Unable to receive data from the target hardware.

I am working on a project to control the speed of a DC motor using an adaptive PID algorithm based on the MIT rule. However, when I upload the code, the motor runs but the MATLAB Command Window displays an error that I cannot resolve. Could anyone please guide me on how to fix this error and check whether my control algorithm is implemented correctly?

%% MRAS Adaptive PID (MIT rule) for DC Motor (Realtime Plot)
% Hardware:
%   - Arduino UNO R3 + L298N
%   - Encoder: 334 pulses/rev × 34 (gear ratio)
%   - No-load: ~160 rpm ≈ 16.76 rad/s
%   - Supply: 12V

clc; clear; close all;

%% --- Arduino setup ---
a = arduino('COM4','Uno','Libraries',{'RotaryEncoder'});
enc = rotaryEncoder(a,'D2','D3',334*34);     % TOTAL_PPR = 11356
in1 = 'D4'; in2 = 'D5'; ena = 'D6';
configurePin(a,in1,'DigitalOutput');
configurePin(a,in2,'DigitalOutput');
configurePin(a,ena,'PWM');

%% --- Parameters ---
T = 0.03;                  % Sample time [s]
am = 6.0; bm = 6.0;        % Reference model
ym = 0;                    % Model output

% MRAS learning parameters
gamma_p = 0.010; gamma_i = 0.003; gamma_d = 0.002;
norm_p  = 0.08;  norm_i  = 0.02;  norm_d  = 0.05;

% PID gains and bounds
Kp = 1.8; Ki = 0.7; Kd = 0.05;
Kp_min=0.2; Kp_max=6.0; Ki_min=0; Ki_max=2.5; Kd_min=0; Kd_max=0.2;

% Filters
speed_alpha = 0.6; deriv_alpha = 0.5;
MAX_SPEED = 31;             % rad/s
PWM_MAX = 255; PWM_DEADZONE = 8;

% States
I = 0; e_prev = 0; yp_filt = 0; d_filt = 0;
count_prev = 0;
setpoint = 5;               % rad/s

disp('MRAS Adaptive PID with realtime plot. Use Ctrl+C to stop.');
fprintf('Current setpoint: %.2f rad/s\n', setpoint);

%% --- Initialize Realtime Plot ---
figure('Name','MRAS Adaptive PID Realtime','NumberTitle','off','Color','w');
subplot(2,1,1);
hRef = animatedline('Color',[0.7 0.7 0.7],'LineWidth',1.5,'LineStyle','--');
hYm  = animatedline('Color',[0.2 0.6 1],'LineWidth',1.8);
hYp  = animatedline('Color',[1 0.3 0.2],'LineWidth',1.8);
xlabel('Time (s)'); ylabel('Speed (rad/s)');
title('Motor Speed Tracking (Y_p vs Y_m)');
legend({'Ref','Model (Y_m)','Plant (Y_p)'},'Location','best');
grid on;

subplot(2,1,2);
hKp = animatedline('Color','r','LineWidth',1.5);
hKi = animatedline('Color','b','LineWidth',1.5);
hKd = animatedline('Color','g','LineWidth',1.5);
xlabel('Time (s)'); ylabel('Gain value');
title('Adaptive PID Gains (Kp, Ki, Kd)');
legend({'Kp','Ki','Kd'},'Location','best');
grid on;

%% --- Main Control Loop ---
t0 = tic;
while ishandle(hRef)  
    t = toc(t0);

    % --- (1) Measure speed ---
    count = readCount(enc);
    delta = count - count_prev;
    count_prev = count;
    rev = double(delta)/11356;
    inst_speed = rev * 2*pi / T;

    if abs(inst_speed) > MAX_SPEED && abs(inst_speed) > 3*abs(yp_filt + 1e-6)
        inst_speed = yp_filt;
    end
    yp_filt = speed_alpha*yp_filt + (1-speed_alpha)*inst_speed;
    yp = yp_filt;

    % --- (2) Reference model ---
    ym = ym + T*(-am*ym + bm*setpoint);

    % --- (3) Error terms ---
    e = setpoint - yp;
    em = ym - yp;

    % --- (4) Derivative & Integral ---
    d_raw = (e - e_prev)/T;
    d_filt = deriv_alpha*d_filt + (1-deriv_alpha)*d_raw;
    I = I + e*T;

    % --- (5) Control law ---
    uP = Kp*e + Kd*d_filt;
    u_tent = uP + Ki*I;
    if (u_tent>=PWM_MAX && e>0) || (u_tent<=0 && e<0)
        I = I*0.999;
    end
    u = uP + Ki*I;

    pwmOut = min(max(u,0),PWM_MAX);
    if pwmOut>0 && pwmOut<PWM_DEADZONE
        pwmOut = PWM_DEADZONE;
    end

    writeDigitalPin(a,in1,1);
    writeDigitalPin(a,in2,0);
    writePWMVoltage(a,ena,5.0*pwmOut/255);

    % --- (6) MIT adaptation ---
    freeze = ( (pwmOut>=PWM_MAX && em>0) || (pwmOut<=0 && em<0) );
    if ~freeze
        phi_p = e; phi_i = I; phi_d = d_filt;
        dKp = gamma_p * em * phi_p / (1 + norm_p*phi_p^2);
        dKi = gamma_i * em * phi_i / (1 + norm_i*phi_i^2);
        dKd = gamma_d * em * phi_d / (1 + norm_d*phi_d^2);
        Kp = Kp + dKp; Ki = Ki + dKi; Kd = Kd + dKd;
        Kp = min(max(Kp,Kp_min),Kp_max);
        Ki = min(max(Ki,Ki_min),Ki_max);
        Kd = min(max(Kd,Kd_min),Kd_max);
    end

    % --- (7) Realtime plot update ---
    addpoints(hRef,t,setpoint);
    addpoints(hYm,t,ym);
    addpoints(hYp,t,yp);
    addpoints(hKp,t,Kp);
    addpoints(hKi,t,Ki);
    addpoints(hKd,t,Kd);
    drawnow limitrate;

    % --- (8) Display info every ~0.3s ---
    if mod(round(t,2),0.3)<T
        fprintf('t=%.1fs | Yp=%.2f | Ym=%.2f | e=%.2f | Kp=%.2f Ki=%.2f Kd=%.2f | PWM=%3d\n',...
            t, yp, ym, em, Kp, Ki, Kd, round(pwmOut));
    end

    e_prev = e;
    pause(T);
end

disp('Stopped MRAS Adaptive PID realtime loop.');

Answer 1

[Taylor]

Have you tried the steps here?