  This article presents an approximation algorithm for a task allocation,
sequencing and scheduling problem involving a team of human operators and
robots. Specifically, we present an algorithm with an approximation ratio as a
function of the number of human operators ($m$) and the number of robots ($k$)
in the team. The approximation ratios are $\frac{7}{2} -\frac{5}{2k}$,
$\frac{5}{2} -\frac{1}{k}$ and $\frac{7}{2} -\frac{1}{k}$ when $m=1$, $m\geq
k\geq 2$ and $k>m\geq 2$ respectively. We also present computational results to
corroborate the performance of the proposed approximation algorithm.
