AGV Localization System Based on Ultra-Wideband and Vision Guidance

Abstract

Aiming at the problems of low localization accuracy and complicated localization methods of the automatic guided vehicle (AGV) in the current automatic storage and transportation process, a combined localization method based on the ultra-wideband (UWB) and the visual guidance is proposed. Both the UWB localization method and the monocular vision localization method are applied to the indoor location of the AGV. According to the corner points of an ArUco code fixed on the AGV body, the monocular vision localization method can solve the pose information of the AGV by the PnP algorithm in real-time. As an auxiliary localization method, the UWB localization method is called to locate the AGV coordinates. The distance from the tag on the AGV body to the surrounding anchors is measured by the time of flight (TOF) ranging algorithm, and the actual coordinates of the AGV are calculated by the trilateral centroid localization algorithm. Then, the localization data of the UWB is corrected by the mean compensation method to obtain a consistent and accurate localization trajectory. The experiment result shows that this localization system has an error of 15mm, which meets the needs of AGV location in the process of automated storage and transportation.Electronics 2020, 9, 448 2 of 15 continuous development of the field of intelligent manufacturing, higher requirements for AGV localization accuracy and flexible configuration were introduced, navigation methods such as visual navigation [11][12][13], QR code navigation [14][15][16], and SLAM navigation [17][18][19] have appeared. Zhang Jianpeng [20] and He Zhen et al. [21] position AGV with visual guidance. Literature [20] proposed a multi-window real-time ranging and localization method using a circular mark on the ground as a localization identifier, with high localization accuracy. Literature [21] proposed a method to measure the pose of AGV by using binocular vision. It can predict and locate the circular landmarks on the edge of the ground guideline with high accuracy. Zhang Haoyue et al. [22] established a large-capacity QR code as an artificial landmark, matched the vision sensor to achieve accurate AGV localization, and had small repeat errors.The method described above can achieve AGV localization only use a single localization technique. Based on the existing navigation methods, two or more navigation methods are merged to realize a complementary advantage of different navigation methods. This hybrid method becomes increasingly normalized in order to accurately navigate for the AGV localization. Literature [23] proposed a novel adaptive fault-tolerant multisensor navigation strategy for automated vehicles on the automated highway system. Literature [24] proposed an AGV navigation system based on GPS/DR information fusion, making GPS signal and DR signal mutually compensate for each other.The localization of the AGV dedicated to the state-of-the-art is SLAM. It can help the AGV to build an indoor environment map for the completely unknown indoor environment through co...

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