R2. Kinematics

Table of Contents

1 Info

The assignment presents properties of serial robot kinematics and Denavit-Hartenberg notation.

The points marked with (*) are optional (not obligatory).

2 Preparation

Before the classes recall from the lecture definitions of robot kinematics and Denavit-Hartenberg notations. Prepare the formulas to calculate the kinematics from D-H parameters. Consider which functions from the toolbox will be needed to solve the current tasks.

3 Tasks

Task 0: Complete unfinished tasks from the previous assignment

Task 1: Kinematics of a 3R robot

  • Find homogenous transformations for an RRR robot:

ex_task1.png

Assume the link lengths are, respectively, 2, 1 and 1.

  • For selected joint angles plot coordinate systems associated with each joint.
  • Assume q1=q2=q3=0. What are expected positions and orientations of coordinate systems? What is expected translation vector in robot kinematics? What is expected rotation?
  • Calculate the kinematics for the joint values from the previous item. Is the result the same as expected?
  • For the same joint angles calculate Euler angles from kinematics transformation. Check the result with the expected value.
  • To report:
    1. Write homogenous transformations for each joint and kinematics for the joint angles q1=0, q2=π/4, q3=-π/6. Include Matlab code used to obtain these matrices.

    2. Find the joint angles for which the translation vector of the kinematics is [0,1,3].

Task 2: SerialLink manipulator

  • Define an RT robot using toolbox functions. Verify its D-H parameters.
>> import ETS3.*
>> rob=SerialLink([Revolute('d',1,'alpha',pi/4) Prismatic('a',1)])
>> rob.name='RT'
  • Calculate kinematics for given joint angle and translation and plot the result
>> rob.fkine([pi/4 1])
  • To report:
    1. Use toolbox function to define the robot from task 1.
    2. Include code.

Task 3*: Kinematics of an industrial robot

  • Find D-H parameters for the Kuka KR16 industrial robot presented below.
  • Calculate kinematics for selected joint angle values.
  • To report:
    1. Include a matrix of D-H parameters
    2. Include a vector of joint angles and kinematic matrix calculated for it.

4 Summary

  • The report should include the result of the tasks and answers to the questions.
  • Please do not forget to indicate the author of the report!
  • The report in PDF format should be submitted before the beginning of next classes using a method defined by the instructor.

5 (appendix) Kuka KR16

Author: Janusz Jakubiak

Created: 2018-04-03 wto 13:51

Emacs 24.4.1 (Org mode 8.2.10)

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