In this paper, we address the stability analysis of swarm robots with heterogeneous abilities for velocity and acceleration. Each robot also has a unique sensing region with a limited angle of field of view. We previously proposed a decentralized navigation method for such swarm robots. With the method, connectivity maintenance is achieved while satisfying physical limitations which are unique to each robot. Here, we focus on the shape of the whole swarm and mathematically prove that the shape and orientations of all robots eventually converge to the equilibrium state. Furthermore, we show experimental results to confirm the convergence.