  The automatic road roller, as a popular type of construction robot, has
attracted much interest from both the industry and the research community in
recent years. However, when it comes to tunnels where the degeneration issues
are prone to happen, it is still a challenging problem to provide an accurate
positioning result for the robot. In this paper, we aim to deal with this
problem by fusing LiDAR and UWB measurements based on optimization. In the
proposed localization method, the directions of non-degeneration will be
constrained and the covariance of UWB reconstruction will be introduced to
improve the accuracy of localization. Apart from these, a method that can
extract the feature of the inner wall of tunnels to assist positioning is also
presented in this paper. To evaluate the effectiveness of the proposed method,
three experiments with real road roller were carried out and the results show
that our method can achieve better performance than the existing methods and
can be applied to automatic road roller working inside tunnels. Finally, we
discuss the feasibility of deploying the system in real applications and make
several recommendations.
