3.3.1 A 2D Kinematic Chain

Before considering a kinematic chain, suppose ${\cal A}_1$ and ${\cal A}_2$ are unattached rigid bodies, each of which is capable of translating and rotating in ${\cal W}= {\mathbb{R}}^2$ . Since each body has three degrees of freedom, there is a combined total of six degrees of freedom; the independent parameters are $x_1$ , $y_1$ , $\theta_1$ , $x_2$ , $y_2$ , and $\theta_2$ .