Arduino上拉磁悬浮

johnsonzzd 于 2012-12-9 16:59 编辑



折腾了几天终于把这个东西搞定了。看似简单，还是有一些小技巧的。

主要材料：

Arduino UNO主控SS495线性霍尔采集位置信息L298N驱动直径12.7mm强磁球电磁铁12V，线圈电阻10欧



主要参数：PID控制，采样周期1ms，PWM频率 3921Hz，悬浮距离30mm，电流300mA

筷子版的，下面是一个磁体，上面是一个小铁块，中间是一截筷子。悬浮距离比较小，但是方便进行建模和控制理论分析。

2012-5-22 18:12 上传
(149.8 KB)

磁球版，悬浮距离很大，不容易进行理论分析。

2012-5-22 18:12 上传
(96.95 KB)

ARDUINO 代码复制打印

const int SS495_PIN = A0;// Analog input pin that the SS495 is attached toconst int PWM_PIN=3;// Pins 3 and 11 are connected to Timer 2.const int SampleTime=600;const int PWM_BIAS=128;int Setpoint=850;double Kp=1, Ki=0.001, Kd=50;void setupCoilPWM(){ // Setup the timer 2 as Phase Correct PWM, 3921 Hz. pinMode(3, OUTPUT); // Timer 2 register: WGM20 sets PWM phase correct mode, COM2x1 sets the PWM out to channels A and B. TCCR2A = 0; TCCR2A = _BV(COM2A1) | _BV(COM2B1) | _BV(WGM20); // Set the prescaler to 8, the PWM freq is 16MHz/255/2/<prescaler> TCCR2B = 0; TCCR2B = _BV(CS21);}void writeCoilPWM(uint8_t pin, int val){  OCR2B = val;}void PID_Compute( ){static int lastError=0;static unsigned long int lastTime=0;static double iiterm=0;unsigned long now,timeChange;int input,output,error,piterm,diterm;now = micros();timeChange = (now - lastTime);if(timeChange>=SampleTime){  lastTime = now;  input=read_input();  error = -(Setpoint - input);  iiterm+= (Ki * error);  iiterm=constrain(iiterm,-255,255);  piterm=Kp * error;  diterm=Kd * (error - lastError)1000/timeChange;  output = PWM_BIAS+(piterm + diterm);  output=constrain(output,0,255);  writeCoilPWM(PWM_PIN, output);  // print the results to the serial monitor:  //sprintf(str,"%04d,%+04d,%+04d,%+04d,%04d",error,piterm,diterm,(int)iiterm,output);  //Serial.println(str);   /Remember some variables for next time*/  lastError = error; }}int read_input(){static int last=0;int r;r=analogRead(SS495_PIN);if(abs(r-last)<4)  r=last;else  last=r;return r;}void setup() {setupCoilPWM();}void loop() {// read the analog in value:PID_Compute();}

const int SS495_PIN = A0;// Analog input pin that the SS495 is attached to


const int PWM_PIN=3;// Pins 3 and 11 are connected to Timer 2.





const int SampleTime=600;


const int PWM_BIAS=128;





int Setpoint=850;


double Kp=1, Ki=0.001, Kd=50;





void setupCoilPWM()


{


// Setup the timer 2 as Phase Correct PWM, 3921 Hz.


pinMode(3, OUTPUT);


// Timer 2 register: WGM20 sets PWM phase correct mode, COM2x1 sets the PWM out to channels A and B.


TCCR2A = 0;


TCCR2A = _BV(COM2A1) | _BV(COM2B1) | _BV(WGM20);


// Set the prescaler to 8, the PWM freq is 16MHz/255/2/<prescaler>


TCCR2B = 0;


TCCR2B = _BV(CS21);


}





void writeCoilPWM(uint8_t pin, int val)


{


OCR2B = val;


}





void PID_Compute( )


{


static int lastError=0;


static unsigned long int lastTime=0;


static double iiterm=0;





unsigned long now,timeChange;


int input,output,error,piterm,diterm;





now = micros();


timeChange = (now - lastTime);


if(timeChange>=SampleTime)


{


lastTime = now;





input=read_input();





error = -(Setpoint - input);





iiterm+= (Ki * error);


iiterm=constrain(iiterm,-255,255);





piterm=Kp * error;


diterm=Kd * (error - lastError)1000/timeChange;


output = PWM_BIAS+(piterm + diterm);


output=constrain(output,0,255);


writeCoilPWM(PWM_PIN, output);





// print the results to the serial monitor:


//sprintf(str,"%04d,%+04d,%+04d,%+04d,%04d",error,piterm,diterm,(int)iiterm,output);


//Serial.println(str); 





/Remember some variables for next time*/


lastError = error;


}


}





int read_input()


{


static int last=0;


int r;


r=analogRead(SS495_PIN);


if(abs(r-last)<4)


r=last;


else


last=r;


return r;


}





void setup() {


setupCoilPWM();


}





void loop() {


// read the analog in value:


PID_Compute();


}

下一步准备加上串口通讯，用matlab做上位机界面。已经做好了Arduino的自平衡车和两旋翼模型，有空也放上来。

自平衡车就在这里：
http://www.geek-workshop.com/thread-2398-1-1.html

单旋翼实验装置，已经发到amobbs了，有详细资料：
http://www.amobbs.com/thread-5505843-1-1.html

via - 极客工坊