Research On Bolt Pre-screw Robot With Visual Control

The balance shaft plays an important role in the shock absorption of the car and the stability of the vehicle.In the automobile balance shaft assembly production line,before tightening the bolts,it is necessary to manually place the bolts at the designated position and pre-tighten.This process consumes manpower and material resources,and affects production efficiency.This paper designs a vision-based robot to place bolts and pre-tighten the system instead of manual operation,which has an important role in reducing the labor intensity and improving the efficiency of the production line.The main research contents of this article are as follows:(1)Designed a pre-twisted robot for bolts and a special flexible claw for grabbing and pre-twisting bolts.The robot adopts a lightweight modular design,which drives the end to grab the bolt through the plane articulated structure.According to the requirements of pre-tightening working conditions of bolts,the flexible adaptive structure with springs at the end adopts force-position fusion control,and the synchronous pulley at the end drives the claw to rotate to realize the pre-tightening of the screws.(2)Establish the robot kinematics model and carry out trajectory planning.The kinematics equations and dynamics equations of the robot are deduced,and the forward and inverse solutions of the robot kinematics are obtained,the camera and the robot hand-eye system are calibrated,and the trajectory is planned in Cartesian space.The correctness of the established system is verified by simulation analysis in the work space.(3)Designed a PMAC-based robot control system,developed a bolt-based grasping and pre-twisting automation control software system,built a robot control cabinet,and conducted joint debugging of the robot's hardware and software control system.(4)The binocular camera bolt feature point recognition algorithm,bolt positioning grab and bolt depth information measurement method based on HALCON were established,and bi-target targeting,robot hand-eye calibration,bolt positioning,bolt posture extraction and grabbing were achieved by The prototype experiment verified that the development of the robot system can achieve automatic bolt grabbing and pre-tightening.