CN104236771B - Method of Estimating Pedaling Torque Using Bicycle Pedaling Speed - Google Patents

Abstract

The invention provides a method for estimating a pedaling torque by utilizing a pedaling speed of a bicycle, wherein the pedaling torque refers to the torque of a crank of the bicycle being pedaled. The method comprises the following steps: detecting the treading speed of a crank of the bicycle for a preset number of times through a speed sensor in a preset time interval; obtaining the area V of the ideal waveform and the actual waveform of the stepping speed₀And V₁And find V₀‑V₁Is taken as Δ V_i(ii) a Obtaining a correction quantity c according to the relation between the stepping speed and the torque; the operation is performed according to the following first formula: Δ M_i/M₀＝ΔV_i/V₀+ c; thereby obtaining the relative variation delta M of the treading moment_i/M₀(ii) a Wherein M is₀To generate V₀Moment of (M)₀Is obtained through practical experiments; m₀‑M₁Is then Δ M_i；M₁To generate V₁Moment of (M)₁I.e. the pedaling moment to be estimated.

Description

Method of Estimating Pedaling Torque Using Bicycle Pedaling Speed

technical field

The present invention is related to bicycles, in particular to a method for estimating pedaling torque by utilizing bicycle pedaling speed.

Background technique

The electric power-assisted bicycle mainly provides an auxiliary power when the rider is pedaling, so that the rider can enjoy the fun of pedaling and riding, and can achieve the pedaling effect without a lot of effort. Therefore, electric power-assisted bicycles have become increasingly popular.

When providing auxiliary power, it is necessary to measure the pedaling force of the rider in order to output the corresponding auxiliary power required by the rider. Otherwise, when the auxiliary power is too large, it will cause the rider to pedal empty, and if it is too small, it will cause The rider cannot feel the boost, and the function of providing boost is invalid. The current detection method of pedaling force (or torque) is to install a torque sensor on the bicycle to sense the pedaling force or torque when the rider pedals the pedal. However, the torque sensor is very complicated and expensive. Therefore, the technology of obtaining the pedaling torque by other means without using the torque sensor has attracted the attention of practitioners in the field because it can reduce the cost.

China Taiwan Publication No. TW201202090A1 "Moment Estimation Method and Device of Pedal Crank Actuator" Invention Patent Case, that is, German Patent No. 10 2010 028 656.7, discloses a method for estimating torque, which mainly uses the detection of angular velocity and The time relationship, after obtaining at least one signal property of the angular velocity, utilizes the predetermined dependence between the at least one signal property and the torque to correlate the torque with the at least one signal property. This method uses the change of the waveform to infer the pedaling force, which has many variables that cannot be decomposed and quantified, such as the acquisition of its signal properties, which can be (1) the AC component power of the angular velocity or (2) the AC component of the angular velocity. The difference between the signal shape and a sinusoidal curve, the technical content and numerical value of the aforementioned (1) and (2) are very different, which can prove that the final torque results will also be very different, and then we can understand what it is The error of the obtained torque is very large, and the accuracy may not be good.

In addition, it can be known from the above case that the change of the pedaling speed is correlated with the change of the pedaling torque, so the technology of estimating the pedaling torque based on the pedaling speed was developed in the above case. However, although the aforementioned estimation methods try to clearly calculate the correlation, the result is not only a large error, but also relatively complicated in calculation. In addition to obtaining at least one signal property of the angular velocity, it also needs The correlation between the signal property and the torque is calculated by using the dependence between the signal property and the torque, so the calculation process is complicated, and a relatively high-speed calculation unit is required for execution, which also increases the cost.

Contents of the invention

The known torque estimation methods have the problems of large errors and complicated calculations. Therefore, the present invention provides a method for estimating the pedaling torque by using the pedaling speed of the bicycle. The pedaling torque refers to the pedaling torque of a crank of the bicycle. The method includes the following steps: within a predetermined time interval, through a The speed sensor detects the pedaling speed of a crank of the bicycle for a predetermined number of times, and then obtains the frequency data and amplitude data of the pedaling speed, and arranges the aforementioned data to form a pedaling speed actual waveform, and then defines a pedaling speed based on the aforementioned data Ideal waveform; get the area of the ideal waveform of the pedaling speed as V ₀ , and get the area of the actual waveform of the pedaling speed as V ₁ , and get the difference between V ₀ -V ₁ as ΔV _i , and then get the relative value of the pedaling speed The amount of change is ΔV _i /V ₀ ; according to the relationship between pedaling speed and torque, a correction amount c is obtained; the calculation is performed according to the following first formula: ΔM _i /M ₀ = ΔV _i /V ₀ +c; The relative variation of velocity ΔV _i /V ₀ is added to the correction amount c to obtain the relative variation of pedaling torque ΔM _i /M ₀ ; among them, M ₀ is the torque that produces V ₀ , and M ₀ is obtained through actual experiments; M The difference between ₀ -M ₁ is ΔM _i ; M ₁ is the torque that generates V ₁ , that is, the pedaling torque to be estimated.

Thereby, the present invention can achieve the effect of estimating the pedal force by using the pedal speed, and achieve the effect of simplifying the calculation and reducing the error.

Description of drawings

Fig. 1 is a schematic diagram of a first preferred embodiment of the present invention, showing data measured by a speed sensor.

Fig. 2 is a schematic waveform diagram of the first preferred embodiment of the present invention, showing the actual waveform of pedaling speed.

FIG. 3A is a schematic waveform diagram of the first preferred embodiment of the present invention, showing the state of deriving the ideal pedaling speed waveform from the actual pedaling speed waveform.

FIG. 3B is another waveform schematic diagram of the first preferred embodiment of the present invention, showing another ideal pedaling speed waveform deduced from the actual pedaling speed waveform.

Fig. 4 is a schematic diagram of the integration of the first preferred embodiment of the present invention, showing the status of the integration operation of the actual waveform of the pedaling speed.

Fig. 5 is another integral schematic diagram of the first preferred embodiment of the present invention, showing the state of the ideal waveform of pedaling speed being integrated.

Fig. 6 is another schematic diagram of the first preferred embodiment of the present invention, showing the overlapping status of the actual pedaling speed waveform and the ideal pedaling speed waveform after integral calculation.

Fig. 7 is a schematic block diagram of the first preferred embodiment of the present invention, showing the relevant components of the bicycle.

Fig. 8 is another schematic block diagram of the first preferred embodiment of the present invention, showing the relevant components of the experimental bicycle.

【Symbol Description】

10 - bicycle;

11 - speed sensor;

13 - memory;

15 - microcomputer;

10' - experimental bike;

11'-speed sensor;

17'-torque sensor;

t _pd - predetermined time interval;

V ₀ - the area of the ideal waveform of pedaling speed;

V ₁ - the area of the actual waveform of the pedaling velocity.

detailed description

As shown in Figures 1 to 7, the first preferred embodiment of the present invention provides a method for estimating the pedaling torque by using the pedaling speed of the bicycle, the pedaling torque refers to the pedaling torque of a crank of the bicycle, the method includes Follow these steps:

As shown in Figure 1, within a predetermined time interval _tpd , a speed sensor 11 is used to measure the pedaling speed of a crank (not shown) of a bicycle 10 for a predetermined number of times (20 times are taken as an example in the figure). Detect, and then obtain the frequency data and amplitude data of the pedaling speed. And arrange the aforementioned data to form an actual pedaling speed waveform, as shown in FIG. 2 . And then define an ideal pedaling speed waveform according to the aforementioned data, as shown in FIG. 3A or FIG. 3B . It can be seen from Fig. 3A that the actual pedaling speed waveform shown by the dotted line is compared with the ideal pedaling speed waveform shown by the solid line. The period is longer, so it can be seen that the amplitude of the ideal waveform of the pedaling speed is obtained by referring to the second half cycle of the actual waveform of the pedaling speed. From Figure 3B, it can be seen that the actual pedaling speed waveform shown by the dotted line is compared with the ideal pedaling speed waveform shown by the solid line. The actual pedaling speed waveform has the same amplitude but a shorter cycle in the first half cycle, and a smaller amplitude in the second half cycle. And the cycle is longer, so it can be seen that the amplitude of the ideal pedaling speed waveform is obtained by referring to the first half cycle of the actual pedaling speed waveform. In this embodiment, the ideal waveform of pedaling speed is shown in FIG. 3A as an example. It can be known from the foregoing that the amplitude of the ideal pedaling speed waveform can refer to the amplitude of a certain cycle of the actual pedaling speed waveform, in fact, it can also refer to the average value of the amplitudes of the first half cycle and the second half cycle, or the amplitude can be defined by the user. In practice, the frequency data and amplitude data of the pedaling speed are stored in a memory 13 . Moreover, a microcomputer 15 provides computing and processing functions. The speed sensor 11 is also installed on the bicycle 10, and the schematic diagram of its connection is shown in FIG. 7 .

As shown in Figures 4 and 5, the area of the ideal waveform of the pedaling speed is obtained as V ₀ through the integral operation, and the area of the actual waveform of the pedaling speed is obtained as V ₁ ; and the value of V ₀ -V ₁ is obtained The difference is taken as ΔV _i , and the relative change in pedaling speed is obtained as ΔV _i /V ₀ .

According to the relationship between pedaling speed and torque, a correction value c is obtained.

Calculate according to the first formula below:

ΔM _i /M ₀ ＝ΔV _i /V ₀ +c……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

Add the correction c to the relative variation of the pedaling speed ΔV _i /V ₀ to obtain the relative variation of the pedaling torque ΔM _i /M ₀ ; where M ₀ is the torque that generates V ₀ and M ₁ is the torque that generates V ₁ Moment, M ₀ is obtained through actual experiments; the difference between M ₀ -M ₁ is ΔM _i . The actual pedaling torque M ₁ can be obtained as an estimated value through the relative variation of the pedaling torque ΔM _i /M ₀ . Wherein, the correction amount c is obtained by obtaining the relative change amount ΔV _i /V ₀ of the pedaling speed and the relative change amount ΔM _i /M ₀ of the pedaling torque through the actual pedaling experiment in advance, and then subtracting the two to obtain The correction amount c. The actual pedaling experiment referred to here is to prepare an experimental bicycle 10', on which a speed sensor 11' is used to sense the pedaling speed, and an external torque sensor 17' is connected to sense the pedaling torque . The connection diagram of the experimental bicycle 10' is shown in FIG. 8 . In practice, after the correction amount c is obtained, its expression form can be defined according to the value obtained in the actual pedaling experiment. If the value is similar at different pedaling speeds (for example, the error range is within ±100%), then take Its average value is defined as the correction amount c, and the correction amount c is a constant at this time; if the values obtained at different pedaling speeds in the actual pedaling experiment are very different (for example, the error range is greater than 100%), then use the control Record in the form of a table, and define the comparison table as the correction amount c, and use the comparison table to obtain the corresponding value for the correction amount c when performing calculations according to the first formula. At this time, the correction amount c It is a comparison table, and since the comparison table is a prior art, it is allowed to no longer represent it with accompanying drawings.

In the above steps, the relative variation of the pedaling speed ΔV _i /V ₀ is obtained by dividing the difference ΔV _i of V ₀ -V ₁ by the area V ₀ of the ideal waveform of the pedaling speed, so the relative variation of the pedaling speed ΔV _i / V ₀ is a value without a unit, so it can be calculated without considering the unit. The first formula can therefore be calculated by the relative change of the correction amount c and the pedaling speed ΔV _i /V ₀ Out of the relative variation of the pedaling torque ΔM _i /M ₀ . Similarly, the relative change amount ΔM _i /M ₀ of the pedaling torque is also a numerical value without a unit. Its calculation is simplified by not having to take into account the units. And because the correction amount c is obtained by the result sensed by the speed sensor 11' and the sensed result of the torque sensor 17' by the experimental bicycle 10', so it will truly correspond to the actual pedaling situation, and therefore has _The excellent accuracy can further make the actual pedaling torque M1 estimated in this case more accurate, and the error is further reduced.

In this way, the first embodiment of the present invention does not need to install a torque sensor on the bicycle, but only needs to install a speed sensor to sense the pedaling speed during riding, and process and process according to the technology of the first embodiment of the present invention. After calculation, the actual pedaling torque M ₁ can be estimated more accurately than the prior art.

In summary, the first embodiment of the present invention can estimate the actual pedaling torque M ₁ from the pedaling speed, and achieve the effect of simplifying the calculation and reducing the error.

The second preferred embodiment of the present invention provides a method for estimating the pedaling torque by using the pedaling speed of a bicycle, the main content of which is roughly the same as that of the aforementioned first embodiment, except that:

The first formula is further modified into a second formula:

ΔM _i /M ₀ =t(ΔV _i /V ₀ )+c……………………………………………………………………………………………………………………….

Wherein, t is the multiple correction amount between ΔM _i /M ₀ and ΔV _i /V ₀ after deducting the correction amount c.

In addition, the acquisition of the multiple correction t is to obtain the relative variation of the pedaling speed ΔV _i /V ₀ and the relative variation of the pedaling torque ΔM _i /M ₀ through the actual pedaling experiment in advance, and follow the linear relationship of the experiment Obtain the correction amount c and the multiple correction amount t. In addition, as described in the aforementioned first embodiment, the actual pedaling experiment of the second embodiment of the present invention is also to prepare an experimental bicycle 10', and the pedaling speed is sensed by the speed sensor 11' on the experimental bicycle 10'. And the pedaling torque is sensed by the torque sensor 17'.

Therefore, the second embodiment of the present invention can provide a more accurate second formula, which can make the estimated actual pedaling torque M ₁ more accurate.

The rest of the technical features and attainable effects of the second embodiment of the present invention are substantially the same as those of the first embodiment, and will not be repeated here.

Through the technology of this case, it uses the technology of integrating the waveform. Since the integral operation itself has an average effect, this method can eliminate the small non-linear noise in the waveform during the integration process. Therefore, this case It also has the function of eliminating noise.

Claims (9)

1. A method for estimating the pedaling torque by pedaling speed of a bicycle, characterized in that, the pedaling torque refers to the moment when a crank of the bicycle is pedaled, and the method comprises the following steps: Within a predetermined time interval, the pedaling speed of a crank of the bicycle is detected by a speed sensor for a predetermined number of times, and then the frequency data and amplitude data of the pedaling speed are obtained, and the aforementioned data are sorted to form an actual waveform of the pedaling speed, And then define an ideal waveform of pedaling speed according to the aforementioned data; The area of the ideal waveform of the pedaling speed is obtained as V ₀ , and the area of the actual waveform of the pedaling speed is obtained as V ₁ , and the difference between V ₀ -V ₁ is obtained as ΔV _i , and the relative variation of the pedaling speed is obtained as ΔV _i /V ₀ ; According to the relationship between pedaling speed and torque, a correction value c is obtained; Calculate according to the first formula below: ΔM _i /M ₀ =ΔV _i /V ₀ +c Add the correction c to the relative variation of the pedaling speed ΔV _i /V ₀ to obtain the relative variation of the pedaling torque ΔM _i /M ₀ ; among them, M ₀ is the torque that produces V ₀ , and M ₀ is obtained through actual experiments ; the difference between M ₀ -M ₁ is ΔM _i ; M ₁ is the moment that produces V ₁ , that is, the pedaling torque to be estimated. 2. The method for estimating the pedaling torque by using the pedaling speed of a bicycle according to claim 1, wherein: the correction amount c is obtained by performing an actual pedaling experiment in advance to obtain the relative variation of the pedaling speed ΔV _i /V ₀ and The correction amount c is obtained by subtracting the relative change amount ΔM _i /M ₀ of the pedaling torque from the two. 3. The method for estimating pedaling torque by pedaling speed of a bicycle according to claim 2, wherein: in the actual pedaling experiment carried out in advance, an experimental bicycle is provided, and the speed sensor is used to sense the pedaling torque on the experimental bicycle. pedaling speed, and the pedaling torque is sensed by the torque sensor. 4. The method for estimating pedaling torque by pedaling speed of a bicycle according to claim 1, wherein: when obtaining the area of the ideal waveform of the pedaling speed or obtaining the area of the actual waveform of the pedaling speed, the waveform is Calculated by integral. 5. The method for estimating pedaling torque by pedaling speed of a bicycle according to claim 1, wherein: the first formula is further modified into a second formula: ΔM _i /M ₀ =t(ΔV _i /V ₀ )+c , where t is the multiple correction amount between ΔM _i /M ₀ and ΔV _i /V ₀ after deducting the correction amount c. 6. The method for estimating the pedaling torque by using the pedaling speed of a bicycle according to claim 5, wherein: the multiple correction amount t is obtained by performing an actual pedaling experiment in advance to obtain the relative variation of the pedaling speed ΔV _i /V ₀ And the relative variation of the pedaling torque ΔM _i /M ₀ , and obtain the correction c and the multiple correction t according to the linear relationship of the experiment. 7. The method for estimating pedaling torque by pedaling speed of a bicycle according to claim 6, wherein: in the actual pedaling experiment carried out in advance, an experimental bicycle is provided, and the speed sensor is used to sense the pedaling torque on the experimental bicycle pedaling speed, and the pedaling torque is sensed by the torque sensor. 8. The method for estimating pedaling torque by bicycle pedaling speed according to claim 1, wherein: the frequency data and amplitude data of the pedaling speed are stored in a memory, and the frequency data and amplitude data of the actual pedaling torque are stored in the memory; in addition, a microcomputer provides computing and processing functions. 9. The method for estimating pedaling torque by pedaling speed of a bicycle according to claim 1, wherein: the correction value c is a constant.