Department Publications

This paper presents a method for localizing an Unmanned Aerial Vehicle (UAV) using geo-referenced aerial images, in case of GPS failure. When flying in urban environments in low altitudes the inaccurate GPS localization has become a major problem. The proposed method fuses measurements from inertial sensors and visual odometer and perform image registration process using the images captured by the onboard down looking camera. A pre-built local orthomosaic map with geotagged aerial images is used for the registration. The problem of unreliable matches caused by the dynamic objects is addressed in our approach. The experiment results show that it is possible to localize the UAV in urban environments with a low margin of error by using our method.

Indoor positioning by wireless means is of significant interest in a wide range of applications; Wi-Fi and Bluetooth Low Energy (BLE) are popular candidate wireless technologies for this. We present a novel BLE beacon placement algorithm that complements existing Wi-Fi infrastructure in a hybrid Wi-Fi/BLE positioning system. Composite signal strength measurements thus obtained, are used to derive machine learning models for location estimation. Our results show that positioning estimates at table-level granularity (0.9 m × 1.8 m) in a computer laboratory can be achieved with 97% accuracy. This is an improvement of 20% and 30% compared to Wi-Fi and BLE only techniques respectively.

This paper has addressed the problem of transporting a long object from a given starting location to an end location using leader-follower robot formation in an environment filled with obstacles. Only the leader robot has the authority to make decisions. It possesses the main controller and is capable of navigating through an unknown environment using the data provided by on-board sensors. In the proposed system, a vision-based feedback method is combined with an explicit control method that oversights the virtual trailer between the leader and the follower. The parameters required to maintain a constant distance between the two robots are computed by the leader and transmitted to the follower directly. A fiducial marker is mounted on the front of the follower robot and is captured by a camera attached to the leader robot. Information exchanging methods based only on impedance control can be expensive …

Travelling along routine paths on foot is an exhausting and mundane task. Current personal mobility vehicles (PMVs), which address this issue, are driven manually and are too heavy to be carried by the user when needed. As a solution to this, an autonomous, self-balancing, lightweight, compact and low-cost PMV is developed. The device is capable of simultaneously self-balancing and navigating autonomously in an indoor environment. Moreover, it can be manually controlled using the developed smart mobile phone application. Self-balancing, localization, navigation and obstacle avoidance are achieved in real time using on-board sensors and processing units. Systematic experiments are carried out with the developed PMV in typical indoor environments in order to assess the robustness of the above features. The results show that the robot is able to successfully achieve its navigation tasks both with and …