, the electric motor is regulated by reducing the electric motor output, wherein the motor output can be reduced in particular by limiting the motor output and / or speed.

It is detected whether there is a frictional connection of the electric motor, for example on the basis of a current supplied to the motor and the motor rotational speed. If, according to the previous detection, there is no frictional connection, the regulation is suspended or deactivated, in particular temporarily, until a frictional connection is present again. In particular, a governor mechanism can limit the speed of rotation of the motor by reducing the motor's electrical output.

With this method, which has a detection of a frictional connection, it can be avoided, among other things, that an engine output is unnecessarily reduced or limited. Furthermore, this method can also be used advantageously for other controls that require detection of a frictional connection, such as for controlling a gear shift.

The features of the method according to the first and the second aspect can be combined with the method according to the third aspect. In particular, features can advantageously be combined with this method that relate to increasing or decreasing an error counter, for example increasing or decreasing the error counter being suspended if it is recognized in the method according to the third aspect that there is no frictional connection.

Furthermore, the method can include a determination of a traction characteristic such as motor current or motor speed. If a predetermined force-fit characteristic value threshold is exceeded, the control of the electric motor begins. For example, an engine control or manipulation detection can be switched on in this way when an engine has started or when a gear shifting process has ended.

A determination of the traction characteristic value and an increment of a counter can also be repeated several times in a loop if a traction is present until a specified value of the counter is exceeded, and the control can be activated when the specified value is exceeded.

Furthermore, when the regulation or the manipulation detection is activated, a determination of a traction characteristic value, which includes, for example, phase current and / or motor speed, can be carried out. The motor speed can in particular be evaluated optionally or in addition to the phase current. The determination of the frictional connection characteristic is repeated as long as a predetermined one The friction-locked characteristic value threshold is exceeded and, as soon as the specified characteristic value threshold is undershot, the control of the motor or the manipulation detection is deactivated.

In particular, the frictional connection characteristic value threshold can be selected such that it indicates that the frictional resistance of an engine transmission has been overcome. Furthermore, the frictional connection characteristic value threshold can include a minimum current and / or a minimum speed of the electric motor.

The method according to the third aspect is particularly suitable for temporarily deactivating an engine control and / or a manipulation detection, wherein the engine control can in particular be based on a detection of an invalid gear ratio.

According to a further aspect, the present specification discloses an apparatus for controlling an electric bicycle driven by an electric motor, having the following features.

A motor speed detecting device configured to continuously detect a motor rotation speed of the electric motor is provided. As mentioned above, the motor speed can be recorded directly or indirectly. For example, the motor speed can be detected by the sensorless method mentioned above, in which the currents and / or voltages of the motor are evaluated electronically. Or a sensor can be attached to the motor shaft or to a part driven off therefrom, which has a fixed transmission ratio to the motor shaft and which is preferably not or only with difficulty accessible for manipulation.

Furthermore, a wheel rotation speed detection device is provided which is designed to simultaneously detect a wheel rotation speed of a wheel of the electric bicycle driven by the motor. A simple spoke magnet and a magnetometer attached to the frame can suffice for this, but other devices can also be used, for example a gyroscope, a centrifugal force meter or a magnetometer, which can also be provided as MEMS components, for example.

Furthermore, the device has a control unit which is designed to form an actual gear ratio from the engine speed and the wheel speed, to compare the actual gear ratio with a predetermined target gear ratio and, if the actual gear ratio from the predetermined target Gear ratio deviates, increasing an error counter. Furthermore, the control device is designed to reduce an electric motor power of the electric motor when the error counter exceeds a threshold value, the reduction in the motor power including a limitation.

The control device can be provided by an electronic component that is arranged on the engine, or by one or more electronic components that can be arranged on the engine or outside it.

The present description also discloses a device for controlling an electric bicycle driven by an electric motor. This device includes a motor speed detection device which is adapted to continuously detect a motor rotation speed of the electric motor. Furthermore, a wheel rotation speed detection device is provided, which is designed to detect a wheel rotation speed of a wheel of the electric bicycle driven by the motor.

In addition, a control unit is provided which is designed to form an actual gear ratio from the engine rotational speed and the wheel rotational speed, to determine a maximum engine rotational speed, for example from a maximum permissible speed, a wheel circumference of a rear wheel and the previously established actual gear ratio, and compare the detected engine speed with the previously determined maximum engine speed. Furthermore, the control device is designed to reduce an electric motor power of the electric motor when the detected motor rotational speed exceeds the maximum motor rotational speed.

In a further aspect, the present description discloses a further device for regulating an electric bicycle driven by an electric motor, which device has a control unit which is designed to regulate the electric motor by reducing the electric motor power, as well as a traction detection device which for this purpose is designed to detect whether a frictional connection of the electric motor is present, for example, based on a current supplied to the motor and a motor rotational speed. The control unit is also designed to receive signals from the traction detection device and to determine whether the motor is traction due to the detected signals and, if there is no traction, to temporarily deactivate or suspend the aforementioned rules.

Furthermore, the present description discloses an electric bicycle that has an electric motor and at least two wheels, the motor being designed to drive at least one of the wheels, and one of the aforementioned devices. The driven wheel of the electric bike can be connected to the motor via a drive train of the electric bike.

In particular, in the case of the electric bicycle, the wheel rotational speed detection device can be arranged in the region of the driven wheel of the electric bicycle, and the motor speed detection device can be arranged on the motor or on a part of the drive train driven by the motor.

In one embodiment, the frictional connection detection device is arranged at least partially in the area of the engine. According to a further exemplary embodiment, the frictional connection detection device is electrically connected to the motor.

Further features of the subject matter of the present description are listed below. In the case of an engine control according to the present description, a first and a second limiting mechanism can be provided.

The first limiting mechanism can be, for example, a limiting mechanism that continuously removes motor assistance by a maximum speed without prior determination of a gear ratio based on a measured speed of a speed sensor or reduces a motor current so that the electric bike cannot exceed the maximum speed. By continuously removing the support, a smooth removal of the support can be achieved during the first motor control.

A simple second speed regulation can be done, for example, in such a way that a speed of the drive motor is limited on the basis of the largest possible gear ratio, so that in the highest gear only a regulation speed calculated from the largest possible transmission ratio is supported.

In contrast to this, the second governing mechanism according to the present description has a calculation of a maximum engine speed on the basis of a current gear ratio. As long as a valid gear ratio is recognized, the engine speed is reduced accordingly so that the maximum speed with the current gear ratio cannot be exceeded.

If manipulation is detected, the engine speed is reduced to such an extent that it is not possible to exceed the maximum speed in any gear. This limiting mechanism is referred to as hard because the engine speed is limited at the maximum speed value that can be reached and there is no transition area. To limit the engine speed, a feedback loop is provided with the current engine speed as input, which is included when specifying the engine power.

In the following description, details are provided which serve to describe the embodiments. However, it should be apparent to those skilled in the art that the embodiments can also be practiced without such details. Furthermore, for the sake of clarity of the illustration, details of an exemplary embodiment cannot be described in the present description.

For example, a method for motor control according to the present description can be used with an electromechanical gearbox, but also with a mechanical gearbox or even without a gearbox. The method can also be used with or without a gear shift sensor.

The electric bike can in particular be a pedelec in which the electric drive is only activated when a driver operates the pedals. Furthermore, it can in particular be a Trade electric bicycles for which approval is required due to the speed, or for which the drive reaches a speed of more than 25 km / h, such as an S-Pedelec.

1. I. Manipulationssicherung durch Prüfen eines Übersetzungsverhältnisses aus Motor- und Radumdrehungen gegen eine Tabelle mit „gültigen“ Übersetzungsverhältnissen und, falls das Übersetzungsverhältnis als ungültig erkannt wurde, inkrementieren eines Fehlerzählers, wobei sobald der Fehlerzähler einen oberen Schwellwert überschreitet die Motordrehzahl und damit die Höchstgeschwindigkeit stark limitiert wird, was auch als Notlaufbetrieb bezeichnet wird.
2. II. Dekrementieren des Fehlerzählers bei Erkennung eines gültigen Übersetzungsverhältnisses bis maximal zu einem unteren Schwellwert.
3. III. Zusätzlich zum Dekrementieren des Fehlerzähler bei gültigem Übersetzungsverhältnis: Ermitteln einer von der aktuellen Übersetzung abhängigen Maximaldrehzahl des Motors, um die Maximalgeschwindigkeit unabhängig von einer normalen Geschwindigkeitsabregelung einzuhalten.
4. IV. Einführen eines zweiten Abregelmechanismus, der bei der für die aktuelle Übersetzung ermittelten Maximaldrehzahl hart abregelt, falls der bestehende erste Abregelmechanismus ausfällt.
5. V. Temporäres Deaktivieren der Manipulationserkennung und zweiten Abregelung bei temporär ungültigen Übersetzungsverhältnissen, bspw. bei Schaltvorgängen

A manipulation protection or motor control according to the present description can provide the following features, among others.

1. I. Tamper protection by checking a gear ratio of engine and wheel revolutions against a table with "valid" gear ratios and, if the gear ratio was recognized as invalid, incrementing an error counter, whereby as soon as the error counter exceeds an upper threshold value, the engine speed and thus the maximum speed is severely limited is what is also referred to as emergency operation.
2. II. Decrementing the error counter when a valid transmission ratio is detected up to a maximum of a lower threshold value.
3. III. In addition to decrementing the error counter when the gear ratio is valid: Determining a maximum motor speed dependent on the current gear ratio in order to maintain the maximum speed regardless of a normal speed limitation.
4. IV. Introduction of a second curtailment mechanism which, at the maximum speed determined for the current ratio, curtails hard if the existing first curtailment mechanism fails.
5. V. Temporary deactivation of the manipulation detection and a second curtailment in the event of temporarily invalid gear ratios, e.g. during gear changes

In the following, the determined transmission ratio is also referred to as the current transmission ratio or “actual transmission ratio” and the valid transmission ratio is also referred to as the “target transmission ratio”.

Furthermore, incrementing or decrementing the error counter is also referred to as “increasing” or “decreasing”.

Figure list

• 1 shows an electric bike,
• 2 FIG. 11 shows a method for regulating an electric motor and for detecting manipulation using a gear ratio of a gearbox of the electric bicycle from FIG 1 ,
• 3 shows a method for activating and deactivating the manipulation detection of 2 ,
• 4th shows the procedure for tampering detection of 2 in more details and the transition to limp home mode, and
• 5 shows a speed limit based on a determined actual gear ratio.

Detailed description

1 shows schematically an electric bicycle 1 . The electric bike 1 has a rear wheel 8th , a front wheel 9 , a frame 10 , a saddle 11 and a handlebar 7th on. A crank drive 22nd of the electric bike 1 is with the rear wheel 8th via a pedal shaft freewheel, a driven gear 6th that is on an output shaft 12th is arranged and via a chain 13 connected.

The electric bike 1 furthermore has an electric drive motor 5 on that by a battery 14th is powered.

The electric drive motor 5 is via an engine output train 4th to an output shaft 12th coupled. A pedal wave 30th of the crank drive 22nd has cranks 15th on. The pedal wave 30th is about an in 1 Not shown pedal shaft freewheel to the output shaft 12th coupled. The engine output train 4th who is in 1 is symbolized by a dashed line, has an engine transmission and an engine freewheel, which in 1 are not shown.

The electric bike 1 has a control unit 16 on which the drive motor 5 and a derailleur 17th is controlled. The control unit 16 is via a bowden cable 18th with the derailleur 17th connected. The derailleur 17th includes a sprocket set 19th that is on a rear hub 20th is arranged and a derailleur 21st on.

A wheel speed detecting device 2 which also works as a wheel speed sensor 2 is referred to is via a cable 28 with the control unit 16 connected and an engine speed detecting device 3 that also works as an engine speed sensor 3 is referred to is via another cable 29 with the control unit 16 connected.

A shift motor of the derailleur 21st is via a second control cable 23 with a manual transmission 24 connected. The manual transmission 24 is via another control cable 25th with the control unit 16 connected. There is also one on the handlebar 7th attached user control unit 26th via a control cable 27 with the control unit 16 connected.

The control unit determines during operation 16 an electrical power generated by the electric drive motor from sensor measured values, from a time curve of the sensor measured values and from variables derived from them 5 provided. The sensor measurement values can include, among other things, cadence, pedal torque, rear wheel speed, battery current and voltage, an engine speed or a selected gear of a bicycle gearshift. Furthermore, the control unit 16 optionally also evaluate user inputs of a driver, such as a desired level of support, and these when activating the electric drive motor 5 consider.

In particular, the control unit 16 the electric drive motor 5 control so that a motor speed of the electric drive motor 5 is limited.

According to various embodiments of the electric bicycle 1 can the manual transmission of the electric bike 1 be mechanically and / or electromechanically switchable and the switching operations can be done by the driver and / or the controller 16 to be triggered. In particular, the gearbox can be in the area of the rear wheel hub 20th of the rear wheel 8th be arranged.

In 1 only one control unit is shown for the sake of simplicity. This control unit can be arranged on the motor or outside the motor, or it can also be provided by several electronic components, one of which can be arranged on the motor.

While driving, the control unit determines 16 from signals from the wheel speed sensor 2 and the engine speed sensor 3 constantly the current ratio of engine shaft revolutions or engine speed to the wheel revolutions of the rear wheel. The calculated gear ratio is regularly compared with a list of valid gear ratios in order to identify an invalid gear ratio.

If the transmission ratio is invalid, an error counter is incremented. As soon as the error counter exceeds a set threshold value, manipulation is assumed and the engine speed is limited so that the vehicle with the highest possible gear ratio does not reach speeds outside the permitted range.

If the transmission ratio is valid, the error counter is decremented and, moreover, a maximum speed of the motor is constantly determined in order to be able to maintain a maximum speed of the electric bike regardless of the normal speed limitation. Here, “constantly” refers to a determination at regular short intervals, for example through an endless loop.

Preferably revolutions of the engine 5 with the help of the engine speed of the engine 5 and without the use of an absolute position specification from signals from the engine speed sensor 3 certainly. In a task with a low cycle time, the current motor speed is used cyclically for this purpose in order to calculate the angle covered by the motor since the last run.

The resulting angle is added up until a complete rear wheel rotation is detected, the complete rear wheel rotation being determined by the current pulse counter of the wheel speed sensor 2 is detected. In order to save floating point operations and at the same time to obtain the necessary accuracy, the angle covered is first added up in milligrades. The following formula gives the calculation of the angle covered by an output shaft of the motor 5 in milligrades to: $$\mathrm{W.}inkel\left[m\mathrm{D.}eG\right]=\mathrm{R.}P{\mathrm{M.}}_{\mathrm{M.}Ot}\left[\frac{U}{min}\right]\mathrm{\ast }\frac{360\left[\frac{\mathrm{D.}eG}{U}\right]}{60\left[\frac{\mathrm{S.}}{min}\right]}\mathrm{\ast }\frac{1000\left[\frac{m\mathrm{D.}eG}{\mathrm{D.}eG}\right]}{1000\left[\frac{ms}{s}\right]}\mathrm{\ast }Zykluszeit\left[ms\right]$$

wobei die Motordrehzahl RPM_Mot in Umdrehungen pro Minute und die Zykluszeit in Millisekunden gemessen werden. Weiterhin bedeutet „360“ die Anzahl von Winkelgrad pro Motorwellenumdrehung. Die weiteren Faktoren sind Umrechnungsfaktoren zwischen Sekunde und Millisekunde, Minute und Sekunde, und Grad und Milligrad. Hier und im Folgenden kann ein unterer Index im Beschreibungstext auch durch einen Unterstrich angezeigt werden.This calculation is reduced by shortening it to the following formula: $$\mathrm{W.}inkel\left[m\mathrm{D.}eG\right]=\mathrm{R.}P{\mathrm{M.}}_{\mathrm{M.}Ot}\mathrm{\ast }\mathrm{6th}\mathrm{\ast }Zykluszeit,$$

where the engine speed RPM_Mot is measured in revolutions per minute and the cycle time in milliseconds. Furthermore, "360" means the number of angular degrees per motor shaft revolution. The other factors are conversion factors between seconds and milliseconds, minutes and seconds, and degrees and milligrades. Here and below, a lower index in the description text can also be indicated by an underscore.

As soon as a configured number of sensor pulses on the wheel speed sensor 2 has been registered, the sum of the individual angles covered is converted into the transmission ratio in degrees / wheel revolution for further tests. $$\mathrm{R.}atiO\left[\frac{\mathrm{D.}eG}{U_{\mathrm{R.}ad}}\right]=\frac{{\displaystyle \sum \mathrm{W.}inkel\left[m\mathrm{D.}eG\right]}}{1000\left[\frac{m\mathrm{D.}eG}{\mathrm{D.}eG}\right]}$$

Here “Deg” is the angle covered by the motor's output shaft 5 , U wheel denotes one wheel revolution of the rear wheel 8th and Σ angle is the sum of the individual partial angles that result from the motor speed and the length of the cycle time in the cycle of the cycle time with the aid of formula (1).

In a more general sense, U_Rad can also refer to a partial revolution of the rear wheel or to a number of revolutions greater than one. The angle calculation and the check for a complete wheel revolution are called with a cycle time that can be 2 ms, for example.

In the motor firmware of the control unit 16 various valid translation tables are stored with the corresponding chainring and cassette. This takes place in a memory of the control unit 16 . For example, the memory in which the gear ratio is stored can be provided by a flash memory or also a ROM BIOS.

worin „Ratio“ der zurückgelegte Rotationswinkel einer Ausgangswelle des Motors 5 pro Umdrehung des Hinterrads 8 bedeutet. Weiterhin bedeuten „N_Ritzel“ die Anzahl der Zähne eines ausgewählten Ritzels, „N_Kettenblatt“ die Anzahl der Zähne des Kettenblatts bzw. eines ausgewählten Kettenblatts und „n_Getriebe“ ein Übersetzungsverhältnis des Motorgetriebes.The following formula becomes the number of teeth on the chainring and the sprocket of the electric bike 1 the gear ratios are calculated: $$\mathrm{R.}atiO\left[\frac{\mathrm{D.}eG}{U_{\mathrm{R.}ad}}\right]=\frac{N_{\mathrm{R.}itzel}\mathrm{\ast }{n}_{Getribe}\left[\frac{U_{\mathrm{M.}Ot}}{U_{\mathrm{A.}btriebswelle}}\right]\mathrm{\ast }360\left[\frac{\mathrm{D.}eG}{U_{\mathrm{M.}Ot}}\right]}{N_{Kettenblatt}},$$

where "Ratio" is the rotation angle covered by an output shaft of the motor 5 per revolution of the rear wheel 8th means. Furthermore, "N_Ritzel" means the number of teeth of a selected pinion, "N_Kettenblatt" the number of teeth of the chainring or a selected chainring and "n_Getriebe" a transmission ratio of the motor gearbox.

The motor gearbox is a reduction gear that is located behind the motor in the torque curve 5 arranged and in 1 is not shown. As a rule, the motor transmission cannot be shifted and is often arranged in a motor-transmission unit.

Furthermore, in the calculation of n gears, “U_Mot” means the number of revolutions of the output shaft of the motor 5 , and "U_Abtriebswelle" the number of revolutions of the output shaft on which the chainring is arranged.

The following table gives an example of a gear ratio that results from the above formula (3) for a given sprocket set with 11 sprockets, which have 11 to 46 teeth, and a chainring with 48 teeth, and a gear ratio of 37. Chainring pinion Gear ratio 48 11 3052 48 13 3607 48 15th 4162 48 17th 4717 48 19th 5272 48 21st 5827 48 24 6660 48 28 7770 48 32 8880 48 37 10267 48 46 12765

The transmission ratio given in the table above is the "Ratio" defined above according to formula (3). The values of this table can be stored in an EPROM of the control unit, for example 16 be filed.

There can also be several such tables in a memory of the control unit 16 be stored, which is stored at the factory which set of chainring and sprocket set in the electric bike 1 is installed. The table can also contain gear ratios of a gearbox with several sprockets or a hub or planetary gear.

worin „Ratio“ ein aktuelles oder gefiltertes Übersetzungsverhältnis zwischen einer Ausgangswelle des Motors 5 und dem Hinterrad 8 bedeutet, „Ratio_closest“ ein nächstgelegenes gültiges Übersetzungsverhältnis und ΔRatio einen Abstand zu einem nächstgelegenen gültigen Übersetzungsverhältnis.The current gear ratio and a filtered gear ratio are used to check the current gear ratio. The filter is used to eliminate fluctuations that have occurred due to the calculation and to intercept incorrect pulses. An exponential low-pass filter is preferably used as the filter. The closest valid transmission ratio and the distance to it are determined for both values. $$\begin{array}{l}\mathrm{R.}ati{O}_{clOset}=\mathrm{R.}ati{O}_{k}wHere\left|{\text{Ratio}}_{\text{k}}-\text{Ratio}\right|\underset{}{\equiv \underset{1\le j\le n}{min}}\left|\mathrm{R.}ati{O}_j-\mathrm{R.}atiO\right|\\ \Delta \mathrm{R.}atiO=\left|\mathrm{R.}ati{O}_{clOsest}-\mathrm{R.}atiO\right|,\end{array}$$

where "Ratio" is a current or filtered transmission ratio between an output shaft of the engine 5 and the rear wheel 8th “Ratio_closest” means a closest valid gear ratio and ΔRatio a distance to a closest valid gear ratio.

Furthermore, the index j denotes a running index which runs from 1 to a predetermined upper limit n, where n is a number of gear ratios provided by the transmission of the bicycle. For example, in a manual transmission according to the table given above, n = 11.

Expressed in words, a ratio Ratio_closest or Ratio_k is determined from the values Ratio_1 to Ratio_n according to the above formula, at which the distance from the predefined value Ratio becomes minimal.

The control unit 16 performs the following steps that are in 2 are shown: If the two closest gear ratios of the raw and the filtered gear ratio differ from each other, the control unit decides 16 in one step 35 that the gear of the electric bike has changed and the current gear ratio is in one step 36 set as invalid.

In one decision step 37 checks the control unit 16 whether a distance ΔRatio or ΔFiltered of the filtered value is below a limit value, which is also referred to as "Margin". If this is the case, the gear ratio is valid and in one step 38 the error counter is decremented as long as it is greater than zero, or up to another predetermined lower limit value. Furthermore, in one step 43 a period of validity is counted up and a further decision step 44 checked whether the validity period is greater than 500 ms. If it does, the ratio is in one step 45 set to "valid".

If the limit value is exceeded, the control unit checks in a decision step 39 the distance ΔRatio of the raw value. If the distance ΔRatio also exceeds the limit value, the control unit decides 16 in one step 40 that the gear ratio is invalid, and the error counter is displayed in one step 41 elevated.

In one step 46 it is determined whether the error counter exceeds a threshold value N_ErrorThreshold after increasing, and if this is the case, in step 47 a cut-off mechanism, for example an emergency run, activated. In the next calculation cycle, the method goes back to step 35 .

If ΔRatio of the filtered value is greater than or equal to the limit value and ΔRatio of the raw value is below the limit value, in one step 42 the filter is reinitialized with the current transmission ratio. This case occurs especially after gear changes, when the actual gear ratio has changed, but the filter would still have to follow the time profile of the gear ratio.

The filter, which is, for example, an exponential low-pass filter, acts as a smoothing filter and is set by the control unit 16 is calculated from a current value of the transmission ratio and from previous values and therefore has, among other things, a time lag.

3 shows an activation or deactivation of the manipulation detection. This causes the engine 5 does not idle during the manipulation detection, since there is generally no defined relationship between engine speed and rear wheel speed when idling.

The control unit 16 determines whether the engine is in a frictional connection. In this way it can be avoided that an invalid ratio is calculated when the engine 5 is not in the frictional connection and the speed behind the motor gearbox is below the corresponding pedal speed.

To determine whether the motor is in a frictional connection, the measured motor current and thus the applied torque is used. When the engine is running after or at a standstill 5 the motor current drops accordingly. The control unit 16 detects this drop in the motor current and deactivates the manipulation detection. Once the control unit 16 detects that the engine 5 then goes back into the frictional connection, the motor current increases accordingly and the manipulation detection is started again.

3 shows the process of activating and deactivating the manipulation detection. After starting the engine 5 in step 50 is the manipulation detection in one step 51 initially switched off. From a specified current intensity I_min, such as 8 amperes phase current, the frictional connection is assumed.

In addition to the motor current, the decision step 52 it is also evaluated whether the engine speed is above a minimum limit value U_min, such as 1000 RPM, in order to intercept the errors caused by the speed estimator and other inaccuracies. If the manipulation detection is deactivated, the in 2 The process shown continues cyclically with checking of the translation ratio, but the error counter is neither incremented nor decremented.

If the condition of the decision step 52 is not met is done in one step 54 the activation duration of the manipulation detection is set to zero and the process goes to step 51 in which the manipulation detection is switched off.

If the condition of the decision step 52 is fulfilled, is done in one step 53 the activation time of the manipulation detection increased. In a further decision step 55 it is determined whether the switch-on time is longer than one second. If not, the procedure goes back to step 51 and the manipulation detection remains switched off. It stays in step 53 previously increased value of Keep on duration. The switch-on time or, optionally, the duration of the frictional connection is increased by the cycle time in each cycle and can therefore exceed the mentioned one second after a few cycles.

If the switch-on time of one second is exceeded, in one step 56 recognition of a wheel rotation angle, such as a complete wheel rotation, is started. For this purpose, in decision step 57 checks whether the corresponding wheel rotation angle has already been measured by the sensors. For example, this can be achieved by counting the signals from a spoke sensor up to a predetermined threshold value. The detection of the wheel rotation angle in the steps 56 to 57 is continued until a threshold value is exceeded and, for example, a complete wheel revolution is determined. In summary, it waits for the next specified gear ratio. This is calculated as soon as the wheel has completed the current revolution.

If on the other hand in the decision step 57 it was determined that a complete wheel revolution has been carried out, becomes a step 58 an operating status is set to "running", ie the manipulation detection is activated.

In a further decision step 59 becomes the test of decision step 52 executed. When the motor current is no longer greater than the threshold value 8th Amps or the engine speed is no longer greater than the threshold value 1000 is the process goes to step 51 back and the manipulation detection is switched off. Otherwise, the process goes to step 58 back, the program remains in the "running" state and the manipulation detection remains active as long as the current> 8A and the speed> 1000 RPM.

wobei „v_max“ eine Maximalgeschwindigkeit in km/h bedeutet, und „U_Rad“ eine Anzahl von Radumdrehungen des abgetriebenen Rades ist. Weiterhin bedeuten „RPM_Mot“ eine Drehzahl einer Ausgangswelle des Motors 5, „Radumfang“ einen Umfang des Hinterrads in Metern, und „Ratio“ das weiter oben gemäß Formel (3) definierte Übersetzungsverhältnis.As long as a valid transmission ratio is recognized in the engine 5 the currently maximum permitted speed is calculated with the set speed limit. This maximum permitted speed is used as a software-independent second speed regulation. The following formula shows the calculation of the engine speed for a given maximum speed, the wheel circumference and the gear ratio: $$\mathrm{R.}P{\mathrm{M.}}_{\mathrm{M.}Ot}\left[\frac{U}{min}\right]=\frac{\mathrm{R.}atiO\left[\frac{\mathrm{D.}eG}{U_{\mathrm{R.}ad}}\right]}{\mathrm{R.}adumfanG\left[\frac{m}{U_{\mathrm{R.}ad}}\right]\mathrm{\ast }360\left[\frac{\mathrm{D.}eG}{U_{\mathrm{M.}Ot}}\right]}\mathrm{\ast }{V}_{\mathrm{M.}ax}\left[\frac{km}{H}\right]\mathrm{\ast }\frac{\left[\frac{m}{s}\right]}{3.6\left[\frac{km}{H}\right]}\mathrm{\ast }60\left[\frac{s}{min}\right],$$

where "v_max" means a maximum speed in km / h, and "U_Rad" is a number of wheel revolutions of the driven wheel. Furthermore, "RPM_Mot" means a speed of an output shaft of the motor 5 , "Wheel circumference" is the circumference of the rear wheel in meters, and "Ratio" is the transmission ratio defined above using formula (3).

In addition to the first limiting mechanism described above, a second limiting mechanism is provided which as a rule only intervenes when the first limiting mechanism fails. With the first curtailment mechanism, the support is only fully set just above the parameterized threshold, the curtailment is relatively soft. A regular or first regulating mechanism of the bicycle gently removes the assistance using the measured wheel speed in a range around the maximum speed. In contrast, the second down-regulation described in the description can be hard and take away the support immediately as soon as a fixed speed limit is reached.

With the second curtailment mechanism, the support is set just below the threshold and the curtailment is much harder. Therefore, the speed threshold for the second mechanism is set higher than for the first, for example by approx. 3 km / h. This ensures that both curtailment mechanisms are fully curtailed at approximately the same speed and that at the same time mainly the first mechanism takes effect.

For example, the first limiting mechanism can regulate from 25 km / h up to a maximum speed and the second regulating mechanism from 28 km / h up to the maximum speed, with the limitation being able to regulate, for example, piecewise linearly from full motor support to no motor support.

The independent curtailment is based on the fact that the gear ratio is correct. In the event of a gear change or otherwise invalid gear ratios, a wrong predetermined speed limit cause the engine 5 cannot enter the frictional connection and no valid transmission ratio is recognized even without manipulation. In this case, the speed limit is temporarily deactivated until the frictional connection and a valid transmission ratio are recognized.

The above 2 shows conditions when the current transmission ratio is valid and the maximum speed is specified. In the event of a manipulation, the error counter in the frictional connection continues to count even if the speed limit is deactivated, and if a limit value “N_ErrorThreshold” is exceeded, the motor speed is limited to a specified safety value according to a second limiting mechanism. The safety value is selected in such a way that a specified speed of 25 km / h, especially with the greatest possible transmission ratio, is not exceeded.

As long as no special value is defined, the default safety value is 1500 RPM. A frictional connection exists when the motor applies power to the rear wheel and thus does not rotate freely. The manipulation detection is only active in the frictional connection, because otherwise there would be no direct connection between the engine speed and the rear wheel speed.

The control unit evaluates whether the engine 5 has started, has been in the frictional connection for over a second, and whether the error counter has subsequently increased to the set limit value of the error counter. In particular, the response time of the manipulation detection in the event of a permanently invalid transmission ratio can be calculated using the following formula: $$T=T_{\mathrm{A.}nlauf}+1s+N_{\mathrm{E.}rrOrTHresHOld}*Zykluszeit.$$

With a limit value of 1000 and a cycle time of 32ms, the response time is 33 seconds if the start-up time is neglected.

• - SE_WHEEL_ERROR_THRESH: Der Fehlergrenzwert N_ErrorThreshold
• - SE_WHEEL_SSC_PARAM_1: Die maximal erlaubte Abweichung ΔRatio vom nächsten gültigen Übersetzungsverhältnis damit das aktuelle Übersetzungsverhältnis gültig ist in (Deg_Mot)/U_Rad
• - SE_WHEEL_SSC_PARAM_2: Der Index der konfigurierten gültigen Übersetzungsverhältnisse (Kettenblatt und Kassette)

The manipulation detection is configured via 3 parameters:

• - SE_WHEEL_ERROR_THRESH: The error limit value N_ErrorThreshold
• - SE_WHEEL_SSC_PARAM_1: The maximum permitted deviation ΔRatio from the next valid transmission ratio so that the current transmission ratio is valid in (Deg_Mot) / U_Rad
• - SE_WHEEL_SSC_PARAM_2: The index of the configured valid gear ratios (chainring and cassette)

Here, SE_WHEEL_SSC_PARAM_2 is a list-like data structure or a pointer to it, and SE_WHEEL_ERROR_THRESH and SE_WHEEL_SC_PARAM_1 are positive values. The parameter SE_WHEEL_SC_PARAM_1 corresponds to the limit value in the decision steps 37 and 39 the 2 is evaluated.

The manipulation detection is based on checking the current transmission ratio with a valid list SE_WHEEL_SSC_PARAM_2 derived from the chainring and cassette.

The sprockets and chainrings of the derailleur are preferably dimensioned in such a way that there are no simple relationships such as doubling between the sprockets, so that simple manipulations such as halving or thirding the number of pulses can be more easily excluded.

For example, a cassette can be dimensioned in such a way that block-wise duplicated pinion numbers, such as 12-14-18-20-24-28-36-40-48, are avoided. This can prevent the vehicle from being able to continue to be driven with valid gear ratios when the pulses from the speed sensor are halved in a sub-range of the gears, although the maximum speed is exceeded.

By limiting the engine speed, the control unit 16 When switching to the larger pinion, only allow a higher engine speed as soon as the change in the gear ratio is recognized. Before that happens, the control unit moves 16 the engine before driving at the derating limit up to the speed limit and cannot reach the frictional connection. This can temporarily decrease the support for the user. Only as soon as a change in the gear ratio is recognized, the engine speed limit can be adjusted and the user receives full support again.

4th shows the procedure for tampering detection of 2 in more details and the transition to limp home mode.

In one step 65 a partial motor shaft rotation angle is calculated and in one step 66 a motor shaft rotation angle is determined by adding up the motor shaft rotation partial angles. In one step 67 it is determined whether a specified wheel rotation angle or a specified number of wheel revolutions has been reached. If so, it is done in one step 68 an actual gear ratio is determined from the determined motor shaft rotation angle and the wheel rotation angle. Otherwise, step 66 the specific motor shaft rotation angle is further increased by adding motor shaft rotation partial angles.

In one step 69 specified gear ratios are fetched from a firmware memory and in one step 70 the target gear ratio is determined from the list of target gear ratios that is closest to the previously determined actual gear ratio.

In one step 71 the previously determined deviation from the selected target transmission ratio, ie the smallest distance, is compared with a predetermined difference value. Then in one step 72 the error counter according to the in 2 procedure shown updated.

If in one step 73 it is recognized that the error counter has been counted up so far that it exceeds a threshold value N_ErrorThreshold, in one step 74 the electric bike is switched to emergency operation.

If manipulation of the electric bike is detected, the drive usually remains in emergency mode, because the error counter is only decremented again when a valid gear ratio is detected. In particular, the motor control can be set in such a way that it is only possible to switch back to regular operation after a restart. For this purpose, the error counter can be reset to zero after the electric motor has been switched off or after it has been recognized that a journey has ended, so that the bike is immediately operational again when restarted with a valid gear ratio and functional wheel speed sensor.

In a departure from the description given above, the wheel angle and the motor rotation angle can also be detected after a predetermined time interval and the actual transmission ratio can be calculated from the quotient of the two angles. This is possible in particular if a wheel speed sensor is used which detects the wheel angle at shorter intervals and does not only deliver a signal after one wheel rotation.

5 shows a software-controlled second speed regulation, the an engine speed of the engine 5 limited on the basis of a previously determined actual gear ratio.

In one step 80 an actual transmission ratio is determined from a previously determined engine rotation angle and a previously determined wheel rotation angle. This determination can in particular according to steps 65 , 66 , 67 the previous one 4th respectively. Alternatively, an actual transmission ratio can also be determined as the ratio of the respective rotational speeds or rotational speeds. In particular, determining an angle of rotation in a predetermined time period corresponds to determining an average rotational speed in the predetermined time period.

In one step 81 it is determined whether the actual transmission ratio is a valid transmission ratio, for which the steps in particular 65 - 73 the previous one 4th can be used to determine a distance to predetermined gear ratios for this purpose. If in the step 81 it is determined that the actual gear ratio is not valid in one step 85 the error counter increases. Then in step 80 the actual transmission ratio is determined again.

In one step 82 the actual transmission ratio is used to determine a maximum engine speed from this and from stored values of a maximum speed v_max and a wheel circumference. In one decision step 83 it is determined whether the maximum engine speed is exceeded. If not, step in 80 the actual transmission ratio is determined again. Otherwise, the motor support is done in one step 84 taken away.

An update of the error counter is described in more detail in 2 shown. In the 5 The engine speed limitation shown on the basis of an actual gear ratio can in a simple embodiment also take place without updating an error counter.

Deviating from the description above, the motor assistance can also be gradually reduced over a specified speed range until the maximum motor speed is reached. In this case, too, this second curtailment takes place “harder” than with the first curtailment, ie over a smaller speed range.

Furthermore, the maximum speed and the wheel circumference can also be stored as part of a proportionality factor with which the actual transmission ratio is multiplied in order to obtain the maximum engine speed.

In the following, the functioning of a motor control according to the present description is described in more detail and with reference to specific applications.

A driver switches the electric bike 1 one and start a bike ride. At the beginning no motor support is selected and the driver accelerates the wheel completely himself. At this point in time there is no connection between the motor speed and the speed of the rear wheel, so no valid gear ratio can be determined. Due to the frictional connection detection, the error counter is not incremented.

Before an ascent, the driver changes the driving mode and the motor begins to provide assistance. The phase current increases and the motor starts rotating. The traction detection detects the starting current as a high phase current and the exceeding of the minimum speed of 1000 RPM. This motor speed depends on the reduction ratio of the motor gearbox and is selected so that it corresponds to a low speed at the output or on the chainring, which is far below a speed limit, for example a speed at the output of 30 RPM.

Since the phase current levels off after a short time, for example around 15 A, which in a special embodiment can correspond to more than 30 Nm at the output, and the motor speed does not drop below 1000 RPM, the traction test determines after one second that a traction is present.

After the current wheel revolution has been completed, there is a newly calculated transmission ratio between the engine speed and the rear wheel speed. The gear ratio for a chainring with 48 teeth and a pinion with 13 teeth at a certain gear ratio of the motor gearbox is 10.0194 motor shaft revolutions per wheel revolution, which can be stored, for example, as 3607 degrees of the motor per wheel revolution. This gear ratio is stored as valid in the configuration of the bicycle and the error counter is thus decremented. Since the error counter is already 0 in this case, it remains the same and is not decremented.

On the ascent, the rider changes the gear of the bike and the engine speed changes accordingly during one wheel revolution. The transmission ratio thus calculated at the end of the wheel revolution lies between the valid values and is therefore recognized as invalid. The error counter is now incremented in each cyclical test run and reaches an error counter value of 17 by the next complete wheel revolution.

After the next complete wheel revolution, the change to a pinion with 15 teeth results in a new value for the transmission ratio, which corresponds to 11.561 motor shaft revolutions or 4162 degrees of the motor per wheel revolution for the above-mentioned reduction of the motor gearbox. This value is recognized as a valid value and the error counter is decremented again.

Once on the hill, the driver switches back to the smallest sprocket and accelerates the bike sharply on a downhill gradient. Until the maximum speed is reached, the motor assistance is continuously reduced by the first limiting mechanism, until the motor is finally deactivated completely and the driver drives downhill above the maximum speed without assistance. By reducing the motor support until the motor only runs in idle, the phase current is also reduced. As a result, the frictional connection that is no longer present is recognized and the error counter is no longer counted by deactivating the manipulation recognition.

The driver is back on the plane, the gear ratio is valid and the driver continues to drive with engine assistance. With the help of the valid gear ratio of 10.0194 motor shaft revolutions per wheel revolution, a maximum motor speed of 1831 RPM is calculated according to the maximum speed, whereby this maximum speed results in the present case for a wheel circumference of 2.28 m and a maximum speed of 25 km / h.

Due to a software error, the first limiting mechanism fails and, without the second limiting mechanism, would allow motor support even above the maximum speed. The rider accelerates the bike and the motor assistance increases quickly to 1831 RPM and cannot exceed this due to the maximum speed specified. The driver feels this limit when a corresponding speed of 25 km / h is reached through a relatively abrupt reduction in engine support. The driver can now continue to drive at this speed.

Switching to a larger pinion changes the gear ratio, whereby the motor continues to rotate at a maximum of 1831 RPM. The driver is now already increasing the speed to maintain the current speed. This leads to a noticeable drop in support for the driver until the current gear ratio is recognized as invalid, since the engine is now lagging behind and there is no direct relationship to the wheel speed. As soon as the gear ratio is recognized as invalid, the speed limit is lifted and the motor accelerates back into the frictional connection, provides support and also accelerates the bike.

For a short time, the second limiting mechanism can now accelerate beyond the maximum speed if the first limiting mechanism continues to fail. As soon as the new gear ratio is recognized as valid, the speed limit is set again accordingly and the maximum speed is maintained again. After the rear wheel rotates at around 3 revolutions per second at 25 km / h, a valid gear ratio is available within one or very few seconds and the speed is properly limited again.

For the next trip, the driver manipulates the speed signal by halving the pulses from the speed sensor. So only half the speed is measured and accordingly the first limiting mechanism, which only uses the measured speed, allows the maximum speed to be exceeded by twice as much. The driver now begins his journey, accelerates the bike and the motor exceeds the limit values for traction detection.

The calculated transmission ratio for a chainring with 48 teeth and a pinion with 13 teeth is now 20.038 motor shaft revolutions per wheel revolution, which as an internally stored value can correspond to 7214 degrees of the motor per wheel revolution. The value is not configured as a valid transmission ratio and is therefore recognized as invalid. The error counter is incremented cyclically in the event of a frictional connection. Since no valid gear ratio was recognized, the second speed limit mechanism does not set the engine speed limit and the driver can initially exceed the maximum speed.

Due to the transmission ratio, which remains invalid, the error counter rises within a short period of time above the error limit value of, for example, 1000 and manipulation of the bicycle is detected. The second cut-off mechanism goes into emergency mode and limits the engine speed to a value with which the maximum speed or a lower speed cannot be exceeded with any transmission ratio.

The driver then removes his manipulation of the speed sensor and drives on. With the transmission ratio now valid, the error counter is decremented again in the frictional connection. If the error limit is undershot, the emergency operation of the second curtailment mechanism is deactivated again and the normal curtailment with the first curtailment mechanism via speed signal with torque reduction and the second curtailment mechanism via gear ratio with speed limitation is active again.

List of reference symbols

1

Electric bike

2

Wheel speed sensor

3

Engine speed sensor

4th

Motor output train

5

electric drive motor

6th

Output gear

7th

Handlebars

8th

Rear wheel

9

Front wheel

10

frame

11

saddle

12

Output shaft

13

Chain

14th

battery

15th

Cranks

16

Control unit

17th

Derailleur

18th

Bowden cable

19th

Sprocket set

20th

Rear hub

21st

Derailleur

22nd

Crank drive

23

Control cable

24

Manual transmission

25th

Control cable

26th

User control unit

27

Control cable

28

electric wire

29

electric wire

30th

Pedal wave

35

Decision step

36

Process step

37

Decision step

38

Process step

39

Decision step

40

Process step

41

Process step

42

Process step

43

Process step

44

Decision step

45

Process step

46

Decision step

47

Process step

50

begin

51

Process step

52

Decision step

53

Process step

54

Process step

55

Decision step

56

Process step

57

Decision step

58

Process step

59

Decision step

65

Process step

66

Process step

67

Decision step

68

Process step

69

Process step

70

Process step

73

Process step

74

Process step

80

Process step

81

Decision step

82

Process step

83

Decision step

84

Process step

85

Process step

71

Process step

72

Process step

Claims (20)

Device for controlling an electric bicycle (1) driven by an electric motor (5), comprising: - A motor speed detection device which is designed to detect a motor rotation speed of the electric motor (5); - A wheel rotation speed detection device which is designed to detect a wheel rotation speed of a wheel (8, 9) of the electric bicycle (1) driven by the motor (5); - A control unit (16) which is designed to form an actual transmission ratio from the engine speed and the wheel speed; to compare the actual gear ratio with a predetermined target gear ratio; if the actual gear ratio deviates from the predetermined target gear ratio: to increase an error counter; and if the error counter exceeds a threshold value: to decrease an electric motor output of the electric motor (5). Device according to Claim 1 , wherein the control unit (16) is further designed to reduce the error counter if the actual gear ratio does not deviate from the predetermined target gear ratio. Device according to Claim 1 or Claim 2 , wherein the control unit is further designed to call up a list of a plurality of target gear ratios, and select the target gear ratio from the list of target gear ratios. Device according to Claim 3 , wherein the control unit is further designed to determine a smallest deviation of the actual gear ratio from the target gear ratios in the list, to select the target gear ratio at which the smallest deviation results from the list of target gear ratios. Device according to one of the Claims 1 to 4th , wherein the control unit (16) is further designed to detect the engine rotational speed so that the detection of the engine rotational speed includes a detection of an engine rotation angle, to detect the wheel rotation speed so that the detection of the wheel rotation speed includes a detection of a wheel rotation angle, and the actual To form gear ratio so that the formation of the actual gear ratio comprises a formation of the actual gear ratio from the engine rotation angle and the wheel rotation angle. Device according to Claim 5 , wherein the control unit (16) is further designed to detect the engine rotation angle such that the detection of the engine rotation angle comprises a detection of engine rotating partial angles and adding up the engine rotating partial angles. Device according to one of the preceding claims, further comprising: a spoke magnet and a Hall sensor attached to a frame of the electric bicycle (1), wherein the control unit (16) is further designed to detect the wheel rotational speed on the basis of an output of the Hall sensor. Device according to one of the preceding claims, wherein the control unit (16) is further designed to form the actual gear ratio so that the formation of the actual gear ratio is a formation of the actual gear ratio based on a current engine speed, a current wheel speed, a includes prior engine speed and prior wheel speed. Device according to Claim 8 , wherein the control unit (16) is further designed to form the actual gear ratio such that the formation of the actual gear ratio includes filtering the current engine speed, the current wheel speed, the previous engine speed and / or the previous wheel speed. Device according to one of the preceding claims, further comprising: a traction detection device, wherein the control unit (16) is further designed to due to an output of the traction detection device to detect whether there is a frictional connection of the electric motor (5); and if there is no frictional connection according to the previous recording: suspend increasing the error counter. Device for controlling an electric bicycle (1) driven by an electric motor (5), comprising: - a motor speed detection device which is adapted to detect a motor rotation speed of the electric motor (5); - A wheel rotation speed detection device which is designed to detect a wheel rotation speed of a wheel (8, 9) of the electric bicycle (1) driven by the motor (5); - A control unit (16) which is designed to form an actual transmission ratio from the engine speed and the wheel speed; to determine a maximum engine speed as a function of the actual gear ratio; compare the detected engine rotational speed with the predetermined maximum engine rotational speed; and when the detected engine rotation speed exceeds the maximum engine rotation speed: decrease an electric motor output of the electric motor (5). Device according to Claim 11 , wherein the control unit (16) is further designed to to detect a failure of a first governor mechanism that limits an engine rotational speed, and to reduce the electric motor output so that the decrease in the electric motor output occurs at a higher motor rotational speed and / or over a smaller motor rotational speed range than the limiting of the motor rotational speed. Device for controlling an electric bicycle (1) driven by an electric motor (5), comprising: - a control unit which is designed to regulate the electric motor (5) by reducing the electric motor power, - A frictional connection detection device which is designed to detect whether there is a frictional connection of the electric motor (5); wherein the control unit is further designed to receive signals from the traction detection device, to determine whether there is a traction of the motor (5) based on the detected signals and, if there is no traction, to suspend the control. Device according to Claim 13 , wherein the control unit is further designed, if the regulation is suspended, to determine a force-fit characteristic value on the basis of an output of the force-fit detection device and, if a predetermined force-fit characteristic value threshold is exceeded, to regulate the electric motor (5) begin. Device according to Claim 14 wherein the output of the traction detection device comprises a phase current and / or a speed of the electric motor (5), and wherein the traction characteristic value threshold comprises a minimum phase current and / or a minimum speed of the electric motor (5). Electric bicycle (1), comprising: - an electric motor (5), - at least two wheels (8,9), wherein the motor (5) is designed to drive at least one wheel (8,9), and - a device according to one the Claims 1 to 15th . Method for regulating an electric bicycle (1) driven by an electric motor (5), comprising the steps: - Detecting a motor rotation speed of the electric motor (5); - Detecting a wheel speed of rotation of a wheel of the electric bicycle (1) driven by the motor; - Formation of an actual gear ratio from the engine speed and the wheel speed; - Comparing the actual gear ratio with a predetermined target gear ratio; if the actual gear ratio deviates from the predetermined target gear ratio: increasing an error counter; and if the error counter exceeds a threshold value: Decreasing an electric motor output of the electric motor (5). Procedure according to Claim 17 which further comprises: if the actual gear ratio does not deviate from the predetermined target gear ratio: reducing the error counter. A method for controlling an electric bicycle (1) driven by an electric motor, comprising the steps of: - detecting a motor rotational speed of the electric motor (5); - Detecting a wheel speed of rotation of a wheel of the electric bicycle (1) driven by the motor; - Formation of an actual gear ratio from the engine speed and the wheel speed; - Determining a maximum engine speed on the basis of the actual gear ratio; - comparing the detected engine speed with the previously determined maximum engine speed; and when the detected engine rotation speed exceeds the maximum engine rotation speed: decreasing an electric motor output of the electric motor (5). A method for controlling an electric bicycle (1) driven by an electric motor, comprising the steps of: - regulating the electric motor (5) by reducing the electric motor power, - Detecting whether there is a frictional connection of the electric motor (5); and if there is no frictional connection according to the previous recording: Suspending the rules.

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