Can someone help me with my code. Calculate the position (coordinates x and y) of points B C and D . Calculate the linear velocity (vx and vy) of points b c d.

compute Th1=th(1i)+w1*t and from 0 to 10s

r(ab)=0.3;

Unrecognized function or variable 'ab'.

w(ab)=0.2;
Th1(1i)=30;
w(bc)=-0.05;
r(bc)=0.25;
Th2(1i)=-20;
r(cd)=0.25;
Th3(1i)=0;
for t=0:0.5:10
    Th1=Th1(1i)+w(ab)*t;
    f=fprintf('Theta1(%.2d degrees) /n', Th1,t);
    disp(f)
    Th2=Th2(1i)+w(bc)*t;
    g=fprintf('Theta2(%.2d degrees) /n', Th2,t);
    disp(g)
    r(b)=[r(ab)*cosd(Th1), r(ab)*sind(Th1)];
    disp(r(b));
    v(b)=[-w(ab)*r(ab)*cosd(Th1), w(ab)*r(ab)*cosd(Th1)];
    disp(v(b));
    v(a)=v(b)-w(ab)*r(ab);
    disp(v(a));
    r(c)=[r(ab)*cosd(Th1)+r(bc)*cosd(Th2), r(ab)*cosd(Th2)+r(bc)*sind(Th2)];
    disp(r(c));
    v(c)=v(b)+[-w(bc)*r(ab)*sind(Th2), w(bc)*r(ab)*cosd(Th2)];
    Dy=0.0645;
    Th(3)=asind(Dy-r(cy))/(r(ab));
    disp(Th(3));
    w(cd)=(-w(ab)*r(ab)*cosd(Th1)-w(bc)*r(ab)*cosd(Th2))/(r(ab)*cosd(Th3));
    disp(w(cd));
    r(d)=r(c)+[r(cd)*cosd(Th3), r(cd)*sind(Th3)];
    disp(r(d));
    v(d)=v(c)+[-w(cd)*r(cd)*sind(Th3), w(cd)*r(cd)*cosd(Th3)];
    disp(v(d));
end

[Mann Baidi]

Hi Avinash,

it would be helpful if you can add comments to the code, so that we can understand the problem statement

[Walter Roberson]

Th1(1i)=30;

The only case in which that could possibly work is if Th1 is an instance of a class that defines it own subsasgn or uses matlab.mixin.indexing.RedefinesParen class so that () indexing means something relatively arbitrary.

Answer 1

[Walter Roberson]

Ultimately the program cannot be run because you do not define

r_ab = 0.3;
w_ab = 0.2;
Th1_1i = 30;
w_bc = -0.05;
r_bc = 0.25;
Th2_1i = -20;
r_cd = 0.25;
Th3_1i = 0;
for t=0:0.5:10
    Th1 = Th1_1i + w_ab * t;
    fprintf('Theta1(%.2d degrees) \n', Th1,t);
    Th2 = Th2_1i + w_bc * t;
    fprintf('Theta2(%.2d degrees) \n', Th2,t);
    r_b = [r_ab * cosd(Th1), r_ab * sind(Th1)];
    disp(r_b); 
    v_b = [-w_ab * r_ab * cosd(Th1), w_ab * r_ab * cosd(Th1)];
    disp(v_b);
    v_a = v_b - w_ab * r_ab;
    disp(v_a);
    r_c = [r_ab * cosd(Th1) + r_bc * cosd(Th2), r_ab * cosd(Th2) + r_bc * sind(Th2)];
    disp(r_c);
    v_c = v_b + [-w_bc * r_ab * sind(Th2), w_bc * r_ab * cosd(Th2)];
    Dy = 0.0645;
    Th3 = asind(Dy-r_cy)/(r_ab);
    disp(Th3);
    w_cd = (-w_ab * r_ab * cosd(Th1) - w_bc * r_ab * cosd(Th2))/(r_ab * cosd(Th3));
    disp(w_cd);
    r_d = r_c + [r_cd * cosd(Th3), r_cd * sind(Th3)];
    disp(r_d);
    v_d = v_c + [-w_cd * r_cd * sind(Th3), w_cd * r_cd * cosd(Th3)];
    disp(v_d);
end

Theta1(30 degrees) 
Theta1(00 degrees) 

Theta2(-20 degrees) 
Theta2(00 degrees) 

    0.2598    0.1500

   -0.0520    0.0520

   -0.1120   -0.0080

    0.4947    0.1964

Unrecognized function or variable 'r_cy'.