A method for controlling the response of an electric motor for an assisted bicycle

Abstract

The application relates to an electric motor response control method for an assisted bicycle, which comprises the following steps: acquiring a real-time torque value at an interval time; judging whether a preset state signal is a starting signal; if the state signal is the starting signal, judging whether the real-time torque value is greater than or equal to a historical torque value; if the real-time torque value is greater than or equal to the historical torque value, generating a corresponding response signal according to the real-time torque value; if the real-time torque value is less than the historical torque value, generating a peak value and a corresponding reference value according to the historical torque value, updating the state signal to a steady signal, and generating a corresponding response signal according to the real-time torque value; if the state signal is the steady signal, judging whether the real-time torque value is greater than the reference value; if the real-time torque value is greater than the reference value, generating a corresponding response signal according to the real-time torque value; and if the real-time torque value is less than or equal to the reference value, generating a corresponding response signal according to the reference value. The application can respond quickly.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power-assisted bicycles, in particular to a motor response control method for a power-assisted bicycle. BACKGROUND

[0002] A power-assisted bicycle (also known as an E-Bike) is a new type of transportation vehicle that adds a battery and a motor to a traditional bicycle. It combines human-powered riding with electric assistance through a power-assisted system. When the rider pedals the power-assisted bicycle pedals, the motor starts to work and provides additional assistance power to the rider. The size of the assistance power is adjusted according to the rider's needs. Usually, a sensor senses the input torque of the rider, and a controller adjusts the output power of the motor according to the input torque, so that the motor of the power-assisted bicycle provides assistance that adapts to the riding conditions of the rider.

[0003] However, the force exerted by the rider on the pedals of the power-assisted bicycle is not constant. When the crank of the power-assisted bicycle is perpendicular to the ground and the pedal is at the highest point above the ground, the rider exerts force, and when the crank moves to be parallel to the ground, the maximum torque is reached, and then the rider's force decreases until the pedal moves to the lowest point above the ground, at which point the pedal on the other side is at the highest point above the ground. Therefore, the input torque of the rider on the crankshaft collected by the sensor varies periodically (as shown in Figure 1 Obviously, if the assistance power provided by the motor directly follows the input torque collected by the sensor, it will cause an uneven ride. The industry usually uses low-pass filtering to filter the torque signal collected by the sensor to reduce the impact of the decrease in input torque during the downward movement of the crank on the output of the assistance power. However, using low-pass filtering to process the torque signal results in slow response speed, which affects the riding experience of the power-assisted bicycle. SUMMARY

[0004] In order to improve the response speed and riding experience, the present application provides a motor response control method for a power-assisted bicycle.

[0005] The motor response control method for a power-assisted bicycle provided by the present application adopts the following technical solution:

[0006] A motor response control method for a power-assisted bicycle, comprising: acquiring a real-time torque value at an interval; determining whether a preset state signal is a start signal,

[0007] If the state signal is a start signal,

[0008] judging whether the real-time torque value is greater than or equal to the historical torque value, if the real-time torque value is greater than or equal to the historical torque value, generating a corresponding response signal according to the real-time torque value; if the real-time torque value is less than the historical torque value, generating a peak value and a corresponding reference value according to the historical torque value, updating the state signal to a steady signal, and generating a corresponding response signal according to the real-time torque value according to the preset state position one;

[0009] if the state signal is the steady signal,

[0010] judging whether the real-time torque value is greater than the reference value, if the real-time torque value is greater than the reference value, generating a corresponding response signal according to the real-time torque value; if the real-time torque value is less than or equal to the reference value, generating a corresponding response signal according to the reference value;

[0011] judging whether the real-time torque value is greater than the historical torque value, if the real-time torque value is greater than the historical torque value, judging whether the state bit is one, if yes, setting the state position to zero; if the real-time torque value is less than or equal to the historical torque value, judging whether the state bit is zero, if yes, setting the state position to one, and updating the peak value and the corresponding reference value according to the historical torque value.

[0012] Optionally, the method further comprises obtaining a current time and an update time of the peak value, judging whether a difference between the current time and the update time is greater than a preset waiting time, and if yes, performing an initialization operation.

[0013] Optionally, the initialization operation comprises setting the state position to zero, switching the state signal to a start signal, setting the peak value to zero and updating the reference value, and setting the current time and the update time to zero.

[0014] Optionally, the reference value is defined according to the peak value, and the reference value is equal to the peak value multiplied by a response function, and the response function is a decreasing function of time.

[0015] Optionally, the reference value is defined according to the peak value, and the reference value is equal to the peak value multiplied by a response coefficient, and the response coefficient is less than one.

[0016] Optionally, the response coefficient is preferably 60%-95%.

[0017] The application provides a control system for an assisted bicycle, which adopts the following technical scheme:

[0018] A control system for an assisted bicycle, comprising:

[0019] a torque sensor for detecting a middle shaft torque and outputting a corresponding real-time torque value;

[0020] a processor for receiving the real-time torque value and generating a corresponding response signal according to the above-mentioned motor response control method for an assisted bicycle; and

[0021] A motor controller for receiving a response signal and controlling the output power of the motor according to the response signal.

[0022] By adopting the technical scheme, the motor can quickly respond to the detected torque signal, and the motor outputs the auxiliary power according to the response signal smoothly without jerk, which greatly improves the riding experience of the rider. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic diagram of the torque signal of the middle shaft of the power-assisted bicycle.

[0024] Figure 2 is a schematic diagram of the response signal obtained according to a control system for a power-assisted bicycle, wherein the reference value is defined according to the peak value and the response function.

[0025] Figure 3 is a schematic diagram of the response signal obtained according to a control system for a power-assisted bicycle, wherein the reference value is defined according to the peak value and the response coefficient. DETAILED DESCRIPTION

[0026] The following will be described in detail in combination with the accompanying drawings. Figures 1-3 Further detailed description will be made to the present application.

[0027] The embodiment of the present application discloses a control system for a power-assisted bicycle, which comprises a torque sensor, a processor and a motor controller.

[0028] The torque sensor can adopt a stress-strain type torque sensor, a magnetic resistance type torque sensor, etc., which collects the torque on the middle shaft of the power-assisted bicycle and outputs the corresponding real-time torque value to the processor. The torque signal collected by the torque sensor is as shown in the dashed line in Figure 2 and Figure 3 , wherein the torque signal changes periodically, but the period time and the period amplitude are not necessarily the same.

[0029] The processor receives the real-time torque value transmitted by the torque sensor, generates a response signal according to the motor response control method, and transmits the response signal to the motor controller. The response signal is as shown in the solid line in Figure 2 or Figure 3 .

[0030] The motor controller receives the response signal, controls the output power and the rotating speed of the motor according to the response signal, and transmits the auxiliary power to the middle shaft through the motor transmission structure.

[0031] The processor adopts a motor response control method for a power-assisted bicycle to generate a response signal, which specifically comprises the following steps.

[0032] The power-up initialization operation is performed, which includes setting the state position to zero, switching the state signal to the start signal, and setting the time T to zero.

[0033] The interval time is set to 2 ms, and the real-time torque value Qn is obtained.

[0034] It is determined whether the preset state signal is the start signal, and the initial value of the state signal is the start signal.

[0035] If the state signal is the start signal, it is determined whether the real-time torque value Qn is greater than the historical torque value Qn-1; if the real-time torque value Qn is greater than or equal to the historical torque value Qn-1, a corresponding response signal is generated according to the real-time torque value Qn; if the real-time torque value Qn is less than the historical torque value Qn-1, a peak value Qmax and a corresponding reference value Qref are generated according to the historical torque value Qn-1, the state signal is updated to the steady signal, the state position is set to one, and a corresponding response signal is generated according to the real-time torque value Qn.

[0036] When the state signal is the start signal, a response signal is generated according to the real-time torque value Qn. The historical torque value Qn-1 is the torque value obtained at the last time, and the initial value of the state position is zero. When the real-time torque value Qn is greater than or equal to the historical torque value Qn-1, the state position is zero, and it is determined that the rising edge of the torque signal is at this time. When the real-time torque value Qn is less than the historical torque value Qn-1, the state position is one, and it is determined that the falling edge of the torque signal is at this time. At this time, the historical torque value Qn-1 is assigned to the peak value Qmax, and the reference value Qref is defined according to the peak value Qmax. At the same time, the state signal is updated to the steady signal. Since the interval time is set to be short, the error between the actual peak of the torque signal and the maximum historical torque value obtained is ignored to quickly respond to the torque signal.

[0037] The reference value Qref has different definition methods.

[0038] Method one: the reference value Qref is equal to the peak value Qmax multiplied by the response function F(t), and the response function F(t) is a decreasing function (such as e -kt ), and the response function F(t) is a time function with respect to the difference time, which is equal to the current time minus the update time of the peak value. It should be noted that the response function can be other functions that are monotonically decreasing, and is not limited to the above example functions, which can be a curve function or a straight line function. At this time, the example waveform of the response signal is shown by a solid line. Figure 2

[0039] Method two: the reference value Qref is equal to the peak value Qmax multiplied by the response coefficient β, and the response coefficient β is preferably 60%-95%, and in this embodiment, the response coefficient β is 95%. At this time, the example waveform of the response signal is shown by a solid line. Figure 3 ​The solid line shows.

[0040] If the state signal is a steady signal, it is determined whether the real-time torque value Qn is greater than the reference value Qref. If the real-time torque value Qn is greater than the reference value Qref, a corresponding response signal is generated according to the real-time torque value Qn. If the real-time torque value Qn is less than or equal to the reference value Qref, a corresponding response signal is generated according to the reference value Qref. It is determined whether the real-time torque value Qn is greater than the historical torque value Qn-1. If the real-time torque value Qn is greater than the historical torque value Qn-1, it is determined whether the state bit is one. If the state bit is one, the state bit is set to zero. If the real-time torque value Qn is less than or equal to the historical torque value Qn-1, it is determined whether the state bit is zero. If the state bit is zero, the state bit is set to one. The peak value Qmax and the corresponding reference value Qref are updated according to the historical torque value Qn-1.

[0041] When the state signal is a steady signal, the real-time torque value Qn is compared with the reference value Qref. When the real-time torque value Qn is greater than the reference value Qref, a response signal is generated according to the real-time torque value Qn. When the real-time torque value Qn is less than or equal to the reference value Qref, a response signal is generated according to the reference value Qref. This eliminates the influence of the decrease of the input torque on the output of the auxiliary power during the downward stroke of the crank. An example waveform of the response signal is shown in FIG. 3, in which the solid line represents the response signal and the dashed line represents the torque signal. Figure 2

[0042] The current time Tn and the update time Tq of the peak value are obtained. It is determined whether the difference between the current time Tn and the update time Tq is greater than a preset waiting time Tw. If the difference between the current time Tn and the update time Tq is greater than the waiting time Tw, an initialization operation is performed, i.e., the state bit is set to zero, the state signal is switched to a starting signal, the peak value Qmax is set to zero and the reference value Qref is updated, and the current time Tn and the update time Tq are set to zero.

[0043] When the peak value is not updated for a long time, it is possible that the rider no longer inputs the torque. When the waiting time exceeds 3s during the downhill process, the initialization operation is performed. When the rider starts to ride again, the initial step is returned to for determination.

[0044] The above are preferred embodiments of the present application, which do not limit the protection scope of the present application. Any equivalent changes made according to the structure, shape, and principle of the present application should be covered by the protection scope of the present application.​

Claims

1. A method for controlling the response of an electric motor for an assisted bicycle, characterized in that: Comprising acquiring a real-time torque value at an interval time; judging whether the preset state signal is a start signal, if the state signal is the start signal, judging whether the real-time torque value is greater than or equal to the historical torque value, if the real-time torque value is greater than or equal to the historical torque value, generating a corresponding response signal according to the real-time torque value; if the real-time torque value is less than the historical torque value, generating a peak value and a corresponding reference value according to the historical torque value, updating the state signal to a steady signal, and generating a corresponding response signal according to the real-time torque value; if the state signal is the steady signal, judging whether the real-time torque value is greater than the reference value, if the real-time torque value is greater than the reference value, generating a corresponding response signal according to the real-time torque value; if the real-time torque value is less than or equal to the reference value, generating a corresponding response signal according to the reference value; judging whether the real-time torque value is greater than the historical torque value, if the real-time torque value is greater than the historical torque value, judging whether the state bit is one, if yes, setting the state bit to zero; if the real-time torque value is less than or equal to the historical torque value, judging whether the state bit is zero, if yes, setting the state bit to one, and updating the peak value and the corresponding reference value according to the historical torque value.

2. A method of motor response control for an assist bicycle according to claim 1, characterized in that: Further comprising acquiring a current time and an update time of the peak value, judging whether the difference between the current time and the update time is greater than a preset waiting time, if yes, performing an initialization operation.

3. A method of motor response control for a power assisted cycle according to claim 2, characterised in that: The initialization operation comprises setting the state bit to zero, switching the state signal to the start signal, setting the peak value to zero and updating the reference value, and setting the current time and the update time to zero.

4. A method of motor response control for a power assisted cycle according to claim 2 characterised in that: The reference value is defined according to the peak value, and the reference value is equal to the peak value multiplied by a response function, the response function being a decreasing function of time.

5. A method of motor response control for a power assisted cycle according to claim 1 or 2, characterised in that: The reference value is defined according to the peak value, and the reference value is equal to the peak value multiplied by a response coefficient, the response coefficient being less than one.

6. A method of motor response control for a power assisted cycle according to claim 5, characterised in that: The response coefficient is 60%-95%.

7. A control system for a power assisted cycle, characterised in that: Comprising a torque sensor for detecting the torque of the middle shaft and outputting a corresponding real-time torque value; a processor for receiving the real-time torque value and generating a corresponding response signal according to any one of the motor response control methods for a power-assisted bicycle according to claims 1-6; and a motor controller for receiving the response signal and controlling the output power of the motor according to the response signal.

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