Rollback prevention method

Abstract

The invention relates to a method for preventing a bicycle (1) from rolling back on an uphill gradient, the bicycle (1) comprising an electric drive system (3) with at least one electric motor. The method comprises the steps of receiving (S1.1) a sensor signal of a rotor position sensor (2) of the electric motor, identifying (S1.2), by means of the received sensor signal, that the bicycle (1) rolls back, and applying (S3), by means of the electric motor, a force counteracting the rollback if such rollback is identified. The invention also relates to an associated control device, an associated computer program product, and an associated bicycle.

Description

[0001] Rollback prevention procedure

[0002] Technical area

[0003] The present invention relates to a method for preventing a bicycle from rolling back on an incline, as well as an associated control device, an associated computer program product, and an associated bicycle.

[0004] State of the art

[0005] Bicycles with electric (assisted) drive, such as e-bikes and pedelecs, are generally known. Sporty e-mountain bikes are also in use. However, if a cyclist stops on an incline, the bike can roll backward if the brakes are not applied in time. This poses a safety risk, especially for inexperienced riders.

[0006] From DE 10 2004 035 089 A1 a braking system with rollback protection for electric hybrid-powered vehicles is known.

[0007] The invention is based on the object of solving the above-mentioned problems of the prior art and of providing a corresponding method, software and a control device for solving this method.

[0008] Description of the invention

[0009] According to a first aspect, the present invention relates to a method for preventing a bicycle from rolling back on an incline, wherein the bicycle comprises an electric drive system with at least one electric motor.

[0010] A bicycle is understood to mean all bicycles that have both an electric (auxiliary) drive and a muscle-powered drive, whereby the bicycle can be powered either purely by muscle power or purely electrically or in hybrid mode both by muscle power and electrically.

[0011] For this electric drive, as defined above, the bicycle is equipped with an electric drive system with at least one electric motor, also known as an electric motor. The corresponding electric motor can be designed, for example, as a mid-drive motor or as a rear-wheel drive. If the electric motor is designed as a mid-drive motor, it is installed near the bottom bracket of the bicycle and coupled to a drive wheel, such as the rear wheel, in such a way that the electric motor can apply power to the drive wheel. Rotation of the drive wheel is also transmitted to the electric motor.

[0012] The method then comprises the step of receiving a sensor signal from a rotor position sensor of the electric motor.

[0013] An electric motor generally has a rotor position sensor. The rotor position sensor can detect the movement of the electric motor's rotor as well as its direction of rotation. This is generally used, for example, to ensure that the rotor is rotating in the correct direction. Such a rotor position sensor is also called a resolver. This can detect even small movements of the rotor and thus even a low motor speed. Since the electric motor is connected to at least one drive wheel of the bicycle in such a way that a force applied to the wheel is transferred to the electric motor, rotation of the drive wheel also causes rotation of the electric motor. Thus, rolling of the bicycle can be detected using the rotor position sensor.Since even a fraction of a rotation of a bicycle wheel results in a movement that can be measured by the rotor position sensor, rolling back of the bicycle can be detected very quickly using the rotor position sensor of the electric motor.

[0014] In a further step, the received sensor signal is used to determine whether the bicycle is rolling backward. This can be based on the movement itself, for example, or on the direction of rotation of the rotor position sensor, which can be determined using the sensor signal.

[0015] The method then includes the step of applying a rollback-counteracting force by means of the electric motor when rollback is detected. Accordingly, the motor is then energized in such a way that the force causing the rollback, generally the slope force, is balanced. For this purpose, as described in more detail below, a force applied by the electric motor, and thus a torque of the electric motor, can be gradually increased until the rotor position sensor detects that no rollback is occurring. Then, in one embodiment, the force can be maintained accordingly.

[0016] In a further embodiment, in the determining step, a sensor value derived from the sensor signal can be compared with a threshold value. Such a threshold value can be predefined or can also be set by a user. This can be, for example, a speed of the electric motor detected by the rotor position sensor. Accordingly, for example, slight rolling back can still be permitted, while more severe rolling back is prevented. A time threshold value can also be provided, whereby brief rolling back is not prevented, but rolling back over a certain predefined period of time is prevented as a threshold value. Such a threshold value can either be predetermined or can also be set by a user.

[0017] In one embodiment, the counteracting force can be increased during the application step until a holding torque is reached. A holding torque is a torque that must be applied to compensate for the force causing the rolling back. This means that, in general, a holding torque is a torque that must be applied to counteract the downhill force. Once the holding torque is reached, this holding torque can be maintained by appropriately controlling the electric motor in order to permanently prevent rolling back while simultaneously not causing any forward movement.

[0018] In a further embodiment, the reception of an angle of inclination from an angle of inclination sensor can also be provided. The angle of inclination is a measure of the steepness of the gradient of a route traveled by the bicycle. To determine this angle of inclination, an angle of inclination sensor can be used, which can be either part of the bicycle or part of an external unit. An external unit can be, for example, a mobile device such as a smartphone, a smartwatch, or a fitness checker. Accordingly, the angle of inclination can be received and transmitted by the angle of inclination sensor either wired or wirelessly. This angle of inclination can then be used to determine an incline in the direction of travel. Accordingly, the angle of inclination is used to determine an incline in the direction of travel.In one embodiment, the inclination angle can be compared with a corresponding inclination angle threshold to determine the gradient or to activate the corresponding functionality only on steep gradients. Such an inclination angle threshold can either be predefined or user-determined.

[0019] The step of applying the force is then only executed if a gradient in the direction of travel has been determined. If no gradient in the direction of travel is determined or if the inclination angle is below the inclination angle threshold, at least the step of applying the force counteracting the rollback using the electric motor is not executed.

[0020] In a further embodiment, receiving a user input signal of a user input device may also be provided.

[0021] Such a user input device can be a control unit on the bicycle, but can also be another wired or wireless device, such as a smartphone. Using this user input device, the user can activate and deactivate the rollback prevention system. A user input signal is sent from the device and received here. The application step is then only performed if the user input signal indicates activation of the rollback prevention system.

[0022] Otherwise, at least the application step is not performed. Thus, the rollback prevention system can be controlled by the user by activating or deactivating it. Deactivation of the rollback prevention system is interpreted as equivalent to not activating the rollback prevention system.

[0023] In a further embodiment, provision can also be made to receive the crank torque from a crank torque sensor. Such a crank torque sensor can be mounted in the region of the pedal crank and can measure the force acting on the pedal crank via the pedals. This crank torque thus represents the force applied by the user to the pedal crank and thus also to the drive wheel. This crank torque can then also be used in the step of applying a counteracting force. Since a force applied by the user also controls or reduces the rolling back, provision can be made for the electric motor to only apply such a force that the sum of the crank torque or the force applied by the user and the force applied by the electric motor compensates for the rolling back and thus corresponds to a holding torque.

[0024] In a further embodiment, it may further be provided to repeatedly perform at least one or all steps of the method described above. Accordingly, repeated reception of the corresponding sensor values, repeated determination of the rollback, and repeated, appropriately adjusted application of a counteracting force may be provided in order to optimally prevent rolling back, even in the event of a change in the force applied by the user or a change in the gradient, and to cause neither rolling back nor a collision.

[0025] The invention further relates to a control device for a bicycle, wherein the control device is connectable to an electric drive system of the bicycle. This corresponding control device has means for implementing the method according to one of the previously described embodiments.

[0026] The present invention then also encompasses a computer program which contains instructions which, when the program is executed by a control device, cause the control device to carry out the method steps described above.

[0027] A bicycle with an electric drive system having at least one electric motor and the control device described above is also disclosed, wherein the electric drive system is connected to the control device. Brief description of the figures

[0028] Figure 1 shows a schematic representation of a bicycle in one embodiment.

[0029] Figure 2 shows a schematic representation of a process sequence for the driving situation from Figure 1 .

[0030] Detailed description of embodiments

[0031] Figure 1 shows a schematic representation of a bicycle 1 according to an exemplary embodiment. The bicycle 1 is designed as an e-bike or pedelec. The bicycle 1 has a pedal crank unit 6, of which only one pedal 4 is shown for clarity. The bicycle 1 also has an electric drive system 3, the electric motor of which can be arranged, for example, in the region of the bottom bracket. Reference numeral 2 schematically represents the position of the rotor position sensor in the electric motor of the electric drive system 3. The electric drive system further has an electrical energy storage device 5, which is connected to the electric motor. The energy storage device 5 can supply the electric motor with electrical energy (motor operation) or can be supplied with electrical energy by means of the motor (generator operation).

[0032] The bicycle's drive wheel, in this case the rear wheel, is operatively connected to both the electric motor and the pedal crank unit 6, so that the bicycle can be powered either purely by muscle power or purely by electricity, or both by muscle power and electricity. The rotation of the rear wheel can also be transmitted to the electric motor.

[0033] The bicycle further comprises a control device 20, which is connected to the electric drive system 3, more precisely to the electronics of the electric drive system 3. The control device 20 can therefore control the electric drive system 3.

[0034] In addition, the bicycle 1 shown here has several sensors connected to the control unit 20. The bicycle here has an incline angle sensor 21, which is configured to determine the current incline angle of the bicycle and thus an incline or decline on which the bicycle is located. The sensor signals of the incline angle sensor 21 are output to and received by the control unit 20, so that the control unit 20 can determine whether the bicycle is on an incline based on the incline angle sensor signals.

[0035] The bicycle 1 can further comprise additional sensors, such as a crank torque sensor 22, which is configured to determine the current crank torque of the bicycle 1. The crank torque sensor 22 can transmit this value to the control device 20.

[0036] Using the rotor position sensor 2 shown above, the rotation of the electric motor can be determined by determining the movement of the electric motor's rotor. The direction of rotation can also be detected using the rotor position sensor 2. Since the electric motor is operatively connected to the bicycle's drive wheel, rotation of the drive wheel, and thus rolling backward, can also be determined by the rotor position sensor 2. The rotor position sensor 2 then transmits this sensor signal to the control device 20. Thus, the rotor position sensor 2 can be used to determine whether the bicycle 1 is rolling backward in the opposite direction of travel due to the incline, as indicated by arrow 7.

[0037] Since the rotor position sensor 2 is used for this purpose, even small movements of the drive wheel can be detected, and rollback can thus be detected much more quickly than if a conventional torque sensor were used on one of the impellers. This is because even a partial rotation of an impeller can cause significant movements in the electric motor, allowing rapid detection by the rotor position sensor 2. Furthermore, the rotor position sensor 2 is already present in every electric motor, allowing a simple implementation of the solution shown here.

[0038] Based on the sensor-determined values, a method for automatically preventing the bicycle 1 from rolling back can be carried out, which method is shown in the process flow diagram in Figure 2.

[0039] Figure 2 shows a schematic representation of the method sequence for the driving situation from Figure 1. First, in step S1.1, a sensor signal from the rotor position sensor 2 is received. In the embodiment shown here, an angle of inclination is received from the angle of inclination sensor 21 at the same time in step S1.2. Then, in step S2.1, the signal received from the rotor position sensor 2 is used to determine whether the bicycle 1 is rolling backward. In the present embodiment, this is done by comparing it with a corresponding threshold value. At the same time, in step 2.2, a comparison of the received angle of inclination with an angle of inclination threshold value can be used to determine whether the bicycle is currently on an incline. Only if both comparisons have a positive outcome, represented here by the "+" sign in the flow chart, is a force counteracting the rolling backward applied by means of the electric motor in step S3.Here the force is increased until a holding torque is reached.

[0040] For the bicycle shown in Figure 1, the angle of incline would thus be used in step S2.2 to detect that the bicycle is on an incline. At the same time, the rotation of the bicycle's drive wheel, indicated by arrow 7, would be detected by the rotor position sensor 2. Accordingly, the electric drive unit 3, or more precisely the electric motor of the electric drive unit 3, would then apply a counterforce until rolling back is prevented.

[0041] Reference symbol Bicycle Rotor position sensor Electric drive system Pedal Energy storage Crank unit Rotation of the drive wheel Control device Inclination angle sensor Crank torque sensor Received from the rotor position sensor Received from the inclination angle sensor Determining a rollback Determining an incline Applying a counterforce

Claims

Patent claims 1 . Method for preventing a bicycle (1) from rolling back on an incline, wherein the bicycle (1) has an electric drive system (3) with at least one electric motor, comprising the steps; - receiving (S1.1) a sensor signal from a rotor position sensor (2) of the electric motor; - determining (S2.1) a rolling back of the bicycle (1) based on the received sensor signal; - applying (S3) a force counteracting the rollback by means of the electric motor when rollback is detected.

2. The method according to claim 1, wherein in the step of determining (S3) a rollback, a sensor value derived from the sensor signal is compared with a threshold value and, if the threshold value is exceeded or not reached, a rollback is determined.

3. Method according to one of the preceding claims, wherein in the step of applying (S3) the counteracting force is increased until a holding torque is reached.

4. A method according to any one of the preceding claims, further comprising: - receiving (S1.2) an inclination angle of an inclination angle sensor (21); - Determining (S2.2) a gradient in the direction of travel based on the angle of inclination, where - the application step (S3) is carried out if a gradient in the direction of travel has been determined and otherwise the application step is not carried out.

5. Method according to one of the preceding claims, further comprising: - receiving a user input signal from a user input device, wherein - the application step (S3) is carried out if the user input signal indicates activation of a rollback prevention device and otherwise the application step is not carried out.

6. Method according to one of the preceding claims, further comprising: - receiving a crank torque of a crank torque sensor (22), wherein - in the application step, such a force is applied by the electric motor that the sum of the crank torque and the force applied by the electric motor compensates for the rolling back and thus corresponds to a holding torque.

7. Method according to one of the preceding claims, wherein the above steps are carried out repeatedly.

8. Control device (20) for a bicycle, wherein the control device (20) is connectable to an electric drive system (3) of the bicycle (1), and wherein the control device (20) comprises means for carrying out the method according to one of the preceding claims.

9. A computer program product comprising instructions which, when the program is executed by a control device (20), cause the control device (20) to carry out the method according to one of claims 1 to 7.

10. Bicycle (1) comprising an electric drive system (3) with at least one electric motor and a control device (20) according to claim 8, wherein the electric drive system (3) is connected to the control device (20).

Images