Vishniu Gopalakrishnan wrote:
The problem is there is no solution for theta 2 and theta 3 which satisfies both constraints for theta4 from 0-90deg for a=1.237,b=3.027,c=3.506 and d=3.144. For example when theta 4=90,the given values dont satisfy the 2 constaints acos(theta2)+bcos(theta3)...=0 and asin(theta2)+bsin(theta3)....=0
I see! And from your drawing its easily seen that the arm c would not be able to move up to 90 degree because arm a is far too short to accomodate that. So you would need additional constraints for a and c (and possibly b, too) to work out and put then in the solve block.
While looking at your drawing I wonder if your two constraint equation are correct. Can you explain that term atan(0.56/sqrt(c^2+0.56^2))? Why is this angle added to theta4?
BTW, the maximum torque is usually NOT exactly at 60 degree and the positions varies depending on the arm lenghts!