Accurate 3-D Position and Orientation Method for Indoor Mobile Robot Navigation Based on Photoelectric Scanning

Position and orientation of indoor mobile robots must be obtained real timely during operation in structured industrial environment, so as to ensure the security and efficiency of cargo transportation and assembly precision. But for such a large-scale space, only 2-D coordinates and heading angle of the mobile robot can be measured with a relatively low precision in current major methods. This paper presents a novel method for 3-D position and orientation measurement of indoor mobile robot. In this method, a rotary-laser transmitter is utilized, which is mounted on the indoor mobile robot measuring the scanning angles relative to photoelectric artificial landmarks and obtaining its own 3-D space location information. The landmarks whose coordinates in navigation frame should be precalibrated are distributed at the most appropriate positions of the structured industrial environment. On the basis of that, an algorithm of multiangle intersection was established and in-depth discussed to solve transmitter's spatial position and orientation. Experimental results show that, in an 8 m × 6 m × 2.5 m working volume, transmitter's position, and orientation measurement accuracy of proposed method were higher than 3.8 mm and 0.104°, respectively. It demonstrates that the proposed method is reliable and flexible for indoor mobile robot navigation tasks and the measurement accuracy can be further improved by increasing layout density of landmarks.