Research On Automatic Positioning And Anti-swing Control Method Of Underactuated Gantry Crane

Gantry crane is a kind of lifting engineering equipment widely used in the fields of manufacturing,warehousing and logistics,and construction.The gantry crane system still relies on manual operation.Due to human factors such as work skills,work experience and fatigue work,there are problems such as inefficient work,inaccurate positioning,and poor anti-swaying in the operation of gantry cranes.Therefore,production safety accidents are prone to occur.Gantry crane is a typical representative of strong coupling and nonlinear underactuated electromechanical system.It is very necessary to study the automatic control method of gantry crane suitable for industrial operation site to improve its control performance.This article takes the under-actuated gantry crane as the research object to study its automatic positioning and anti-sway control methods.The main work is as follows:Firstly,in view of the lack of positioning detection of the gantry crane system,which requires the passive input of target displacement to generate positioning errors,this paper designs a gantry crane target displacement positioning method based on machine vision.We use the Quick Response(QR)code as a positioning identification beacon to establish the reference coordinate system of the gantry crane working surface,and identify and determine the gantry crane target displacement.Not only that,if people intrude into the dangerous area of the gantry crane during the lifting process,early warning shutdown is required to avoid production safety accidents.To this end,this paper designs a positioning method for gantry crane safety early warning parking displacement based on machine vision.By improving the classic YOLOV3 network structure of target recognition and combining the camera coordinate conversion ranging method,a visual detection and positioning model of humanoid target intrusion into the dangerous working face of the gantry crane was established.Secondly,most of the existing literatures study the trajectory planning and nonlinear anti-sway control of two dimensional single pendulum underractuated gantry crane models.However,the gantry and the trolley often move at the same time in order to improve the operating efficiency.At this time,the three dimensional underactuated gantry crane has more state quantities,stronger system coupling and non-linearity,and research is more challenging.To this end,this paper uses the Euler-Lagrange equation to establish a dynamic model of a single pendulum underactuated gantry crane in a three-dimensional model.We designed an S-shaped trajectory that satisfies the smooth start of the trolley and the mast and reaches the target displacement accurately.A non-linear controller with precise positioning and anti-swing is designed by using the scalar function constructed by the mechanical energy model of the shaped single pendulum under-driven gantry crane.The designed controller not only enables the trolley and the mast to reach the target displacement accurately,but also effectivelysuppresses and eliminates the load swing in the three-dimensional space.Thirdly,in order to solve the control problem of underactuated gantry cranes with hook and load swinging at the same time,this paper establishes a double pendulum underactuated gantry crane dynamic model.We define a coupling signal that includes the load swing angle,the hook swing angle,and the displacement of the trolley,which improves the energy function of the double-swing gantry crane.A non-linear and precise anti-sway control method for a double pendulum underactuated gantry crane is studied,which does not depend on system parameters.Lyapunov’s second theorem and La Salle’s invariant principle are used to effectively prove the stability of the closed-loop system.The above control method is verified by the gantry crane experimental platform and numerical simulation.The experimental and simulation results show that the proposed control method in this paper shows a good control effect.It provides a theoretical reference for the practical application of gantry cranes.