Method for controlling a drive unit of a vehicle powered by muscle and / or motor power, in particular a Pedelec, S-Pedelec or Ebike

Abstract

Method for controlling a drive unit of a vehicle powered by muscle and / or motor power, in particular a Pedelec, S-Pedelec or Ebike, comprising the steps: -Detecting an activation of a push mode, - Controlling the drive unit in the push mode depending on a speed of a front wheel of the vehicle.

Description

Disclosure of the InventionThe invention relates to a method for controlling a drive unit, to a drive unit for carrying out the method according to the invention, and to a vehicle having a drive unit according to the invention.Prior ArtEP 3 251 936 B1 discloses a control method for an electric motor for regulating a sliding aid of a vehicle as a function of a detected angle of inclination of the vehicle.DE 10 2016 213 691 A1 describes a control method which adjusts a control of the motor by means of data from a surroundings sensor system.From DE 198 02 937 A1, a bicycle with an auxiliary drive is known, in which a user can manually activate a sliding support in front of a staircase, so that the bicycle can be pushed up the staircase more easily.There is a need for a further improvement in the sliding aid in specific driving situations.Disclosure of the InventionThe method according to the invention for controlling a drive unit of a vehicle operated with muscle and / or engine power, in particular Pedelec, S-Pedelec or Ebike, having the features of claim 1, has for this purpose a detection of an activation of a sliding mode. After the activation has been detected, a drive unit is controlled or, in particular, regulated in the sliding mode as a function of a speed of a front wheel.The drive unit comprises in particular an electric motor which is designed to generate a first torque with respect to the sliding mode or to generate a second torque with respect to a driving mode. The first torque and the second torque are representative of a first and second torque range, respectively. In particular, the first torque is generated up to a legally prescribed maximum speed for the shift mode. The maximum speed is defined in particular in a country-specific manner. The speed of the vehicle must not exceed the maximum speed.The speed of the front wheel is in particular a linear speed. The speed of the front wheel can be determined in particular indirectly or directly. In a first embodiment, the speed of the front wheel is determined directly. For this purpose, the speed of the front wheel can be determined in particular by means of a wheel circumference and a rotational speed, wherein the rotational speed can be determined by means of a tachometer or, in the case of a hub engine, for example by means of a control unit. The speed of the front wheel can in particular also be determined by means of a speed sensor which comprises for example at least one detection element which rotates with the wheel and is detected in particular during each rotation. In a further embodiment, the speed of the front wheel can be determined in particular by means of an estimate and comprises, for example, a transmission ratio, an engine speed and a position of the vehicle. Alternatively or additionally, the speed can be determined by means of an acceleration sensor, wherein the acceleration sensor measures the change in the speed of the vehicle. Further methods for determining the speed of the front wheel are also conceivable, for example by means of geo-information, for example GPS.The drive unit comprises an electric motor and in particular a control unit which is configured to actuate or regulate the electric motor. The drive unit can preferably be designed as a central motor. Alternatively or additionally, the drive unit can be a hub motor, wherein the hub motor is installed on a hub of a front wheel and / or a hub of a rear wheel.The detection comprises in particular the detection or detection of an electrical signal or of information representing an activation of the shift mode. The electrical signal or the information can be generated in particular by a user of the vehicle or automatically by an algorithm. The detection is preferably carried out by means of the control unit of the drive unit. For example, the user can be operated by means of an input device, for example by means of a switch, button, touchscreen, pushbutton or the like. The detection of the activation of the sliding mode is detected in particular only in the case of a continuous input or continuous actuation by means of the input means. Alternatively or additionally, the activation of the sliding mode can be detected by means of information by the control unit of the drive unit.The slide mode assists the user of the vehicle in a slide operation of the vehicle. In particular, a two-stage configuration is required for activating the shift mode, wherein the activation of the shift mode forms in particular a second stage. The detection of the activation of the sliding mode by means of a detection of the input of the user takes place in particular and advantageously after a detection of a sliding. The detection of the pushing is advantageously carried out on a sensor basis, as a result of which an automatic detection of the pushing by means of the control unit results. In one configuration, an activation of the sliding mode can also be detected before the detection of the sliding.In particular, in an optional step, a detection of a sliding direction can take place, wherein the sliding direction represents in particular a direction of travel of the vehicle. The detection of the sliding direction may precede the detection of the activation of the sliding mode. In an alternative, the detection of activation of the shift mode may be performed first.The speed of the front wheel is preferably determined sensor-less, in particular without a speed sensor. Sensorless means preferably that the speed of the front wheel is determined indirectly. In particular, sensorless means that the speed of the front wheel is calculated or estimated. For example, the speed of the front wheel can be derived by means of geometric relationships of the vehicle, such as a tire size or the like. Furthermore, in particular by means of a sensor signal, which is initially not configured to represent a speed, can be used to determine the speed of the front wheel. "Sensorless" refers in particular to the determination of the speed, wherein the use of a sensor is possible in an indirect manner. An advantage of this preferred embodiment is that no further sensor system has to be installed on a frame of the vehicle in a complicated manner in order to determine the speed of the front wheel.In a preferred embodiment, the following further steps are also carried out:• determining a steering angle of the front wheel of the vehicle,• Determining the speed of the front wheel taking into account the determined steering angle.The steering angle of the front wheel of the vehicle is, in particular, an angle which results from a steering device turning. For this purpose, the vehicle has, in particular, a running direction along a longitudinal axis of the vehicle, into which the vehicle is generally driven or pushed. The steering angle results in particular from the included acute angle which is included by the longitudinal axis of the vehicle and, for example, the front wheel. The steering angle can be determined, for example, by means of a rotation sensor, an inertial sensor system or the like, wherein the rotation sensor, the inertial sensor system or the like are mounted on a steering device, a fork of the vehicle, a front part or another vehicle component which rotates together in the event of a steering angle.The speed of the front wheel is preferably determined taking into account the determined steering angle. For this purpose, the control unit can in particular calculate a relationship between the steering angle and the speed of the front wheel by means of an algorithm. For example, a steering angle of 45° or more leads in particular to a low speed of the front wheel or a stop of the drive. One advantage that results for the user of the vehicle is that in tight turns and with a large steering angle only the most necessary assistance is provided without losing control of the vehicle.The steering angle is preferably determined in a sensorless manner, in particular without a steering angle sensor. Sensorless means preferably that the steering angle is determined indirectly. In particular, sensorless means that the steering angle is calculated or estimated. Furthermore, in particular by means of a sensor signal which is initially not configured to represent a steering angle, it can be used to determine the steering angle. "Sensorless" refers in particular to the determination of the steering angle, wherein the use of a sensor is possible in an indirect manner. An advantage of this preferred embodiment is that no further sensor system, which is expensive to install on a frame of the vehicle, has to be installed in order to determine the steering angle.In particular, a sensorless determination of parameters such as, for example, the steering angle is based on the evaluation of existing environmental data which are already detected. In particular, signals or information present, which are generated by other sensor units or systems, are used in this case in order to draw conclusions about the parameters to be determined. Preferably, sensorless means that information, signals or the like are received, analyzed and processed centrally in the control unit. For this purpose, the control unit can be equipped, in particular, with an algorithm which processes the incoming signals and derives the relevant parameters determined in a sensorless manner from these. The algorithm can be based in particular on known patterns or relationships which are stored in a database. In order to improve, in particular, an accuracy of the parameters determined in a sensorless manner, the control unit can also be equipped with a learning function. This makes it possible to learn the relationships between the signals present and the parameters over time and to adapt the ascertainment of the sensorless parameters accordingly. Advantages of these embodiments are in particular a cost-effective, reliable and maintenance-free solution.The following further steps are preferably carried out:• Determining a speed of a rear wheel of the vehicle• Determining the speed of the front wheel taking into account the speed of the rear wheelThe speed of the rear wheel is in particular a linear speed. In particular, the speed of the rear wheel is determined directly, that is to say in particular by means of a speed sensor. The speed of the rear wheel is in particular a speed which is generated by means of a drive unit, wherein the speed of a rear wheel in this preferred embodiment represents a first input variable of a control loop. For example, in common drive concepts, a torque is generated by means of an electric motor, which torque is transmitted to a rear wheel, for example, by means of a chain and sprocket. The resulting speed of the vehicle, measured at the rear wheel, represents the speed of a rear wheel in this embodiment. In particular, the speed of the rear wheel is less than or equal to the speed of the front wheel. Specifically, the speed of the rear wheel substantially corresponds to the speed of the front wheel when the vehicle does not have a steering angle.The following further steps are preferably carried out:• determining a yaw rate of the vehicle,• Determining the steering angle in consideration of the yaw rate and the speed of the rear wheel.The determination of the yaw rate can be determined, for example, by means of an inertial sensor system, which is preferably arranged in the drive unit. Since the steering angle is determined in particular sensorlessally, the steering angle can be determined by means of geometric relationships which result from a right-angled triangle of instantaneous pole of front and rear wheel and radii of instantaneous pole to front and rear wheel. In this case, in particular the speed of the rear wheel, in addition to the radius to, for example, the rear wheel, is a component of the quotient of the yaw rate. The yaw rate refers in particular to the change in the direction of travel of the vehicle about the vertical axis of the vehicleThe following further steps are preferably carried out:• determining a setpoint speed of the rear wheel,• Controlling the vehicle additionally taking into account the target speed of the rear wheelThe setpoint speed of the rear wheel is, in particular, an adapted speed of the front wheel. For example, the speed of the rear wheel is formed from the speed of the front wheel by means of an algorithm. The algorithm can describe, for example, a linear or nonlinear relationship between the speed of the front wheel and the speed of the rear wheel. In particular, by determining the setpoint speed of the rear wheel, safe control of the vehicle can be made possible, since the user can push the bicycle through the curve at a reduced speed in the sliding mode.The following further step is preferably carried out, in particular after the activation of the shift mode has been detected:• Determining a target speed of the front wheel of the vehicle.• Controlling the driving unit in consideration of the target speed of the front wheelPreferably, the target speed of the front wheel limits the target speed of the rear wheel. Further preferably, the setpoint speed of the front wheel can be an input variable for ascertaining the setpoint speed of the rear wheelIn a first case, the setpoint speed of the front wheel can be, in particular, a predefined speed. This is based on a running speed of a user and is additionally limited by country-specific upper limits. For example, the target speed of the front wheel is at most 6 km / h.In a second case, the setpoint speed of the front wheel can be, in particular, a determined setpoint speed of the front wheel. Determined means that the setpoint speed of the front wheel is limited by a legal determination and may be lowered further due to external influences on the vehicle. In the second case, the setpoint speed of the front wheel is determined in particular by means of an inertial sensor system. By means of the inertial sensor system, for example, an acceleration in a longitudinal axis and / or a vertical axis of the vehicle and / or a pitch angle about a transverse axis of the vehicle is detected. On an uneven underlying surface, the detected accelerations in the direction of the vertical axis are in particular greater than on a planar underlying surface. Furthermore, the detected acceleration in a longitudinal axis can allow a conclusion to be drawn about a ground of the vehicle in the event of a regular strong fluctuation. The detected angle of inclination with respect to the transverse axis, which is arranged perpendicular to a longitudinal axis and perpendicular to the vertical axis of the vehicle, represents a current gradient or the gradient of a travel route in the direction of travel of the vehicle. Consequently, a setpoint speed of the front wheel can be indirectly determined, in particular using the inertial sensor system, in such a way that, in the case of a difficult subsurface or in the case of a detected position on a gradient, the setpoint speed of the front wheel, or an upper limit for the speed of the front wheel, is set. In other words, firstly, in particular a maximum sliding speed, or a setpoint speed of the front wheel, is limited as a function of a position of the vehicle and the underlying surface condition. The setpoint speed of the front wheel, which is dependent on the position and the underlying surface condition, is used in particular as a specification for the speed of the front wheel. The speed of the front wheel is transmitted in particular by means of an algorithm to the rear wheel, which is preferably driven and thus forms the setpoint speed of the rear wheel.The speed of the front wheel and / or the speed of the rear wheel is preferably determined by means of a speed sensor. This means in particular that the speed is determined directly. The speed may be determined, for example, by a magnet attached to a wheel and a sensor mounted on a bicycle frame. Each time the magnet passes the sensor, a signal is generated which makes the speed of the front or rear wheel detectable. In this preferred embodiment, the control and / or in particular the regulation of the drive unit is carried out particularly easily in such a way that the speed of the front wheel can be comfortably adjusted as a controlled variable by means of, for example, a speed regulation.The invention further relates to a drive unit comprising a control unit for carrying out the method according to the embodiments described above.The invention further relates to a vehicle operated with muscle and / or engine power, in particular Pedelec, S-Pedelec or Ebike, with a drive unit described above.Brief Description of the FiguresFIG. 1 shows a bicycle, in particular a vehicle operated with muscle and motor power, with a drive unit according to the invention in a schematic illustration, and FIG. 2 shows a block diagram of an embodiment of the method according to the invention, and FIG. 3 shows a bicycle, in particular a vehicle operated with muscle and motor power, in a schematic top view.Identical elements or elements with the same function are provided with the same reference numerals in the figures.FIG. 1 shows a simplified schematic view of a bicycle 100, in particular a pedelec or S-pedelec, having a drive unit 2. the bicycle 100 has a front wheel 115 and a rear wheel 116, wherein the rear wheel 116 is driven on a rear wheel hub 118 by means of a connecting element 101, in particular a chain, and by means of the drive unit 2 by a pedaling force of the cyclist on the pedals 108. For this purpose, the pedals 108 are connected to cranks 119, which in turn are connected to respectively different ends of the pedal shaft 103. The drive unit 2 is configured to assist a rider torque acting on the pedal shaft 103 and to transmit it to an output pinion 107 which is in direct engagement with the connecting element 101 for driving the bicycle 100. The frame component 102 of the vehicle 100 comprises in particular a seat tube 106, a seat strut 104, a down tube 111, an upper tube 110, a head tube 112, a chain strut 105, which are connected to one another in an insoluble manner, for example are welded to one another. Furthermore, the bicycle 100 comprises a steering unit 120. Schematically shown is an input device 10 attached to the steering unit 120, such as a user display 122 and a brake device 121. The drive unit 2 is connected via a cable (indicated) to a battery module 109 and is fed by the latter. Furthermore, FIG. 1 schematically shows an electrically actuatable gear shifting device 102. In addition to the control unit 124, the drive unit also comprises a sensor unit 123, wherein the sensor unit is designed as an inertial sensor unit 123. Furthermore, FIG. 1 shows that the bicycle 100 is located on an incline downhill, which is characterized by an inclination 91 with respect to a horizontal 90.FIG. 2 shows a block diagram of an embodiment of the method 1 according to the invention. In order to provide a user with the greatest possible safety during a pushing of the bicycle, a control of the drive unit 2 is carried out by means of the method 1 shown in FIG. 2 depending on a speed 302 of the front wheel 115. A background to this improved embodiment of a slide mode is that the front wheel 115 is turning faster because it passes through a larger radius 202a than the rear wheel 116. In a turn, the front wheel 115 must travel a distance further than the rear wheel 116 to travel the same distance. However, since both wheels 115, 116 are rotating at the same speed, the front wheel 115 must have a higher linear speed 301 to travel the greater distance in the same time. This results in the front wheel 115 turning faster than the rear wheel 116.In a first step 150, a detection of an activation of a shift mode takes place. For this purpose, an electrical signal is detected, which represents an activation of the shift mode. The electrical signal is generated by a user of the bicycle 100. The detection takes place by means of a control unit 124 of the drive unit 2. the user can make an input by means of an input device 10 which comprises a button. The detection of the activation of the sliding mode 150 is detected in particular only in the case of a continuous input or continuous actuation by means of the button.In a further step 160, a speed of the rear wheel 303 is initially determined. The speed 301 of the rear wheel 116 of the bicycle 100 is directly detected by a rotating magnet (not shown) and a sensor (not shown).In a further step 170, a steering angle 200 of the bicycle 100 is determined in a sensorless manner, in particular without a steering angle sensor. To ascertain the steering angle 200, a yaw rate 305 of a sensor signal of the sensor unit 123 is determined. The yaw rate 305 refers specifically to the change in the direction of travel of the vehicle 100 about the vertical axis (parallel to X). By determining the yaw rate 305, the control unit 124 of the bicycle 100 may output a target speed of the rear wheel 303 to ensure safe control of the bicycle 100. The steering angle 200 can be determined via radii 202 a,bfrom a momentary pole to front wheel 115 and rear wheel 116, the yaw rate 305 and with the aid of a right-angled triangle. The right-angled triangle is formed from the radii 202 a, bto the instantaneous pole (illustrated in FIG. 3 ) and a wheel base 203. For this purpose, in a step 171 which belongs to step 170, the bicycle-specific wheel base 203 is called up. The right angle is disposed in the area of the rear wheel hub 118.In a further step 180, at least one sensor signal is detected, which represents a ground. The sensor signal comprises a plurality of signals or a signal sequence and is detected by the sensor unit 123. The ground preferably describes the ground of the bicycle 100, for example a flat road, a path with obstacles, a staircase or the like. Furthermore, slipping or sliding friction can also be determined. The underlying surface is in particular not limited to road conditions to which the vehicle is exposed, but can also comprise an inclination 91 of the vehicle with respect to the horizontal 90, wherein the inclination is the rotation about the transverse axis (parallel to Z) of the vehicle 100. In particular, it can be seen from FIG. 1 that the longitudinal axis of the vehicle represents a parallel to Y, the transverse axis represents a parallel to Z and the vertical axis represents a parallel to X. In a case where an inclination 91 substantially changes, i.e., pitch motions about a parallel to Z occur, the acceleration in the Y direction exhibits fluctuations because the bicycle 100 is subjected to vibrations, the target speed of the front wheel can be output at 2 km / h, for example.In the following step 181, the one target speed 304 of the front wheel 115 is set as a target value specification for the speed of the front wheel 301. The target speed 304 of the front wheel serves as an input for determining the target speed of the rear wheel 301.In the following step 190, the control of the drive unit 2 in the slide mode is performed in consideration of the speed 302 of the front wheel 115. Because the steering angle 200 decreases the setpoint speed 301 of the rear wheel 116, the relationship arises that the setpoint speed 301 of the rear wheel 116 is less than or equal to the setpoint speed 304 of the front wheel 116. In particular, the setpoint speed 301 of the rear wheel 116 is adjusted by means of speed regulation or torque regulation.The method shown in FIG. 2 can be carried out again at arbitrarily short intervals.FIG. 3 schematically shows a bicycle 100 in a plan view. In particular, the longitudinal axis 201 is shown and a steering angle 200 is indicated by means of a dashed line. The steering angle 200 results in particular from the included acute angle which is included by the longitudinal axis 201 and, for example, the front wheel 115. The figure shows a steering angle 200 of 0° and indicates, by way of example, a steering angle 200 of greater than 0° by means of the dashed line.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 3 251 936 B1

[0002] DE 10 2016 213 691 A1

[0003] DE 198 02 937 A1

[0004]

Claims

Method (1) for controlling a drive unit (101) of a vehicle (100) operated with muscle and / or engine power, in particular Pedelec, S-Pedelec or Ebike, comprising the steps: • detecting activation of a sliding mode (150), • controlling the drive unit (190) in the sliding mode (150) as a function of a speed (302) of a front wheel (115) of the vehicle (100).Method (1) according to Claim 1, wherein the speed (302) of the front wheel (115) is determined sensor-less, in particular without a speed sensor.Method according to Claim 1 or 2, characterized bythe following further steps: • determining a steering angle (200) of the front wheel (115) of the vehicle (100), • determining the speed (302) of the front wheel (115) taking into account the determined steering angle (200).Method (1) according to Claim 3, wherein the steering angle (200) is determined in a sensorless manner, in particular without a steering angle sensor.Method according to one of Claims 3 or 4, characterized bythe following further steps: - determining a speed (303) of a rear wheel (116), - determining the speed (302) of the front wheel (115) taking into account the speed (303) of the rear wheel (116).Method according to Claim 5, characterized bythe following further steps: - determining a yaw rate (305) of the vehicle (100), - determining the steering angle (200) taking into account the yaw rate (305) and the speed (303) of the rear wheel (116) of the vehicle (100).Method according to one of the preceding claims, characterized bythe following further steps: • determining a setpoint speed (301) of the rear wheel (116), • controlling the vehicle (100) taking into account the setpoint speed (301) of the rear wheel (116).Method (1) according to one of the preceding claims, wherein the following further step is carried out, in particular after the detection (150) of the activation of the sliding mode: • determining (180) a setpoint speed (304) of the front wheel (115), wherein the setpoint speed (304) of the front wheel (115) is less than or equal to the speed (302) of a front wheel (115), • controlling the drive unit (2) taking into account the setpoint speed (304) of the front wheel (115).).Method according to Claim 8, characterized in that the setpoint speed of the rear wheel (301) is less than or equal to a setpoint speed of the front wheel (304)Method according to Claim 1, characterized in that the speed (302) of the front wheel (115) is determined by means of a speed sensor.Drive unit (2) for carrying out the method according to one of Claims 1 - 8, comprising a control unit (124) and at least one sensor unit (123), wherein the sensor unit (123) in particular does not comprise a speed sensor.Vehicle (100), operated with muscle and / or engine power, in particular Pedelec, S-Pedelec or Ebike, with a drive unit (2) according to claim 11.

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