In this paper, we present a novel tightly coupled probabilistic monocular visual-odometric simultaneous localization and mapping (VOSLAM) algorithm using wheels and a MEMS gyroscope, which can provide accurate, robust, and long-term localization for ground robots. First, we present a novel odometer preintegration theory on manifold; it integrates the wheel encoder measurements and gyroscope measurements to a relative motion constraint that is independent of the linearization point and carefully addresses the uncertainty propagation and gyroscope bias correction. Based on the preintegrated odometer measurement model, we also introduce the odometer error term and tightly integrate it into the visual optimization framework. Then, in order to bootstrap the VOSLAM system, we propose a simple map initialization method. Finally, we present a complete localization mechanism to maximally exploit both sensing cues, which provides different strategies for motion tracking when: 1) both measurements are available; 2) visual measurements are not available; and 3) wheel encoders experience slippage, thereby ensuring the accurate and robust motion tracking. The proposed algorithm is evaluated by performing extensive experiments, and the experimental results demonstrate the superiority of the proposed system.

This work reports a master-slave separate parallel intelligent mobile robot for the fully autonomous transportation of pallets in the smart factory logistics. This separate parallel intelligent mobile robot consists of two independent sub robots, one master robot and one slave robot. It is similar to two forks of the forklift, but the slave robot does not have any physical or mechanical connection with the master robot. A compact driving unit was designed and used to ensure access to the narrow free entry under the pallets. It was also possible for the mobile robot to perform a synchronous pallet lifting action. In order to ensure the consistency and synchronization of the motions of the two sub robots, high-gain observer was used to synchronize the moving speed, the lifting speed and the relative position. Compared with the traditional forklift AGV (Automated Guided Vehicle), the mobile robot has the advantages of more compact structure, higher expandability and safety. It can move flexibly and take zero-radius turn. Therefore, the intelligent mobile robot is quite suitable for the standardized logistics factory with small working space.