Research On Kinematic Calibration Method Of Precise Positioning Robot For Building Components

At present,prefabricated building has a broad development prospect,but in the prefabricated building construction field,there are problems such as low automation,low precision,low efficiency,high labor intensity and difficulty in safety assurance.According to the "construction 4.0" strategy proposed by the state,key technologies of industrial robots are introduced to form new construction robots for different application scenarios,so as to reduce the working intensity,improve the working efficiency and finally achieve complete autonomy of building construction.Therefore,it is of great significance to study the new roboticized construction equipment and key technologies in the field of prefabricated buildings.Installed in place of building components is a key link in the process of prefabricated building construction process,the problem of low installation accuracy of building components in place is solved in this paper,relying on industrial robot structure for the prototype theory,a new robot structure for precise positioning of building components is designed,and according to the field research,a set of specific robot construction process for the positioning and installation of prefabricated components in prefabricated buildings is formed.Six-axis control robot is the main executive mechanism of the component accurate positioning robot,and its absolute positioning accuracy directly affects whether the prefabricated components can be precisely emplaced.Therefore,aiming at the problem of low absolute positioning accuracy of robot,which directly affects the positioning and installation accuracy of prefabricated components,a robot kinematics calibration method based on POE formula of minimum model and visual measurement is proposed,and the six-axis controll robot is taken as the object for simulation and experiment,thus the effectiveness of this method is proved.Aiming at the singularity and parameter redundancy in the current robot kinematics calibration model,the product of exponentials(POE)formula describe the robotic forward kinematics,thereby positive kinematics equation is gained,then the linear error model is established by taking the differential and the redundant parameters are eliminated by the minimization,and the kinematic calibration equation is finally obtained.The least square method is used to identify the parameters of the calibration equation,which effectively avoids the normalization and orthogonalization during the iteration process of the traditional model.Kinematics calibration simulation based on pose measurement and position measurement is carried out respectively,and the effectiveness of the method is verified by the simulation results.For the measurement methods used in traditional robot kinematic calibration,there are problems such as tedious measurement and long measurement time,a vision-based measurement method is adopted in this paper,and a vision-based calibration system is established,an automatic robot calibration scheme is designed,Zhang Zhengyou's camera calibration method and a hand-eye calibration method based on matrix direct product are used to implement the vision system calibration,at the same time,the distance error model is introduced to avoid the cumulative error introduced by the coordinate system transformation and realize the online automatic calibration of the robot.The six-axis control SR10C robot is taken as the experimental object,and the checkerboard format calibration board is introduced as the auxiliary measuring tool,the effectiveness and feasibility of the method is verified by the experimental results.