Influence of robot grasping on rotation of the measured object

Roboti postajajo vse bolj prisotni na mnogih področjih, tako v vsakdanjem življenju, kot v industriji. Pomembna je tudi uporaba robotov v kontroli kakovosti izdelkov, kjer roboti nadomeščajo potrebne posege operaterja v merilni sistem in s tem izločijo vpliv človeškega faktorja. Kljub dobri ponovljivosti robotskih gibov, pa vključitev robota v merilni sistem še zdaleč ne zagotavlja popolne točnosti. Naš cilj je bil ugotoviti, ali robot vpliva na zasuk objekta, ki ga merimo, in kako se ta vpliv odraža na zasukih merjenca. Zanimalo nas je, kateri parametri robotskega prijemanja vplivajo na zasuk: preverjali smo vpliv sile prijemanja, vpliv vertikalnega pomika robota ter vpliv dotikanja merjenca z merilnim sistemom Renishaw Equator, ki je bil uporabljen za izvedbo kontaktnih meritev. S kombinacijo dveh laserskih senzorjev smo zasnovali brezkontaktni merilni sistem. Za manipuliranje merjenca znotraj merilnega območja Equatorja je bil uporabljen sodelujoči robot UR5e z nameščenim prijemalom. Ugotovili smo, da je vpliv robota na zasuk merjenca pri večkratnem ponavljanju gibov robota znaten. Najbolj opazno je sukanje merjenca okrog lastne glavne geometrijske osi, pri čemer je opazen tudi trend sukanja vedno v isto smermanj opazni pa sta spremembi zasuka okrog ostalih dveh osi merjenca. Največje povečanje zasuka merjenca je doseženo pri izpenjanju merjenca iz ležišča, v primerjavi samo z dotikanjem merjenca. Manjši vpliv povzroči povečana sila prijemanja, vpliv izvedbe kontaktnih meritev z Equatorjem pa je še nekoliko manjši, vendar kljub temu opazen.Robots are becoming ever more present in many fields, both in everyday life and in industry. Especially essential is their use in product quality control, where, by replacing operator interventions, human influence on the manufacturing process can be significantly reduced. Despite the good repeatability of robotic movements, the presence of a robot in a measuring system does not guarantee the perfect accuracy of the measurements. Our goal was to determine whether robot influences the rotation of the measured object and how it manifests itself. Furthermore, our objective was to find out which parameters of robotic grasping impact the rotation. The study included evaluation of the influence of the grasping force, the influence of the vertical movement of the robot during repetitions of the measurements, and the presence of the Renishaw Equator gauging system for conducting contact measurements. A contactless measurement system was designed using a combination of two laser scanners. A collaborative robot UR5e with an attached gripper was used to manipulate the measured object within the measuring range of the Equator system. Our findings confirm the significant influence of robotic actions on the rotation of the measured object, especially following various repetitions. Its influence is most notable when observing rotation around the main geometric axis of the measured object, where the tendency to always rotate in the same direction was also observed. The rotation around the other two axes is less pronounced. The change in rotation is most significant when the measured object is removed from the fixture, contrary to only touching it with the gripper. Increasing the gripper force has a smaller effect on the rotation of the measured object than its removal from the fixture. The impact of its contact with the Equator system during contact measurements is even smaller but still noticeable