Method and control device of a vehicle operated at least periodically by muscle power

Abstract

The invention relates to a method for controlling a drive device (5) of a vehicle (1) operated at least periodically by muscle power, and an associated control device (6), wherein the drive device (5) is used to transmit a supporting drive force of an electric machine and a drive force of a crank device (4) operable by muscle power to a drive wheel (3), wherein a transmission ratio between the crank device (4) and the drive wheel (3) can be automatically adjusted. The method comprises the following steps: (S1) detecting a rotational speed of the crank device (4); (S2) detecting operating parameters during operation of the vehicle (1), including a torque applied to the crank device (4); (S3) evaluating a current rotational speed profile, which is determined on the basis of the detected rotational speed of the crank device (4), taking into account the detected operating parameters and an expected rotational speed profile (D) with respect to the detected operating parameters; and (S4) intervening in the control of the drive device (5) in such a way that the current rotational speed profile is brought closer to the expected rotational speed profile (D).

Description

[0001] Method and control device for a vehicle driven at least temporarily by muscle power

[0002] The present invention relates to a method for controlling a drive device of a vehicle that is at least temporarily powered by muscle power. In particular, the invention relates to a method and a control device for controlling a drive device of a vehicle that is at least temporarily powered by muscle power and configured as a pedelec or e-bike, in which a gear ratio between a crank mechanism and a drive wheel of the vehicle is automatically adjustable.

[0003] Vehicles that are at least temporarily powered by muscle power, which are designed in particular as e-bikes or pedelecs, are known. Furthermore, vehicles that are temporarily powered by muscle power are known in which a gear ratio between a crank device and a drive wheel can be automatically adjusted.

[0004] The automatic adjustment of the gear ratio between the crank mechanism and the vehicle's drive wheel offers a high level of driving comfort, but is challenging in certain operating situations.

[0005] It is the object of the present invention to provide a method for controlling a drive device of a vehicle which is at least temporarily operated by muscle power, with which the control of the drive device and the gear ratio between the crank device and the drive wheel of the vehicle leads to improved driving comfort.

[0006] The object is achieved by a method for controlling a drive device of a vehicle which is at least temporarily operated by muscle power, having the features of claim 1. Advantageous developments of the invention are described in the dependent

[0007] claims stated.

[0008] A method for controlling a drive device of a vehicle that is at least temporarily powered by muscle power is specified, wherein the drive device transmits an assist drive force of an electric machine and a drive force of a crank device operable by muscle power to a drive wheel, wherein a transmission ratio between the crank device and the drive wheel is automatically adjustable. The method comprises the following steps:

[0009] - Detecting a rotational speed of the crank device;

[0010] - Recording operating parameters during vehicle operation, including torque applied to the crank mechanism;

[0011] - evaluating a current speed profile determined on the basis of the detected speed of the crank mechanism, taking into account the detected operating parameters and a speed profile expected with regard to the detected operating parameters; and

[0012] - Intervening in the control of the drive device in such a way that the current speed profile is approximated to the expected speed profile if, during the evaluation of the current speed profile, it is determined that the current speed profile deviates from the expected speed profile by a predetermined amount.

[0013] The method is applicable to a vehicle in which a drive device is provided that can be controlled by a control device. The control device can control the assist drive force of the electric motor and the gear ratio between the crank device and the drive wheel of the vehicle.

[0014] According to one embodiment, the current speed profile can be based on the speed of the crank device detected within a predetermined period of time. In particular, the speed profile can be based on an average value of the detected speed of the crank device within the predetermined period of time. The predetermined period of time can be determined and set in advance. The predetermined period of time can be variable. The predetermined period of time can comprise a period of a few seconds, for example, 5 or 10 seconds. The predetermined period of time can also comprise a longer period of time, for example, several minutes or hours.

[0015] According to one embodiment, the expected speed profile can be based on a speed of the crank mechanism within a predetermined speed range, taking the operating parameters into account. In this context, the detected operating parameters can be used to select the expected speed profile, for example, from a plurality of speed profiles.

[0016] Alternatively, the current speed profile and the expected speed profile can be represented as specific speed values. Additionally or alternatively, the expected speed profile and the current speed profile can be based on gradients of the detected speed and the expected speed of the crank mechanism.

[0017] In one embodiment, the operating parameters detected during operation of the vehicle may include at least one of the following parameters in addition to the torque applied to the crank device:

[0018] - a vehicle speed;

[0019] - a gradient of a vehicle speed;

[0020] - a slope of a road on which the vehicle is travelling;

[0021] - a speed of the crank mechanism;

[0022] - a gradient of a rotational speed of the crank device;

[0023] - a gradient of the torque applied to the crank mechanism. Based on one or more of the aforementioned parameters, it is possible to determine which speed profile is to be expected for the current operating condition. An expected speed profile can be present if it is determined that the detected speed is plausible, taking into account the detected operating parameters. In particular, by evaluating the aforementioned parameters, it is possible to determine whether a high speed or a low speed of the crank mechanism is to be expected or plausible.

[0024] In one embodiment, the intervention in the control can be carried out by at least one of the following measures:

[0025] - Changing the assist drive power of the electric machine;

[0026] - Changing the gear ratio between the crank mechanism and the drive wheel.

[0027] Through the aforementioned measures, the operating state of the vehicle can be adjusted such that the current speed profile approximates the expected speed profile. In particular, by changing the assist drive force of the electric machine, the torque required to be applied to the crank device can be changed, resulting in a state with the expected speed profile. Furthermore, by changing the gear ratio between the crank device and the drive wheel, the speed of the crank device can be directly influenced. The aforementioned measures can be carried out individually or jointly. Furthermore, it is possible to apply one or both of the aforementioned measures sequentially, taking into account the degree of deviation between the current speed profile and the expected speed profile.

[0028] In one embodiment, the assist drive force of the electric machine can be increased if it is detected that the current speed profile has a speed of the crank device that is lower than the speed of the crank device of the expected speed profile, wherein the assist drive force of the electric machine can be reduced if it is detected that the current speed profile has a speed of the crank device that is higher than the speed of the crank device of the expected speed profile. With this measure, in an operating state in which the speed of the crank device deviates from the expected speed, the corresponding deviation is counteracted by the operation of the electric machine.With this measure, the torque applied to the crank device can be brought into line with the speed of the crank device by appropriately adjusting the assist drive force of the electric machine.

[0029] In one embodiment, the gear ratio between the crank mechanism and the drive gear can be adjusted to increase the speed of the crank mechanism when it is detected that the current speed profile has a speed of the crank mechanism that is lower than the speed of the crank mechanism of the expected speed profile, wherein the gear ratio between the crank mechanism and the drive gear is adjusted to decrease the speed of the crank mechanism when it is detected that the current speed profile has a speed of the crank mechanism that is higher than the speed of the crank mechanism of the expected speed profile. With this measure, the speed of the crank mechanism can be immediately adjusted to an expected speed that is consistent with the torque applied to the crank mechanism and the operating state of the vehicle.

[0030] In one embodiment, it may be determined that the current speed profile has a speed of the crank device that is lower than the speed of the crank device of the expected speed profile if, in addition, at least one of the following conditions is met:

[0031] - a detected inclination angle of the road on an uphill slope is greater than a threshold value, with an inclination angle on a downhill slope being defined as a positive value;

[0032] - the detected vehicle speed is less than a predetermined threshold; - a gradient of the detected vehicle speed is less than a predetermined threshold;

[0033] - the torque introduced into the crank mechanism is higher than a predetermined threshold;

[0034] - a gradient of the torque introduced into the crank device is greater than a predetermined threshold value;

[0035] - the detected speed of the crank device is lower than a minimum permissible speed.

[0036] In one embodiment, it may be determined that the current speed profile has a speed of the crank device that is higher than the speed of the crank device of the expected speed profile if, in addition, at least one of the following conditions is met:

[0037] - a detected inclination angle of the roadway on a downhill slope is less than a threshold value, where an inclination angle on a downhill slope is defined as a negative value;

[0038] - the detected vehicle speed is higher than a predetermined threshold;

[0039] - a gradient of the detected vehicle speed is greater than a predetermined threshold;

[0040] - the torque introduced into the crank mechanism is less than a predetermined threshold value;

[0041] - a gradient of the torque introduced into the crank device is less than a predetermined threshold value;

[0042] - the detected speed of the crank device is higher than the maximum permissible speed.

[0043] The conditions mentioned above can improve the reliability in determining the expected speed profile. In particular, certain operating states and other circumstances during vehicle operation require a specific expected speed profile that is directly linked to the operation and circumstances. For example, when the vehicle is operated on an incline, the user of the vehicle increases the torque applied to the crank mechanism, while the vehicle speed may decrease significantly. For this reason, the current speed profile may exhibit a speed that drops sharply when the vehicle speed decreases. Such a sharply decreased speed of the crank mechanism does not correspond to the expected speed profile for a vehicle with an automatically adjustable gear ratio between the crank mechanism and the drive wheel.Similar relationships arise with regard to the vehicle speed and the torque introduced into the crank mechanism.

[0044] The aforementioned minimum permissible speed or maximum permissible speed as well as the stated threshold values ​​can be determined empirically. Alternatively, the minimum permissible speed, the maximum permissible speed and the stated threshold values ​​can each be set to a fixed value that is typical for normal operation of a vehicle that is at least temporarily powered by muscle power. The minimum permissible speed can be set depending on the torque introduced into the crank mechanism. Furthermore, the maximum permissible speed can be set to a fixed value that is still achievable during normal operation of such a vehicle, such as a crank mechanism speed of 90 rpm. Other values ​​can be selected without restriction within a technically reasonable range.Overall, to carry out the method, a characteristic map can be provided for the above-mentioned parameters linked to the conditions, which can be read in and used by the control device for controlling the drive device.

[0045] According to a further aspect, a control device for a drive system for a vehicle that can be operated at least temporarily by muscle power is provided. The control device is equipped with an input interface for receiving signals relating to an operating state of the vehicle and an output interface for outputting signals for controlling the drive system. The control device is configured to carry out the method with one or more of the features specified above. The vehicle specified above can be configured as a pedelec or e-bike.

[0046] However, the vehicle can alternatively be designed as a multi-track vehicle with more than two wheels.

[0047] Figure 1 shows an embodiment of a vehicle designed as a pedelec to which the method is applicable;

[0048] Figure 2 is a schematic flow diagram used to explain the method according to one embodiment.

[0049] Embodiments of the method are described below with reference to the drawings. First, the structure of a vehicle 1 designed as a pedelec, to which the method is applicable, is described with reference to Figure 1. The vehicle 1 shown in Figure 1 has a front wheel 2 and a rear wheel 3. The front wheel 2 and the rear wheel 3 are mounted in the usual way on a frame of the vehicle 1. In addition to a steering device, a seat and a braking system, which are not described further below, the vehicle 1 has a crank device 4 that can be operated by the user of the vehicle 1. By rotating the crank device 4, a driving force is transmitted via a transmission means in the form of a chain or a belt to the rear wheel 3, which is thus designed as the drive wheel of the vehicle 1.Furthermore, the vehicle 1 has a drive device 5, which in the present embodiment is provided in the region of the crank device 4. The drive device 5 has an electric machine that is operated by electrical energy that can be supplied from a storage device for electrical energy, not shown, in the form of a rechargeable battery. The drive device 5 is connected to the rear wheel 3 for power transmission, so that the drive force generated by the electric machine can be transmitted to the rear wheel 3. The vehicle 1 also has a control device 6 that is provided for controlling the drive device 5. To detect a rotational speed of the crank device 4, a rotational speed sensor (not shown) is provided, which emits a signal that is suitable for determining the rotational speed of the crank device 4. The signal from the rotational speed sensor is fed to the control device 6.Furthermore, the vehicle 1 has a torque sensor as a torque detection device, which is provided for detecting the torque introduced into the crank device 4. The torque sensor emits a signal suitable for determining the torque introduced in the crank direction 4, and the signal is fed to the control device 6. In addition, the vehicle 1 in the embodiment shown in Figure 1 has a user interface 7 in the form of a display device, with which the user of the vehicle 1 can be provided with information about the vehicle 1 and via which the user can make inputs.

[0050] Furthermore, the vehicle 1 has a transmission with which a gear ratio between the crank mechanism 4 and the drive wheel 3 can be variably adjusted. For this purpose, an operating device in the form of a gear lever is provided on the vehicle 1, with which the user of the vehicle 1 can select a gear ratio. Furthermore, it is provided that the gear ratio can be automatically adjusted by the control device 6 according to the setting.

[0051] The method for controlling the drive device 6 of the vehicle 1, which is at least temporarily operated by muscle power, according to one embodiment is described below with reference to Figure 2. Figure 2 shows a schematic representation of the individual steps that are continuously carried out by the method according to the invention. The steps are executed by the control device 6 provided on the vehicle 1. For this purpose, the control device 6 has a memory device, a processor, and an input interface and an output interface for communication with various sensors and the drive device 6. As shown in Figure 2, in step S1 the rotational speed of the crank device 4 is first recorded.For this purpose, the speed sensor provided on the crank device 4 is queried. In the next step S2, operating parameters of the vehicle 1 during operation, including the torque applied to the crank device 4, are queried. The operating parameters are queried from corresponding sensors and include a vehicle speed or a gradient of a vehicle speed, an incline of a road on which the vehicle 1 is traveling, a speed or a gradient of a speed of the crank device 4 and a gradient of the torque applied to the crank device 4. The vehicle speed is determined in this case by the wheel speed sensor provided on the front wheel 2. To detect the incline of the road on which the vehicle 1 is traveling, an inclination sensor mounted on the vehicle 1 is used. The speed of the crank device 4 is queried via the corresponding speed sensor.The torque applied to the crank device 4 as well as the gradient of the torque applied to the crank device 4 are queried via the torque sensor on the crank device 4.

[0052] In a subsequent step S3, a current speed profile is evaluated. The current speed profile is determined on the basis of the detected speed of the crank device 4. For this purpose, in the present embodiment, an average value of the speed of the crank device 4 is determined continuously over a preset period of time. In addition, a gradient of the detected speed of the crank device 4 is determined. Based on the detected operating parameters, an expected speed profile D is determined in step S3. In the present embodiment, a range is determined in which the expected speed should lie, taking the operating parameters into account. For example, if a very high torque is detected introduced into the crank device 4, it is determined that the speed of the crank device should be comparatively high.This relationship arises from the consideration that, for example, on an incline or on flat ground with a headwind, a high power should be introduced via the crank device 4, which requires a comparatively high speed of the crank device 4. However, if the actual speed of the crank device 4 is comparatively low, it is determined that the current speed profile deviates from the expected speed profile D to a predetermined extent. If, for example, the vehicle 1 reaches an incline so that the speed of the vehicle 1 drops while the gear ratio between the crank device 4 and the drive wheel 3 is held constant, the speed of the crank device 4 drops significantly. If, for example, a speed of the crank device of 20 rpm results, the user of the vehicle 1 is only able to provide propulsion for the vehicle 1 to a limited extent.In order to be able to supply sufficient power to the crank mechanism 4, a crank mechanism speed of at least 70 rpm would be appropriate, for example. Thus, in step S4, as applied to this example, it is determined that the current speed profile deviates from the expected speed profile D by a predetermined amount. In step S4, an intervention in the control of the drive mechanism 5 is performed such that the current speed profile approximates the expected speed profile D.

[0053] In the present embodiment, the intervention in the control provided in step S4 is carried out in such a way that, on the one hand, the gear ratio between the crank mechanism 4 and the drive wheel 3 is changed such that the rotational speed of the crank mechanism 4 is increased. In addition, the electric machine of the drive mechanism 5 is controlled such that the assist drive force and thus the torque transmitted to the drive wheel 3 is increased.

[0054] By combining both measures, a speed of the crank device 4 is achieved which is expected by the driver and which is suitable for comfortable operation of the vehicle 1.

[0055] In further embodiments, in the event of a change in the vehicle speed, a change in the inclination of the roadway on which the vehicle 1 is traveling, changes in the rotational speed of the crank device 4 and changes in the corresponding gradients, the control of the drive device is intervened in such a way that the expected rotational speed profile D is achieved.

[0056] In an alternative embodiment, intervention in the control of the drive device 5 occurs sequentially. In this embodiment, if there is a slight deviation of the current speed profile from the expected speed profile D, the gear ratio between the crank device 4 and the drive wheel 3 is first adjusted. In the event that the current speed profile cannot yet be approximated to the expected speed profile D with this measure, additional intervention is made in the control of the electric machine in order to further approximate the current speed profile to the expected speed profile D.

[0057] The above embodiment of the method was described in application to a vehicle 1 designed as a pedelec. In alternative embodiments, the method is equally applicable to vehicles with more than two wheels, which are designed, for example, as cargo bikes or other vehicles, which are designed, in particular, as multi-track vehicles.

[0058] Reference symbol

[0059] 1 vehicle

[0060] 2 front wheel

[0061] 3 Rear wheel (drive wheel)

[0062] 4 Crank device

[0063] 5 Drive device

[0064] 6 Control device

[0065] 7 User interface

[0066] S1 Detecting the speed of the crank device

[0067] S2 Recording operating parameters

[0068] S3 Evaluate current speed profile

[0069] S4 Intervention in the control of the drive device

[0070] D Expected speed profile

Claims

Patent claims 1. A method for controlling a drive device (5) of a vehicle (1) that is at least temporarily powered by muscle power, wherein the drive device (5) transmits an auxiliary drive force of an electric machine and a drive force of a crank device (4) that can be operated by muscle power to a drive wheel (3), wherein a transmission ratio between the crank device (4) and the drive wheel (3) can be automatically adjusted, comprising the following steps: (51) detecting a rotational speed of the crank device (4); (52) detecting operating parameters during operation of the vehicle (1), including a torque applied to the crank device (4); (53) Evaluating a current speed profile, which is determined on the basis of the detected speed of the crank device (4), taking into account the detected operating parameters and a speed profile (D) expected with respect to the detected operating parameters; and (54) Intervening in the control of the drive device (5) such that the current speed profile is approximated to the expected speed profile (D) if, during the evaluation of the current speed profile, it is determined that the current speed profile deviates from the expected speed profile (D) by a predetermined amount.

2. Method according to claim 1, characterized in that the current speed profile is based on the speed of the crank device (4) detected within a predetermined period of time.

3. Method according to claim 1 or 2, characterized in that the expected speed profile (D) is based on a speed of the crank device (4) expected taking into account the operating parameters within a predetermined speed range.

4. Method according to one of the preceding claims, characterized in that the operating parameters recorded during operation of the vehicle (1) are additionally relative to the torque applied to the crank device (4), have at least one of the following parameters: - a vehicle speed; - a gradient of a vehicle speed; - a gradient of a road surface on which the vehicle (1) travels; - a rotational speed of the crank device (4); - a gradient of a rotational speed of the crank device (4); - a gradient of the torque applied to the crank device (4).

5. Method according to one of the preceding claims, characterized in that the intervention in the control is carried out by at least one of the following measures: - Changing the assist drive power of the electric machine; - Changing the gear ratio between the crank mechanism (4) and the drive wheel (3).

6. Method according to one of the preceding claims, characterized in that the assist drive force of the electric machine is increased when it is detected that the current speed profile has a speed of the crank device (4) that is lower than the speed of the crank device (4) of the expected speed profile (D), wherein the assist drive force of the electric machine is reduced when it is detected that the current speed profile has a speed of the crank device (4) that is higher than the speed of the crank device (4) of the expected speed profile (D).

7. Method according to one of the preceding claims, characterized in that the gear ratio between the crank device (4) and the drive wheel (3) is adjusted to increase the speed of the crank device (4) when it is detected that the current speed profile has a speed of the crank device (4) that is lower than the speed of the crank device (4) of the expected speed profile (D), wherein the gear ratio between the crank device (4) and the drive wheel (3) is adjusted to reduce the speed of the crank device (4) when it is detected that the current speed profile has a speed number of the crank device (4) which is higher than the speed of the crank device (4) of the expected speed profile (D).

8. The method according to claim 6 or 7, characterized in that it is determined that the current speed profile has a speed of the crank device (4) which is lower than the speed of the crank device (4) of the expected speed profile (D) if, in addition, at least one of the following conditions is met: - a detected inclination angle of the road on an incline is greater than a threshold value; - the detected vehicle speed is lower than a predetermined threshold; - a gradient of the detected vehicle speed is less than a predetermined threshold; - the torque introduced into the crank device (4) is higher than a predetermined threshold value; - a gradient of the torque introduced into the crank device (4) is greater than a predetermined threshold value; - the detected speed of the crank device (4) is lower than a minimum permissible speed.

9. Method according to claim 6 or 7, characterized in that it is determined that the current speed profile has a speed of the crank device (4) which is higher than the speed of the crank device (4) of the expected speed profile (D) if, in addition, at least one of the following conditions is met: - a detected inclination angle of the road on a downhill slope is less than a threshold value; - the detected vehicle speed is higher than a predetermined threshold; - a gradient of the detected vehicle speed is greater than a predetermined threshold; - the torque introduced into the crank device (4) is less than a predetermined threshold value; - a gradient of the torque introduced into the crank device (4) is smaller than a predetermined threshold value; - the detected speed of the crank device (4) is higher than a maximum permissible speed.

10. A control device (6) for a drive device (5) for a vehicle (1) that can be operated at least temporarily using muscle power, comprising an input interface for receiving signals relating to an operating state of the vehicle (1) and an output interface for outputting signals for controlling the drive device (5); wherein the control device (5) is configured to carry out the method according to one of the preceding claims.

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