Investigation of object manipulation positioning accuracy by bernoulli gripping devices in robotic cells

Abstract

Ensuring the necessary accuracy of positioning the objects of manipulation of Bernoulli's grippers in robotic cells is an urgent task and can be achieved by choosing rational parameters of the gripping process. The article conducts experimental studies of the process of handling by Bernoulli grippers of objects of manipulation at different operating parameters and their weight. For this purpose, an experimental setup was developed, which consists of an industrial robot IRB 4600, an IRC5 controller, a Raspberry Pi microcontroller and two clock-type micrometers. The method of determining the total positioning error of the "robot-gripper-object" system is presented, which takes into account the positioning errors of the industrial robot, the errors of the gripping device and the errors of basing the object of manipulation relative to the axis of symmetry of the gripping device. The ABB IRB 1600 industrial robot was programmed in the ABB RobotStudio environment to cyclically simulate the handling operation and to determine the deviation of the position of the manipulation object after its gripping from different distances. The first cycle of automatic mode was used to calibrate the micrometer indicators, while gripping the object was carried out from a distance of 0.02 mm. For better reliability of research results, 20 measurement cycles were performed for each of the variable parameters. As a result, it was found that the maximum base error of objects does not exceed 0.4 mm. When capturing objects from a distance of 0.5…1 mm, the mean value of the base error will be 0.08…0.15 mm, with a standard deviation of 0.025…0.035 mm. The paper studies the effect of the displacement Δ of the center of mass of the gripped object relative to the axis of the Bernoulli gripper on the accuracy of the base of the objects. It is established that when the center of mass of the gripped objects is shifted relative to the Bernoulli gripper axis up to 20 mm, the maximum base error of the objects increases 2.2 times.