1. Design of 3R Manipulator to Operate in Space Team Members
Aniket Shirsat Anandrao Biradar Prasannakumar Ghadage
2. Motivation Design a versatile system that can perform
different tasks in inaccessible or hazardous environment for
humans. Incorporate various sensors in the system. Implement
obstacle avoidance.
3. Methodology Generating the D-H parameters for the robot.
Utilizing the Forward kinematics that we get from the D-H
Parameters to form the Manipulability Jacobian. Using the Jacobian
to perform the following phases o Phase 1: Sinusoidal end effector
path . o Phase 2: Reaching a particular spot in space ( spot
welding in an space environment). o Phase 3: Avoiding a certain
obstacle ( i.e. detecting oncoming debris and assuming a position
to avoid the debris. Getting the force and the velocity ellipsoids
in each phase. Implementing the simulated MATLAB code into the LEGO
Brick.
4. D-H Parameters and Jacobian Matrices d a 0A1 1 D1 L1 /2 1A2
2 0 L2 0 2A3 3 0 L3 0 Forward Kinematics
5. Phase 1
6. Phase 1
7. Phase 2
8. Phase 2
9. Phase 3
10. Phase 3
11. Simulation & Lego ? MATLAB LEGO Curves smoother and
continuous Piecewise Linear and jerky No real effects like inertia
and are modeled Inertia and delays are present. No gears are
modeled Gears come with backlash error.
12. Video
13. Difficulties The most foremost difficulty is getting the
dynamics for the 3R case in 3 dimensions. The equations turn out to
be highly non-linear and coupled . Thus getting an analytic
solution for torque is computationally intense. LEGO is a good tool
for educational purposes but it lacks the versatility in terms of
motor control. LEGOs dont generate feedback thus errors cannot be
reduced hampering accuracy.
14. Solutions & Future scope Get a sturdier frame to mount
the actuators. Getting feedback from the sensors ( if possible) and
thus making it more precise and accurate. Better modeling of the
system. Using a better board like Arduino for interfacing with the
computer.