A dynamic self-adaptive measurement method for a cycling platform speed

Abstract

The application discloses a kind of dynamic self-adapting measurement methods of riding platform speed, comprising the following steps: S1, signal emitting module emits signal to the reflection module on damping wheel;S2, the reflected signal is obtained after the transmission signal is reflected by the reflection module, and signal receiving module receives the reflected signal and converts into reflected signal voltage U and sends to control module;S3, the control module determines threshold voltage U according to power supply voltage U0 and reflected signal voltage U Yi ;S4, whether the threshold voltage U Yi is qualified, if yes, then the threshold voltage U Yi It is the adaptive threshold voltage U Y Of the riding platform;S5, according to the adaptive threshold voltage U Y , the control module calculates the rotating speed n of the damping wheel after the reflected signal voltage U is binarized.It can automatically calculate and verify threshold voltage, correctly identify the waveform of voltage signal, greatly reduce production requirements, and improve yield and reduce production cost.

Description

Technical Field

[0001] This invention relates to the technical field of motion parameter analysis, and specifically to a dynamic adaptive measurement method for cycling train speed. Background Technology

[0002] A cycling trainer, also known as an indoor bicycle training platform, is a fitness device that allows users to train by cycling indoors. It simulates the feeling of real cycling, providing resistance and measuring the user's output power. To measure the user's output power, it's necessary to accurately measure the trainer's resistance and rotation speed; therefore, the stability and accuracy of speed measurement become core performance indicators for cycling trainers.

[0003] In the field of cycling trainers, speed measurement primarily utilizes the principle of infrared reflection. An infrared emitter emits an infrared signal of a certain intensity onto paper. The intensity of the reflected infrared signal is directly proportional to the darkness of the paper's black and white color; the darker the paper, the lower the reflected infrared signal intensity. This signal is received by an infrared receiver and converted into an output voltage signal waveform. The strength of the received infrared signal can be determined by the strength of the output voltage signal. Furthermore, according to the principle of infrared signal reflection, the farther the infrared emitter and receiver are from the paper, the weaker the reflected infrared signal becomes, even attenuating exponentially. Therefore, the intensity of the reflected infrared signal is closely related to the distance from the paper. Additionally, factors such as different sensor models or different paper reflectivity can lead to different output voltage signal waveforms. It is impossible to adapt all waveforms using a suitable threshold voltage, resulting in a low yield rate for the equipment.

[0004] In summary, there is a need to design a dynamic adaptive measurement method for cycling train speed to solve the above-mentioned problems in the existing technology. Summary of the Invention

[0005] This invention provides a dynamic adaptive measurement method for cycling train speed, which solves the problem of low yield caused by the inability to accurately identify waveforms in the existing technology for measuring the rotational speed of cycling trains.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A dynamic adaptive measurement method for cycling train speed includes the following steps:

[0008] S1. The signal transmitting module transmits a signal to the reflection module on the damping wheel;

[0009] S2. The transmitted signal is reflected by the reflection module to obtain a reflected signal. The signal receiving module receives the reflected signal and converts it into a reflected signal voltage U, which is then sent to the control module.

[0010] S3. The control module determines the threshold voltage U based on the power supply voltage U0 and the reflected signal voltage U. Yi ;

[0011] S4. Verify the threshold voltage U Yi Is it qualified? If so, then the threshold voltage U Yi That is, the adaptive threshold voltage U of the cycling train. Y ;

[0012] S5, based on the adaptive threshold voltage U Y The control module binarizes the reflected signal voltage U and then calculates the rotational speed n of the damping wheel.

[0013] In some embodiments of the present invention, both the signal transmitting module and the signal receiving module employ infrared sensors.

[0014] In some embodiments of the present invention, the reflective module is a sticker with alternating black and white colors, the shape of which matches the shape of the damping wheel.

[0015] In some embodiments of the present invention, step S3 specifically includes the following steps:

[0016] S31. Define the threshold voltage U based on the power supply voltage U0. Yi The value range is [0.1, U0];

[0017] S32, Traversing the threshold voltage U Yi Calculate the threshold voltage U Yi The inter-class variance gi;

[0018] S33, Select the maximum value of the inter-class variance gi as g. max According to the maximum value g of the inter-class variance gi max The corresponding voltage is used as the threshold voltage U. Yi The reflected signal voltage U is binarized.

[0019] In some embodiments of the present invention, the formula for calculating the inter-class variance gi is as follows: ;in, For the reflected signal voltage U, the voltage is lower than the threshold voltage U. Yi The average voltage, For the reflected signal voltage U, the voltage is lower than the threshold voltage U. Yi The proportion, For the reflected signal voltage U, the voltage is higher than the threshold voltage U. Yi The average voltage, For the reflected signal voltage U, the voltage is higher than the threshold voltage U. Yi The percentage.

[0020] In some embodiments of the present invention, step S4 specifically includes the following steps:

[0021] S41, according to the threshold voltage U Yi The reflected signal voltage U is binarized to obtain high voltage and low voltage;

[0022] S42. Calculate the average value of the high voltage. and the average of low voltage And calculate the mean difference. ;

[0023] S43, when the mean difference Reaching the critical value If the above is true, then the threshold voltage U is verified. Yi qualified.

[0024] In some embodiments of the present invention, the critical value The range is (0, α), where α is an empirical value.

[0025] In some embodiments of the present invention, step S5 specifically includes the following steps:

[0026] S51, according to the adaptive threshold voltage U Y The reflected signal voltage U is binarized to obtain high and low levels;

[0027] S52, the time interval between adjacent high levels or adjacent low levels is T, according to

[0028] The rotational speed n is calculated based on the time interval T.

[0029] In some embodiments of the present invention, the formula for calculating the rotational speed n is as follows: Where N is the number of black stickers in the black and white stickers; the unit of the rotation speed n is revolutions per minute.

[0030] In some embodiments of the present invention, the connection port between the signal receiving module and the control module is an ADC / comparator composite port. When the control module verifies the threshold voltage U... Y If the connection is successful, the control module will switch the connection port to the comparator port; otherwise, the connection port will be the ADC port.

[0031] The technical solution of the present invention has the following technical effects compared with the prior art:

[0032] This invention automatically calculates and verifies the threshold voltage based on the collected voltage signal. Therefore, this calculation process shields the effects of different sensor models, different reflection coefficients of reflection modules, or different distances between them in mass production equipment. The control module in this invention can correctly identify the waveform of the voltage signal, which greatly reduces production requirements, improves yield, and reduces production costs. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic flowchart illustrating the measurement method of the embodiment described.

[0035] Figure 2 This is a schematic diagram illustrating the structure of the cycling trainer used in the embodiment described.

[0036] Figure 3 The waveform diagram of the reflected signal voltage is shown for the embodiment described. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0039] Reference Figure 1 As shown, a dynamic adaptive measurement method for cycling train speed includes the following steps:

[0040] S1. The signal transmitting module transmits a signal to the reflection module on the damping wheel;

[0041] In this step, the signal transmitting module is an infrared sensor, which sends infrared signals to the damping wheel; while the reflection module is generally a black and white sticker fixed on the damping wheel.

[0042] S2. The transmitted signal is reflected by the reflection module to obtain a reflected signal. The signal receiving module receives the reflected signal and converts it into a reflected signal voltage U, which is then sent to the control module.

[0043] Specifically, the signal receiving module is also an infrared sensor. When the damping wheel rotates, the infrared signal intensity reflected by the black and white intervals is different, which will cause the reflected signal voltage U generated by the signal receiving module to change.

[0044] S3. The control module determines the threshold voltage U based on the power supply voltage U0 and the reflected signal voltage U. Yi ;

[0045] S31. Define the threshold voltage U based on the power supply voltage U0. Yi The value range is [0.1, U0];

[0046] S32, Traversing the threshold voltage U Yi Calculate the threshold voltage U Yi The inter-class variance gi;

[0047] The formula for calculating the inter-class variance gi is as follows: ;in, For the reflected signal voltage U, the voltage is lower than the threshold voltage U. Yi The average voltage, For the reflected signal voltage U, the voltage is lower than the threshold voltage U. Yi The proportion, For the reflected signal voltage U, the voltage is higher than the threshold voltage U. Yi The average voltage, For the reflected signal voltage U, the voltage is higher than the threshold voltage U. Yi The percentage.

[0048] S33, Select the maximum value of the inter-class variance gi as g. max According to the maximum value g of the inter-class variance gi max The corresponding voltage is used as the threshold voltage U. Yi The reflected signal voltage U is binarized.

[0049] Specifically, the power supply voltage U0 is the driving voltage of the signal receiving module. When the power supply voltage U0 is 3.0;

[0050] First, assume the threshold voltage U. Y1 Given a voltage of 0.1V, calculate the average of all voltages below this threshold voltage. and percentage Then calculate the average value of each voltage above this threshold voltage. and percentage ;

[0051] Substituting the formula for calculating the inter-class variance gi, we can calculate the inter-class variance g1 corresponding to this threshold voltage.

[0052] Then assume the threshold voltage U Y2 Given 0.2V, following the same procedure as above, calculate the corresponding inter-class variance g2;

[0053] Next, repeat the above process to calculate g3 to g30. Since the larger the value of the inter-class variance gi, the greater the dispersion of the two types of voltage values, that is, the more significantly they can be distinguished as high and low voltages, the maximum value g among g1 to g30 is... max The corresponding threshold voltage U Ymax This is the optimal threshold voltage;

[0054] S4. Verify the threshold voltage U Yi Is it qualified? If so, then the threshold voltage U Yi That is, the adaptive threshold voltage U of the cycling train. Y ;

[0055] S41. Based on the optimal threshold voltage calculated above, the reflected signal voltage U is binarized to obtain high voltage and low voltage.

[0056] S42. Calculate the average value of the high voltage. and the average of low voltage And calculate the mean difference. ;

[0057] S43, when the mean difference Reaching the critical value If the above is true, then the threshold voltage U is verified. Yi Qualified, then the threshold voltage U Yi That is, the adaptive threshold voltage U of the cycling train. Y .

[0058] Generally, a high-level output from a microcontroller port will have a voltage drop of about 0.3V, and similarly, a low-level output will also have a voltage drop of about 0.3V, the sum of which is 0.6V. To make this measurement method applicable to more microcontrollers, the aforementioned threshold value... In the range, α is generally taken as 0.6.

[0059] S5, based on the adaptive threshold voltage U YThe control module binarizes the reflected signal voltage U and then calculates the rotational speed n of the damping wheel.

[0060] S51, according to the adaptive threshold voltage U Y The reflected signal voltage U is binarized to obtain high and low levels;

[0061] S52. The time interval between adjacent high levels or adjacent low levels is T, that is, the period of the damping wheel rotating from the previous black sticker to the next black sticker is T. The rotational speed n is calculated based on the time interval T.

[0062] In some embodiments of the present invention, the formula for calculating the rotational speed n is as follows: Where N is the number of black stickers in the black and white stickers; the unit of the rotation speed n is revolutions per minute.

[0063] Generally, black and white stickers use reflective stickers that are half black and half white. In this case, the time it takes for the damping wheel to rotate one revolution is the time from the previous black sticker to the next, denoted as T. In this embodiment, the formula for calculating the rotational speed n is: The unit is revolutions per minute.

[0064] In some embodiments of the present invention, the reflective module is a sticker with alternating black and white colors, the shape of which matches the shape of the damping wheel.

[0065] In some embodiments of the present invention, reference is made to... Figure 2 As shown, the connection port between the signal receiving module and the control module is an ADC / comparator composite port. When the control module verifies the threshold voltage U... Y When the voltage judgment value U0 is reached or higher, the control module will switch the connection port to the comparator port; otherwise, the connection port will be the ADC port.

[0066] In other words, when the riding platform is powered on, the control module first switches the connection port to the ADC port; after the threshold voltage passes the verification, the control module then switches the connection port to the comparator port.

[0067] In some embodiments of the present invention, as the cycling train is used, the reflectivity of the black and white sticker or other waveforms of the output voltage of the signal receiving module caused by wear of the cycling train may change. The control module can recalculate the threshold voltage at any time or periodically to ensure the accuracy of the damping wheel speed calculation.

[0068] The technical solution of the present invention has the following technical effects compared with the prior art:

[0069] In actual speed measurement, due to differences in equipment mass production, the voltage signal waveform of the signal receiving module can vary. Generally, the ideal waveform threshold voltage is 1.5V. Using this threshold voltage, signals above 1.5V are converted to a high level (1), and signals below 1.5V are converted to a low level (0), thus correctly identifying the signal waveform. Additionally, other devices may produce different waveforms due to variations in the reflectivity of the black and white sticker or the distance between the sticker and the sensor. Figure 3 For example, waveform A has a threshold voltage of 0.65V and a maximum voltage of 1.35V, while waveform B has a threshold voltage of 2.25V and a minimum voltage of 1.6V. Therefore, if 1.5V (the ideal waveform) is used as the threshold voltage, the ideal waveform can be successfully identified, but waveform A cannot be identified (because the maximum voltage of waveform A, 1.35V, is lower than 1.5V, meaning waveform A is identified as a low level 0, with no high level 1, thus the time difference between high and low levels cannot be obtained to calculate the rotational speed), nor can waveform B be identified (because the minimum voltage of waveform B, 1.6V, is higher than 1.5V, meaning waveform B is identified as a high level 1, with no low level 0, thus the time difference between high and low levels cannot be obtained to calculate the rotational speed). If 0.65V is used as the threshold voltage, waveform A can be successfully identified, but waveform B cannot (the principle is the same). If 2.25V is used as the threshold voltage, waveform B can be successfully identified, but waveform A cannot be identified (the principle is the same).

[0070] This invention automatically calculates and verifies the threshold voltage based on the collected voltage signal. Therefore, this calculation process shields the effects of different sensor models, different reflection coefficients of reflection modules, or different distances between them in mass production equipment. Compared with traditional methods, this method has a dynamic adaptive function. Regardless of the distance between the signal receiving module and the black and white sticker, the optimal binarized threshold voltage can be automatically calculated using the above method. This converts the continuous infrared reflected voltage signal into a binarized high and low pulse signal, thereby calculating the real-time rotational speed of the damping wheel. The calculation process has very low requirements for the distance between the infrared receiving device and the sticker, and the threshold voltage calculation is fully automated, eliminating the need for manual calculation. This greatly improves the product qualification rate, reduces material costs, significantly reduces manual operation, lowers labor costs, and increases the yield rate.

[0071] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0072] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dynamic adaptive measurement method for cycling train speed, characterized in that, Includes the following steps: S1. The signal transmitting module transmits a signal to the reflection module on the damping wheel; S2. The transmitted signal is reflected by the reflection module to obtain a reflected signal. The signal receiving module receives the reflected signal and converts it into a reflected signal voltage U, which is then sent to the control module. S3. The control module determines the threshold voltage U based on the power supply voltage U0 and the reflected signal voltage U. Yi ; S4. Verify the threshold voltage U Yi Whether it is qualified, if so, then the threshold voltage U Yi That is, the adaptive threshold voltage U of the cycling train. Y ; S5, based on the adaptive threshold voltage U Y The control module binarizes the reflected signal voltage U and then calculates the rotational speed n of the damping wheel. Step S3 specifically includes the following steps: S31. Define the threshold voltage U based on the power supply voltage U0. Yi The value range is [0.1, U0]; S32, Traversing the threshold voltage U Yi Calculate the threshold voltage U Yi The inter-class variance gi; S33, Select the maximum value of the inter-class variance gi as g. max According to the maximum value g of the inter-class variance gi max The corresponding voltage is used as the threshold voltage U. Yi The reflected signal voltage U is binarized.

2. The dynamic adaptive measurement method according to claim 1, characterized in that, Both the signal transmitting module and the signal receiving module employ infrared sensors.

3. The dynamic adaptive measurement method according to claim 1, characterized in that, The reflective module is a sticker with alternating black and white colors, and the shape of the sticker matches the shape of the damping wheel.

4. The dynamic adaptive measurement method according to claim 1, characterized in that, The formula for calculating the inter-class variance gi is as follows: ;in, For the reflected signal voltage U, the voltage is lower than the threshold voltage U. Yi The average voltage, For the reflected signal voltage U, the voltage is lower than the threshold voltage U. Yi The proportion, For the reflected signal voltage U, the voltage is higher than the threshold voltage U. Yi The average voltage, For the reflected signal voltage U, the voltage is higher than the threshold voltage U. Yi The percentage.

5. The dynamic adaptive measurement method according to claim 1, characterized in that, Step S4 specifically includes the following steps: S41, according to the threshold voltage U Yi The reflected signal voltage U is binarized to obtain high voltage and low voltage; S42. Calculate the average value of the high voltage. and the average of low voltage And calculate the mean difference. ; S43. When the mean difference reaches a critical value If the above is true, then the threshold voltage U is verified. Yi qualified.

6. The dynamic adaptive measurement method according to claim 5, characterized in that, The critical value The range is (0, α).

7. The dynamic adaptive measurement method according to claim 1, characterized in that, Step S5 specifically includes the following steps: S51, based on the adaptive threshold voltage U Y The reflected signal voltage U is binarized to obtain high and low levels; S52, the time interval between adjacent high levels or adjacent low levels is T, according to The rotational speed n is calculated based on the time interval T.

8. The dynamic adaptive measurement method according to claim 3, characterized in that, The formula for calculating the rotational speed n is as follows: Where N is the number of black stickers in the black and white stickers; the unit of the rotational speed n is revolutions per minute.

9. The dynamic adaptive measurement method according to claim 1, characterized in that, The connection port between the signal receiving module and the control module is an ADC / comparator composite port. When the control module verifies the threshold voltage U... Y If the connection is successful, the control module will switch the connection port to the comparator port; otherwise, the connection port will be the ADC port.

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