Method for controlling a push-walking assist for an electric bicycle, a device including a control unit therefor, and an electric bicycle

Abstract

[Solution] According to the invention, a method and device for controlling a pushing assist of an electric bicycle, as well as an electric bicycle with such a pushing assist are claimed. In order to implement the invention, the electric bicycle has a drive unit for generating a moving or propulsive force, a speed detector, and a gear shift device between the drive unit and the driving wheel. The method for controlling the pushing assist first detects a speed quantity representing the speed of the electric bicycle using the speed detector. The pushing assist is then controlled depending on the speed quantity and the detected or determined gear ratio between the drive unit and the driving wheel or rear wheel. The essence of the invention is that after the pushing assist is activated, a quantity representing the rotational motion of the drive unit is first detected, and the pushing assist is open-loop controlled and / or closed-loop controlled depending on the detected rotational motion or rotational momentum quantity.

Description

[Technical field]

[0001] The present invention relates to a method and device for controlling a push-assist for an electric bicycle, as well as to a correspondingly equipped electric bicycle. [Background technology]

[0002] In addition to providing mobility assistance while riding the electric bicycle, which has become widespread for several years, the on-board drive can also be operated in a push-walk mode. This allows the user to move the bicycle, possibly with luggage, or over obstacles such as stairs without exerting significant force. In order to comply with legal regulations, the push-walking assistant allows the electric bicycle to be driven at a maximum speed of 6 km / h without the rider having to pedal. During this push-walking mode, the speed of the electric bicycle is usually detected by a speed detector attached to the wheel in order to control the drive force to achieve the required maximum speed. However, there is often still no valid speed detection value (Geschwindigkeitserfassung) when the push-walking assistant starts.

[0003] From the patent DE 10 200 03 133 A1 an electric bicycle push-walking assist is known in which the gear ratio between the drive and the drive wheels is detected and used to control the electric motor, starting from the maximum possible gear ratio as the starting value for the gear shift, so that the resulting speed is below the maximum speed of the push-walking assist.

[0004] Patent Document 2 and Patent Document 3 each describe a start-assist operation mode for an electric bicycle, in which the start-assist can also be used as a push-walking assist. The start-assist is activated by operating a switch on the handlebars. This activation causes the electric motor to generate torque to drive the electric bicycle without pedaling assistance from the cyclist. As a result, the speed of the electric bicycle is barely below the legally regulated start-up or push-walking assist speed limit. In Patent Document 2, the electric bicycle additionally has a gear shift device that changes the gear ratio between the pedal shaft and the rear wheel shaft. To generate a specified speed for the start-assist, a known gear ratio of the gear shift device is changed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] European Patent No. 3251935 [Patent Document 2] German Utility Model No. 202005018126 [Patent Document 3] German Utility Model No. 202005006684 Summary of the Invention

[0006] According to the present invention, a method and a device for controlling a pushing assist of an electric bicycle, as well as an electric bicycle having such a pushing assist are claimed. In this case, for the implementation of the present invention, it is considered that the electric bicycle has a drive unit for generating a moving or propulsive force, a speed detector, and a gear shift device between the drive unit and the driving wheel. The method for controlling the pushing assist first detects a speed quantity representing the speed of the electric bicycle using the speed detector. Then, the pushing assist is controlled depending on the speed quantity and the gear ratio between the drive unit and the driving wheel or the rear wheel determined depending on the speed quantity. In this case, the essence of the present invention is that after the pushing assist is activated, a quantity representing the rotational motion of the drive unit is first detected, and the pushing assist is controlled in an open loop and / or a closed loop depending on the detected rotational motion or rotational momentum.

[0007] In this case, the advantage of the above control is that, by detecting the rotational movement of the drive unit, it is possible to know how the electric bicycle was moved before or after the activation of the pushing assist, and depending on this movement, the pushing assist can be controlled so as not to provide the user with assistance too late or even insufficiently.

[0008] In one development of the invention, it is provided that the number of rotations of the drive unit, in particular the direction of rotation, is detected as the rotational movement. For this purpose, it is assumed that there is a positive rotational movement when the drive unit is controlled to generate a longitudinal movement of the electric bicycle. If the method or the corresponding device recognizes that the rotational movement has a negative direction of rotation, it can be assumed that the electric bicycle moves backwards and the chain correspondingly rotates the drive unit in the negative direction of rotation. In this case, a predefined gear ratio is used when controlling the walking assistance, at least during the first control for starting the walking assistance. In this case, it is possible to use a maximum gear ratio between the drive unit and the driving wheel or the rear wheel as an option.

[0009] If the walking assistant has already been used before this activation, this previously used gear ratio can possibly be used for the initial control before the current gear ratio can be determined from the available sensor data. For example, it can be checked whether the previous use of the walking assistant was deactivated within a predetermined time period, for example within 10 s, or within a predetermined distance, for example within 5 m. In such a case, the last determined gear ratio can be used as the predetermined gear ratio for the control of the walking assistant, in particular for the start condition of the control of the walking assistant.

[0010] On the other hand, if it is recognized that the drive device is rotated in the forward direction after activation, the current gear ratio can be determined depending on the detected speed amount and used for controlling the walking assistance. Alternatively or additionally, the gear ratio can be detected using a separate sensor.

[0011] Furthermore, the determination or detection of the current gear ratio can take place depending on a comparison of the rotational speed of the drive device with a threshold value, in which case, for example, the use of the current gear ratio can be dependent on the rotational speed exceeding a predefined threshold value.

[0012] Further advantages emerge from the following description of exemplary embodiments or from the dependent claims. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of the device using a block circuit diagram. [Diagram 2] 2 is a flow chart of a method according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In order to take into account the effect of the motor speed generated by the driving device on the propulsive force, the gear ratio between the driving device and the driving wheel or the rear wheel can be used when controlling the pushing assist to monitor the speed of the electric bicycle. In this case, the internal transmission and the gear shift device of the electric bicycle can be the targets for detecting the gear ratio.

[0015] When the pushing assistance starts, since there is no speed value for the electric bicycle at this point, first, the motor speed of the driving device is slowly increased until the speed detector provides an amount that can determine the gear that is in. If the speed is 4-5km / h lower than the typical speed when pushing a bicycle, it may take a relatively long time to reach this speed amount, and therefore the user will receive less assistance when pushing, and the increase will occur after a short time.

[0016] The incorrect generation of the speed amount can also be detrimental when starting off with the push-assist. It can happen that while pushing the electric bicycle uphill, by going backwards and then forwards, the speed detector detects a speed amount indicating that the bicycle is moving too fast. This will lead to an incorrect and excessively large gear ratio being determined in conjunction with an increase in the motor speed. As a result, the power of the drive unit is reduced or increases more slowly, which first results in less assistance from the push-assist, or in extreme cases, no assistance at all for the push. Only when the speed detector determines the speed again can it be recognized that the set gear ratio is smaller, so that the drive force for the push-assist can be increased and the user achieves the desired speed.

[0017] In this case, the following invention is correct, wrong Gear Ratio Use In order to prevent this, methods and inventions are described which make it possible to recognise setbacks.

[0018] A possible device in which the invention can be implemented is shown diagrammatically in the block circuit diagram of FIG. 1. In this case, a control unit 100 is provided, which may optionally have a memory device 110. The control unit 100 detects the activation of the push-assistance, for example in the form of a rider or user request, via a corresponding input 120. Furthermore, the direction of rotation of the motor 130 and at least one speed quantity or only one pulse of the speed detector 140 are detected. The speed detector may for example be a magnetic sensor that outputs a pulse depending on the approach of a magnet to one of the wheels. In another embodiment, it can be provided that information regarding the direction of movement of the electric bicycle is detected by a cadence sensor. Optionally, it can be provided that means 150 are provided for detecting the gear ratio of the gear shift device or making the last determined gear ratio available to the control unit 100. Based on the detected activation and the detected direction of rotation of the motor 130, or on other information representative of the backward movement of the electric bicycle, the control unit 100 detects whether the speed quantity detected by the speed detector 140 should be used to control the push-assistance of the drive device 160. In this regard, a corresponding method is illustrated by means of a flow chart in FIG.

[0019] The method of FIG. 2 can be started, for example, after the recognition of the activation of the push-walking assistance. In this case, activation can be by the rider or user or by automatic recognition based on attendant circumstances. In a first step 200 of the method, the speed amount is detected by the speed detector 140. The speed amount is usually a magnetic sensor, which generates a lead signal, i.e. at least two pulses detected at a time interval from each other, indicating the degree of speed of the electric bicycle. Then, in a next step 210, the direction of rotation of the motor of the drive device is detected, advantageously at the same time as the detection of the speed amount in step 200. In a next step 220, it is checked whether the motor rotates forwards or backwards. Due to the connection between the rear wheel and the pedal cranks by a chain, when the bicycle moves backwards, the chain moves and thus the motor of the drive device rotates. Alternatively or additionally, a cadence sensor can be used to recognize the direction of rotation of the motor. A cadence sensor can be used in particular when the motor is equipped with a freewheel. In this case, if it is recognized in step 220 that the motor does not rotate in the negative direction, i.e. rotates in the positive direction when generating the propulsive force, the walking assistance is controlled in step 230, otherwise it is controlled in step 240. In that case, in step 230, the initial control or the activation control of the walking assistance is controlled based on the detected current speed amount and with a gear ratio based on this speed amount. However, as long as a new current speed amount is not detected, for example as long as there are not yet two lead signals, the last determined and stored gear ratio is used for the initial control of the walking assistance. Then, in a further step 250, a further open-loop or closed-loop control of the walking assistance can be performed in a known manner. In this case, as already mentioned above, an open-loop or closed-loop control can be performed depending on the current gear ratio that can be determined or detected.

[0020] However, if it is recognized in step 220 that the motor has a negative rotation direction, it can be inferred from this that the electric bicycle will first move backwards. With this recognition, in step 240, the detected current speed amount or the (bicycle) speed derived from this amount is ignored or no gear ratio is derived on the basis of this speed amount. Instead, the initial control of the walking assistance is performed on the basis of the stored or last derived gear ratio. In this case, the stored or last derived gear ratio can be optionally taken into account depending on the distance or the length of time traveled since the last deactivation of the walking assistance. For example, it is considered that no new gear change has been performed within 5 or 10 s since the last deactivation of the walking assistance, especially if no active pedaling is detected during that time. The same applies to the distance traveled, for example by detecting the wheel speed. After step 220, in step 250, the walking assistance can be operated in the usual open-loop and / or closed-loop control methods.

[0021] In step 220, it may be optionally checked whether the number of rotations in the forward direction of the motor exceeds a threshold value. If not, in step 240, the detected current speed amount, or the gear ratio derived therefrom, may be ignored for initial control. However, if it is recognized that the number of positive rotations is greater than a predetermined and / or stored threshold value, it may be recognized that the electric bicycle is moving in a forward direction and that sufficient assistance for pushing assistance is provided. In this case, the method continues with step 230. [Explanation of symbols]

[0023] 100 Control Unit 110 Storage device 120 Input 130 Motor 140 Speed ​​Detector Means of making 150 gear ratio available 160 Drive Unit 200 steps 210 Steps 220 Steps 230 Steps 240 steps 250 steps

Claims

1. A method for controlling a pushing assist for an electric bicycle, the electric bicycle comprising: a drive unit (160) for generating propulsion for the electric bicycle; A speed detector (140); a gear shift device between the drive device (160) and the drive wheels, The method comprises: - detecting a speed quantity representative of the speed of the electric bicycle using the speed detector (140); A method for controlling the walking assistance depending on the detected speed and the gear ratio between the drive device (16) and the drive wheels, After the pushing walking assist is activated, A method for detecting a rotation direction of the drive device (160) as a rotational motion, and a positive rotation direction is recognized when the drive device (160) generates a thrust, comprising: In particular, for initial control, when a negative rotation direction is detected as the rotational movement of the drive device (160), the pushing walking assistance is controlled depending on a predetermined gear ratio; When a positive rotation direction is detected as the rotational motion of the drive device (160), determining a gear ratio in dependence on said detected speed quantity; A method for controlling the pushing assistance in dependence on the determined gear ratio, in particular for initial control.

2. The method according to claim 1, characterized in that the maximum gear ratio of the gear shift device is used as the predetermined gear ratio.

3. The method comprises: The length of time since the end of the last execution of the pushing walking assistance is detected, The method according to claim 1, characterized in that, depending on the detected length of time, the gear ratio of the gear shift device determined during the last execution of the pushing assistance is used as the predetermined gear ratio.

4. The method comprises: Detecting the distance traveled since the end of the last execution of the pushing walking assistance; The method according to claim 1, characterized in that, depending on the distance traveled, the gear ratio of the gear shift device determined during the last execution of the pushing assistance is used as the predetermined gear ratio.

5. When the positive rotation direction is detected, - detecting the number of revolutions of the drive unit (160); The method according to claim 1, characterized in that, in particular for initial control, the pushing assistance is controlled depending on a gear ratio determined using the detected speed amount depending on a comparison of the rotation speed with a threshold value.

6. The method of claim 5, wherein the comparison checks whether the rotation speed exceeds the threshold value.

7. An apparatus comprising a control unit (100) for controlling a push-walking assist of an electric bicycle, the electric bicycle comprising: a drive unit (160) for generating propulsion for the electric bicycle; A speed detector (140); - has a gear shift device between the drive device (160) and the drive wheels, The control unit (100) - Apparatus for carrying out the method according to any one of claims 1 to 6.

8. An electric bicycle equipped with the device described in claim 7.

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