You are asked to design a crank-rocker for a rocker amplitude. Link $r_2$ is the crank and $r_4$ is the rocker. The rocker link is required to pass through two positions $B_1$ and $B_2$, with a rocker amplitude of $\theta = 90^\circ$ (CCW) from $B_1$ to $B_2$ and the transmission angle of the linkage at position 2 must be $90^\circ$. The frame link is chosen to be $0.5 \, \text{m}$, and assume the limiting position of the output link at position 1 ($B_1$) is $70^\circ$. Complete the design of the 4-bar using the GCP synthesis approach.
$B_1$
$\theta = 90^\circ$
$r_4$
$70^\circ$
$B_2$
$\mu_2 = 90^\circ$
$O_2$
$r_1 = 0.5 \, \text{m}$
$O_4$
$r_2$
$A_2$
