File content as of revision 11:44b1c5b3b378:

#include "mbed.h"
#include "encoder.h"
#include "HIDScope.h"
#include "math.h"

HIDScope scope(4);          // defines the amount of channels of the scope

// Define Tickers and control frequencies
Ticker          controller1, controller2, main_filter, cartesian;
    // Go flag variables belonging to Tickers
    volatile bool motor1_go = false, motor2_go = false, emg_go = false, cart_go = false;

// Frequency control
    double controlfreq = 200 ;    // controlloops frequentie (Hz)
    double controlstep = 1/controlfreq; // timestep derived from controlfreq
    
    double EMG_freq = 200;
    double EMG_step = 1/EMG_freq;

//////////////////////// IN-OUTPUT /////////////////////////////////////////////
//MOTOR OUTPUTPINS
    PwmOut motor1_aan(D6), motor2_aan(D5);      // PWM signaal motor 2
    DigitalOut motor1_rich(D7), motor2_rich(D4); // digitaal signaal for direction

// ENCODER INPUTPINS
    Encoder motor1_enc(D12,D11), motor2_enc(D10,D9);        // encoderinputpins

// EXTRA INPUTS AND REQUIRED VARIABLES
//POTMETERS (used for debugging purposes, not reliable due to mechanical failure)
    AnalogIn potright(A4);      // define the potmeter outputpins
    AnalogIn potleft(A5);
    
// Analoge input signalen defineren
    AnalogIn    EMG_in(A0);
    AnalogIn    EMG_int(A2);

// BUTTONS 
    // control flow             
    DigitalIn   buttonlinks(PTA4);       // button for starting the motor controller
    DigitalIn   buttonrechts(PTC6);     // button for startin calibration procedures
    DigitalIn   reset_button(D1);       // button for returning the arm to the start position
    DigitalIn   switch_xy_button(D0);     // button for starting a preprogrammed movement. (pick up cup)
        // init values
        bool loop_start = false;
        bool calib_start = false;
        bool reset = false;
        bool program = false;

        
// LED outputs on bioshield
    DigitalOut led_right(D2);
// LED outputs on dev-board
    DigitalOut ledred(LED1);
    DigitalOut ledgreen(LED2);
    DigitalOut ledblue(LED3);
    

//////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////// GLOBAL VARIABLES ///////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////

// switch axes
    // bool switch_xy = false; // bool for switching axes
    double sw1 = 0; // counter for switching axes
    double t_switch = 0.8; // seconds for switching
    bool switch_xy = false; // set the start value
    
// physical constants
    const double L = 36;           // lenght of arms
    const double pi = 3.1415926535897;      // pi

    // angle limitations (in radians)
    // motor1
    const double limlow1 = 0.5;             // min height in rad
    const double limhigh1 = 6.3;            // max height in rad
    // motor 2
    const double limlow2 = -4.0;            // maximum height, motor has been inverted due to transmission
    const double limhigh2 = 2.5;              // minimum height in rad
    
    // offset angle (radians needed to change the arms to horizontal position from reset position)
    const double phi_one_offset = 2.8;
    const double phi_two_offset = 1.85;

///////////////////////////
// Main control loop transfer variables
// here all variables that transfer bewtween the primary control functions

// filter to calibration
    double output1;
    double output2;
// filter to x-y
    double output1_amp;
    double output2_amp;
// x-y to motor control
    double phi_one;
    double phi_two;

////////////////////////////
// NOTE: start position is [x,y] = [60,0], reset position is [phi1,phi2] = [0,0]
// define smooth variables (is to create a slowed movement instead of going to ref value inmediately)
    double start_up_time = 3;
    double start_loops = start_up_time*controlfreq;
    int rc1 = 0;            // counters in function to enable relatively smooth movement
    int rc2 = 0;
    
// define return to start variables
double reset_phi_one = 0;
double reset_phi_two = 0;

// storage variables to store the location at the beginning of the smoothed movement (0 on startup)
double phi_one_curr = 0;
double phi_two_curr = 0;

// REFERENCE SETTINGS
    double input_threshold = 0.25;   // the minimum value the signal must have in order to change the reference.
 // Define storage variables for reference values (also start position)
    double c_reference_x = 60, c_reference_y = 0;
// x-settings   (no y-settings because these are calculated from the current x-position)
    double x_min = 47, x_max = 70, y_min_max = -32;
    double xx,yy,y_min,y_max;
    // Define the maximum rate of change for the x and y reference signals (velocity)
    double Vmax_x = 10, Vmax_y = 15;  // [cm/s]          


// CONTROLLER SETTINGS
    // motor 1
    const double m1_Kp = 5;         // Proportional constant     
    const double m1_Ki = 0.5;         // integration constant
    const double m1_Kd = 0.4;         // differentiation constant
    // motor 2
    const double m2_Kp = 3;
    const double m2_Ki = 0.5;
    const double m2_Kd = 0.4;
// storage variables.   these variables are used to store data between controller iterations
    // motor 1
    double m1_err_int = 0; 
    double m1_prev_err = 0;
    // motor 2
    double m2_err_int = 0;
    double m2_prev_err = 0;

// EMG calibration variables (standard is 7)
double emg_gain1 = 7;       
double emg_gain2 = 7;

double cal_time = 2.5;       // amount of time calibration should take (seconds)
double cal_samples = EMG_freq*cal_time;  // amount of samples that is used (dependent on the frequency of the filter)
double normalize_emg_value = 1;      // set the desired value to calibrate the signal to (eg max signal = 1)

// FILTER VARIABLES
    // storage variables
        // differential action filter.
            double m_f_v1 = 0, m_f_v2 = 0;
        // input filter to smooth angle reference signals
            double r1_f_v1 = 0, r1_f_v2 = 0, r2_f_v1 = 0, r2_f_v2 = 0;
        // Define the storage variables and filter coeficients for eight filters
        // EMG filter 1
            double f1_v1 = 0, f1_v2 = 0, f2_v1 = 0, f2_v2 = 0, f3_v1 = 0, f3_v2 = 0,f4_v1 = 0, f4_v2 = 0;
        // EMG filter 2
            double f1_v1t = 0, f1_v2t = 0, f2_v1t = 0, f2_v2t = 0, f3_v1t = 0, f3_v2t = 0,f4_v1t = 0, f4_v2t = 0;
        
    // Filter coefficients
        // differential action filter (lowpass 5Hz at 200Hz)
            const double m_f_a1 = -1.1430, m_f_a2 = 0.4128, m_f_b0 = 0.0675, m_f_b1 = 0.1349, m_f_b2 = 0.0675;
        // input filter (lowpass 1Hz at 200Hz) (used to make the angle signals smooth)
            const double r1_f_a1 = -1.6475, r1_f_a2 = 0.7009, r1_f_b0 = 0.0134, r1_f_b1 = 0.0267, r1_f_b2 = 0.0134;    

    // EMG-Filter (calculated for 200)
    
    const double numnotch50biq1_1 = 1;
    const double numnotch50biq1_2 = 1.11568254634875e-11;
    const double numnotch50biq1_3 = 1.00000002278002;
    const double dennotch50biq1_2 = -0.0434777721916752;
    const double dennotch50biq1_3 = 0.956543692050407;
    // biquad 2 coefficienten
    const double numnotch50biq2_1 = 1;
    const double numnotch50biq2_2 = -1.11571030192437e-11;
    const double numnotch50biq2_3 = 0.999999977219980;
    const double dennotch50biq2_2 = 0.0434777721916751;
    const double dennotch50biq2_3 = 0.956543692050417;
 
    // highpass filter 20 Hz coefficienten
    const double numhigh20_1 = 0.638945525159022;
    const double numhigh20_2 = -1.27789105031804;
    const double numhigh20_3 = 0.638945525159022;
    const double denhigh20_2 = -1.14298050253990;
    const double denhigh20_3 = 0.412801598096189;
 
    // lowpass 5 Hz coefficienten
    const double numlow5_1 =0.000241359049041961;
    const double numlow5_2 =0.000482718098083923;
    const double numlow5_3 =0.000241359049041961;
    const double denlow5_2 =-1.95557824031504;
    const double denlow5_3 =0.956543676511203;    
    
   
////////////////////////////////////////////////////////////////
/////////////////// START OF SIDE FUNCTIONS ////////////////////
//////////////////////////////////////////////////////////////
// these functions are tailored to perform 1 specific function

// this funtion flips leds on and off accordin to input with 0 being on
void LED(int red,int green,int blue)
{
    ledred.write(red);
    ledgreen.write(green);
    ledblue.write(blue);
}    
    
// counts 2 radians
// this function takes counts from the encoder and converts it to the amount of radians from the zero position. 
// It has been set up for standard 2X DECODING!!!
double get_radians(double counts)       
{
    double radians = (counts/4200)*2*pi;        // 2X DECODING!!!!! ((32 counts/rotation, last warning)
    return radians;
}


// This functions takes a 0->1 input, uses passing by reference (&c_reference)
// to create a reference that moves with a variable speed. It is meant for -1->1 values
double reference_f(double input, double &c_reference, double limlow, double limhigh, double Vmax)
{
    double reference = c_reference + input * controlstep * Vmax ;
            //  two if statements check if the reference exceeds the limits placed upon the arms
            if(reference < limlow){reference = limlow;}
            if(reference > limhigh){reference = limhigh;}
           c_reference = reference; // change the global variable to the latest location.
    return reference;
}


// This function takes the controller outputvalue and ensures it is between -1 and 1
// this is done to limit the motor input to possible values (the motor takes 0 to 1 and the sign changes the direction).
double outputlimiter (double output, double limit)
{
    if(output> limit)                                
    {
        output = 1;
    }
    else if(output < limit && output > 0)
    {
        output = output;
    }
    else if(output > -limit && output < 0)
    {
        output = output;
    }
    else if(output < -limit)
    {
        (output = -1);
    }
    return output;
}


// BIQUADFILTER CODE GIVEN IN SHEETS (input format: den, den, nom, nom, nom)
double biquadfilter(double u, double &v1, double &v2, const double a1, const double a2, const double b0, const double b1, const double b2)
{
    double v = u - a1*v1 - a2*v2;
    double y = b0*v + b1*v1 + b2*v2;
    v2 = v1;
    v1 = v;
    return y;
    }

// PID Controller given in sheets
// adapted to use the same differential filter, and to split the different terms
double PID(double e, const double Kp, const double Ki, const double Kd, double Ts,double &e_int, double &e_prev)
{
// Proportional
double P = Kp * e;
// Integral
e_int = e_int + Ts * e;
double I = e_int * Ki;
// Derivative   
double e_derr = (e - e_prev)/Ts;
e_derr = biquadfilter(e_derr, m_f_v1, m_f_v2, m_f_a1, m_f_a2, m_f_b0, m_f_b1, m_f_b2);
// 
e_prev = e;
double D = Kd* e_derr;
// PID
double output = P + I + D;
return output;
}


// function that limits the angles that can be used in the motor reference signal
 double angle_limits(double phi, double limlow, double limhigh)
{
    if(phi < limlow)            // determine if the reference is lower than the minimum angle
    {
        phi = limlow;       // if lower, set the lower limit as reference.
    }
    if(phi > limhigh)           // determine if the reference is higher than the maximum angle
    {
        phi = limhigh;
    }
    return phi;
}

// this function adapts the filtered emg signal for use in the reference generation
// adds threshold value and normalizes between 0 and 1
double adapt_signal(double input)
{
    // add threshold value for outputs
    if(input < input_threshold){input = 0;}     // set the input as zero if the signal is lower than the threshold
        
    // return the input to a value between 0 and 1 (otherwise you will get jumps in input)
    input = (input-input_threshold) * (1/(1-input_threshold));
     
    // if below 0 = 0       (otherwise values like -input_threshold start popping up)
    if(input < 0){input = 0;}
      
    // limit signal maximum to 1
    if(input > 1){input = 1;}
    return input;
}
    
// funtion switches the direction that is controlled
void switch_axes (double input1,double input2)
{
    if(input1 > input_threshold && input2 > input_threshold)    // when both signals are above the threshold, add one to global counter
    {
        sw1++;
    }
    if(sw1 == t_switch*controlfreq)           // if global counter > t*freq flip the bool.
    {
        switch_xy = !switch_xy;     
        led_right.write(!led_right.read());  // turn on led when switched
        sw1 = 0;
    }
    if(input1 < input_threshold || input2 < input_threshold)    // if one becomes lower than the threshold, set the global variable to zero
    {
        sw1 = 0;
    }
}


/////////////////////////////////////////////////////////////////////
////////////////// PRIMARY CONTROL FUNCTIONS ///////////////////////
///////////////////////////////////////////////////////////////////
// these functions are called by go-flags and are used to update main variables and send signals to motor

// function that updates the values of the filtered emg-signal
void EMG_filter()
{
// filtering of EMG signal 1 (A0) first notch(2 biquads), then highpass, rectify(abs()), lowpass
    double u1 = EMG_in.read();
    double y1 = biquadfilter( u1, f1_v1, f1_v2,dennotch50biq1_2, dennotch50biq1_3,numnotch50biq1_1,numnotch50biq1_2,numnotch50biq1_3);
    double y2 = biquadfilter( y1, f2_v1, f2_v2,dennotch50biq2_2, dennotch50biq2_3,numnotch50biq2_1,numnotch50biq2_2,numnotch50biq2_3);
    double y3 = biquadfilter( y2, f3_v1, f3_v2, denhigh20_2,denhigh20_3,numhigh20_1, numhigh20_2, numhigh20_3);
    double y4 = abs(y3);
    double y5 = biquadfilter( y4, f4_v1, f4_v2, denlow5_2,denlow5_3,numlow5_1, numlow5_2, numlow5_3);
    // update global variables
    output1 = y5;   // output for calibration
    output1_amp = y5*emg_gain1;  // output for control loop 

// filtering of EMG signal 2 (A2) same as before
    double u1t = EMG_int.read();
    double y1t = biquadfilter( u1t, f1_v1t, f1_v2t,dennotch50biq1_2, dennotch50biq1_3,numnotch50biq1_1,numnotch50biq1_2,numnotch50biq1_3);
    double y2t = biquadfilter( y1t, f2_v1t, f2_v2t,dennotch50biq2_2, dennotch50biq2_3,numnotch50biq2_1,numnotch50biq2_2,numnotch50biq2_3);
    double y3t = biquadfilter( y2t, f3_v1t, f3_v2t, denhigh20_2,denhigh20_3,numhigh20_1, numhigh20_2, numhigh20_3);
    double y4t = abs(y3t);
    double y5t = biquadfilter( y4t, f4_v1t, f4_v2t, denlow5_2,denlow5_3,numlow5_1, numlow5_2, numlow5_3);
    // update global variables
    output2 = y5t;
    output2_amp = y5t*emg_gain2; 
}
 
 
 // function that updates the required motor angles from the current filtered emg
 void det_angles()
{
    // convert global to local variable
    double xy_input1 = output1_amp;
    double xy_input2 = output2_amp;

    // use potmeter for debugging purposes (note: does not give a smooth signal due to mechanical breakdown)
    xy_input1 = potright.read();
    xy_input2 = potleft.read();
    
    // add a threshold to the signals and limit to [0,1]
    xy_input1 = adapt_signal(xy_input1);
    xy_input2 = adapt_signal(xy_input2);
    
    // function that when both muscles are above a threshold for 3/5s switches the axes
    switch_axes(xy_input1,xy_input2);       
    
    double xy_main_input = xy_input1 - xy_input2 ;    // subtract inputs to create a signal that can go from -1 to 1

    // limit the output between -1 and 1 (signal is not supposed to be able to go above but last check)
    if(xy_main_input>1) {xy_main_input = 1;}
    if(xy_main_input<-1) {xy_main_input = -1;}
  
    // calculate the y limits belonging to that particular x coordinate and update global variables
    y_min = - sqrt(5041 - pow(xx,2));
    if(y_min<y_min_max){y_min = y_min_max;} // make sure the arm cannot hit the table (may later be removed)
    y_max = sqrt(5041 - pow(xx,2));
    
    // add x_max (trial) !!!!
    x_max = sqrt(5041 - pow(yy,2));
    if (x_max > 70){x_max = 70;}
    
    // use the signal to change the x-reference
    if(switch_xy == false){xx = reference_f(xy_main_input,c_reference_x,x_min,x_max,Vmax_x);}
    // use the signal to change the y-reference
    if(switch_xy == true){yy = reference_f(xy_main_input,c_reference_y,y_min,y_max,Vmax_y);}
    
    // x-y to arm-angles math
    double r = sqrt(pow(xx,2)+pow(yy,2)); // vector naar end effector
    double alfa = acos((2*pow(L,2)-pow(r,2))/(2*pow(L,2))); // alfa is de hoek tussen upper en lower arm
    double beta = acos((pow(r,2))/(2*L*r)); // beta is de hoek tussen upper arm en r
    double theta_one = (atan2(yy,xx)+beta); 
    double theta_two = (-pi + alfa); 
    
    // convert arm-angles to motor angles( (x transmission) and offset (+ offset) to account for reset position)
    double phi1 = 4*(theta_one) + phi_one_offset;
    // math assumes angle relative to first arm. motor does not change relative orientation, so angle wrt horizontal position is needed.
    double phi2 = 4*(theta_one+theta_two) + phi_two_offset;       
    phi2 = -phi2;   // reverse angle because of transmission.

    // check the angles and apply the limits
    phi1 = angle_limits(phi1,limlow1,limhigh1);
    phi2 = angle_limits(phi2,limlow2,limhigh2);
    
    // smooth the input signal (lowpass 1Hz). (to reduce the freq content after reaching limits and to make the signal less jittery)   
    phi1 = biquadfilter(phi1, r1_f_v1, r1_f_v2, r1_f_a1, r1_f_a2, r1_f_b0, r1_f_b1, r1_f_b2);
    phi2 = biquadfilter(phi2, r2_f_v1, r2_f_v2, r1_f_a1, r1_f_a2, r1_f_b0, r1_f_b1, r1_f_b2);
    
    // write into global variables
    phi_one = phi1;
    phi_two = phi2;
    // if the reset button has been pressed, continiously write the start position into the global variables to reset the arm  
    if(reset == true)
    {
        phi_one = reset_phi_one;
        phi_two = reset_phi_two;
    }
}


// MOTOR 1
void motor1_control()
{
     // change global into local variable  
    double reference1 = phi_one;  
    
    // add smooth start up
    // for a certain amount of function iterations slowly add the delta phi between positions
    // (used to gently move to start position or move to reset position)
    if(rc1 < start_loops)
    {
        rc1++;
        reference1 = phi_one_curr + ((double) rc1/start_loops)*(reference1-phi_one_curr);
    }
    double rads1 = get_radians(motor1_enc.getPosition());    // determine the position of the motor
    double error1 = (reference1 - rads1);                       // determine the error (reference - position)
    double m_output1 = PID(error1, m1_Kp, m1_Ki, m1_Kd, controlstep, m1_err_int, m1_prev_err);
    m_output1 = outputlimiter(m_output1,1); // relimit the output between -1 and 1 for safety
    if(m_output1 > 0) {                    // uses the calculated output to determine the direction  of the motor
        motor1_rich.write(0);
        motor1_aan.write(m_output1);
    } else if(m_output1 < 0) {
        motor1_rich.write(1);
        motor1_aan.write(abs(m_output1));
    }
}

// MOTOR 2
void motor2_control()
{
    double reference2 = phi_two;
      
    // add smooth start up
    // for a certain amount of function iterations slowly add the delta phi between positions
    // (used to gently move to start position [x,y] = [60,0] or move to the reset position [phi1,phi2] = (0,0)
    if(rc2 < start_loops)
    {
        rc2++;
        reference2 = phi_two_curr + ((double) rc2/start_loops)*(reference2-phi_two_curr);
    } 
    double rads2 = get_radians(motor2_enc.getPosition());    // determine the position of the motor
    double error2 = (reference2 - rads2);                    // determine the error (reference - position)   
    double m_output2 = PID(error2, m2_Kp, m2_Ki, m2_Kd, controlstep, m2_err_int, m2_prev_err);
    m_output2 = outputlimiter(m_output2,1);     // final output limit (not really needed, is for safety)
    if(m_output2 > 0) {                    // uses the calculated output to determine the direction  of the motor
        motor2_rich.write(0);
        motor2_aan.write(m_output2);
    } else if(m_output2 < 0) {
        motor2_rich.write(1);
        motor2_aan.write(abs(m_output2));
    }
}

// calibrate the emg-signal
// works bij taking a certain amount of samples taking the max value then normalize to the desired value
// went to max-value type. must be tested.!
void calibrate_amp()
{
    double max1 = 0;
    double max2 = 0;
    for(int i = 0; i<cal_samples; i++)
    {
        EMG_filter();       // run filter
        double input1 = output1;        // take data from global variable
        if(input1>max1){max1 = input1;}       // take max input
        double input2 = output2;
        if(input2>max2){max2 = input2;}       // take max input
        wait(EMG_step);      // !! has to run at same interval as filter in main loop !! otherwise a 'different' signal will be used for calibration
    }
    emg_gain1 = normalize_emg_value/max1;  // normalize the amplification so that the maximum signal hits the desired one
    emg_gain2 = normalize_emg_value/max2;
   }
//////////////////////////////////////////////////////////////////
//////////// DEFINE GO-FLAG FUNCTIONS ///////////////////////////
////////////////////////////////////////////////////////////////

// go-flag functions
void EMG_activate(){emg_go = true;}
void angle_activate(){cart_go = true;}
void motor1_activate(){motor1_go = true;}
void motor2_activate(){motor2_go = true;}

int main()
{
    // call go-flag tickers
    main_filter.attach(&EMG_activate, EMG_step);
    cartesian.attach(&angle_activate, controlstep);
    controller1.attach(&motor1_activate, controlstep);      
    controller2.attach(&motor2_activate, controlstep); 
    while(true) 
    {
        // button press functions
        // flow buttons
        if(buttonlinks.read() == 0)
        {
            loop_start = !loop_start;     
            wait(0.2);
            while(buttonlinks.read() == 0);             
        }
        if(buttonrechts.read() == 0)
        {
            calib_start = !calib_start;     
            wait(0.2); 
        while(buttonrechts.read() == 0);            
        }
        // switch axes
        if(switch_xy_button.read() == 0)
        {
           switch_xy = !switch_xy;
           led_right.write(!led_right.read());
           wait(0.2);  
           while(switch_xy_button.read() == 0);           
        }
        if(reset_button.read() == 0)
        {
            reset = !reset;     
            phi_one_curr = phi_one;
            phi_two_curr = phi_two;
            rc1 = 0;
            rc2 = 0;     
            wait(0.2);
            while(reset_button.read() == 0);
        }
        //////////////////////////////////////////////////
        // Main Control stuff and options
        if(loop_start == true && calib_start == false)        // check if start button = true then start the main control loops
        {
            LED(1,1,0); // turn blue led on
            if(cart_go)   { cart_go = false; det_angles();}
            if(emg_go)    { emg_go = false; EMG_filter();}
            if(motor1_go) { motor1_go = false; motor1_control();}
            if(motor2_go) { motor2_go = false; motor2_control();}
        }
        // shut off both motors 
        if(loop_start == false) {motor1_aan.write(0); motor2_aan.write(0);}
        
        // turn green led on // start calibration procedures
        if(loop_start == false && calib_start == true) 
        {   LED(1,0,1); 
            motor1_aan.write(0); 
            motor2_aan.write(0);
            calibrate_amp();        // 10 second calibration
            calib_start = false;    // turn calibration mode off
        }
        
        // turn red led on (show both buttons have been pressed)
        if(loop_start == true && calib_start == true) 
        { 
        LED(0,1,1); 
        motor1_aan.write(0); 
        motor2_aan.write(0);
        }
        
        // turn leds off (both buttons false)
        else { LED(1,1,1);}
    }
}