1. Learning Robot Kinematics using RoboAnalyzer*
Hands-on Sessions on
Learning Robot Kinematics using RoboAnalyzer*
Prof. S. K. Saha
Dept of Mech Engg
IIT Delhi
Mr. Rajeevlochana G. Chittawadigi
Amrita School of Engineering, Bengaluru
*Developed at IIT Delhi

2. Contents Robotics Robotics Education Homogenous Transformation
Denavit-Hartenberg Parameters
Forward Kinematics
Inverse Kinematics
Motion Planning (Virtual Robot Module)

3. Source: Mechatronics Lab and PAR Lab, IIT Delhi
Robotics
Design, development, control and application
Industries
Academics
Research
Entertainment
Medical applications etc.
Included in curriculum of universities
Source: Mechatronics Lab and PAR Lab, IIT Delhi

4. Source: http://images.google.com
Robotics Education
Courses* usually include:
Theory:
Design and working of robot in the form of drawing and pictures
Mathematically intensive
2. Practical:
CAD modeling and simulation
Real robots in action
Not many institutes have facilities
*Mechanical Engineering
Source:

5. Robotics Concepts Homogenous Transformations DH Parameters Kinematics
Dynamics
Motion Planning …
Difficult to Visualize
RoboAnalyzer Software: Priceless!!
Free to use:

6. RoboAnalyzer 3D Model Based Robotics Learning and Teaching Software
Developed by Prof. S. K. Saha and Team (IIT Delhi)
Main Developer: Mr. Rajeevlochana G. Chittawadigi
Other Developers
Dr. Suril V Shah
Mr. Ratan Sadanand
Mr. Ravi Joshi
Mr. Amit Jain
Ms. Jyoti Bahuguna
Mr. Sasanka Sekhar Sinha
Mr. Sai Vikas Maram
Mr. Yashaswi Kuruganti …

7. RoboAnalyzer Website:
Download latest version (V7.5) from
After download, unzip it
RoboAnalyzer.exe

9. Homogenous Transformation Matrix (HTM) Module
Top Panel Button of RoboAnalyzer Window
Translation
Local Frame
Global Frame
Rotation
Homogenous Transformation Matrix (HTM)

10. Task 1: Translation in HTM
Translate along X, Y and Z axes
Observe the last column (fourth) of the HTM
Translation alone is commutative

11. Task 2: Rotation in HTM Rotate about X, Y and Z axes
Observe the first 3x3 matrix of the HTM
Direction Cosine
Projection of smaller axis vector on bigger frame
3 columns => 3 vector projections
Rotation is not commutative

12. Task 3: Local v/s Global in HTM
Current transformation => Multiplication of individual HTMs
Local transformation => Post-Multiplication of HTMs
Global transformation => Pre-Multiplication of HTMs

13. Geometric Model of a Serial Robot
moves in Cartesian frame
controlled at joints
Mapping
Geometric model
Robot Architecture
Denavit-Hartenberg (DH) Parameters

14. Line represented with respect to a coordinate frame
Denavit-Hartenber (DH) Parameters
Line represented with respect to a coordinate frame
Common normal between Z and line
Generally used in Robotics

15. Denavit-Hartenber (DH) Parameters
1. Frame and Line
2. Z axis of Frame
3. Find Common Normal (Shortest Distance) between Z axis of Frame and Line

16. Denavit-Hartenber (DH) Parametersα θ b
1. Translate Z (b) till Intersection of Z axis and Common Normal
Joint Offset
2. Rotate Z (θ) so that
X axis aligns with Common Normal
Joint Angle
3. Translate X (a) till Intersection of Common Normal and Line
Link Length
4. Rotate X (α) so that
Z axis aligns with the
Line
Twist Angle

17. Video on DH Parameters

18. Joint Axes

19. Joint Axes

20. Joint Axes

21. Joint Axes

22. DH Parameters α1 Geometrical description 4 parameters α2X1 θ1 θ2 α2 b1 a1 b2 a2 X2 Z2 Z1 X3 Z3 α1
Demo
Geometrical description
4 parameters
Joint offset (b)
Joint angle (θ)
Link length (a)
Twist angle (α)
Relates frames attached on consecutive links

23. Visualize DH Parameters
A. 3 DOF and 3R Robot
C. Visualize with Animation
B. Modify DH Parameters

24. Kinematics
Study of motion of links without considering the forces
Forward Kinematics
θ1 and θ2
Joint Angles
Demo
Inverse Kinematics

25. [ ] Q Forward Kinematics Demo Joint to Cartesian space
End-effector configuration in base frame
Tee = T1 T2 T3 =
[ ] Q Px Py Pz

26. Task 4: Transformations
RoboAnalyzer Main Application
2R Robot (Spatial)
DH Parameters
Verify Transformation
Try for Different Joint Angles =

27. Task 5: Forward Kinematics
KUKA KR5 Arc
FKin
Animation
Plots
Verify Position of
EE Config
Try Different Motion

28. Task 6: Inverse Kinematics
Ikin Button
MTAB Aristo Robot
IKin: 8 Solutions
Verify in RA
Visualize in RA
Try Different Robots

29. Dynamics Demo Study of forces and moments causing the motion of links
Forward Dynamics
Inverse Dynamics
Forward Dynamics
Joint Force
Joint Accl.
Inverse Dynamics
Demo
Due to complexity, these are usually not taught in most of the UG courses

30. Virtual Robot Module Joint Jogging Cartesian Jogging 17 Robots
Integration with MATLAB
Interface with Physical Teach Pendant
Demo

31. Task 7: Virtual Robot Module
VRM_XML…
ABB IRB1520
Start Record Motion
Cartesian Control
Draw a Square of Side
100mm
Stop Record Motion
Read and Playback

32. Contest: Virtual Robot Module
VRM_XML…
ABB IRB1520
Start Record Motion
Cartesian Control
Draw a Cube of Side
100mm
Stop Record Motion
Read and Playback
Least Number of Motion Sequences!!!

33. RoboAnalyzer Team www.roboanalyzer.com Subir K. Saha (1996- present)
S. Goel and S. Ramakrishnan ( )
A. Patle ( )
Rajat Jain ( )
Suril V. Shah ( )
Rajeevlochana G. Chittawadigi (2009 – 2013, 2015-present)
Amit Jain ( )
Jyoti Bahuguna ( )
Ratan Sadanand ( )
Ravi Joshi ( )
Keshav Bimbraw and Ishaan Mehta (2016 Summer)
Sasanka Sekhar Sinha (2017-present)
Sai Vikas Maram and Yashaswi Kuruganti ( )
The feedback/suggestion of the below are sincerely acknowledged:
Mr. Arun Dayal Udai (2010): Suggested importing of CAD files in STL format
Dr. Sandipan Bandyopadhyay (2012): Suggested to make RA/VRM as an API/COM server to be integrated with other software
Prof. Sudipto Mukherjee ( ): Suggested an interfacing with MATLAB
Dr. Nayan Kakoty (2013): Suggested to have custom trajectory file input for joints Prof. Peter Corke (2015): Discussion on integration of RoboAnalyzer (VRM) with Robotics Toolbox
Mr. Vinay Gupta (2016): Suggestion on having a link in the software for online feedback and contact form
Mr. Dharmender Jaitly, Dr. Majid Koul, Mr. Aamir Hayat, Mr. Riby Boby, many more

34. Complementary
Illustrations
Examples
Effective!!!

35. Feedback

36. Thank You rg_chittawadigi@blr.amrita.edu saha@mech.iitd.ac.in