Research On Disassembly Planning Of Electromechanical Products Based On Industrial Robots

Traditional manufacturing always pays much attention to economic benefit without due regard to environment and resource protection.Future manufacturing pays more attention to environment protection and manufacturing resource reutilization without reducing the economic benefits.Based on End-of-life(EoL)products,remanufacturing is proposed to recover the quality and performance of EoL products.The performance of remanufactured product is as good as a new one.Remanufacturing takes full advantages of EoL products and reduces environmental pollution caused by EoL products.It helps to realize manufacturing resources reutilization and environment protection.Disassembly is a key step of remanufacturing and the traditional disassembly process is usually finished by manual labor which has the disadvantages of low efficiency and high cost.Industrial robot,which is an important manufacturing equipment to realize intelligent manufacturing,has been widely applied to the assembly,welding and machining fields.Compared with manual disassembly,robotic disassembly(disassembly based on industrial robots)has higher disassembly efficiency,better repeatability and lower disassembly cost.Before executing the disassembly process,disassembly planning helps to improve disassembly efficiency and reduce disassembly cost.Disassembling EoL electromechanical products using industrial robots is an important research branch of remanufacturing.Under this condition,research on disassembly planning of electromechanical products based on industrial robots has great significance to improve disassembly efficiency and intelligentialize the disassembly process.This thesis is to study disassembly planning of electromechanical products based on industrial robots.It is conducted under the projects from the National Natural Science Foundation of China,the Engineering and Physical Sciences Research Council of UK and joint-program from China Scholarship Council.Considering characteristics of robotic disassembly,much work has been conducted in terms of disassembly constraint modeling,disassembly tasks assignments in the robotic disassembly line and swarm intelligence optimization.The following research work has been finished.(1)Considering the characteristics of movement of industrial robot’s end-effector,the traveling time of industrial robot’s end-effector along the obstacle-avoiding path was calculated by the length of obstacle-avoiding path and the linear velocity of industrial robot’s end-effector.Consequently,the optimization objectives were described.Based on this,disassembly constraint model was built by the following method: the feasible disassembly sequence and disassembly direction were obtained by improved space interference matrices and feasible sequence generation method.After that,disassembly sequence planning of electromechanical products based on industrial robots was solved by enhanced discrete Bees algorithm.In this research,the gear pump and the camera were the EoL products to be disassembled.To minimize the total disassembly time,enhanced discrete Bees algorithm was proposed to find the optimal disassembly solutions(both the disassembly sequence and disassembly direction).In addition,disassembly process simulations of robotic disassembly cell using RoboDK software were conducted to verify the proposed method.(2)Based on the improved space interference matrices and feasible sequence generation method,considering the characteristics of workstations in robotic disassembly line,with the help of allocation matrix,disassembly task assignment was proposed to assign suitable disassembly tasks to the robotic workstations within given cycle time.To minimize the number of robotic workstations,the balancing index and the demand index of robotic disassembly line,multi-optimization objectives were established.With the help of efficient non-dominated Pareto sorting method,based on the gear pump and camera,improved multi-objective discrete Bees algorithm was proposed to find the Pareto optimal solutions of disassembly line balancing problem based on industrial robots.After that,based on RoboDK software,disassembly process simulations of robotic disassembly line were conducted to verify the proposed method.(3)Considering the optimization objectives of robotic disassembly cell and robotic disassembly line,based on the interaction relationships between different optimization objectives,analytic network process was used to assign suitable weights to the objectives.Consequently,collaborative optimization problem of robotic disassembly sequence planning(disassembly sequence planning based on industrial robots)and robotic disassembly line balancing problem(disassembly line balancing problem based on industrial robots)was proposed to simultaneously optimize the two problems,the optimization objectives were also built.Based on the gear pump and camera,improved discrete Bees algorithm with variable neighbor search strategy was proposed to obtain the optimal solutions of the collaborative optimization problem.At last,based on RoboDK software and the results of collaborative optimization problem,disassembly process simulations were conducted to verify the proposed method.(4)Based on KUKA iiwa robotic disassembly cell and KUKA robotic disassembly line,with the help of JAVA Web technology and data communication methods,disassembly planning service platform of electromechanical products based on industrial robots was developed,which contains user login module,data management module,configuration data uploading module,planning service module and control service module.After visiting this service platform,the users can read the information(coordinate information,torque information,etc.)of industrial robots,control the coordinates(both joint and cartesian coordinates)of industrial robots and obtain the optimal disassembly planning solutions.In addition,the users can send disassembly commands,which correspond to the optimal solutions obtained by planning service modules,to the industrial robot’s controller.After receiving the disassembly commands,the controller analyzed these commands and then called the functions which were pre-loaded to execute the disassembly operations.