Method for adjusting torque assist of drive unit of vehicle

Abstract

The invention relates to a method for adjusting a torque assist of a drive unit of a vehicle, in particular a single-track vehicle, for example an electric bicycle, the torque assist being based on a portion of a system model and on an enhanced portion of a pedaling torque provided by a rider with an assist coefficient, the assist coefficient is determined dependent on the pedaling torque, in particular progressively dependent, and wherein the system model is based at least on the speed and / or acceleration of the vehicle and on compensation of disturbance variables, in particular gradient, inertia and frictional resistance.

Description

Technical Field

[0001] The invention relates to a method for regulating a torque assistance of a drive unit of a vehicle, in particular a single-wheel vehicle such as an electric bicycle, an electric assisted bicycle or the like.

[0002] The invention further relates to a vehicle, in particular a single-wheel vehicle, such as an electric bicycle, an electric assisted vehicle or the like, having a drive unit, wherein the drive unit is designed to increase the pedaling torque by means of a regulated torque assistance.

[0003] Although the present invention is applicable to any vehicle, the present invention will be explained in terms of an electric bicycle. Background Art

[0004] Electric bicycles can provide torque assistance to the rider, for example to increase the rider's pedaling torque when going uphill. Here, external disturbances such as wind or slope can be compensated by torque assistance through a suitable system model (which is the basis for determining the magnitude of the torque assistance).

[0005] However, the calculation of the disturbing influences is slow, since the speed and / or acceleration required for this can only be determined with a delay. Therefore, if the rider suddenly requires an increase in torque, for example when he starts to go uphill, the torque assistance initially provides too low a torque. This impairs the rider's riding experience. Summary of the invention

[0006] In one embodiment, the invention provides a method for adjusting the torque assistance of a drive unit of a vehicle, in particular a single-wheel vehicle, such as an electric bicycle, wherein the torque assistance is based on a proportion of a system model and on a proportion of an increase in the pedaling torque provided by the rider with an assistance factor, wherein the assistance factor is determined in dependence on the pedaling torque, in particular in asymptotically dependent manner, and wherein the system model is based at least on the speed and / or acceleration of the vehicle and on a compensation of disturbance variables, in particular gradient, inertia and frictional resistance. When using this method for adjusting the torque assistance of a drive unit of a load-bearing bicycle, inertia plays a special role as a disturbance variable. Due to the partially high loads, inertia plays a special role.

[0007] In one embodiment, the present invention provides a vehicle having a drive unit, in particular a single-wheel vehicle, such as an electric bicycle, wherein the drive unit is configured to enhance a pedaling torque by means of a regulated torque assistance, wherein the torque assistance is based on a share of a system model and on an enhanced share of the pedaling torque provided by a rider with an assistance factor, wherein the assistance factor is determined in relation to the pedaling torque, and wherein the system model is based at least on a speed and / or acceleration of the vehicle and on compensation for disturbance variables, in particular gradient, inertia and frictional resistance.

[0008] The advantage of this is that the system model together with the enhancement of the pedaling torque by the assistance factor allows a fast response to changing torque requirements, while at the same time longer-term disturbances such as gradient, inertia or air resistance can be compensated by the system model. In this way, the torque assistance can be adjusted quickly and precisely. In addition, the adjustment can also be adapted to the individual needs of the rider, for example by simulating an artificial tailwind by the torque assistance.

[0009] The term "system model" is understood, in particular in the description, preferably in the claims, as a model with the aid of which the driving characteristics of the vehicle can be described. The system model describes an idealized or predeterminable driving style, for example driving on a flat surface at a speed of 20 km / h. A predeterminable, required or idealized pedaling torque is then determined from this. If the actual pedaling torque differs from the idealized pedaling torque, i.e., additional disturbance variables affect the vehicle, the residual torque can be compensated by torque assistance of the drive unit. The system model can have the following form:

[0010]

[0011] Here, M describes the previously determined mass of the vehicle, describes the acceleration of the vehicle, D describes the friction value of the vehicle, v describes the speed of the vehicle, describes the disturbance variable, such as the slope, Q describes the auxiliary factor, f h describes the pedaling torque, α describes the proportional coefficient of the disturbance parameter compensation, Describes disturbance variable compensation. The left side of the equation thus describes the forces that must be overcome by the vehicle, such as acceleration, friction, gradient, and the right side describes how the required forces are generated, such as pedal torque, torque assistance by the drive, disturbance variable compensation.

[0012] Enhancement factor Q and pedaling torque f h Related, that is, Q = Q (f h ). Therefore, when increasing the pedaling torque f h When the driving torque is Q*f h The torque assistance is thus responsive and can respond quickly to changing torque requirements, because when the rider increases the pedaling torque, the torque assistance is directly increased due to the super-proportional relationship of the amplification factor to the pedaling torque.

[0013] The pedaling torque is defined in particular as the portion of the total torque acting on the vehicle which is provided by the rider, in particular generated by the rider's pedaling.

[0014] Compensation for one or more disturbance variables, also referred to below as disturbance variable compensation, describes a method in which disturbance variables that influence the driving characteristics of a vehicle, such as the gradient, inertia or air resistance, are compensated by torque assistance. For example, if the vehicle is traveling uphill, i.e. the required total drive torque increases due to the gradient, this influence is compensated by increasing the torque assistance, which "compensates" for the disturbance variable. The rider of the vehicle thus perceives the driving characteristics as if no disturbance variable was present. The magnitude of the disturbance variable compensation, i.e. the magnitude of the torque required to compensate for all disturbance variables, can vary over time. The rate of change of the compensation of the disturbance variable is defined as the change over time of the total torque utilized to compensate for the disturbance variable, in particular the first-order derivative.

[0015] Further features, advantages and further embodiments of the invention will be described below or will be apparent from the invention.

[0016] In one embodiment of the method according to the invention, the proportion of the system model and the proportion of the enhancement of the pedaling torque provided by the rider with the assistance factor are coordinated with each other so that a high assistance factor is provided by the enhanced proportion in the case of high pedaling torques, until the proportion of the pedaling torque by the system model becomes so low that a small assistance factor or essentially no assistance factor is provided. "Essentially no assistance factor is provided" is to be understood as an assistance factor that is essentially zero. In this case, in particular in the case of low interference, it is possible to ride completely without motor assistance.

[0017] In another configuration, the assistance coefficient is determined in relation to the pedaling torque, in particular in a progressive manner, so that in a range below a threshold value of the pedaling torque, the assistance coefficient is essentially constant, in particular zero, and in a range above the threshold value, the assistance coefficient increases in a progressive manner in relation to the pedaling torque.

[0018] According to an advantageous further development of the invention, the system model is based on a previously determined mass of the vehicle and / or the rider. This improves the reliability of the system model. The previously determined mass of the vehicle can differ from the actual weight of the vehicle and the rider. This makes it possible to simulate different vehicle weights. For example, the model weight can correspond to the weight of the vehicle and the rider without a suspended load. In this way, the weight of the suspended load can be considered as a disturbance variable, which is compensated by the system model by the torque assistance. The vehicle can thus behave as if there were no suspended loads.

[0019] According to an advantageous further development of the invention, the previously determined mass of the vehicle is determined in dependence on the speed of the vehicle. This has the advantage that the driving characteristics of the vehicle can be adapted to different speeds. For example, the previously determined mass of the vehicle can be higher at low speeds, so that the vehicle can be maneuvered more easily. It is also possible to reduce the previously determined mass of the vehicle when the vehicle is stationary, in order to enable easier starting. In other words, in the above equation of the system model, M=M(v).

[0020] According to an advantageous extended configuration of the present invention, the system model is based on a model gradient and / or friction values, in particular air friction values ​​and / or rolling friction values. The speed-dependent friction effect of the vehicle is represented by the friction value. This allows the friction effect to be better compensated and / or set by the rider. The slope of the terrain is not taken into account in the equations of the system model and is therefore considered to be a disturbance factor, which can be compensated by torque assistance with the help of the system model. As a result, the rider has the same riding experience when going uphill as when riding on a flat surface. Since the system model is based on the model gradient, the influence of the gradient on the driving characteristics is at least partially retained. For this purpose, a sensor for determining the gradient of the vehicle can be arranged in particular. For training purposes, a constant gradient can also be simulated or pre-set.

[0021] According to an advantageous extended configuration of the invention, the friction value is determined in dependence on the speed of the vehicle, in particular wherein the friction value is determined in an unproportional manner to the speed of the vehicle. Since the friction losses are not modeled as a disturbance variable in the system model and are therefore not compensated by torque assistance, the required pedaling torque increases as the speed increases. Due to the speed-dependent, in particular unproportional friction value, the required pedaling torque increases only proportionally as the speed increases. For example, in the case of an anti-correlation D=D(1 / v), the friction losses will be independent of the speed of the vehicle. This provides the rider with a comfortable riding experience at high speeds.

[0022] According to an advantageous extension of the present invention, the system model is based on a model wind. The model wind can be used to simulate an artificial tailwind and / or headwind in the system model. This can improve the riding experience of the rider. For example, the model wind can be expressed as D*(vv Wind ) is incorporated into the system model.

[0023] According to an advantageous further development of the invention, this portion of the system model is filtered by a filter, in particular a low-pass filter. The disturbance variable compensation can be based on the speed and acceleration of the vehicle. Since these values ​​may not be measured continuously, the speed and acceleration values ​​determined may fluctuate around a mean value, which leads to a changing torque, in particular a suddenly changing torque, due to which the drive unit may be damaged or at least strongly loaded. These fluctuations can be compensated by a filter, in particular a low-pass filter, preferably a first-order low-pass filter. The advantage is that the torque assistance can be achieved more evenly, which improves the riding feel or riding experience.

[0024] According to an advantageous further development of the invention, the proportion of the system model is filtered in relation to the rate of change of the compensation of the disturbance variable. For example, the strength of the filter can be influenced by changing the time constant of the filter. In particular, the time constant of the filter in the case of a negative rate of change of the compensation of the disturbance variable can be smaller than the time constant of the filter in the case of a positive rate of change of the compensation of the disturbance variable. Thus, when the torque assistance for compensating the disturbance variable increases, the strength of the filter is higher, and when the torque assistance for compensating the disturbance variable decreases, the strength of the filter is lower. The time constant of the filter can delay the offset (Ausschlag) of the torque assistance, so that the noise of the torque assistance is smaller and / or the fluctuation is smaller. However, the responsiveness of the torque assistance may be slowed down by the filter. Thus, for example, when driving over the top of a hill, the torque assistance can still provide a high torque, although this is undesirable. Since the time constant of the filter is related to the rate of change of the compensation of the disturbance variable, in particular to the first-order derivative of the compensation of the disturbance variable, the responsiveness of the torque assistance can be greater at the top of the hill than at the foot of the hill, for example. Thus, "overshooting" can be prevented, that is, excessive torque can be prevented from being provided when driving over the turning point of the top of the hill. The rate at which the contribution of the torque assistance from the system model is therefore increased advantageously is slower than the rate at which it is reduced.

[0025] According to an advantageous embodiment of the invention, the system parameters of the system model, in particular the previously determined mass of the vehicle, the friction value, the model gradient and / or the model wind, can be set by the user. As a result, the ride characteristics can be adapted to the rider's wishes, for example by setting a tailwind or setting a constant gradient.

[0026] According to an advantageous development of the invention, the assistance factor is determined in dependence on the rate of change of the pedaling torque. The rate of change of the pedaling torque can in particular be the first derivative of the pedaling torque. This can reduce sudden changes in the torque assistance.

[0027] Further important features and advantages of the invention emerge from the preferred embodiments, the drawings and the associated description of the drawings.

[0028] It is understood that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case but also in other combinations or alone, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Preferred embodiments and implementations of the invention are shown in the drawings and explained in more detail in the following description, wherein identical reference numerals relate to identical or similar or functionally identical components or elements.

[0030] Here it is shown:

[0031] Figure 1 A method according to one embodiment of the present invention is shown in schematic form;

[0032] Figure 2 The variation process of the torque assist coefficient according to one embodiment of the present invention is shown in a schematic form; and

[0033] Figure 3 A single wheel track vehicle according to one embodiment of the invention is shown in schematic form. DETAILED DESCRIPTION

[0034] Figure 1 A method according to one embodiment of the invention is shown in schematic form.

[0035] Figure 1 The regulation of torque assistance for a single-track vehicle 101 with a drive unit 102 is shown. The torque assistance is based on a system model 103 and an enhancement of the pedaling torque provided by the rider (not shown). To this end, an idealized riding situation is first simulated and the pedaling torque required in the idealized situation is determined. In the idealized riding situation, interfering influences such as air resistance and slope are not taken into account. The required pedaling torque multiplied by a constant assistance factor 105 corresponds to the total torque required in the idealized riding situation.

[0036] If the pedaling torque actually applied by the rider is greater than the idealized pedaling torque, a disturbance variable compensation 104 is determined with the aid of the system model 103. Based on the disturbance variable compensation 104, the auxiliary torque of the drive unit 102 is adjusted so that the rider only needs to apply the pedaling torque determined by the idealized riding situation to maintain the desired speed. In this case, the auxiliary coefficient 105 is constant.

[0037] The determination of the disturbance variable compensation 104 by the system model 103 is based on the speed and / or acceleration of the vehicle. For example, if the speed of the vehicle is obtained by sensors on the wheels, the speed can only be obtained each time the wheel rotates a full circle. The acceleration of the vehicle can be calculated from the speed. Therefore, the determination of the disturbance variable compensation 104 is slow and cannot be calculated in real time. Therefore, sudden changes in the required pedaling torque cannot be immediately compensated by the disturbance variable compensation 104. In order to compensate for this delay, the auxiliary coefficient 105 is based on the pedaling torque.

[0038] Figure 2 The variation process of the pedaling torque assistance coefficient according to one embodiment of the present invention is shown in a schematic form.

[0039] exist Figure 2 2 shows a graph 201 of a variation 202 of the assistance coefficient of the pedaling torque. The X-axis 203 shows the pedaling torque in arbitrary units generated by the rider, and the Y-axis 204 shows the dimensionless assistance coefficient of the pedaling torque. The variation 202 is divided into two regions, a permanent region 205, in which the assistance coefficient is approximately constant, and a "downshift (torque increase)" region 206, in which the assistance coefficient increases approximately linearly.

[0040] The torque assistance is based on two components: disturbance variable compensation, such as gradient compensation, via a system model, and pedaling torque assistance, which is characterized by an assistance factor.

[0041] When the rider is riding on a flat surface 207, the influence of the slope is compensated by the system model and the assistance factor is low. Therefore, the drive unit of the bicycle is in the persistent region 205. Once the rider reaches the transition region 207' of the slope, the influence of the slope increases rapidly. However, the disturbance variable compensation achieved by the system model is slow, so that the rider must pedal hard to maintain speed. In order to minimize this effect, the assistance factor is gradually related to the pedaling torque, for example linearly. When the pedaling torque increases sharply, the drive unit of the bicycle is in the downshift region 206 and the assistance factor increases. Therefore, the torque increase required due to the slope is at least partially compensated by the higher torque assistance achieved due to the higher assistance factor. Once the rider has ridden on the increased slope for a sufficient time and is in the stable region 207" of the slope, the influence of the slope is compensated again by the disturbance variable compensation of the system model and the rider's pedaling torque decreases. Since the drive unit of the bicycle is again in the persistent region 205, the assistance factor is also reduced and is constant again.

[0042] Figure 3 A single wheel track vehicle according to one embodiment of the invention is shown in schematic form.

[0043] exist Figure 3 1 shows a single-wheel-track vehicle 101 with a drive unit 102. The vehicle may be an electric bicycle. The drive unit 102 is designed to increase the pedaling torque by means of a regulated torque assistance, wherein the torque assistance is based on a system model having an increase in the pedaling torque provided by a rider (not shown) with an assistance factor, wherein the assistance factor is based on the pedaling torque, and wherein the system model is based at least on the speed and / or acceleration of the single-wheel-track vehicle 101 and on compensation of disturbance variables.

[0044] In order to determine the pedaling torque actually provided by the rider, a torque sensor can be arranged on the drive unit 102 and / or on the vehicle 101. The speed of the vehicle 101 can be measured by a speed sensor 304. The acceleration of the vehicle can be determined from the speed and / or determined by an acceleration sensor 305. The slope of the ground can optionally be measured by a slope sensor 306, so that this slope can be incorporated into the system model.

[0045] In summary, at least one embodiment of the present invention has at least one of the following features and / or provides at least one of the following advantages:

[0046] -Fast response to changing torque requirements,

[0047] - Provides riders with a comfortable riding experience.

[0048] - Individual setting of torque assistance.

[0049] Although the present invention has been described with reference to preferred embodiments, it is not limited thereto but can be modified in many ways.

Claims

1. A method for regulating a torque assistance of a drive unit (102) of a vehicle (101), in particular a single-wheel vehicle, such as an electric bicycle, wherein: The torque assistance is based on a share of a system model (103) and on a share of an enhancement of a pedaling torque provided by a rider with an assistance factor (105), wherein the assistance factor (105) is determined in relation to the pedaling torque, in particular in a progressive manner, and wherein the system model (103) is based at least on a speed and / or acceleration of the vehicle (101) and on a compensation (104) for disturbance variables, in particular gradient, inertia and frictional resistance.

2. The method according to claim 1, wherein: The proportion of the system model (103) and the proportion of the enhancement of the pedaling torque provided by the rider with the assistance factor (105) are coordinated with each other so that a high assistance factor (105) is provided when the pedaling torque is high through the enhanced proportion, until the pedaling torque becomes so low through the proportion of the system model (103) that a small assistance factor (105) is provided or essentially no assistance factor (105) is provided.

3. The method according to claim 1 or 2, wherein: The assistance coefficient (105) is determined in relation to the pedaling torque, in particular in a progressive manner, so that in a range below a threshold value of the pedaling torque, the assistance coefficient (105) is essentially constant, and in a range above the threshold value, the assistance coefficient (105) increases in a progressive manner in relation to the pedaling torque.

4. The method according to any one of the preceding claims, wherein: The system model (103) is based on a previously determined mass of the vehicle (101) and / or of the rider.

5. The method according to claim 4, wherein: The previously determined mass of the vehicle is determined in dependence on the speed of the vehicle (101).

6. The method according to any one of the preceding claims, wherein: The system model (103) is based on model gradients and / or friction values, in particular air friction values ​​and / or rolling friction values.

7. The method according to claim 6, wherein: The friction value is determined as a function of the speed of the vehicle (101), in particular wherein the friction value is determined in a sub-proportional manner to the speed of the vehicle (101).

8. The method according to any one of the preceding claims, wherein: The system model (103) is based on model wind.

9. The method according to any one of the preceding claims, wherein: The proportion of the system model is filtered by a filter, in particular a low-pass filter.

10. The method according to claim 9, wherein: The proportion of the system model is filtered as a function of the rate of change of the compensation of the disturbance variable.

11. The method according to any one of the preceding claims, wherein: System parameters of the system model (103) can be set by a user, in particular previously determined masses of the vehicle, friction values, model gradients and / or model winds.

12. The method according to any one of the preceding claims, wherein: The assist coefficient (105) is determined in relation to the rate of change of the pedaling torque.

13. A vehicle having a drive unit (102), the vehicle being in particular a single-wheel vehicle, such as an electric bicycle, wherein: The drive unit (102) is designed to increase the pedaling torque by means of a regulated torque assistance, wherein the torque assistance is based on a share of a system model (103) and on a share of the pedaling torque provided by the rider that is increased by an assistance factor (105), wherein the assistance factor (105) is determined in relation to the pedaling torque, and wherein the system model (103) is based at least on a speed and / or acceleration of the vehicle (101) and on a compensation (104) for disturbance variables, in particular gradient and frictional resistance.

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