Research On The Visual Grasping Of Spatial Objects Of The Manipulator Of Industrial Picking And Discharging Link

In order to reduce human cost and improve production efficiency,robot and machine vision technology has been gradually applied to various fields of modern production and manufacturing.Due to the high cost of hardware and software of manipulator and machine vision technology,most of the small and medium-sized enterprises in China are unable to bear it,and they are still using the method of manual loading and unloading.In order to improve the automation level of small and mediumsized enterprises and reduce the cost of human and material resources,this paper designs and develops a kind of low-cost intelligent picking and discharging mechanical device based on the combination of linkage manipulator and machine vision,which has the ability of independent identification,independent measurement and independent decision-making.The main contents of this paper are as follows:(1)According to the requirements of visual recognition and positioning and control of linkage manipulator,the hardware selection of visual positioning system and servo control system of linkage manipulator is completed.The performance parameters of industrial camera and camera lens are determined according to the size of the workpiece and the position of the camera layout.In view of the fact that each joint of the manipulator is mainly driven by AC servo motor and harmonic reducer,a scheme of servo control with STM32 single chip microcomputer and servo driver is developed,and the hardware construction of the whole visual positioning system and servo control system is completed.(2)The monocular camera is used in the visual positioning.According to the material and imaging effect of the workpiece,the image preprocessing scheme is developed to remove the image noise points and obtain a higher quality workpiece image.Through edge detection and morphological operation,the clear and closed contour of workpiece is extracted,and the coordinates of workpiece in camera coordinate system are obtained by PNP algorithm.(3)The coordinate system of the manipulator is established by D-H parameter method,and the forward kinematics and inverse kinematics of the manipulator are analyzed.The inverse kinematics analysis can obtain the rotation angle of each joint of the link manipulator when the end position of the manipulator is known,and then calculate the rotation angle of each joint motor when the end of the manipulator reaches the designated position.(4)The servo control system is mainly composed of the upper computer and the lower computer.The upper computer is mainly responsible for the joint angle calculation of the linkage manipulator and the sending of the control command.In order to ensure the stability and safety of the control system,the upper computer has the functions of teaching and debugging.The lower computer is used to receive the control instructions from the upper computer,and control the servo driver according to different signal instructions to complete the control of each joint of the linkage manipulator.