File content as of revision 24:56db31267f10:

#include "mbed.h"
#include "HIDScope.h"
#include "MODSERIAL.h"
#include "biquadFilter.h"
#include "QEI.h"
#include "math.h"

/*--------------------------------------------------------------------------------------------------------------------
-------------------------------- BIOROBOTICS GROUP 14 ----------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------*/

//Define important constants in memory
#define     PI              3.14159265
#define     SAMPLE_RATE     0.002   //500 Hz EMG sample rate
#define     CONTROL_RATE    0.01    //100 Hz Control rate
#define     ENCODER1_CPR    4200    //encoders have 64 (X4), 32 (X2) counts per revolution of motor shaft
#define     ENCODER2_CPR    4200    //gearbox 1:131.25 ->  4200 counts per revolution of the output shaft (X2), 

/*--------------------------------------------------------------------------------------------------------------------
---- OBJECTS ---------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------*/

MODSERIAL pc(USBTX,USBRX);      //serial communication
DigitalIn button(PTA1);         //buttons
DigitalIn button1(PTB9);        //

//EMG shields
AnalogIn    emg1(A0);           //Analog input - Biceps EMG
AnalogIn    emg2(A1);           //Analog input - Triceps EMG
AnalogIn    emg3(A2);           //Analog input - Flexor EMG
AnalogIn    emg4(A3);           //Analog input - Extensor EMG

Ticker      sample_timer;       //Ticker for EMG sampling
Ticker      control_timer;      //Ticker for control loop
HIDScope    scope(4);           //Scope 4 channels

// AnalogIn potmeter(A4);       //potmeters
// AnalogIn potmeter2(A5);      //

//Encoders 
QEI Encoder1(D13,D12,NC,32);    //channel A and B from encoder, counts = Encoder.getPulses();
QEI Encoder2(D10,D9,NC,32);     //channel A and B from encoder, 

//Speed and Direction of motors - D4 (dir) and D5(speed) = motor 2, D7(dir) and D6(speed) = motor 1
PwmOut pwm_motor1(D6);          //PWM motor 1
PwmOut pwm_motor2(D5);          //PWM motor 2
DigitalOut dir_motor1(D7);      //Direction motor 1
DigitalOut dir_motor2(D4);      //Direction motor 2

//Limit Switches
DigitalIn shoulder_limit(PTA4);  //using FRDM buttons for now
DigitalIn elbow_limit(PTC6);     //using FRDM buttons for now


/*--------------------------------------------------------------------------------------------------------------------
---- DECLARE VARIABLES -----------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------*/

//EMG variables
double emg_biceps; double biceps_power; double bicepsMVC = 0;
double emg_triceps; double triceps_power; double tricepsMVC = 0;
double emg_flexor; double flexor_power; double flexorMVC = 0;
double emg_extens; double extens_power; double extensMVC = 0;

//PID variables
double u1; double u2;                                               //Output of PID controller (PWM value for motor 1 and 2)
double m1_error=0; double m1_e_int=0; double m1_e_prev=0;           //Error, integrated error, previous error
const double m1_kp=0; const double m1_ki=0; const double m1_kd=0;   //Proportional, integral and derivative gains.

double m2_error=0; double m2_e_int=0; double m2_e_prev=0;                 //Error, integrated error, previous error
const double m2_kp=0; const double m2_ki=0; const double m2_kd=0;   //Proportional, integral and derivative gains.

//highpass filter 20 Hz
const double high_b0 = 0.956543225556877;
const double high_b1 = -1.91308645113754;
const double high_b2 = 0.956543225556877;
const double high_a1 = -1.91197067426073;
const double high_a2 = 0.9149758348014341;
 
//notchfilter 50Hz
/*  ** Primary Filter (H1)**
Filter Arithmetic = Floating Point (Double Precision)
Architecture = IIR
Response = Bandstop
Method = Butterworth
Biquad = Yes
Stable = Yes
Sampling Frequency = 500Hz
Filter Order = 2

Band  Frequencies (Hz)    Att/Ripple (dB)       Biquad #1                                               Biquad #2

1     0, 48               0.001                 Gain = 1.000000                                         Gain = 0.973674
2     49, 51              -60.000               B = [ 1.00000000000, -1.61816176147,  1.00000000000]    B = [ 1.00000000000, -1.61816176147,  1.00000000000]
3     52, 250             0.001                 A = [ 1.00000000000, -1.58071559235,  0.97319685401]    A = [ 1.00000000000, -1.61244708381,  0.97415116257]
*/

//biquad 1
const double notch1gain = 1.000000;
const double notch1_b0 = 1;
const double notch1_b1 = -1.61816176147 * notch1gain;
const double notch1_b2 = 1.00000000000 * notch1gain;
const double notch1_a1 = -1.58071559235 * notch1gain;
const double notch1_a2 = 0.97319685401 * notch1gain;
 
//biquad 2
const double notch2gain = 0.973674;
const double notch2_b0 = 1 * notch2gain;
const double notch2_b1 = -1.61816176147 * notch2gain;
const double notch2_b2 = 1.00000000000 * notch2gain;
const double notch2_a1 = -1.61244708381 * notch2gain;
const double notch2_a2 = 0.97415116257 * notch2gain;
 
//lowpass filter 7 Hz  - envelop
const double low_b0 = 0.000119046743110057;
const double low_b1 = 0.000238093486220118;
const double low_b2 = 0.000119046743110057;
const double low_a1 = -1.968902268531908;
const double low_a2 = 0.9693784555043481;



/*--------------------------------------------------------------------------------------------------------------------
---- Filters ---------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------*/

//Using biquadFilter library
//Syntax: biquadFilter     filter(a1, a2, b0, b1, b2); coefficients. Call with: filter.step(u), with u signal to be filtered.
biquadFilter     highpass( high_a1 , high_a2 , high_b0 , high_b1 , high_b2 );               // removes DC and movement artefacts
biquadFilter     notch1( notch1_a1 , notch1_a2 , notch1_b0 , notch1_b1 , notch1_b2 );       // removes 49-51 Hz power interference
biquadFilter     notch2( notch2_a1 , notch2_a2 , notch2_b0 , notch2_b1 , notch2_b2 );       //
biquadFilter     lowpass( low_a1 , low_a2 , low_b0 , low_b1 , low_b2 );                     // EMG envelope    
biquadFilter     derfilter( 0.0009446914586925257 , 0.0018893829173850514 , 0.0009446914586925257 , -1.911196288237583 , 0.914975054072353 );   // derivative filter 

/*--------------------------------------------------------------------------------------------------------------------
---- DECLARE FUNCTION NAMES ------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------*/
void keep_in_range(double * in, double min, double max);
void sample_filter(void);
void control();
void calibrate_emg(int muscle);
void calibrate_arm(void);
void start_sampling(void);
void stop_sampling(void);
void start_control(void);
void stop_control(void);
double pid(double error, double kp, double ki, double kd,double &e_int, double &e_prev);

void mainMenu();
void caliMenu();

/*--------------------------------------------------------------------------------------------------------------------
---- MAIN LOOP -------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------*/

int main()
{
    pc.baud(115200);
    // make a menu, user has to initiate next step
    mainMenu();
    caliMenu();            // Menu function
    calibrate_arm();        //Start Calibration
    start_sampling();       //500 Hz EMG 
    calibrate_emg(1);       //calibrate muscle 1 
    start_control();        //100 Hz control
    
    //maybe some stop commands when a button is pressed: detach from timers.
    //stop_control();
    //stop_sampling();
    
    while(1) {
    scope.set(0,emg_biceps);
    scope.set(1,emg_triceps);
    scope.set(2,emg_flexor);
    scope.set(3,emg_extens);
    scope.send();        
    }
    //end of while loop
}
//end of main

/*--------------------------------------------------------------------------------------------------------------------
---- FUNCTIONS -------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------*/

//Sample and Filter  
void sample_filter(void)
{
    double emg_biceps = emg1.read();    //Biceps
    double emg_triceps = emg2.read();    //Triceps
    double emg_flexor = emg3.read();    //Flexor
    double emg_extens = emg4.read();    //Extensor
    
    //Filter: high-pass -> notch -> rectify -> lowpass or moving average
    // Can we use same biquadFilter (eg. highpass) for other muscles or does each muscle need its own biquad?
    biceps_power = highpass.step(emg_biceps); triceps_power = highpass.step(emg_triceps); flexor_power = highpass.step(emg_flexor); extens_power = highpass.step(emg_extens);
    biceps_power = notch1.step(biceps_power); triceps_power = notch1.step(triceps_power); flexor_power = notch1.step(flexor_power); extens_power = notch1.step(extens_power);
    biceps_power = notch2.step(biceps_power); triceps_power = notch2.step(triceps_power); flexor_power = notch2.step(flexor_power); extens_power = notch2.step(extens_power);
    biceps_power = abs(biceps_power); triceps_power = abs(triceps_power); flexor_power = abs(flexor_power); extens_power = abs(extens_power);
    biceps_power = lowpass.step(biceps_power); triceps_power = lowpass.step(triceps_power); flexor_power = lowpass.step(flexor_power); extens_power = lowpass.step(extens_power);
    
    /* alternative for lowpass filter: moving average
    window=30;                      //30 samples
    int i=0;                        //buffer index
    bicepsbuffer[i]=biceps_power    //fill array
    
    i++;                             
    if(i==window){
        i=0;
    }
    
    for(int x = 0; x < window; x++){
        avg1 += bicepsbuffer[x];
        }
    avg1 = avg1/window;    
    */
    
}

//Send arm to mechanical limits, and set encoder to 0. Then send arm to starting position.
void calibrate_arm(void)
{
    bool hit = true;
    dir_motor1=1;   //ccw
    dir_motor2=1;   //ccw
    while(shoulder_limit != hit){
        pwm_motor1.write(0.4);
    }
    Encoder1.reset();
    
    while(elbow_limit != hit){
        pwm_motor2.write(0.4);
    }
    Encoder2.reset();
}

//EMG Maximum Voluntary Contraction measurement
void calibrate_emg(int muscle)
{
    start_sampling();
    
    //double sampletime=0;
    //sampletime=+SAMPLE_RATE;
    //
    // if(sampletime<5)
    
    for(int index=0; index<2500;index++){   //measure 5 seconds@500hz = 2500 samples
        if(muscle==1){
            
            if(biceps_power>bicepsMVC){
            bicepsMVC=biceps_power;
            }    
        }  
        
        if(muscle==2){
            
            if(triceps_power>tricepsMVC){
            tricepsMVC=triceps_power;
            }    
        }
        
        if(muscle==3){
            
            if(flexor_power>flexorMVC){
            flexorMVC=flexor_power;
            }    
        }
        
        if(muscle==4){
            
            if(extens_power>extensMVC){
            extensMVC=extens_power;
            }    
        }
    }
    stop_sampling();
   
}


//Input error and Kp, Kd, Ki, output control signal
double pid(double error, double kp, double ki, double kd,double &e_int, double &e_prev)
{
    // Derivative
    double e_der = (error-e_prev)/ CONTROL_RATE;
    e_der = derfilter.step(e_der);
    e_prev = error;
    // Integral
    e_int = e_int + CONTROL_RATE * error;
    // PID
    return kp*error + ki*e_int + kd * e_der;
 
}

//Analyze filtered EMG, calculate reference position from EMG, compare reference position with current position,convert to angles, send error through pid(), send PWM and DIR to motors 
void control()
{
    //analyze emg (= velocity, averages?)
    
    //calculate reference position based on the average emg (integrate)
    
    //calculate error (refpos-currentpos) currentpos = forward kinematics
    
    //inverse kinematics (pos error to angle error)
    
    //PID controller
    
    u1=pid(m1_error,m1_kp,m1_ki,m1_kd,m1_e_int,m1_e_prev);    //motor 1
    u2=pid(m2_error,m2_kp,m2_ki,m2_kd,m2_e_int,m2_e_prev);    //motor 2
    
    keep_in_range(&u1,-1,1);    //keep u between -1 and 1, sign = direction, PWM = 0-1
    keep_in_range(&u2,-1,1);
    
    //send PWM and DIR to motor 1
    dir_motor1 = u1>0 ? 1 : 0;          //conditional statement dir_motor1 = [condition] ? [if met 1] : [else 0]], same as if else below. 
    pwm_motor1.write(abs(u1));
    
    //send PWM and DIR to motor 2
    dir_motor1 = u2>0 ? 1 : 0;          //conditional statement, same as if else below
    pwm_motor1.write(abs(u2));
    
    /*if(u1 > 0)
    {
        dir_motor1 = 0;
    else{
        dir_motor1 = 1;
        }
    }    
    pwm_motor1.write(abs(u1));
    
  
    if(u2 > 0)
    {
        dir_motor1 = 1;
    else{
        dir_motor1 = 0;
        }
    }    
    pwm_motor1.write(abs(u2));*/
    
}

void mainMenu(){};
void caliMenu(){};

//Start sampling
void start_sampling(void)
{
    sample_timer.attach(&sample_filter,SAMPLE_RATE);   //500 Hz EMG 
}

//stop sampling
void stop_sampling(void)
{
    sample_timer.detach();
}

//Start control
void start_control(void)
{
    control_timer.attach(&control,CONTROL_RATE);     //100 Hz control
}

//stop control
void stop_control(void)
{
    control_timer.detach();
}


void calibrate()
{

}


//keeps input limited between min max
void keep_in_range(double * in, double min, double max)
{
    *in > min ? *in < max? : *in = max: *in = min;
}