Franka Emika Panda

Introduction

In this repository there is the control code to perform a bimanual manipulation by implementing the task priority algorithm considering two manipulators as a single robot. The manipulator adopted is the Franka Panda by Emika, a versatile 7-DOF manipulator for researchers. Moreover, a simulation in python is provided, in order to visualize the two robots and test yours Matlab implementation.

System requirements and installation

In the repository you will find the folder bimanual_manipulation_exercise in which you have the simulator and the matlab code. In order to be able to run the code you need to have:

• Matlab installed, version > 2019a with the following toolbox installed:
  – Robotic System Toolbox
  – DSP System Toolbox
• Ubuntu version > 18.04 (probably the simulator works with other distributions, but additional installations of python packages may be required.):
  – python3 working
  – pyBullet installed
• To check the correct functioning of your python environment on Ubuntu simply type in a shell:
  python3 --version if a python version is retrieved the check is done, if not follows the guide: https://phoenixnap.com/kb/how-to-install-python-3-ubuntu.
• To install pyBullet simply digit in a shell: pip install pybullet.
  Consider the possibility of using a virtual machine for the simulator if you don’t have Ubuntu on your PC. Matlab can run on windows since the data are sended to the simulation using UDP communication.

The simulator

In order to run the visualization of the bimanual system simply go to the root of the folder bimanual_manipulation_exercise and type in a shell

python3 pybullet_simulation/franka_panda_simulation

to launch the simulator. A scene with two Franka Panda, the left Arm and the Right Arm will appear
Rotate the camera by pressing ctrl+left_button while dragging the mouse, move the camera by ctrl+Alt+left_button while dragging the mouse.

Robot configuration

First the transformation matrices were defined between the word frame and the two end-effector frames. The transformations between the word and the base of each robot must be computed knowing that:

• The left arm base coincides with the word frame.
• The right arm base is rotated of π w.r.t. z-axis and is positioned 1.05 meters along the x-axis Then the tool frame for both manipulators are defined with the following characteristics: the tool frames must be placed at 10 cm along the z-axis of the end-effector frame, and rotated with an angle of -43.1937 degrees around the z-axis of the end-effector.

The objectives

The first objective is to move the tool frame of both manipulators to the grasping points. The goal frames for each manipulator is defined such that their origin correspond to the grasping points depicted in the following picture which reports also the origin of the object frame ^wO_o = [0.5, 0, 0.59] and the object length reported as 10cm

Once the manipulator reach the grasping points the second phase of the mission should start. Now the Bimanual Rigid Grasping task to carry the object as a rigid body is implemented.

1. Defining the object frame as a rigid body attached to the tool frame of each manipulator.
2. Defining the rigid grasp task
3. Finally, you have to move the object to another position while both manipulators hold it firmly. Below the object goal position ^wO_g = [0.5, −0.5, 0.5]