Design And Implementation Of Motion Planning For AGV With Mecanum Wheel In Narrow Rectangular Corner

The motion planning of AGV is an important research content in the field of robot. In the actual industrial scene or intelligent warehouse threre existing narrow rectangular corner which results in conventional AGV unable to pass or low passing rate. AGV with mecanum wheel has a variety of ways of turning in the narrow scene since its character of the omni-directional move, which has advantages in the narrow scene. However, currently there lacks specific research on the steering planning of mecanum AGV in a narrow rectangular corner as well as mature solutions. So on the basis of considering the limited characteristics, the research about turning planning combining the movement characteristics of AGV with mecanum wheels, which aims to improve the trafficability characteristic of AGV with mecanum wheel in narrow rectangular corner has practical significance and theoretical value.Aiming at the problem of lacking effective planning method of Mecanum wheel AGV, based on the analysis of limited narrow right-angle bend characteristics and the movement characteristics of the mecanum wheel AGV, firstly, this research establish the mecanum wheel steering kinematics model of AGV considering outer contour, which is used to describe the state of turning. Secondly, this paper establish environment description model based on line feature, which is used to describe right angle bend and the initial state of AGV. Then this paper put forward a method of motion planning of AGV with mecanum wheel which combines kinematic characteristics of mecanum wheel. Finally the proposed scheme is verified in the actual mecanum wheel of AGV platform to realize the process. The main research contents include:(1) Steering kinematics modeling of AGV whih Mecanum wheel. Firstly, the movement characteristics of mecanum wheeled mobile mechanism is analyzed. And then we adopt speed representation to establish the kinematics model based on centroid and implement traffic prediction algorithm. Based on the established, kinematics model which considering outer contour is established, which is used to describe the steering motion state and achieve global positioning. At last, the final design physical experiment verify the validity of the model. The experimental results show that this model can effectively describe the contour information of AGV during turning and have a good precision.(2) Environment modeling based on laser radar. This paper analyzes the geometrical characteristics of the laser radar distance image in the right-angle bend, and then proposes a modified split- the merge feature extraction algorithm by improving the threshold and criterion of merge and split. And then based on line feature in narrow rectangular geometry description model of is established to describe information of right angle bend and the initial state of AGV. At last, through contrast experiment shows that the algorithm in environment modeling accuracy is superior to the algorithm of the original one which can effectively reduce the line fitting error.(3) The planning method of AGV with Mecanum wheel in narrow rectangular corner. Firstly this article analyses the limited situation AGV in narrow rectangular corner and puts forward a steering motion planning algorithm based on rule type. This method divides the process of turning according to state, under the conditions of different has taken a different strategy. At last, by experimental verification, the algorithm overcome the problem of space limitation and guarantee trafficability characteristic of AGV with mecanum wheel in in narrow rectangular.Finally, to summarize the research achievements above-mentioned, it forms solutions to overcome space constraints in narrow rectangular bent and design the system applied to the mecanum wheel AGV platform. The experimental results show that system can accurately describe the state of AGV including the outer contour and environmental information, compared to other ways of turning such as steering mode of circular arc and in-situthe, which can ensure good performance of trafficability characteristic in narrow rectangular corner.