CN107600296A - A kind of power assist control method of electric assisted bicycle - Google Patents

Abstract

The invention relates to the technical field of electric bicycles, in particular to a power assist control method for electric power assist bicycles. This method is aimed at electric power-assisted bicycles including vehicle body, pedals, power-assisted motors and power-assisted controllers. The sensor obtains the inclination value of the car body; S2, using the power boost controller to establish a corresponding boost coefficient value according to the rotation speed value and the tilt angle value, so that the power boost controller controls the boost motor to output power according to the boost coefficient value. The invention enables the bicycle to automatically adjust the power assist according to the rider's operation of the vehicle and the road conditions on which the vehicle is driving, and provides conditions for enhancing the riding experience of the electric bicycle; The acceleration gyro sensor in the consumer product is used to detect the inclination angle of the bicycle, which can effectively reduce the installation cost and use cost of the sensor.

Description

A method of power-assisted control of an electric power-assisted bicycle

technical field

The invention relates to the technical field of electric bicycles, in particular to a power assist control method for electric power assist bicycles.

Background technique

As we all know, electric power-assisted bicycles are different from electric bicycles in the traditional sense. They are not intended to replace the rider to provide power, but to assist the rider to compensate for the power in a timely manner in a riding environment with high resistance, such as: The power assist compensation is performed during climbing or running against the wind to increase the comfort of the rider while riding, and at the same time retain the pleasure of riding with his own strength. Therefore, electric power-assisted bicycles will not be as strenuous to ride as ordinary bicycles, and will not easily cause safety problems and loss of riding due to the fact that the electric bicycle is separated from the pedals and directly controlled by the handle and accelerator. The fun of the line itself.

At present, there are mainly the following two power-assisted control methods adopted by electric power-assisted bicycles on the market, namely:

1. Control the output power of the booster motor based on the detection of the speed of the pedals as the input, that is, when the rider steps on the pedals faster, the motor assists more, and when the pedals stop, the booster is turned off; this method The advantage is that it is easy to detect the pedal speed and the installation and use cost of related sensors is relatively low, and there will be a good riding experience when riding on a flat road; but when going uphill, it will cause the speed of the pedal to When descending, the corresponding boost will be smaller, and the smaller the boost, the harder it will be to go uphill, thus forming a vicious circle; from the perspective of riding needs, more boost is needed when going uphill, so that As a result, a good boost effect cannot be achieved when going uphill. When riding downhill, it is easy to ride and the speed of the pedals is also high. From the perspective of riding needs and energy saving, downhill does not need or only needs a lot of power. Small power assist; but this control method cannot detect the riding slope because it directly detects the rotation speed of the pedals, so it provides more power assist when going uphill, and reduces or does not provide power assist when going downhill. Travel experience is poor.

2. Control the output power of the booster motor based on detecting the torque on the pedal as the input, that is, when the detected force on the pedal is greater, the booster will be greater, otherwise, the booster will be smaller; this method The advantage is that the riding experience is very good, but the disadvantage is that there is no good torque detection method at present, and the cost of the torque sensor used is extremely high, the installation is difficult and easy to damage, and the life of the sensor cannot be guaranteed, so it can only be used On some high-end models, it cannot be widely popularized.

Contents of the invention

In view of the deficiencies in the above-mentioned prior art, the object of the present invention is to provide a power assist control method for an electric power assist bicycle.

In order to achieve the above object, the present invention adopts the following technical solutions:

A power-assisted control method for an electric power-assisted bicycle, the electric power-assisted bicycle includes a vehicle body, a pedal mounted on the vehicle body, a power-assisted motor, and a power-assisted controller; the method includes the following steps:

S1. Use the rotational speed measurement sensor to obtain the rotational speed value of the pedals, and use the three-axis acceleration gyro sensor to obtain the inclination value of the car body relative to the horizontal riding road surface;

S2. Using the booster controller to establish a corresponding booster coefficient value according to the rotational speed value and the inclination value, and make the booster controller control the booster motor to output booster power according to the booster coefficient value.

Preferably, in the step S1, the unit horizontal distance value of the vehicle body and the height drop generated by the unit horizontal distance value are obtained by using the three-axis acceleration gyro sensor, and the vehicle body is obtained according to the formula P _Angle = H/L × 100%. In the formula, P _Angle is the inclination angle of the car body relative to the horizontal riding road; H is the height difference generated by the unit horizontal distance, which is obtained by the three-axis acceleration gyro sensor It is obtained after twice integrating the acceleration value in the vertical direction, and the unit is m; L is the unit horizontal distance, which is obtained by twice integrating the acceleration value of the three-axis acceleration gyro sensor in the horizontal direction. The unit is m.

Preferably, in the step S1, the acceleration values of the three axes of the three-axis acceleration gyro sensor are used to obtain the vehicle body according to the formula P _Angle =ar tan2(ax/Sqrt(ax ² +ay ² +az ² )) The inclination value relative to the horizontal riding road surface; where, P _Angle is the inclination angle of the vehicle body relative to the horizontal riding road surface; ax, ay, and az are the acceleration values of the three axes of the three-axis acceleration gyro sensor, and the unit is Both are m/s ² .

Preferably, in the step S1, the rotation speed value of the pedal is continuously obtained by using the rotation speed measurement sensor, and the inclination value of the vehicle body relative to the horizontal riding road surface is continuously obtained by the three-axis acceleration gyro sensor;

In the step S2, the boost coefficient value is changed according to the change of the speed value and the change of the inclination value.

Preferably, when the rotational speed value is positive and the inclination value is positive, it is regarded as riding uphill, the boost coefficient value increases with the increase of the tilt angle value, and the boost controller controls the boost power according to the boost coefficient value Motor output assist;

When the speed value is negative or zero and the inclination value is negative, it is considered to be riding downhill, the boost coefficient value is zero or negative, and the boost controller controls the boost motor to stop according to the boost coefficient value;

When the inclination value is zero, it is regarded as riding on a flat road, the boost coefficient value is zero, and the boost controller controls the boost motor to stop according to the boost coefficient value.

Preferably, the rotational speed measurement sensor is installed on the intermediate shaft of the pedal.

Preferably, the assist coefficient value is a plurality of thresholds or threshold ranges preset in the assist controller.

Due to the adoption of the above scheme, the present invention enables the bicycle to automatically adjust the power assist according to the rider's operation of the vehicle and the road conditions on which the vehicle is running. For example, when driving on a downhill road section, the driving speed can be limited by stopping the power assist or braking. In order to reduce the risk of riding safety, when driving on an uphill section, it can be properly assisted to achieve a more relaxed and labor-saving effect, and when driving on a flat road, it can be properly assisted or not to maintain the bicycle riding and fitness fun; and Using the acceleration gyroscope sensor widely used in electronic consumer products such as mobile phones to detect the inclination angle of the bicycle can effectively reduce the installation cost and use cost of the sensor.

Description of drawings

FIG. 1 is a reference schematic diagram of the structure of an electric power-assisted bicycle according to an embodiment of the present invention.

detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways defined and covered by the claims.

As shown in Fig. 1, the power-assisted control method of an electric power-assisted bicycle provided in this embodiment is aimed at an electric power-assisted bicycle with the following structure, that is: the electric power-assisted bicycle includes a vehicle body and is installed on the vehicle body to drive the wheels Rotating pedal 1, booster motor 2 and booster controller 3; and the control method includes the following steps:

S1, using the rotational speed measuring sensor 2 to obtain the rotational speed value of the pedal 1, and utilizing the three-axis acceleration gyro sensor built in the booster controller 3 to obtain the inclination value of the vehicle body relative to the horizontal riding road surface;

S2. Utilize the booster controller 3 to establish a corresponding booster coefficient value according to the rotational speed value and the inclination value, and enable the booster controller 3 to control the booster motor 4 to output corresponding booster power according to the booster coefficient value.

Thus, the state of the bicycle itself and the rider's operating state and related data (such as when the bicycle is in an idle state, the pedal 1 is usually stopped, and the bicycle is usually stopped when the bicycle is ridden) can be obtained by using the rotational speed measurement sensor 2 Riders usually make the pedal 1 rotate forward to drive the wheels forward according to the road conditions and riding speed, and make the pedal 1 stop or reverse to maintain the riding speed), so that the rotational speed value can be displayed Positive value, zero or negative value and other three situations; using the three-axis acceleration gyro sensor can obtain the relevant status and data of bicycles placed idle or on the road (such as bicycles placed or traveling on an uphill section, placed or traveling In the case of a flat road section and placing or traveling on a downhill road section), so that the inclination value presents three situations such as positive value, zero or negative value; based on this, the speed value and Inclination value, so as to match different assist coefficient values for different situations, so that the assist motor can output corresponding assist ("output corresponding assist" can be understood as assisting the motor to perform forward rotation assist, stop without applying force or braking) , so as to enable the power-assisted bicycle to automatically adjust the power-assisted bicycle according to the operation of the vehicle by the rider and the road conditions on which the vehicle is driving, which provides favorable conditions for enhancing the riding experience effect and mode of the electric bicycle; at the same time, using It is widely used in acceleration gyroscope sensors in electronic consumer products such as mobile phones to detect the inclination angle of bicycles, which can effectively reduce the installation cost and use cost of the sensor.

As a preferred solution, in step S1, the unit horizontal distance value of the car body and the height drop generated by the unit horizontal distance value can be obtained through the three-axis acceleration gyro sensor, and according to the formula P _Angle = H/L × 100% to obtain the inclination value of the car body relative to the horizontal riding road surface; in the formula, P _Angle is the inclination angle of the car body relative to the horizontal riding road surface; The acceleration value of the gyro sensor in the vertical direction is obtained after the second integral (that is, according to Newton's law of motion, the velocity V _x in the vertical direction can be obtained by integrating the acceleration ax of the sensor in the vertical direction, where V _x ＝int egrate(ax,dt), the height difference H can be obtained by integrating the velocity in the vertical direction, where H＝int egrate(V _x ,dt)), the unit is m; L is the unit horizontal distance, where It is obtained by twice integrating the acceleration value of the three-axis acceleration gyro sensor in the horizontal direction (that is, according to Newton's law of motion, the speed in the horizontal direction can be obtained by integrating the acceleration az of the sensor in the horizontal direction V _z , where, V _z =int egrate(az,dt), the horizontal distance L can be obtained by integrating the velocity in the vertical direction, where L=int egrate(V _z ,dt)), and the unit is m. Of course, in order to obtain the inclination value of the car body more simply and reduce the calculation difficulty of related data, in step S1, the acceleration values of the three axes of the three-axis acceleration gyro sensor can also be utilized and according to the formula P _Angle =ar tan ( ax/Sqrt(ax ² +ay ² +az ² )) to obtain the inclination value of the car body relative to the horizontal riding road surface; where, P _Angle is the inclination angle of the car body relative to the horizontal riding road surface; ax, ay, az are respectively the acceleration values of the three axes of the three-axis acceleration gyro sensor, and the unit is m/s ² .

In order to ensure that the booster controller 3 can adjust the output power of the booster motor 2 in real time to determine whether to adjust the working conditions such as booster, stop booster, or brake, in step S1, the rotational speed measurement sensor 2 is used to continuously obtain the foot power. The rotation speed value of the pedal 1 is continuously obtained by using the three-axis acceleration gyro sensor to obtain the inclination value of the vehicle body relative to the horizontal riding road surface; at the same time, in step S2, the power assist coefficient value can be adjusted according to the rotation speed value by using the power assist controller 3 The change of the speed and the change of the inclination value, that is, different speed values and inclination values should correspond to different assist coefficient values. In this way, the magnitude of the assisting force of the assisting motor 4 can be determined.

As a preferred solution, the booster controller 3 can be set in the following manner, specifically:

1. When the speed value is positive and the inclination value is positive (or greater than a preset threshold or falls within a preset threshold range), it is considered to be riding uphill. At this time, the boost coefficient value should be It increases with the increase of the inclination value, and the power assist controller 3 controls the power assist motor 4 to output power assist according to the value of the assist coefficient at this time; And the riding slope to control the size of the assist.

2. When the speed value is negative or zero and the inclination value is negative (or less than a preset threshold or falls within a preset threshold), it can be regarded as downhill riding, and the power assist The coefficient value is zero or a negative value, and the boost controller 3 can control the boost motor 4 to stop according to the boost coefficient value at this time; thus, when the bicycle is considered to be riding downhill, it can control the boost motor 4 to stop boosting Or apply the brakes to control the speed of the bicycle, thereby reducing safety risks.

3. When the inclination value is zero (or equal to a preset threshold or falls within a preset threshold range), it is considered to be riding on a flat road, and the boost coefficient value is zero. The boost controller 3 according to this time The boost coefficient value is used to control the boost motor 4 to stop.

It should be noted that it can be seen that the bicycle is placed in a restricted state, so as to avoid misoperation of the power assist motor 4 and achieve the purpose of saving electric energy.

In order to ensure the accuracy of the detection of the rotational speed of the pedal 1, the rotational speed measuring sensor 2 can be installed on the intermediate shaft of the pedal 1, so that the rotational speed measuring sensor 2 can obtain the rotational speed synchronous with the pedal 1 data.

In addition, the boost coefficient value of this embodiment can adopt multiple thresholds or threshold ranges preset in the boost controller 3 according to the situation; thus, it is equivalent to the boost controller 3 using fuzzy calculation means to control the output of the boost motor 4 Power, such as when the inclination value is greater than -2 degrees and less than 2 degrees, it can also be considered that the inclination value is a positive value. At this time, the booster controller 3 can control the power output of the booster motor 4 according to a relatively small booster coefficient value; When the inclination value is greater than 2 degrees, the booster motor 4 is controlled to output corresponding power according to a relatively large boost coefficient value; Control booster motor 4 to stop running.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process conversion made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related All technical fields are equally included in the scope of patent protection of the present invention.

Claims (7)

1. a kind of power assist control method of electric assisted bicycle, the electric assisted bicycle includes car body and is installed on car Step tread, assist motor and assist controller on body；It is characterized in that：It the described method comprises the following steps：

S1, the tachometer value using rotating speed measuring sensor acquisition step tread, utilize 3-axis acceleration gyro sensor to obtain Car body is ridden the inclination value on road surface relative to level；

S2, using assist controller corresponding power-assisted coefficient value is established according to tachometer value and inclination value, and make assist controller root According to power-assisted coefficient value control assist motor output power-assisted.

A kind of 2. power assist control method of electric assisted bicycle as claimed in claim 1, it is characterised in that：The step S1 In, obtained using 3-axis acceleration gyro sensor caused by the unit level distance value and unit level distance value of car body Height fall, and according to formula P_Angle=H/L × 100% draws inclination value of the car body relative to horizontal road surface of riding；In formula, P_AngleAngle of inclination for car body relative to horizontal road surface of riding；H is difference in height caused by unit horizontal range, and it is to pass through 3-axis acceleration gyro sensor is drawn after the acceleration magnitude of vertical direction makees quadratic integral, unit m；L is single Position horizontal range, it is by being obtained after making quadratic integral to the acceleration magnitude of 3-axis acceleration gyro sensor in the horizontal direction Go out, unit m.

A kind of 3. power assist control method of electric assisted bicycle as claimed in claim 1, it is characterised in that：The step S1 In, using three axles of 3-axis acceleration gyro sensor acceleration magnitude and according to formula P_Angle=artan2 (ax/Sqrt (ax²+ay²+az²)) ridden the inclination value on road surface relative to level to obtain car body；In formula, P_AngleRidden for car body relative to level The angle of inclination in walking along the street face；Ax, ay, az are respectively the acceleration magnitude of three axles of 3-axis acceleration gyro sensor, unit It is m/s²。

A kind of 4. power assist control method of electric assisted bicycle as any one of claim 1-3, it is characterised in that：

In the step S1, the tachometer value of step tread is routinely obtained using rotating speed measuring sensor, is accelerated using three axles Degree gyro sensor routinely obtains inclination value of the car body relative to horizontal road surface of riding；

In the step S2, the power-assisted coefficient value changes according to the change of tachometer value and the change of inclination value.

A kind of 5. power assist control method of electric assisted bicycle as claimed in claim 4, it is characterised in that：

When the tachometer value be on the occasion of and inclination value be to ride on the occasion of being then considered as upward slope, the power-assisted coefficient value with inclination value increasing Add and increase, the assist controller controls assist motor output power-assisted according to power-assisted coefficient value；

When the tachometer value be negative value or zero and inclination value be negative value when be then considered as descending and ride, the power-assisted coefficient value be zero or Negative value, the assist controller control assist motor to stop according to power-assisted coefficient value；

Then it is considered as level road when the inclination value is zero to ride, the power-assisted coefficient value is zero, and the assist controller is according to helping Force coefficient value control assist motor stops.

A kind of 6. power assist control method of electric assisted bicycle as claimed in claim 5, it is characterised in that：By the rotating speed Measurement sensor is installed in the middle rotating shaft of step tread.

A kind of 7. power assist control method of electric assisted bicycle as claimed in claim 5, it is characterised in that：The power-assisted system Numerical value is multiple threshold values or the threshold range defaulted in assist controller.