How I can to resolve the code below?

function [x, y, z] = Forward_Kinematics1(theta1, theta2, theta3)
syms x y z
% kinematic parameters
R = 94.52;
L1 = 170;
L2 = 319.5;
r = 65;

% Calculate sine and cosine values
c1 = cosd(theta1); s1 = sind(theta1);
c2 = cosd(theta2); s2 = sind(theta2);
c3 = cosd(theta3); s3 = sind(theta3);
% define B1'
B1 = [0; -R - L1*c1 + r; L1*s1];
% define B2'
B2 = [(-sqrt(3)/2)*(-R-L1*c2+r); (-1/2)*(-R-L1*c2+r); L1*s2];
% define B3'
B3 = [(sqrt(3)/2)*(-R-L1*c3+r); (-1/2)*(-R-L1*c3+r); L1*s3];
% Define constants
a1 = 2*(B1(1) - B2(1)); a2 = 2*(B1(1) - B3(1));
b1 = 2*(B1(2) - B2(2)); b2 = 2*(B1(2) - B3(2));
c1 = 2*(B1(3) - B2(3)); c2 = 2*(B1(3) - B3(3));
d1 = (B2(1)^2 + B2(2)^2 + B2(3)^2) - (B1(1)^2 + B1(2)^2 + B1(3)^2);
d2 = (B3(1)^2 + B3(2)^2 + B3(3)^2) - (B1(1)^2 + B1(2)^2 + B1(3)^2);
% Define coefficients for z
A = 1;
B = -2*B1(3);
C = B1(3)^2 - L2^2 + (B1(1))^2 + (B1(2))^2;
% Define equations as symbolic expressions
eq1 = a1 * x + b1 * y + c1 * z - d1;
eq2 = a2 * x + b2 * y + c2 * z + d2;
eq3 = A * z^2 + B * z + C;

[Anjaneyulu Bairi]

can you post the error that you are getting?

Thanks

[Ky]

I'm calculating Forward kinematics for delta robot. Programe of me is bellow:

function [x, y, z] = Forward_Kinematics1(theta1, theta2, theta3)

syms x y z real

% kinematic parameters

R = 94.52;

L1 = 170;

L2 = 319.5;

r = 65;

% Calculate sine and cosine values

c1 = cosd(theta1); s1 = sind(theta1);

c2 = cosd(theta2); s2 = sind(theta2);

c3 = cosd(theta3); s3 = sind(theta3);

% define B1'

B1 = [0; -R - L1*c1 + r; L1*s1];

% define B2'

B2 = [(-sqrt(3)/2)*(-R-L1*c2+r); (-1/2)*(-R-L1*c2+r); L1*s2];

% define B3'

B3 = [(sqrt(3)/2)*(-R-L1*c3+r); (-1/2)*(-R-L1*c3+r); L1*s3];

% Define constants

a1 = 2*(B1(1) - B2(1)); a2 = 2*(B1(1) - B3(1));

b1 = 2*(B1(2) - B2(2)); b2 = 2*(B1(2) - B3(2));

c1 = 2*(B1(3) - B2(3)); c2 = 2*(B1(3) - B3(3));

d1 = (B2(1)^2 + B2(2)^2 + B2(3)^2) - (B1(1)^2 + B1(2)^2 + B1(3)^2);

d2 = (B3(1)^2 + B3(2)^2 + B3(3)^2) - (B1(1)^2 + B1(2)^2 + B1(3)^2);

% Define coefficients for z

A = 1;

B = -2*B1(3);

C = B1(3)^2 - L2^2 + (B1(1))^2 + (B1(2))^2;

% Define equations as symbolic expressions

eq1 = a1 * x + b1 * y + c1 * z - d1;

eq2 = a2 * x + b2 * y + c2 * z + d2;

eq3 = A * z^2 + B * z + C;

% Convert equations to functions

equations = matlabFunction([eq1; eq2; eq3], 'vars', [x; y; z]);

% Solve the system of equations

initial_guess = [0; 0; 0];

result = fsolve(equations, initial_guess);

% Extract results

x = result(1);

y = result(2);

z = result(3);

% Display results

fprintf('Nghiệm x: %.4f\n', x);

fprintf('Nghiệm y: %.4f\n', y);

fprintf('Nghiệm z: %.4f\n', z);

end

and error, when I run program is

[x, y, z] = Forward_Kinematics1(0,0,0)

Not enough input arguments.

Error in symengine>@(x,y,z)[x.*(-3.455787771261424e+2)-y.*5.9856e+2;x.*3.455787771261424e+2-y.*5.9856e+2;z.^2-6.227201960000001e+4]

Error in fsolve (line 264)

fuser = feval(funfcn{3},x,varargin{:});

Error in Forward_Kinematics1 (line 46)

result = fsolve(equations, initial_guess);

Caused by:

Failure in initial objective function evaluation. FSOLVE cannot continue.

Answer 1

[Sandeep Mishra]

Hi Ky,

I executed the code snippet in MATLAB R2022a and encountered the same error.

After investigating further, I came across a relevant MATLAB Answers post addressing a similar issue:

https://www.mathworks.com/matlabcentral/answers/693640-failure-in-initial-objective-function-evaluation-fsolve-cannot-continue-please-help#comment_1211945

The root cause of the error is related to the ‘fsolve’ function, to resolve this, you can update the code snippet by passing the inputs in the following manner:

equations = matlabFunction([eq1; eq2; eq3], 'Vars', {[x; y; z]}); 

Please refer to the below MathWorks documentation to learn more about ‘fsolve’ function of MATLAB:

https://www.mathworks.com/help/releases/R2022a/optim/ug/fsolve.html

I hope this helps.