Vehicle and method for controlling a propulsion unit of the vehicle

Abstract

The invention relates to a vehicle comprising: a propulsion unit which can be operated by muscle power and has an adjustable transmission ratio; a control device for adjusting (IV) the transmission ratio of the propulsion unit; and a detection device for the high-resolution detection of a change in the rotational angle for determining (III) a rotational-speed gradient of at least one wheel of the vehicle. The control device is configured to adjust (IV) the transmission ratio of the propulsion unit while taking into account a target operating state and an actual operating state. The control device is configured to adjust (IV) the transmission ratio of the propulsion unit while taking into account the rotational-speed gradient.

Description

[0001] Vehicle and method for controlling a drive unit of the vehicle

[0002] Technical area

[0003] The present invention relates to a vehicle and a method for controlling a drive unit of a vehicle.

[0004] State of the art

[0005] Vehicles with methods for automatically adjusting the gear ratio of a vehicle's drive unit, which can be operated at least partially by muscle power, are known. The gear ratio can be automatically adjusted based on a driver-selectable cadence range. This results in gear ratios that result in very high pedaling power.

[0006] Description of the invention

[0007] It is an object of the present invention to provide an improved vehicle with which driving comfort can be increased.

[0008] The object is achieved by a vehicle having the features of claim 1. Advantageous further developments are the subject of the dependent claims.

[0009] A vehicle has a drive unit operable with muscle power and having an adjustable gear ratio, a control device, and a detection device. The control device is configured to determine the gear ratio. The detection device is configured for high-resolution detection of a change in the angle of rotation in order to determine a speed gradient of at least one wheel of the vehicle. The vehicle can be formed by an e-bike or pedelec. The vehicle can be operable at least temporarily with muscle power. The drive unit can have a mechanical drive. The drive unit can have a pedal crank unit with a pedal crank. The drive unit can have an electric drive, for example an electric motor, to assist the mechanical drive. The drive unit can have a power storage device for operating the electric drive.The drive unit can have at least one of a sprocket transmission, a toothed belt transmission, a continuously variable transmission, or a power-split transmission to provide a transmission ratio. The drive unit can have a number of gears, each associated with a transmission ratio of the drive unit. A high gear can be associated with a lower transmission ratio than a low gear. The control device can be configured to shift gears. The transmission ratio can be switched from one gear to the transmission ratio of another gear via a gear step. The vehicle can have a shift-by-wire transmission. The wheel can be a drive wheel. The wheel can be a rear wheel.

[0010] The control device is configured to adjust the gear ratio of the drive unit taking into account a target operating state and an actual operating state. The control device is configured to adjust the gear ratio of the drive unit taking into account the speed gradient. The control device can be configured to adjust the gear ratio of the drive unit for selected actual operating states of the vehicle, deviating from the target operating state.

[0011] The actual operating state can include as parameters at least one of an actual gear ratio, a wheel speed of the wheel, a speed gradient of the wheel, a cadence, a pedal force, a crank torque, a vehicle acceleration, and a vehicle inclination. The cadence can be determined via a speed sensor on the pedal crank. The cadence can be determined via the wheel speed and the actual gear ratio, for example, by the control device. The pedal force can be determined by a pressure sensor. The determined pedal force can be related to a pedal force applied by the rider. The crank torque can be determined via the pedal force together with a crank radius of the pedal crank, for example, by the control device. The crank torque can be determined via a torque sensor, for example, an appropriately placed force sensor or strain gauge, on the pedal crank unit.

[0012] The detection device can be configured to detect a portion of a wheel revolution. The wheel revolution can occur, for example, during a driving movement of the vehicle. The portion of a wheel revolution can be a fraction of a complete wheel revolution. The portion of a wheel revolution can be formed by a wheel sector. The portion of a wheel revolution can be associated with an angle of less than 360°, for example, less than 180°, for example, less than 10°. The portion of a wheel revolution can be associated with an angle of 1°. The angle can, for example, be associated with a rotation angle of the wheel. A change in the rotation angle can be detected for each portion of a wheel revolution. The detection device can be configured to detect the change in the rotation angle over time. The detection device can be configured to determine a speed for each portion of a wheel revolution.The detection device may be configured to determine a wheel speed based on one or more speeds for one or more portions of a wheel revolution.

[0013] The wheel speed can be determined based on the change in angle of rotation over time. The speed gradient can be determined based on a wheel speed change over time. Multiple speed gradients can be determined for one complete wheel revolution. This also makes it possible to determine a wheel speed fluctuation for one complete wheel revolution. This can be made possible by using a detection device designed for high-resolution detection of a change in angle of rotation. With a conventional detection device based on detecting a single pulse per wheel revolution, one speed gradient can only be determined for one complete wheel revolution. The number of detectable speed gradients or their mean values ​​for one wheel revolution can be related to the number of detectable components of a wheel revolution.The detection device is configured for high-resolution detection of a change in the angle of rotation by determining multiple speed gradients or their average values ​​during one wheel rotation. The detection unit can be configured to detect the change in the angle of rotation at the wheel. The detection unit can be configured to detect the change in the angle of rotation at an element of the drive unit, for example, the pedal crank unit, taking into account the actual transmission ratio of the drive unit.

[0014] The selected actual operating state can be formed by an actual operating state for which at least one parameter for the actual operating state has a specific value. At least one of emergency braking, slippage, entering a gradient, entering a gradient with increased pedal force, off-road driving, standstill, and multiple gear changes can form the specific actual operating state.

[0015] The target operating state can be at least one of a rider cadence range and a pedaling force as a parameter. The pedaling force can include a minimum pedaling force and a maximum pedaling force. The pedaling force can be provided as a pedaling torque over a crank radius of a pedal crank as a parameter for a target operating state. The rider cadence range can include a minimum cadence and a maximum cadence.

[0016] The control device can be configured to adjust the gear ratio of the drive unit such that a measured pedal force is less than a pedaling force. The control device can be configured to adjust the gear ratio of the drive unit such that a measured cadence lies within the rider's cadence range.

[0017] The control device can have at least one input interface for inputting parameters, for example parameters for the target operating state, into the control device and an output interface for controlling the drive unit. The input interface can comprise an input device. For example, the input device can comprise at least one of a bicycle computer, a touchpad, a switch, or a lever. The deviation from the target

[0018] Operating status can be legitimized by the driver via the input interface.

[0019] The control device may include a computing unit. The computing unit may be configured to execute a method for controlling the drive unit. The control device may include a data memory. The control device may include a location determination unit, for example, a GPS module. The control device may include a data transmission unit, for example, a Bluetooth, Wi-Fi, or mobile network module.

[0020] In one embodiment, the control device for adjusting the gear ratio of the drive unit, taking into account the speed gradient, can be configured such that at least one parameter of the target operating state is adjusted. The control device can be configured such that a parameter of the target operating state is adjusted temporarily, for example for the duration of a selected actual operating state or beyond, for adjusting the gear ratio. The control device can be configured such that a rider cadence range is adjusted. The control device can be configured such that the minimum cadence is reduced. The control device can be configured such that the maximum cadence is increased. The control device can be configured such that the pedaling force is adjusted. The control device can be configured such that the minimum pedaling force is reduced.This allows the gear ratio to be adjusted to suit the situation, ensuring a high level of driving comfort. The gear ratio can be adjusted taking into account the driver's input, which is detected by the control system.

[0021] In one embodiment, the detection device can comprise a rotation angle reference element that is rotationally fixedly connected to the wheel and a rotation angle sensor for detecting the change in the rotation angle. The rotation angle sensor can be formed by a high-resolution rotation angle sensor that is configured for high-resolution detection of a change in the rotation angle. The detection device can be designed to determine a relative rotation of the wheel to a bicycle frame. The rotation angle reference element can be connected or mounted on the wheel. The rotation angle reference element can be connected or connectable to the wheel in a rotationally fixed manner indirectly, for example via a gear stage. The rotation angle reference element can be connected to an element of the drive unit, for example a sprocket, a chain, a pedal crank, or a motor shaft. The rotation angle reference element can be connected to a rim of the wheel.The angle of rotation reference element can be connected to a wheel hub. This allows a change in the wheel's angle of rotation to be determined, for example, taking into account the actual gear ratio of the drive unit.

[0022] The angle of rotation reference element can be designed as a pulse disk. The angle of rotation reference element can have detectable elements. The angle of rotation reference element can, for example, have 360 ​​detectable elements. The detectable elements can be evenly distributed in the circumferential direction. One of the detectable elements can be formed by a sequence of at least two slots. The slots can be arranged one behind the other in the circumferential direction. The guards can overlap in a radial direction. The angle of rotation reference element can extend circumferentially in a circumferential direction of the wheel. The angle of rotation reference element can extend in sections in the circumferential direction.

[0023] The angle of rotation sensor can be connected to the bicycle frame. The angle of rotation sensor can be configured such that, when the wheel rotates, a detectable element is moved past the angle of rotation sensor, so that the angle of rotation sensor can detect the detectable element. The angle of rotation sensor can be configured such that it generates a signal, for example an electrical signal, when one of the detectable elements is moved past the angle of rotation sensor. The angle of rotation sensor can be configured such that it generates an on-off signal when several detectable elements are moved past the angle of rotation sensor one after the other. At least one of the detection device and the control device can be configured to determine a wheel speed based on the signal from the angle of rotation sensor. The angle of rotation sensor can be formed by at least one of a Hall sensor, an inductive sensor, a light sensor, and an acoustic sensor.

[0024] In one embodiment, the vehicle may include an acceleration sensor for detecting an acceleration of the vehicle as a parameter of the actual operating state.

[0025] The acceleration can comprise a longitudinal acceleration in the direction of travel. The acceleration can comprise a lateral acceleration perpendicular to the longitudinal acceleration. The acceleration can comprise a normal acceleration perpendicular to the longitudinal acceleration and the lateral acceleration. The control device can be set up such that it can determine an inclination of the vehicle or an incline of a roadway in the direction of travel, taking into account an acceleration due to gravity. The control device can be set up such that it divides an inclination of the vehicle during travel into classes, for example into the classes level, slight decline, steep decline, slight incline, steep incline. The control device can be set up such that it divides the longitudinal acceleration during travel into classes, for example into the classes standstill, slight acceleration, steep acceleration, slight deceleration, steep deceleration.

[0026] The control device can be configured to determine the vehicle's inclination using torque balancing. For example, a residual torque can be determined using the crank torque, a pre-stored torque loss, which occurs, for example, due to friction losses in the drive unit and between the wheels and the road surface, and a wheel diameter. The control device can be configured to determine the inclination using the residual torque, the vehicle mass, and the wheel diameter. The control device can be configured to determine driving resistance due to headwind using the residual torque.

[0027] In one embodiment, the vehicle may include a pedal crank for driving the drive unit using muscle power. The vehicle may include a crank sensor for detecting at least one of the crank torque, the pedal force, and the cadence of the pedal crank as a parameter of the actual operating state. The pedal crank sensor may be formed by at least one of a torque sensor, a strain gauge, or a pressure sensor.

[0028] The control device can be configured to detect a change in gradient when, while the actual gear ratio remains constant, a change in the wheel speed or speed gradient is detected. For example, a downward gradient in the direction of travel, such as a negative gradient or a decline, can be detected when the wheel speed increases or a positive speed gradient is detected. For example, an upward gradient in the direction of travel, such as a positive gradient or a hill, can be detected when the wheel speed decreases or a negative speed gradient is detected.

[0029] This allows the detection device to be configured to recognize the condition of a surface. For example, a curb can be detected if a negative incline, i.e., a negative speed gradient caused, for example, by a downward movement of a front wheel, is first detected, followed by a positive incline, i.e., a positive speed gradient caused, for example, by a downward movement of the rear wheel. Uneven terrain can be detected with corresponding changes in the speed gradient, for example, with alternating positive and negative speed gradients, while maintaining a constant cadence.

[0030] In one aspect, a method for controlling a drive unit for a vehicle according to one of the preceding embodiments comprises determining at least one parameter of a target operating state. The method further comprises determining at least one parameter of an actual operating state. The method further comprises determining a speed gradient of a wheel of the vehicle. The method further comprises adjusting a gear ratio of the drive unit taking into account the speed gradient, the at least one parameter of the target operating state, and the at least one parameter of the actual operating state. The method may comprise a step in which a gear ratio or a support level of the electric drive is changed when the cadence leaves the driver cadence range.For example, a gear ratio of a lower gear can be set when the cadence is lower than a minimum cadence. For example, a gear ratio of a higher gear can be set when the cadence is higher than a maximum cadence. In this case, a gear that is set based on the driver cadence range and the wheel speed can form a theoretical gear. The method can comprise a step in which a gear ratio of the drive unit is set that deviates from the theoretical gear. The method can comprise a step in which the gear ratio is specifically optimized by taking into account at least one of an output behavior, which includes, for example, the wheel speed and the speed gradient, the inclination, and the acceleration of the vehicle.

[0031] In particular, the method may comprise a step in which the transmission ratio is specifically optimized in the special actual operating conditions of full braking, slippage, entering an incline, entering an incline with increased pedal force, off-road driving, standstill and multiple gear shifting.

[0032] In one embodiment, a parameter of the actual operating state may be formed by at least one of a wheel speed, a cadence, a pedal force, a crank torque, a vehicle acceleration, and a vehicle inclination.

[0033] The actual operating state may include as parameters at least one of an actual gear ratio, a wheel speed of the wheel, a speed gradient of the wheel, a cadence, a crank torque, a pedal force, a vehicle acceleration and an inclination of the vehicle.

[0034] In one embodiment, a parameter of the desired operating state can be formed by at least one of a rider cadence range, a pedaling torque, and a pedaling force. In one embodiment, the gear ratio can be adjusted by adapting the preset rider cadence range when the speed gradient exceeds or falls below a threshold. This allows a temporary shift lock to be provided in one step.

[0035] The method may include a step in which an actual gear ratio is maintained if a significantly negative speed gradient is detected. Such a significantly negative speed gradient may occur, for example, during emergency braking. The wheel may lock and the wheel speed may drop to zero. The time during which no change to the actual gear ratio is made can be determined by a presettable locking time. The method may include a step in which, during this locking time, the vehicle behavior is evaluated based on the acceleration and a smaller gear step than the theoretical gear is performed, or even no change to the actual gear ratio is made at all. During this locking time, the minimum cadence can be reduced, at least temporarily.

[0036] The method may include a step in which an actual gear ratio is maintained if a significantly positive speed gradient is detected. Such a significantly positive speed gradient may occur in the event of slippage, for example, when the drive wheel spins on ice. The time during which no change to the actual gear ratio is made can be determined by a presettable locking time. The method may include a step in which, during this locking time, the vehicle behavior is evaluated based on acceleration and a smaller gear step than the theoretical gear is performed, or even no change to the actual gear ratio is made at all. During this locking time, the maximum cadence can be increased, at least temporarily.

[0037] In one embodiment, the gear ratio adjustment may be performed by adapting the preset driver cadence range when a gradient is detected. The gear ratio adjustment may be performed by adapting the preset driver cadence range when a change in gradient is detected.

[0038] The method may include a step in which a gear ratio of a low gear is set when entry onto an incline, i.e., a vehicle incline, is detected. The gear ratio can be optimized depending on the speed gradient and vehicle acceleration. For example, a gear ratio can be set in which several gears are skipped in a single shift. In this case, the maximum cadence can be increased, at least temporarily.

[0039] The method may include a step in which the actual gear ratio is maintained if, based on the vehicle's acceleration and the speed gradient, driving over terrain, for example, uneven terrain, is detected. The maximum cadence may be at least temporarily increased. The minimum cadence may be at least temporarily reduced. A driver cadence range may be at least temporarily expanded. The driver cadence range may be at least temporarily adjusted based on at least one of the acceleration and a determined gradient.

[0040] In one embodiment, adjusting the gear ratio may be performed by adapting the preset driver cadence range when at least one of the crank torque and the pedal force exceeds a threshold.

[0041] This can provide a temporary switching lock.

[0042] The method may include a step in which an actual gear ratio is maintained when a driver-initiated acceleration, for example, increased pedaling force, is detected in combination with an incline or the entry into an incline. The actual gear ratio can then be maintained to generate more driver power, for example, by at least temporarily increasing the maximum cadence. Depending on the vehicle acceleration, setting the gear ratio of a higher gear can be delayed. Alternatively, setting the gear ratio of a lower gear can be performed earlier. In this case, the maximum cadence can be increased, at least temporarily.

[0043] The method can comprise a step in which a large change in an actual gear ratio across multiple gears is made when a significant acceleration initiated by the driver, for example increased pedal force, is detected. For example, a shift to a higher gear can be carried out as a multiple shift in which individual gears are skipped. This can increase the time spent in a gear. The maximum cadence can be increased, at least temporarily. This can result in a smooth driving experience. For example, for a vehicle starting off and operating with a high level of assistance, a gear ratio of sixth gear can initially be set. As the vehicle accelerates further, a gear ratio of ninth gear can be set. As the vehicle accelerates further, a gear ratio of eleventh gear can be set.As the vehicle accelerates further, the gear ratio can then be adjusted using simple shifts without a gear change.

[0044] In one embodiment, the gear ratio adjustment may be performed by adapting the preset driver cadence range when a wheel speed falls below a threshold.

[0045] The method may include a step in which the wheel speed 0 falls below the threshold value. If the threshold value is undershot, the vehicle can be detected as being stationary. Wheel speed 0 can be detected, for example, if the wheel sensor does not emit a signal for a preset period of time. A gear ratio for starting off can then be set. The gear ratio for starting off can be set taking into account a detected incline of the vehicle and the driver's cadence range. On a positive gradient, for example when starting up an uphill slope, the gear ratio of a lower gear can be set. On a negative gradient, for example when starting down a slope, the gear ratio of a higher gear can be set.The control device of the drive unit of the bicycle can be configured to carry out a method according to one of the preceding embodiments.

[0046] Short description of the characters

[0047] Figure 1 shows a flowchart of a method for controlling a drive unit for a vehicle.

[0048] Detailed description of embodiments

[0049] Figure 1 shows a flowchart of a method for controlling a drive unit for a vehicle, in this case a bicycle. The vehicle has a drive unit, a control device, a detection device, and a wheel, in this case a rear drive wheel. The drive unit can be operated temporarily using muscle power and has an electric drive, an energy storage device, in this case a battery, and a mechanical drive, in this case a pedal crank unit with a pedal crank. A gear ratio of the drive unit can be adjusted via the control device. The drive unit has a number of gears, each of which is associated with a gear ratio of the drive unit. A high gear is associated with a lower gear ratio than a low gear. During a gear shift, the control device changes the gear ratio of the drive unit. This results in a gear change.

[0050] The detection device is configured for high-resolution detection of a change in the angle of rotation. The detection device is configured for determining a speed gradient of the wheel. The control device is configured for adjusting the transmission ratio of the drive unit, taking into account a target operating state and an actual operating state. The target operating state comprises parameters specified by a driver. The actual operating state comprises parameters determined on the vehicle during operation. The control device is further configured for adjusting the transmission ratio of the drive unit, taking into account the speed gradient. The control device adapts at least one parameter of the target operating state for specific actual operating states.

[0051] Further details of the bike and the procedure are described below.

[0052] The target operating state includes a rider cadence range and pedal force as parameters. The pedal force can be provided as pedal torque via a crank radius of a pedal crank as a parameter for a target operating state. The rider cadence range includes a minimum cadence and a maximum cadence. During vehicle operation, a minimum cadence should not be undercut and a maximum cadence should not be exceeded, except in certain actual operating states. A rider can enter the parameters for the target operating state into the control unit via an input device, in this case a bicycle computer with input buttons.

[0053] The actual operating state includes as parameters an actual gear ratio, a wheel speed of the wheel, a cadence, a pedal force, a crank torque, a vehicle acceleration and an inclination of the vehicle.

[0054] The wheel speed is determined by the detection device via a rotation angle reference element that is connected to the wheel in a rotationally fixed manner, and a rotation angle sensor for detecting a change in the rotation angle. The rotation angle reference element is designed as a pulse disk that extends in a continuous and annular manner in the circumferential direction of the wheel. The rotation angle reference element has detectable elements, which in this case are formed by 359 slots that are evenly distributed in the circumferential direction and overlap in the radial direction. The rotation angle sensor is formed by a Hall sensor and is connected to a bicycle frame in a rotationally fixed manner to detect the slots on the bicycle. When one of the slots is moved past the rotation angle sensor, the rotation angle sensor generates a pulse signal. If several slots are moved past the rotation angle sensor one after the other, the speed sensor generates an on-off signal.If the angle sensor delivers an on-off signal, a wheel rotation with a corresponding wheel speed is detected. This rotation is relative to the bicycle frame. A wheel sector of a wheel circumference is formed between two consecutive slots in the circumferential direction. A speed is determined for each wheel sector. As the wheel rotates, each of the wheel sectors is moved past the angle sensor in succession. The detection device determines 360 speeds for one complete wheel rotation.

[0055] The speed gradient is determined from consecutive speeds. If consecutive speeds of two consecutive wheel sectors are the same, the detection device determines a speed gradient of 0. If a speed of one wheel sector is greater than a speed of a subsequent wheel sector, the detection device determines a speed gradient of < 0. The wheel is then negatively accelerated or decelerated relative to the bicycle frame. If a speed of one wheel sector is less than a speed of a subsequent wheel sector, the detection device determines a speed gradient of > 0. The wheel is then positively accelerated relative to the bicycle frame. A wheel speed is precisely determined for each individual wheel sector from the speed gradient. In an alternative embodiment, a wheel speed for several wheel sectors is determined based on an average value of the speeds of these wheel sectors.

[0056] In this case, the cadence is determined by the detection device using the wheel speed and the actual gear ratio of the drive unit. In an alternative embodiment, the cadence is determined using a speed sensor that detects the speed of the bicycle's pedal crank.

[0057] The crank torque is determined by the detection device using a pressure sensor on a pedal on the crank, the crank radius, and a crank position. The pressure sensor detects the rider's pedaling force as a pedal force.

[0058] The vehicle acceleration and the inclination of the vehicle are determined by the detection device via an acceleration sensor. The inclination of the vehicle relates to a direction of travel of the vehicle. The control device sets a gear ratio of the drive unit according to the following method. In a first step, the control device determines (I) the parameters of a desired operating state. In a further step, the control device determines (II) the parameters of the actual operating state. In a further step, the control device determines (III) the speed gradient of the vehicle wheel. In a further step, the control unit sets (IV) a gear ratio of the drive unit taking into account the speed gradient, the parameters of the desired operating state, and the parameters of the actual operating state.The procedure is then carried out again.

[0059] The detection device detects the specific actual operating states: full braking, slippage, entering a gradient, entering a gradient with increased pedal force, off-road driving, standstill and multiple gear changes.

[0060] The detection device detects a large negative speed gradient during emergency braking. The speed is significantly reduced for consecutive wheel sectors. The speed gradient falls below a negative threshold. Emergency braking is detected when the wheel locks and the wheel speed drops to 0. For emergency braking, the control unit changes the minimum cadence to 0 and does not change the actual gear ratio. This provides a temporary shift lock.

[0061] Slippage is detected by the detection device for a large positive speed gradient. The speed increases significantly for consecutive wheel sectors. The speed gradient exceeds a positive limit. For slippage, the control unit increases the maximum cadence and either does not change the actual gear ratio or does so with a delay. This provides a temporary shift lock.

[0062] The detection device detects the approach to an incline when the speed gradient increases slightly for successive wheel sectors and the acceleration sensor detects a corresponding change in the orientation of the gravitational acceleration with respect to the bicycle frame. When approaching an incline, in this case an uphill climb, the control unit increases the maximum cadence. Based on the actual gear ratio, a gear ratio of a lower gear is set in advance. Depending on the gradient (e.g., a gradient class) and the acceleration (e.g., a longitudinal acceleration class) of the vehicle, a multiple shift is performed. A multiple shift changes the gear ratio by the control device skipping one or more gears during the shifting process.

[0063] The detection device detects the entry of an incline with increased pedaling force if, in addition to entering an incline, the detection device detects that the rider's pedaling force exceeds a certain limit over one crank revolution. For the entry of an incline with increased pedaling force, the control unit increases the maximum cadence. Based on the actual gear ratio, a lower gear ratio is set early, or a higher gear ratio is set with a delay.

[0064] Off-road riding is detected by the detection device when the speed gradient alternates slightly increasing and decreasing for successive wheel sectors, and the acceleration sensor detects a corresponding change in the orientation of the gravitational acceleration relative to the bicycle frame. For off-road riding, the control unit increases the maximum cadence and reduces the minimum cadence. This expands the rider's cadence range and reduces the number of gear changes during off-road riding.

[0065] The detection device detects that the vehicle is stationary when the angle of rotation sensor does not generate a pulse signal for a specific period of time. When the vehicle is stationary, the control unit sets a gear ratio for a corresponding gear based on the detected incline and the rider's cadence range. The maximum cadence is increased when the vehicle is stationary. A multiple shift is detected by the detection device when the rider's pedaling force exceeds a specific limit over one pedal crank revolution. The control unit increases the maximum cadence for a multiple shift. The control device changes the gear ratio by skipping one or more gears during the shifting process.For example, starting from a gear ratio of a sixth starting gear 6, first a triple shift is set to a gear ratio of a ninth gear, then a double shift to a gear ratio of an eleventh gear and finally the gear ratio of the next higher gear is set via single shifts.

[0066] Reference symbol

[0067] I Determining at least one parameter of a target operating state

[0068] II Determining at least one parameter of an actual operating state

[0069] III Determining a speed gradient of a wheel of the vehicle

[0070] IV Setting a gear ratio of the drive unit

Claims

Patent claims 1. Vehicle with a drive unit operable by muscle power with an adjustable gear ratio, a control device for setting (IV) the gear ratio of the drive unit and a detection device for high-resolution detection of a change in the angle of rotation for determining (III) a speed gradient of at least one wheel of the vehicle, wherein the control device is configured to set (IV) the gear ratio of the drive unit taking into account a desired operating state and an actual operating state, the control device is configured to set (IV) the gear ratio of the drive unit taking into account the speed gradient.

2. Vehicle according to claim 1, characterized in that the control device for adjusting (IV) the gear ratio of the drive unit, taking into account the speed gradient, is arranged such that at least one parameter of the desired operating state is adapted.

3. Vehicle according to one of the preceding claims, characterized in that the detection device has a rotation angle reference element which is connected in a rotationally fixed manner to the wheel, and a rotation angle sensor for detecting the change in the rotation angle.

4. Vehicle according to one of the preceding claims, characterized in that the vehicle has an acceleration sensor for detecting an acceleration of the vehicle as a parameter of the actual operating state.

5. Vehicle according to one of the preceding claims, characterized in that the vehicle has a pedal crank for driving the drive unit with muscle power, the vehicle has a crank sensor for detecting at least one of a crank torque, a pedal force and a cadence of the pedal crank as a parameter of the actual operating state.

6. A method for controlling a drive unit for a vehicle according to any one of the preceding claims, wherein the method comprises - Determining (I) at least one parameter of a target operating state, - Determining (II) at least one parameter of an actual operating state, - Determining (III) a speed gradient of a wheel of the vehicle, - Setting (IV) a transmission ratio of the drive unit taking into account the speed gradient, the at least one parameter of the target operating state and the at least one parameter of the actual operating state.

7. The method according to claim 6, characterized in that a parameter of the actual operating state is formed by at least one of a wheel speed, a cadence, a pedal force, a crank torque, a vehicle acceleration and an inclination of the vehicle.

8. The method according to claim 7, characterized in that a parameter of the desired operating state is formed by at least one of a driver cadence range, a pedaling torque and a pedaling force.

9. Method according to claim 8, characterized in that the adjustment (IV) of the gear ratio is carried out by adapting the preset driver cadence range when the speed gradient exceeds or falls below a limit value.

10. Method according to claim 8 or 9, characterized in that the adjustment (IV) of the gear ratio is carried out by adapting the preset driver cadence range when an inclination is detected.

11. Method according to one of claims 8 to 10, characterized in that the adjustment (IV) of the gear ratio is carried out by adapting the preset driver cadence range when at least one of the crank torque and the pedal force exceeds a limit value.

12. Method according to one of claims 8 to 11, characterized in that the setting (IV) of the gear ratio is carried out by adapting the preset driver cadence range when a wheel speed falls below a limit value.

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