Reserch On Robot Assemply Technology Of Circle-rectangle Hole Parts

In industrial production,the assembly operation is a very important part of the process of product production.The assembly process is large in workload and the task is heavy.How to carry out the assembly operation efficiently is the focus of research in production management and equipment technology.With the development of automation technology,industrial robots are currently widely used in handling,welding,spraying,assembly and other sectors.The special feature of the assembly is the shape of the workpiece and the need to contact the environment with a small gap,which requires more accurate robot force control technology and testing technology.At present,the parts’ shape of the robot assembly line are regular,completely symmetrical.the research on the assembly of complex shapes is less,so the robot assembly is still a field that needs further study.Adopting the modular combination manipulator arm with the introduction of force control technology,this paper carry out reserch on robot assemply technology of circle-rectangle hole parts.In order to realize the automatic assembly of circle-rectangle hole parts,the geometrical shape analysis of the parts is carried out and the preliminary assembly strategy is worked out.It is concluded that the composite parts need to adjust the position and along the three axes to control relative deviation with the hole.The joint modulars are designed and assembled into assembly of the six DOF modular combination manipulator arm and the kinematic relationship between the forward and the inverse kinematics is obtained.Secondly,the contact static analysis was carried out on the assembly process,and the contact distribution of the part along the plane is classified.The contact state is complicated,especially in the hole posture adjustment stage,the soft fitting model of space is used to deduce the mathematical model of assembly force and assembly depth,and the force characteristics of one point contact,two point contact and three point contact are analyzed.The influence of the hole depth and the surface quality on the assembly is analyzed by analyzing the phenomenon of "block" and "wedge tightening" that hinder assembly.The assembly strategy of circle-rectangle hole parts is put forward,which is divided into three stages: proximity hole,contact and posture adjustment.The proximity hole belongs to non-contact state,and the coarse locating hole is designed for the specific trajectory.Contact after the first search square hole,and then search the circle hole so that the workpiece into the hole;Posture adjustment according to whether the movement is blocked,the the corresponding relationship is established between the workpiece position adjustment and contact force,that is,to achieve soft control.The assembly force in the assembly process will hinder the assembly,seriously damage to the workpiece and the robot.The impedance control uses lateral position adjustment to reduce the lateral force and torque to ensure the smooth assembly.The establishment of contact with the environment of the spring Model,combined with the impedance model to analyze the influence of impedance parameters on the force control deviation.The controller is designed and programmed in Matlab / Simulink.The circular-rectangular composite hole is used as the assembly object.The robot arm model is established in Adams,and the simulation is carried out to verify the assembly strategy.The simulation results show that,while ensuring the success of the assembly,the contact force can be controlled within a certain range,which verified the feasibility of the assembly strategy.