En SCARA-robot som ritar kräver en hög noggrannhet och precision. Syftet med detta projekt är att skapa en robotarm som kan rita bilder som generas av en användare i ett ritprogram, armens rörelse beräknas med hjälp av inverskinematik. Projektet undersöker hur precisionssäker roboten är samt dennes snabbhet. Under projektets gång har upprepade tester gjorts för att mäta dessa egenskaper. Roboten uppnådde en hög grad av noggrannhet när den gjorde punkter på samma ställe upprepade gånger, men den har svårt att med hög precision återskapa bildens korrekta geometri, detta visas med ett test då den skall rita en cirkel. Detta kan bero på flera olika faktorer. Det mest sannolika är att det finns glapp i armarnas kuggremsdrift, när roboten gör en cirkulär rörelse så uppkommer felet när någon av armarna byter rörelseriktning. I rapporten redogörs hur roboten har konstruerats och programmerats. / A SCARA-robot that draws requires a high level of precision and accuracy. This project aims to build a three degree of freedom robot arm that uses inverse kinematics, to draw a picture that has been assigned to it. The project explores the robot’s accuracy as well as its speed. Several measurements were conducted during the project to assess the Robot Arm’s reliability. When the robot makes points in the same position several times, it achieves near-perfect precision, but it has trouble recreating the proper geometrics of the picture being drawn. It may be caused by a variety of factors, it is most likely caused by a play in the timing belt. When the robot performs a circular movement, the problem arises when one of the arms switches its direction. In this paper, the robot’s construction and programming are described.

<p>Atlas Copco Surface Drilling Equipment is one of the leading manufacturers of surface drill rigs. To stay in the top segment it is of great importance to have a well functioning development strategy as well as rig functions that makes the work as easy as possible for the operator. In this master thesis one development strategy has been evaluated and a dub tip control has been developed from idea to test on rig.</p><p> </p><p>Today the conventional method to position the drill is to use two joysticks with three axes each where each axis corresponds to one hydraulic actuator on the boom and feeder structure. The dub tip control system enables the operator to position the drill in Cartesian coordinates with only one 3-axes joystick. After the definition of the desired drill angle is done, the control system makes sure that this angle is obtained throughout the positioning motion. This system makes it considerably easier for an inexperienced operator to position the drill.</p><p> </p><p>For development, simulation and verification of the control algorithms and regulators <em>Matlab/Simulink</em> has been used. To test the control system on rig, a configuration with <em>LabVIEW</em> together with a <em>compactDAQ</em> has been evaluated. <em>LabVIEW </em>is chosen because it provides the opportunity to create a user friendly graphical user interface. To use this configuration is however not recommended for persons with little or none experience from using <em>LabVIEW</em>.</p><p> </p><p>This development strategy can be used for tests and verifications of control algorithms, but since neither <em>Windows </em>nor the <em>compactDAQ </em>are real time systems, there are solutions that are better but of course to a higher price.</p><p> </p><p>The master thesis work has shown that it is possible to implement a dub tip control on a rig of this dimension. It has also concluded that compensated valves are necessary to achieve optimal performance of a velocity controlled dub tip positioning.</p>

Atlas Copco Surface Drilling Equipment is one of the leading manufacturers of surface drill rigs. To stay in the top segment it is of great importance to have a well functioning development strategy as well as rig functions that makes the work as easy as possible for the operator. In this master thesis one development strategy has been evaluated and a dub tip control has been developed from idea to test on rig.   Today the conventional method to position the drill is to use two joysticks with three axes each where each axis corresponds to one hydraulic actuator on the boom and feeder structure. The dub tip control system enables the operator to position the drill in Cartesian coordinates with only one 3-axes joystick. After the definition of the desired drill angle is done, the control system makes sure that this angle is obtained throughout the positioning motion. This system makes it considerably easier for an inexperienced operator to position the drill.   For development, simulation and verification of the control algorithms and regulators Matlab/Simulink has been used. To test the control system on rig, a configuration with LabVIEW together with a compactDAQ has been evaluated. LabVIEW is chosen because it provides the opportunity to create a user friendly graphical user interface. To use this configuration is however not recommended for persons with little or none experience from using LabVIEW.   This development strategy can be used for tests and verifications of control algorithms, but since neither Windows nor the compactDAQ are real time systems, there are solutions that are better but of course to a higher price.   The master thesis work has shown that it is possible to implement a dub tip control on a rig of this dimension. It has also concluded that compensated valves are necessary to achieve optimal performance of a velocity controlled dub tip positioning.

The concept of a robotic manipulator is widely used throughout many industries. In this project, a manipulator of the type SCARA, selective compliance articulated robot arm, is constructed. The aim was to examine how such a robot could be constructed using 3D-printing and how accurate it would be. Other than 3D-printing, parts in the form of guiding rods, lead screw, bearings, pulleys and timing belts were used. Together with a microcontroller, the robot operates using three stepper motors. In the end it resulted in a SCARA with reasonable accuracy considering the methods used, more specifically the largest average error was 3.6cm in the X direction and 2.3 cm in the Y direction. The largest drawback of the final construction was the negative balance between tightening the belts and friction in the inner joint. Tightening the belts meant larger friction and thereby undesired movement properties. Doing the opposite meant that the belts could start slipping and enabled backlash. / Konceptet av en robotarm används brett inom många industrier. Detta projekt syftar till att konstruera en robot avtypen SCARA, selective compliance articulated robot arm. Målet var att undersöka hur en sådan robot kan 3D-printas och dess precision. Förutom 3D-printade delar användes även guidestänger, kullager, kamremmar och remskivor. Robotens rörelser styrs tillsammans med en mikrokontroller och tre stegmotorer. Med tillvägagångssätten i åtanke resulterade projektet in en SCARA med rimlig precision. Mer specifikt var medelfelet 3.6 cm i X-led och 2.3 cm i Y-led. Den största nackdelen med den slutgiltiga konstruktionenvar den negativa jämvikten mellan att spänna kamremmarna och friktionen i den inre armleden. Att spänna kamremmarna innebar en ökning i friktion och därmed oönskade rörelseegenskaper. Att göra tvärtom innebar att bältena löpte större risk att glida ur och möjliggjorde dödgång.

Today, there is an increasing demand for smart robots that can make decisions on their own and cooperate with humans in changing environments. The application areas for robotic arms with camera vision are likely to increase in the future of artificial intelligence as algorithms become more adaptable and intelligent than ever. The purpose of this bachelor’s thesis is to develop a robotic arm that recognises arbitrarily placed objects with camera vision and has the ability to pick and place the objects when they appear in unpredictable positions. The robotic arm has three degrees of freedom and the construction is modularised and 3D-printed with respect to maintenance, but also in order to be adaptive to new applications. The camera vision sensor is integrated in an external camera tripod with its field of view over the workspace. The camera vision sensor recognises objects through colour filtering and it uses an edge detection algorithm to return measurements of detected objects. The measurements are then used as input for the inverse kinematics, that calculates the rotation of each stepper motor. Moreover, there are three different angular potentiometers integrated in each axis to regulate the rotation by each stepper motor. The results in this thesis show that the robotic arm is able to pick up to 90% of the detected objects when using barrel distortion correction in the algorithm. The findings in this thesis is that barrel distortion, that comes with the camera lens, significantly impacts the precision of the robotic arm and thus the results. It can also be stated that the method for barrel distortion correction is affected by the geometry of detected objects and differences in illumination over the workspace. Another conclusion is that correct illumination is needed in order for the vision sensor to differentiate objects with different hue and saturation. / Idag ökar efterfrågan på smarta robotar som kan ta egna beslut och samarbeta med människor i föränderliga miljöer. Tillämpningsområdena för robotar med kamerasensorer kommer sannolikt att öka i en framtid av artificiell intelligens med algoritmer som blir mer intelligenta och anpassningsbara än tidigare. Syftet med detta kandidatexamensarbete är att utveckla en robotarm som, med hjälp av en kamerasensor, kan ta upp och sortera godtyckliga objekt när de uppträder på oförutsägbara positioner. Robotarmen har tre frihetsgrader och hela konstruktionen är 3D-printad och modulariserad för att vara underhållsvänlig, men också anpassningsbar för nya tillämpningsområden. Kamerasensorn ¨ar integrerad i ett externt kamerastativ med sitt synfält över robotarmens arbetsyta. Kamerasensorn detekterar objekt med hjälp av en färgfiltreringsalgoritm och returnerar sedan storlek, position och signatur för objekten med hjälp av en kantdetekteringsalgoritm. Objektens storlek används för att kalibrera kameran och kompensera för den radiella förvrängningen hos linsen. Objektens relativa position används sedan till invers kinematik för att räkna ut hur mycket varje stegmotor ska rotera för att erhålla den önskade vinkeln på varje axel som gör att gripdonet kan nå det detekterade objektet. Robotarmen har även tre olika potentiometrar integrerade i varje axel för att reglera rotationen av varje stegmotor. Resultaten i denna rapport visar att robotarmen kan detektera och plocka upp till 90% av objekten när kamerakalibrering används i algoritmen. Slutsatsen från rapporten är att förvrängningen från kameralinsen har störst påverkan på robotarmens precision och därmed resultatet. Det går även att konstatera att metoden som används för att korrigera kameraförvrängningen påverkas av geometrin samt orienteringen av objekten som ska detekteras, men framför allt variationer i belysning och skuggor över arbetsytan. En annan slutsats är att belysningen över arbetsytan är helt avgörande för om kamerasensorn ska kunna särskilja objekt med olika färgmättad och nyans.