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M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Simulator of a SCARA Robot with LABVIEW Ing. Luca Baglivo, Ing. Alberto Fornaser Department.

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Presentation on theme: "M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Simulator of a SCARA Robot with LABVIEW Ing. Luca Baglivo, Ing. Alberto Fornaser Department."— Presentation transcript:

1 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Simulator of a SCARA Robot with LABVIEW Ing. Luca Baglivo, Ing. Alberto Fornaser Department of Structural Mechanical Engineering, University of Trento

2 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion INTRO

3 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Simulink Diagram

4 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Simulink Diagram

5 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Time Trajectory Speed of the End Effector Using the q it is possible to retrive the pose of the robot and the carthesian coordinate of the End Effector. Jacobian evaluation Compensate the error of the position due to numerical integration

6 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion LabView Diagram

7 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion LabView Diagram: GUI

8 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Main Logic Blocks

9 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Main Logic Blocks

10 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Simulator

11 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Software Main Structure The software is thought in order to pilot a robot. It is a good approach organize the software it in the following way: - First Task -> Move the robot to the HOME position (safe pose); - Second Task -> Move the robot, our simulatoin; - Third Task -> Go back to HOME. This logic can be achieved through a Sequence structure.

12 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Trajectory -Time dependent Input: Center x Center y Radius T Output: x(t) y(t) Name: Trajectory.vi

13 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Trajectory The robot must be settled avoiding a singular initial pose. In such way it is possible to achieve and follow a feasible path without problems Initial Conditions: Q1 -> -pi/2 Q2 -> pi/2 Q3 -> 0 A1 A2 Geometry of the robot: A1 -> 300mm A2 -> 350mm A3 -> 0mm

14 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion ROBOT VISUALIZATION This Vi helps the user to understand the pose of the robot and monitor the evolution of the motion. We need to have the full structure as output, this will simplify the programming interface a lot. Arm_visualizer.vi

15 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Jacobian and Pseudoinversion This Vi must evaluate the Jacobian Matrix. The input are the angles of the joints. The output should be a matrix, and this should be inverted in a second Vi. NB: J is related to the dimension of the joints, so it is usefull to create a Vi that output these informations.

16 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Derivator This Vi must evaluate the velocity of the End Effectot Important: during the first loop we cannot evaluate the speed, so we need to pass directly a value. This VI must have 2 additional imput, 2 single value ( double ). These inputs will be used later to introduce a numeric error compensation.

17 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Integrator This VI is used after the multiplication between the presudoinverse Jacobian and the End Effector Velocity Vector. By integrating the output of that multiplication the qs (angles of the joijts) of the robot can be evaluated. Using the Output of this Vi it is possible to connect the Robot Visualization Vi, and watch the motion of the robot directly during the processing loop.

18 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Images: Some Hints A Good methodology in LabView is to start building your Vi referring to an example, copying part of the code and then start adding your own «code». So, how can we open an Image in Labview? Go to: …Program Files (x86)\National Instruments\LabVIEW 2010\examples\Vision\1. Getting Started

19 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion How Initialize and Load an Image We should works with 2 images at the same time: -One is the source image -One is the destination Image This is due to the library related to the image processing. LabView does not allow the user to overwrite an image from the same function.

20 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Camera View Simulation Vi that simulates the camera mounted on the End Effector Input: - Image of the ground - Coordinates of the End Effector Vi that performs the chek of the image, the task is to identify the center of a dot seen by the camera. Use Vision Assistant! Vi that returns the coordiante of the identified dot in the world coordiante system GIVEN

21 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Camera Simulation The simulation is based on the identification of a region of 640x480 pixels centered and oriented according to the actual pose of the End Effector. NB: Camera and Robot Reference Coordinate Systems are different! World RCS Camera RCS

22 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Camera Simulation One of the limits of the graphic library in LabView is that you can not crop region of image using any orientation. To overcome this issue is possible to shift and rotate the image. Region to Crop ROI Centered to the origin 0,0 with dimensions 800x800 pixels Why 800x800? In this region i can have all the possible 640X480 sub regions with any generic orientation!

23 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Camera Simulation Region to Crop We shift the image, not the reference system!

24 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Camera Simulation Now we can apply the rotation to the image.

25 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Camera Simulation We can now Crop the image to the 640x480 region. This is the resulting image that simulates the view of the camera!

26 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Camera Simulation NB: The rotation of the image is done around the center of the image itself.

27 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Vision Assistant

28 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion Vision Assistant Operation Order

29 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion From Camera to World RCS Now we have the estimation of the position of the dot expressed in the camera reference coodinate system, but the robot usually works inside its own space (called also World). We need a Vi that performs the transformation between the camera rcs and the world rcs. Dot identified inside the image Field of view of the camera inside the world reference system Coordinates of the dot expressed in the world system Camera Reference System

30 M. De Cecco - Lucidi del corso di Robotica e Sensor Fusion


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