CN103529850B - Double-wheel self-balancing car control method - Google Patents

Abstract

A kind of double-wheel self-balancing car control method, comprises the following steps: (1) initializes；(2) value of gyroscope, accelerometer and rotary angle transmitter and the pulse number of encoder are read respectively；(3) car body inclination angle, handlebar corner, motor speed and speed are asked for；(4) then upright control, direction controlling and the PWM value of speed controlling are calculated respectively by pid control algorithm；(5) three PWM value are superimposed output to left and right motor；(6) data of gyroscope, accelerometer, car body inclination angle, cell voltage, current of electric and speed are then sent to host computer, to monitor the running status of car load；(7) when monitoring cell voltage and being more than preset value less than preset value, current of electric or speed, then corresponding LED warning lamp is opened；(8) when monitoring car body inclination angle more than predetermined angle, it is determined that car body is fallen and out of service, come back in the middle of initialization program.The present invention uses more accurate operation method.

Description

Double-wheel self-balancing car control method

Technical field

The present invention relates to double-wheel self-balancing car, especially double-wheel self-balancing car control method.

Background technology

Self-balance electric vehicle autobalance operation principles is mainly built upon one and is referred to as " dynamic stability " (Dynamic Stabilization) in ultimate principle, the namely autobalance ability of vehicle itself.With built-in accurate solid-state gyro Instrument (Solid-State Gyroscopes) judges the posture state residing for vehicle body, through the accurate and micro-process of central authorities at a high speed After device calculates suitable instruction, motor is driven to accomplish the effect of balance.Current balance car allows user when riding Arbitrarily rocking, control system thereon can automatically be driven motor process and be balanced revising；Due to existing control system Algorithm errors, cause drive motor balance correction time longer, make the Self-Balancing vehicle of this type deposit in use Risk bigger.

Summary of the invention

For solving above-mentioned technical problem, the technical scheme is that a kind of double-wheel self-balancing car control method, including with Lower step:

(1), after double-wheel self-balancing car powers on operation, system initially enters each initialization program, initialize including phaselocked loop, AD conversion initializes, intervalometer initializes, PWM initializes and and port initialization；

(2), after then time delay 1s waiting system is stable, gyroscope, accelerometer and rotary angle transmitter initial value are then read, Time delay 1s waits Parameters variation again；

(3) program setting 1ms interrupt function, upright controlling, direction controlling and speed controlling be all placed on period simultaneously Carry out；When 1ms interrupts producing, read the value of gyroscope, accelerometer and rotary angle transmitter and the arteries and veins of encoder the most respectively Rush number；

(4) carry out gyroscope and accelerometer data fused filtering by Kalman filtering, ask for car body inclination angle；Pass through The value of rotary angle transmitter calculates handlebar corner；Motor speed and speed is calculated by the pulse number of encoder；

(5) then upright control, direction controlling and the PWM value of speed controlling are calculated respectively by pid control algorithm；

(6) three PWM value are superimposed output to left and right motor；

(7) data of gyroscope, accelerometer, car body inclination angle, cell voltage, current of electric and speed are then sent to upper Position machine, to monitor the running status of car load；

(8) when monitoring cell voltage and being more than preset value less than preset value, current of electric or speed, then open corresponding LED warning lamp；When monitoring car body inclination angle more than predetermined angle, it is determined that car body is fallen and out of service, again return In the middle of initialization program.

The present invention is compared with prior art had the benefit that

The present invention uses more accurate operation method, and the time making driving motor balance correction is shorter, reduces from flat The risk that weighing apparatus car exists in use.

Accompanying drawing explanation

Fig. 1 is control flow chart of the present invention.

Detailed description of the invention

Below in conjunction with Figure of description, the invention will be further described.

As it is shown in figure 1, a kind of double-wheel self-balancing car control method, comprise the following steps:

(1), after double-wheel self-balancing car powers on operation, system initially enters each initialization program, initialize including phaselocked loop, AD conversion initializes, intervalometer initializes, PWM initializes and and port initialization；

(2), after then time delay 1s waiting system is stable, gyroscope, accelerometer and rotary angle transmitter initial value are then read, Time delay 1s waits Parameters variation again；

(3) program setting 1ms interrupt function, upright controlling, direction controlling and speed controlling be all placed on period simultaneously Carry out；When 1ms interrupts producing, read the value of gyroscope, accelerometer and rotary angle transmitter and the arteries and veins of encoder the most respectively Rush number；

(4) carry out gyroscope and accelerometer data fused filtering by Kalman filtering, ask for car body inclination angle；Pass through The value of rotary angle transmitter calculates handlebar corner；Motor speed and speed is calculated by the pulse number of encoder；

(5) then upright control, direction controlling and the PWM value of speed controlling are calculated respectively by pid control algorithm；

(6) three PWM value are superimposed output to left and right motor；

(7) data of gyroscope, accelerometer, car body inclination angle, cell voltage, current of electric and speed are then sent to upper Position machine, to monitor the running status of car load；

(8) when monitoring cell voltage and being more than preset value less than preset value, current of electric or speed, then open corresponding LED warning lamp；When monitoring car body inclination angle more than predetermined angle, it is determined that car body is fallen and out of service, again return In the middle of initialization program.

Correlation value calculation aa+=P_enc*enc_anglespeed*dt*0.001+ (1-P_enc) * (acc_angle- angle)；// Dip countion；

The inclination angle that aa: gyroscope draws after merging with accelerometer；

P_enc: proportionality coefficient；

The AD value of enc_angkespeed: gyroscope；

Dt: gyroscope time of integration；

Acc_angle: angular velocity AD value；

Angle: inclination angle.

PWM_angle=(int)(pp*angle+D_angle*enc_anglespeed);// upright PWM calculates；

PP: proportionality coefficient；

D_angle: differential coefficient；

PWM_angle: upright PWM value.

PWM_turn=(int)(P_turn*turn)；// turn to PWM to calculate；

P_turn: ratio of turning coefficient；

The AD value of turn: rotation direction sensor；

PWM_turn;Turn to PWM value.

1, double-wheel self-balancing car each parts parameter designing and calculating

Single shaft electric motor car parameter designing of riding instead of walk mainly determines population structure size, mass parameter, Specifeca tion speeification, electricity Machine nominal parameter, gear ratio size, battery capacity size etc..

1.1, complete vehicle structure parameter

(1) contour dimension

What scooter was focused on is portable, motility, and car body is similar with the shoulder breadth of people at floor projection area.Therefore, just Fixed overall contour dimension is long 680mm, and wide 360mm, high 1140mm, wherein step height is 250mm.

(2) wheelspan

For scooter, wheelspan change is main and has influence on roll stiffness.Increase wheelspan, be conducive to having increased inclination just Degree, lateral stability is good, but adjoint be the increase of full car length and quality.Therefore, after considering, selection wheelspan is 600mm。

(3) mass parameter

What scooter quality accounting was maximum is lithium battery group, motor, decelerator and wheel, and quality is the biggest, and power consumption is the most, from And reduce cruise mileage.In order to control mass value, body part have employed truss structure, pedal and car shell and uses carbon fiber Structure, it is ensured that alleviate complete vehicle quality while attractive in appearance to greatest extent.

Owing to the detailed quality of each parts is not known, complete vehicle curb weight cannot accurately obtain.But in order to from energy-conserving and environment-protective, The lightest setting out, elect 40kg at the beginning of complete vehicle curb weight as, mounted mass is 100kg.(4) Specifeca tion speeification

According to investigation, general scooter max. speed is 15-25km/h, accelerates to the time used by max. speed from static be 2-5s, the highest gradient that can climb up is 15-30 °；It is thus determined that single shaft is ridden instead of walk, electrical vehicular power parameter is: max. speed 20km/h, acceleration time 3s, max. climb slope 20 °.Owing to scooter is as short distance running vehicle, speed is unsuitable too high, Otherwise easily cause unstability, reduce safety coefficient；Acceleration time is at mild cement pavement under the inclination angle that car body allows Accelerating to the time used by max. speed continuously, scooter is quick on the draw, and typically just can reach high-speed cruising shape with little time State；Scooter is that level road use is more, and occasional runs into uphill condition, thus sets maximum climbing attitude 20 °, with satisfied difference The demand of crowd.

Owing to scooter left and right motor all can independently control, realize turning to differential control by control system, therefore minimum Radius of turn is zero, maneuverability.

1.2, the parameter of electric machine

All actions of scooter are all to be completed by motor, and the parameter of electric machine determines the most crucial, it is necessary to select suitable motor Meet car load and use requirement.Power of motor is the biggest, and dynamic property is the best, but also along with in quality increase, volume increase, price Rise.Therefore, motor parameters is it is crucial that determine the rated power of motor.

Scooter herein with max. speed run time as declared working condition, power demand:

$P=\frac{1}{\mathrm{\η}}(\frac{G{\mathrm{fu}}_a}{3600}+\frac{C_D{\mathrm{Au}}_a^3}{76140})$

(2-1)

Wherein, η is transmission efficiency, and G is to act on the gravity (N) on automobile, and f is coefficient of rolling resistance, u_aFor the highest car Speed (km/h), C_DFor coefficient of air resistance；A is front face area (m²), then: during scooter zero load, G=40 × 9.8N, f=0.012, C_D=0.3,A=1.2m²,u_a=20km/h,η=0.95

$P=\frac{1}{0.95}(\frac{40\×9.8\×0.012\×20}{3600}+\frac{0.3\×1.2\×{20}^3}{76140})=0.094\mathrm{kW}$

Scooter full load, G=140 × 9.8N, f=0.012, C_D=0.3,A=2m²,u_a=20km/h,η=0.95

$P=\frac{1}{0.95}(\frac{140\×9.8\×0.012\×20}{3600}+\frac{0.3\×2\×{20}^3}{76140})=0.163\mathrm{kW}$

But the stand-by power that it is critical only that motor that scooter can keep balance at any time is sufficiently large, empirical tests Bright, the rated power of motor must be calculate power demand more than 3 times.Therefore, selected herein direct current generator major parameter It is: rated voltage 24V, rated power 500W, rated speed 4500r/min, nominal torque 1.06Nm.

1.3, gear ratio

Gear ratio is determined by relation between car load max. speed and Rated motor rotating speed.Tire outside diameter is 14in herein, looks into Table can obtain vehicle wheel roll radius r=180mm, max. speed v=20km/h=333.3m/min, and wheel circumference C=2 π r=2 × 3.14 × 0.18=1.13m(2-2)

Then wheel rated speed=(2-3)

Gear ratio $i=\frac{4500}{294.9}\≈15$ (2-4)

1.4, lithium ion battery

Lithium ion battery parameter determination, it is crucial that battery capacity size, can be obtained by car load cruise mileage calculation.By In being affected by various factors such as temperature, humidity, battery material, service conditions, the impossible full capacity of battery, put the most completely Electricity, will quit work to certain voltage.Therefore, battery capacity availability coefficient λ=0.8 is set during calculating.

Scooter when max. speed is run, electric current(2-5)

Cruise mileage is 35km required time(2-6)

Then battery capacity is $Q=\frac{\mathrm{It}}{\mathrm{\λ}}=\frac{6.79\×1.75}{0.8}=14.85\mathrm{Ah}$ (2-7)

Therefore, the lithium battery group of 24V15Ah assembled in series is selected.

2, dynamic property is checked

2.1, the acceleration time checks

Calculating below under rated voltage, scooter, from the static time t accelerated to needed for max. speed, was derived in detail Journey is as follows:

Motor speed(2-8)

Motor output torque(2-9)

Wheel drive torque(2-10)

Can obtain car load acceleration:

$a=\frac{\mathrm{du}}{\mathrm{dt}}=\frac{F}{m}=\frac{T_t/r-\mathrm{Gf}}{m}=\frac{318.3\frac{P_N\mathrm{\π\η}}{u}-\mathrm{mgf}}{m}$ (2-11)

Arrange:

$\frac{\mathrm{du}}{\mathrm{dt}}=\frac{318.3\×3.14\×0.5\×2\×0.95}{140u}-0.012\×9.8=\frac{6.78}{u}-0.12$ (2-12)

Above formula both sides integration simultaneously is obtained:

$\∫\mathrm{dt}=\∫\frac{u}{6.78-0.12u}\mathrm{du}$ (2-13)

That is:

$t={\∫}_0^{5.6}\frac{u}{6.78-0.12u}\mathrm{du}$ (2-14)

Order $m=\frac{u}{6.78-0.12u},$ ? $u=\frac{6.78-m}{m},\mathrm{du}=-8.33\mathrm{dm}$

$\begin{array}{c}t=8.33{\∫}_{6.1}^{6.8}\frac{6.78-m}{0.12m}\mathrm{dm}\\ =8.33\×(56.5\ln m-8.33m{|}_{6.1}^{6.8})\\ =2.4s\end{array}$ (2-15)

As can be seen here, the single shaft designed herein is ridden instead of walk electric motor car, is dried cement pavement in level, accelerates to from static beginning Max. speed 20km/h, the acceleration time is 2.4s, and less than preset value 3s, dynamic property is good.

2.2, max. climb slope is checked

When scooter goes up a slope, main stress is resistance to rolling, grade resistance and driving force effect, and wherein resistance to rolling is F_f =Gfcos α (2-16)

Grade resistance is F_i=Gsin α (2-17)

Rated motor moment of torsion $T_N=9550\frac{P_N}{n_N}=9550\frac{0.5}{4500}=1.06\mathrm{Nm}$ (2-18)

Motor maximum torque T_max=λT_N(2-19)

Wherein, λ is overload factor, generally 1.8-2.2, takes λ=2, then;

T_max=λT_N=2×1.06=2.12Nm

During owing to seeking max. climb slope, scooter at the uniform velocity advances,Obtained by stress balance:

F_t=F_f+F_i(2-20)

I.e. G (fcos α+sin α)=F_t(2-21)

Arrange:

$\cos \mathrm{\α}+50\sin \mathrm{\α}=\frac{335.7\×50}{140\×9.8}=12.2$ (2-22)

$\frac{\cos \mathrm{\α}}{\sqrt{1+{50}^2}}+\frac{50\sin \mathrm{\α}}{\sqrt{1+{50}^2}}=\frac{12.2}{\sqrt{1+{50}^2}}$ (2-23)

Order $\sin \mathrm{\β}=\frac{1}{\sqrt{1+{50}^2}},\cos \mathrm{\β}\frac{50}{\sqrt{1+{50}^2}},$ Then:

$\sin \mathrm{\β}\cos \mathrm{\α}+\cos \mathrm{\β}\sin \mathrm{\α}=\frac{12.2}{\sqrt{1+{50}^2}}$ (2-24)

$\sin (\mathrm{\α}+\mathrm{\β})=\frac{12.2}{\sqrt{1+{50}^2}}$ (2-25)

Solve $\mathrm{\α}+\mathrm{\β}=\arcsin \left(\frac{12.2}{\sqrt{1+{50}^2}}\right)=25.3.$

$\mathrm{\β}=\arcsin \left(\frac{1}{\sqrt{1+{50}^2}}\right)=1.15.$

Max. climb slope α=alpha+beta-β=25.3-1.15=24.15 ° (2-26)

Therefore, max. climb slope is bigger than preset value 20 °, meets requirement.

Claims (1)

1. a double-wheel self-balancing car control method, it is characterised in that comprise the following steps:

(1) after double-wheel self-balancing car powers on operation, system initially enters each initialization program, turns including phaselocked loop initialization, AD Change initialization, intervalometer initializes, PWM initializes and and port initialization；

(2), after then time delay 1s waiting system is stable, then reads gyroscope, accelerometer and rotary angle transmitter initial value, then prolong Time 1s wait Parameters variation；

(3) program setting 1ms interrupt function, upright controlling, direction controlling and speed controlling be all placed on period and carry out simultaneously； When 1ms interrupts producing, read the value of gyroscope, accelerometer and rotary angle transmitter and the pulse of encoder the most respectively Number；

(4) carry out gyroscope and accelerometer data fused filtering by Kalman filtering, ask for car body inclination angle；Pass through corner The value of sensor calculates handlebar corner；Motor speed and speed is calculated by the pulse number of encoder；

(5) then upright control, direction controlling and the PWM value of speed controlling are calculated respectively by pid control algorithm；

(6) three PWM value are superimposed output to left and right motor；

(7) data of gyroscope, accelerometer, car body inclination angle, cell voltage, current of electric and speed are then sent to upper Machine, to monitor the running status of car load；

(8) when monitoring cell voltage and being more than preset value less than preset value, current of electric or speed, then open corresponding LED warning lamp；When monitoring car body inclination angle more than predetermined angle, it is determined that car body is fallen and out of service, come back to In the middle of initialization program；

Complete vehicle structure parameter: overall contour dimension is long 680mm, and wide 360mm, high 1140mm, wherein step height is 250mm； The wheelspan of wheel is 600mm；Pedal and car shell use carbon fiber structural；Max. speed 20km/h, acceleration time 3s, maximum is climbed The gradient 20 °；

The parameter of electric machine: rated voltage 24V, rated power 500W, rated speed 4500r/min, nominal torque 1.06Nm；

Gear ratio: between car load max. speed and Rated motor rotating speed, relation gear ratio i is 15；

Acceleration time check includes:

Calculating below under rated voltage, double-wheel self-balancing car, from the static time t accelerated to needed for max. speed, is derived in detail Process is as follows:

Motor speed

Motor output torque

Wheel drive torque

Can obtain car load acceleration:

$a=\frac{du}{dt}=\frac{F}{m}=\frac{T_t/r-Gf}{m}=\frac{318.3\frac{P_N\mathrm{\π}\mathrm{\η}}{u}-mgf}{m}---(2-11)$

Arrange:

$\frac{du}{dt}=\frac{318.3\×3.14\×0.5\×2\×0.95}{140u}-0.012\×9.8=\frac{6.78}{u}-0.12---(2-12)$

Above formula both sides integration simultaneously is obtained:

$\∫dt=\∫\frac{u}{6.78-0.12u}du---\left(2-13\right)$

That is:

$t={\∫}_0^{5.6}\frac{u}{6.78-0.12u}du---(2-14)$

Order?Du=-8.33dm

$\begin{array}{c}t=8.33{\∫}_{6.1}^{6.8}\frac{6.78-m}{0.12m}dm\\ =8.33\×(56.5\ln m-8.33m{|}_{6.1}^{6.8})\\ =2.4s\end{array}$

Being dried cement pavement in level, start to accelerate to max. speed 20km/h from static, the acceleration time is 2.4s, less than presetting Value 3s；

Max. climb slope is checked and is included:

When double-wheel self-balancing car goes up a slope, main stress is resistance to rolling, grade resistance and driving force effect, wherein

Resistance to rolling is F_f=Gf cos α

(2-16)

Grade resistance is F_i=G sin α

(2-17)

Rated motor moment of torsion

Motor maximum torque T_max=λ T_N

(2-19)

Wherein, λ is overload factor, for 1.8-2.2, takes λ=2, then；

T_max=λ T_N=2 × 1.06=2.12Nm

During owing to seeking max. climb slope, double-wheel self-balancing car at the uniform velocity advances,Obtained by stress balance:

F_t=F_f+F_i

(2-20)

I.e. G (f cos α+sin α)=F_t

(2-21)

Arrange:

$\cos \mathrm{\α}+50\sin \mathrm{\α}=\frac{335.7\×50}{140\×9.8}=12.2---(2-22)$

$\frac{\cos \mathrm{\α}}{\sqrt{1+{50}^2}}+\frac{50\sin \mathrm{\α}}{\sqrt{1+{50}^2}}=\frac{12.2}{\sqrt{1+{50}^2}}---(2-23)$

OrderThen:

$\sin \mathrm{\β}\cos \mathrm{\α}+\cos \mathrm{\β}\sin \mathrm{\α}=\frac{12.2}{\sqrt{1+{50}^2}}---(2-24)$

$\sin (\mathrm{\α}+\mathrm{\β})=\frac{12.2}{\sqrt{1+{50}^2}}---(2-25)$

Solve

Max. climb slope α=alpha+beta-β=25.3-1.15=24.15

(2-26)

Max. climb slope is bigger than preset value 20 °, meets requirement；

U is car maximum speed, and r is vehicle wheel roll radius, and η is transmission efficiency, and G is to act on the gravity on automobile, and f is for rolling resistance Force coefficient.