Forward and Inverse Kinematics for robot

Hi @Mohd Musharaf Hussain Sarwari,

You mentioned, “ I WANT SCARA ROBOT forward-and-inverse-kinematics MATLAB CODE”

Please refer to this link which should help resolve your problem. https://www.mathworks.com/matlabcentral/fileexchange/128529-inverse-kinematics-of-scara-robot

Hi @Ram Bodhe ,

I executed your code and got error message "Not enough input arguments" which indicates that the function is being called without the required input vector ph. To resolve this issue, you need to make sure that the function is called with the appropriate input. Additionally, enhance the function to include input validation, ensuring that the input is a three-element vector. Here is the corrected and updated version of the inv_kinematics function:

function q = inv_kinematics(ph)
  % Check if the input is a 3-element vector
  if nargin < 1 || length(ph) ~= 3
      error('Input must be a 3-element vector [ph1, ph2, ph3].');
  end

    % Define the lengths of the robotic arm segments
    l1 = 0.05; 
    l2 = 0.28; 
    l3 = 0.2; 
    d1 = 0.03;

    % Extract the position components from the input vector
    ph1 = ph(1); 
    ph2 = ph(2); 
    ph3 = ph(3);

    % Calculate the radius and angle for the inverse kinematics
    r = sqrt(ph1^2 + (ph3 - d1)^2); 
    alpha = acos((r^2 + l2^2 - l3^2) / (2 * r * l2));

    % Initialize the joint angles vector
    q = zeros(3, 1); 

    % Calculate the joint angles using inverse kinematics equations
    q1 = atan2(ph2, ph1); 
    q2 = atan2(ph1, ph3 - d1) - alpha; 
    q3 = atan2(ph1 - l2 * sin(q2), ph3 - d1 - l2 * cos(q2)) - q2;

    % Combine the joint angles into a single output vector
    q = [q1; q2; q3];
  end

Explanation of Changes Made

Input Validation: The function now checks if the input ph is provided and whether it contains exactly three elements. If not, it raises an error with a descriptive message. This prevents the function from executing with invalid inputs.

Code Structure: The overall structure of the code remains intact, ensuring that the calculations for the joint angles are preserved.

Comments: Additional comments have been added to clarify each step of the process, making the code more understandable for future users or developers.

Now, to utilize the inv_kinematics function, you can call it with a three-element vector representing the desired position of the end effector. For example:

% Define the desired position
desired_position = [0.1, 0.2, 0.15]; 

% Call the inverse kinematics function
joint_angles = inv_kinematics(desired_position);

% Display the results
disp('Calculated Joint Angles (radians):');
disp(joint_angles);

Please see attached.

When you will run the above example with a valid input vector, the function will compute and display the joint angles required to position the robotic arm at the specified coordinates. Hope, this answers your question.