bug with ikine_sym

[petercorke]

Hi, I am trying to get the symbolic inverse kinematics for a RRR robot but i am getting some errors. Below is the input:

L1 = Revolute('alpha', 0, 'a',1, 'd', 0, 'qlim', [-pi pi]);
L2 = Revolute('alpha', 0, 'a',1, 'd', 0, 'qlim', [-pi pi]);
L3 = Revolute('alpha', 0, 'a',1, 'd', 0, 'qlim', [-pi pi]);
R = SerialLink([L1 L2 L3]);
sol = R.ikine_sym(3);

And the output:

----- solving for joint 1
subs sin/cos q1 for S/C
cant solve this equation
k = 1 2
ans = txcos(q1) + tysin(q1) - 1 == cos(q2) + cos(q2)cos(q3) - sin(q2)sin(q3)
tycos(q1) - txsin(q1) == sin(q2) + cos(q2)*sin(q3) + cos(q3)*sin(q2)

Error using SerialLink/ikine_sym (line 191)
cant solve

Error in closedform (line 17)
sol = R.ikine_sym(3);