Research On Shaft Hole Assembly Of Industrial Robot Based On Active Compliance Control

In recent years,with the implementation of the major strategic plan "Made in China 2025",Chinese industrial automation technology has developed rapidly.Polishing,grinding,assembly of holes and shafts,and other tasks that have high control requirements in contact with the environment urgently require automation.However,in the process of shaft hole assembly,assembly failures such as "jam" and even "wedge" often occur.It not only damages the assembly parts and the robot body,affects production safety,but also restricts the development of assembly automation technology.Aiming at the "jam" assembly failure phenomenon that occurs in the automatic assembly operation of shaft holes,this paper conducts in-depth research on its related theories,and uses the UR5 six-degree-of-freedom industrial robot to establish a flexible automatic assembly scheme based on force / position hybrid control.Effectively eliminate the "jam" phenomenon in the assembly process,so that the industrial robot can reliably complete the shaft hole assembly operation.Firstly,this paper conducts an in-depth study on the relevant theories of shaft hole assembly,establishes the shaft hole assembly model,and uses the shaft hole assembly model to perform motion analysis,perform mechanical research on the chamfering stage,one-point contact stage,and two-point contact stage that appear in the assembly of shaft holes,get the judgment conditions at the corresponding stage,the inclination of the assembly shaft / hole,and study the "jam" to get the conditions to remove the "jam",and design the assembly strategy.Then,according to the assembly requirements,the model of the assembly robot and the model of the six-dimensional force sensor are selected,and the forward and inverse kinematics and dynamics calculations of the robot are performed to lay the foundation for the force / position control of the robot.In order to improve the accuracy of the assembly of the shaft hole,the gravity of the industrial robot's installation inclination and hand grip is compensated,and the six-dimensional force sensor is zero-calibrated.After that,the related theories of impedance control and hybrid force / position control were studied,and the control effects of each compliance control algorithm were analyzed,comparing their advantages and disadvantages,adapting to the occasion,etc.,using the hybrid force / position control as the control algorithm for shaft hole assembly,and designing the hybrid force / position controller.Finally,the simulation experiment platform of active compliance assembly control system is established,and the verification of shaft hole assembly experiment is carried out.During the experiment,the UR5 six-degree-of-freedom industrial robot can adjust the shaft / hole position and attitude deviation through the information of the six-dimensional force sensor,and can successfully complete the shaft hole assembly.The entire assembly process is smooth and continuous,and there are no "jam" and "wedge" assembly failure phenomena.The effectiveness of the proposed compliance control algorithm and the shaft hole assembly strategy is verified by the shaft hole assembly experiment.