CN111924037B

CN111924037B - Climbing compensation processing method for electric power-assisted bicycle

Info

Publication number: CN111924037B
Application number: CN201911231139.6A
Authority: CN
Inventors: 张培峰; 缪鹏程
Original assignee: Nanjing Lishui Electronics Research Insititue Co ltd
Current assignee: Nanjing Lishui Electronics Research Insititue Co ltd
Priority date: 2019-12-05
Filing date: 2019-12-05
Publication date: 2022-04-05
Anticipated expiration: 2039-12-05
Also published as: CN111924037A; WO2021109174A1

Abstract

The invention discloses a climbing compensation processing method for an electric power-assisted bicycle, which comprises the following steps: (1) measuring the rolling friction coefficient; (2) measuring inertia coefficients; (3) pre-estimating a road surface; (4) step frequency phase locking; (5) pre-estimating the pedaling force; (6) obtaining a compensated output value; the method of the invention realizes the self-adaptation of the uphill or load change of the vehicle by processing the pulse signal of the pedal speed sensor, the output power of the motor and the vehicle speed signal and driving the motor by the processed power-assisted signal.

Description

Climbing compensation processing method for electric power-assisted bicycle

Technical Field

The invention relates to a climbing compensation processing method for a bicycle, in particular to a climbing compensation processing method for an electric power-assisted bicycle.

Background

Most of the existing electric moped are equipped with a Speed Sensor (Speed Sensor), and the function of the Speed Sensor is to determine the output power of the motor according to the pedal frequency of a rider. Generally, the faster the foot is stepped on, which means that the rider needs a faster speed, the power output by the motor should be increased accordingly, so as not to cause much energy consumption by the rider. Conversely, the slower the pedaling, the less the output power of the motor. Because the prior power-assisted method is that the power-assisted output calculated according to the pedaling frequency is weak, the power-assisted riding feeling is poor.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a climbing compensation processing method for an electric power-assisted bicycle, which obtains output values with road slope compensation and load compensation to drive a motor and realize automatic boosting during load or uphill riding.

The technical scheme is as follows: the processing method comprises the following steps: measuring the rolling friction coefficient; (2) measuring inertia coefficients; (3) the road surface estimation (4) is used for locking the tread frequency phase (5) and the tread force estimation (6) is used for obtaining a compensated output value. The detailed calculation is as follows:

1. the step (1) of measuring the rolling friction coefficient comprises the following steps:

(1.1) measuring the current vehicle speed V;

(1.2) measuring the current output current I and the current output voltage U of the controller

(1.3) calculating output power P ═ U ═ I

(1.4) when the vehicle is runningThe speed is at the speed limit point, and after the controller limits the speed for 3 seconds, the rolling friction coefficient G is calculated_f＝P/V；

2. The step (2) of measuring the inertia coefficient comprises the following steps:

(2.1) vehicle speeds V0 and V1 at times t0 and t1, respectively, are measured, and t1-t0 is 3S;

(2.2) when V0<V1, measuring average power P output by the controller in t0 and t1_avg；

(2.3) calculating inertia coefficient Gv ═ P_avg/V-G_f)Dt/Dv；

3. And (3) road surface estimation:

road surface coefficient Gi ═ P/V-G_f-G_V*Dv/Dt

4. Step-frequency phase locking in step (4):

the speed sensor generates n pulses every time the speed sensor steps on one circle, the current value I (t) of the motor is recorded every time the pulse is output in the n pulses, and t belongs to (0, n). The maximum value I (t) max and the minimum value I (t) min of I (t) are calculated.

Tmax pulses are generated to represent 270 ° or 90 ° of fig. 2, and tmin pulses are generated to represent 180 ° or 0 ° of fig. 2. If the value of tmin-tmax is close to n/4, the foot is stepped at 0 degree for tmin pulses

5. Step (5) estimating the pedaling force:

tracking the phase of the pedal based on the phase lock value, the controller measures the current I of the pedal at 90 DEG and 0 DEG_90°And I_0°。

The peak value Im of the current fluctuation is I_90°-I_0°

Im is proportional to the magnitude of the pedaling force.

6. Step (6) compensating the output value (V)_ref)：

V_ref＝Vs+KGi+K₁Im

Wherein Vs is a power assisting value calculated according to the pedaling frequency, K is a constant coefficient adjusted within the range of 0 to 1 according to the riding effect, and K is₁The moment compensation coefficient riding effect is adjusted within the range of 0 to 1.

Has the advantages that: compared with the prior art, the invention has the following remarkable effects: 1. the boosting value is increased during acceleration, and the acceleration boosting effect is improved; 2. when riding on an uphill slope, the power assisting value can be increased, and the climbing riding is more labor-saving; 3. when the load is large or light, the force-assisting value can be adjusted, and the riding feeling of too heavy or too light is avoided; 4. the riding feeling of the speed sensor with low configuration price is close to the riding feeling of the torque sensor with high configuration price.

Drawings

FIG. 1 is a waveform diagram of a pedal turn torque signal according to the present invention;

FIG. 2 is a schematic crank angle diagram of the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and the detailed description.

A climbing compensation processing method for an electric power-assisted bicycle comprises the following steps:

(1) determination of coefficient of Rolling Friction

The magnitude of the rolling friction force depends on the material of the tire, the friction coefficient of the road surface, the width of the tire, the size of the wheel diameter, the static pressure on the road surface and other factors. This coefficient, which cannot be a constant value, may change at any time as the ride changes. When the bicycle is ridden to the speed limit point, the speed can not change any more, and the bicycle is normally considered to be ridden on a flat road or downhill. The vehicle speed V measured by the vehicle speed sensor fluctuates near the speed limit point, and the average value is the speed limit point. The bus current I and the bus voltage U of the controller can be directly measured by the controller. The output power P of the controller is U × I. Continuously monitoring the measured vehicle speed V, and if the fluctuation is small within 3 seconds, calculating the rolling friction coefficient G_fIf 5 ═ P/V<G_f<15, then G_fIs a usable value, otherwise the calculation needs to be re-checked.

(2) Determination of inertia coefficient

The instantaneous value of the speed is recorded every 3 seconds, the last time being t0 and the current time being t 1. The speed at the previous time is denoted as V0, and the speed at the current time is denoted as V1. When V0<At V1, the vehicle may be considered to be in an acceleration phase. In the time period from t0 to t1, the power value may fluctuate greatly, so that the power value needs to be calculated for multiple times in the time periodPower value to obtain average power P_avg。

Calculating the time difference Dt-t 1-t 0;

calculating the speed difference Dv between V1 and V0;

calculating the inertia coefficient Gv when 2< Dv < 3:

Gv＝(P_avg/V-G_f)Dt/Dv

if Gv >0, then Gv is an available value.

(3) Road surface estimation

Due to a single calculated G_fAnd Gv, possibly with errors, and influenced by measurement noise, with discrepancies in their values, using dereferences and first-order low-pass filtering, for G_fAnd Gv.

G_ffilter＝G_ffilter*k_coeff+(1-k_coeff)*Mid[G_f(n-2),G_f(n-1),G_f(n)]

G_ffilterIs filtered G_fValue, k_coeffThe filtering weight coefficient takes a value in the range of 0 to 1 and is adjusted according to the actual riding feeling; mid [ 2 ]]To calculate the median of the three input values.

G_f(n) G representing a single calculation at time n_f；

Gv_filter＝Gv_filter*k_coefv+(1-k_coefv)*Mid[Gv(n-2),Gv(n-1),Gv(n)]

Gv_filterFor the filtered value of Gv, k_coefvThe filtering weight coefficient takes a value in the range of 0 to 1 and is adjusted according to the actual riding feeling; mid [ 2 ]]To calculate the median of the three input values.

G_v(n) G representing a single calculation at time n_v；

Gi＝P/V-Gf_filter-Gv_filter*Dv/Dt

Gi is a composite coefficient value containing road surface gradient and load information. Gi is greater when the gradient is greater and greater when the load is greater.

(4) The step frequency phase locking is as follows:

the speed sensor can generate n pulses every time the speed sensor steps one circle, the current value I (t) of the motor is recorded every time the pulse is output in the n pulses, and t epsilon (0, n). The maximum value I (tmax) and the minimum value I (tmin) of I (t) are calculated.

Tmax pulses are generated to represent 270 ° or 90 ° of fig. 2, and tmin pulses are generated to represent 180 ° or 0 ° of fig. 2. If the value tmin-tmax is close to n/4, then the pedal is 0 ° for tmin pulses.

(5) Estimation of pedal force

Tracking the phase of the pedal according to the phase-locked value, and measuring the current I of the pedal at 90 DEG and 0 DEG_90°And I_0°。

The peak value Im of the current fluctuation is I_90°-I_0°

Im is proportional to the magnitude of the pedaling force.

(6) Compensation value

The compensated boost output may be expressed as

V_ref＝KGi+K₁Im

K is a constant coefficient and is adjusted within the range of 0 to 1 according to the actual riding effect; k₁The moment compensation coefficient is adjusted within the range of 0 to 1 according to the actual riding effect.

Processed compensation power-assisted output value V_refThe output voltage duty ratio of the motor can be controlled by directly utilizing a PID closed-loop control method, so that the power is automatically increased when a rider rides on a load or an uphill slope, and the rider can feel easier and more labor-saving. In addition, the assisting force value is increased correspondingly during the acceleration riding process.

Claims

1. The climbing compensation processing method of the electric power-assisted bicycle is characterized by comprising the following steps of: (1) measuring the rolling friction coefficient; (2) measuring inertia coefficients; (3) pre-estimating a road surface; (4) step frequency phase locking; (5) pre-estimating the pedaling force; (6) obtaining a compensated output value;

wherein the determination of the rolling friction coefficient in the step (1) comprises the following steps:

(1.1) measuring the current vehicle speed V;

(1.2) measuring the current output current I and the current output voltage U of the controller;

(1.3) calculating output power P ═ U × I;

(1.4) when the speed of the vehicle is at the speed limit point and the controller limits the speed for 3s (seconds), calculating the rolling friction coefficient G_f＝P/V；

The determination of the inertia coefficient in the step (2) comprises the following steps:

(2.1) vehicle speeds V0 and V1 at times t0 and t1, respectively, are measured, and t1-t0 is 3 s;

(2.2) when V0<V1, measuring the average power P output by the controller in the time from t0 to t1_avg；

(2.3) calculating inertia coefficient Gv ═ P_avg/V-G_f) Dt/Dv, wherein Dv-V1-V0, Dt-t 1-t 0;

the road surface estimation in the step (3) is as follows: road surface coefficient Gi ═ P/V-G_f-G_V*Dv/Dt；

The step frequency phase locking in the step (4) is as follows:

when the speed sensor steps one turn, n pulses are generated, the current value I (t) of the motor is recorded when the pulse is output every time in the n pulses, and t belongs to (0, n); calculating the maximum value I (t) max and the minimum value I (t) min in I (t);

the foot pedal is 270 degrees or 90 degrees when generating tmax pulses, and 180 degrees or 0 degrees when generating tmin pulses; if the value of tmin-tmax is close to n/4, pedaling is 0 degree when tmin pulses occur;

estimating the pedaling force in the step (5) as follows:

tracking the phase of the pedal based on the phase lock value, the controller measures the current I at 90 DEG and 0 DEG of the pedal_90°And I_0°The peak value Im of the current fluctuation is I_90°-I_0°(ii) a Im is in direct proportion to the magnitude of the pedaling force;

the compensated output value V in the step (6)_refComprises the following steps:

V_ref＝Vs+KGi+K₁Im

vs is a power assisting value calculated according to the pedaling frequency, and K is a constant coefficient which is adjusted within the range of 0 to 1 according to the riding effect; k₁Adjusting the moment compensation coefficient riding effect within the range of 0 to 1;

processed compensation power-assisted output value V_refUsing PIDThe closed-loop control method controls the duty ratio of the output voltage of the motor, so that the power assistance is automatically increased when a user rides on a load or an uphill slope.