Trouble Coding Kinematics Problem

Question

Bailey Smith 2018-10-9

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/423090-trouble-coding-kinematics-problem

回答： Sebastian Castro 2018-10-9

I am trying to code this problem into MATLAB. I want to solve for theta3, theta4, w3, and w4 (w being omega). I am having some trouble getting my thetas to work. When I try to solve, say, for theta2=95 degrees, I keep getting 0 and 1 degree, respectively. Is my problem just setting up the code incorrectly, or is it something else?

Thank you in advance!

 clear; clc;
 theta2=input('Enter a Value For Theta 2 in Degrees: ');
 w2=10;
 OC=10;
 OA=4;
 AB=12;
 BC=7;
 w1=0; %ground; can't move
 theta1=0; %ground; no angle
 syms theta3 theta4
 %R2+R3=R1+R4 -> OA+AB=OC+BC -> OA+AB-OC-BC=0
 eq1=OA*cos(theta2)+AB*cos(theta3)-BC*cos(theta4)-OC*cos(theta1)==0;
 eq2=OA*sin(theta2)+AB*sin(theta3)-BC*sin(theta4)-OC*sin(theta1)==0;
 sol1=solve([eq1,eq2], [theta3 theta4]);
 theta3_=sol1.theta3;
 theta4_=sol1.theta4;
 % syms w3 w4
 % 
 % %time derivative equations = velocity equations
 % eq3=-(OA*sin(theta2)*(w2))-(AB*sin(theta3)*w3)+(BC*sin(theta4)*w4)==0;
 % eq4=(OA*cos(theta2)*(w2))+(AB*cos(theta3)*w3)-(BC*cos(theta4)*w4)==0;
 fprintf('Theta 3 is %.f degrees\n',theta3_(1))
 fprintf('Theta 4 is %.f degrees\n',theta4_(1))
 % fprintf('The angular velocity of omega 3 is %.f rad/s\n',w3)
 % fprintf('The angular velocity of omega 4 is %.f rad/s\n',w4)