| Compared with the traditional mechanical spraying,robots have greatly improved the quality and efficiency of spraying.Thus many enterprises have introduced spraying painting robot technology.However,due to the traditional spray robots often worked through compiling program or box teaching,it has a greater technical difficulty to realize the trajectory planning for complex work pieces to be sprayed.It is unrealistic for small or medium-sized enterprises to use spraying robots because they are not equipped with specialized technical staff,that will program and maintenance robots.As a result,the promotion of spraying robots is limited.Therefore,it is necessary to study simpler and easier-to-use spray robot control system,which can effectively solve the complex spray trajectory problems.In this study,the control system makes the robot work by trajectory reappearance.There are three ways to get reproduction trajectory.One way is to get dragging teaching trajectory through direct teaching.The second way is to get some straight line,arc or other programming trajectories through the input linear interpolation,circular interpolation or other programming instructions.Third way is to get some new combinatorial trajectories through the existing track stitching,allowing these combinatorial trajectories include dragging teaching tracks and programming trails at the same time.This way of working makes the spraying robot easy to use,which can achieve complex spray trajectory efficiently.Aiming at the hardware structure of system,the mechanical structure of robot body is analyzed.Then,the structure of the control hardware platform is analyzed and designed,which include industrial computer and motion controller,servo drive and servo motor,position detection device etc.For the system software structure,the modular design idea is used to classify the software architecture in order to be able to manage the system development process and ensure the stability of the system,and improve the progress of the system development and clear system requirements.The kinematics model of the self-developed spray robot body has been established and analyzed by using the D-H rules.And the connecting rod coordinates system for the spraying robot has been established.At the same time,the transformation matrix of each connecting rod has been obtained by the connecting rod transformation.Finally,the kinematics of the robot is solved.Aiming at the core function module of the control system,which includes direct teaching module and simple programming module,to realize all these function.Among them,the direct teaching module is mainly to obtain some dragging teaching trajectory,which consists of two links including dragging teaching function and teaching trajectory reproduction function.These links are respectively discussed and designed.At the same time the problems such as determining the sampling period and applying the auxiliary force had been discussed,and some algorithms had been designed.In addition,the simple programming module is mainly generated by straight lines,arcs or other regular trajectories through programming instructions.For the design and implementation of simple programming module,the compiler had been designed to explain the programming instructions based on lexical analysis tool LEX and parser tool YACC.And then generate the same format as the teaching trajectory program through semantic analysis,which can be reproduced directly through the trajectory reproduction function.The control system has been applied to the self-developed spray robot,and some key experiments are designed to carry out the comprehensive test of the spray robot control system.In addition,3D simulation software is designed based on OpenGL library to verify the correctness of the derived robot motion model and positive and inverse solution.Finally,the specific application examples of spray robots that have been put into production had been introduced to confirm the reliability and stability of the control system. |
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