two intervals const a p1

• Acceleration $$\tag{D1} a(t) = \left\{ \begin{array}{cc} a_0, & t_0 \le t < t_1, \\[0.5em] a_1, & t_1 \le t < t_2, \end{array} \right. $$ with $t_{n+1} = t_n + \tau_n$, where $\tau_n$ is $n$-th time interval.