Robotic Arm

Michael Man, 2006–2007

Michael Man constructed this project from basic parts and materials.
He followed Karl Williams' design (Build Your Own Humanoid Robots,
2004, pages 44–90). The arm rotates on a base and has six
degrees of freedom. Finishing this project was a major achievement.
An article about Michael and his robotic arm appeared in British
Columbia Bearing Communicator. Photographs of Michael with his
robotic arm are included in the News Articles section of this website.
Unfortunately, upon completion insufficient time remained to resolve
the programming issues with Visual Basic.

Ploy Piyawassopon, 2017–2018

Ploy Piyawassopon converted the robotic arm to work with Arduino.
She constructed a new wiring harness and linked it to an Arduino
Uno programmer. New jaws for the grippers were designed and
built. Ploy experimented with a force sensitive resistor (Interlink
FSR 1027–1028). C++ code was written for the FSR that
prevented the jaws from breaking the servos or damaging
the object being held. Ploy calibrated and controlled
a single servo.
The programs were referenced from Michael Margolis' Arduino
Cookbook (2012). However, the power output from an Uno
programmer supports only two servos. The weight of the arm
segments and their servos demanded more power. Ploy used a
direct current digital power supply to energize the project.
Her programming experiments revealed that the design
of the arm needed improvement. The aluminum sheet
metal (18 gauge) used in the horizontal base plate and supporting
brackets was too weak. The HS–311 servos were underpowered
and could not support the weight of the arm. With this electronics
experience, her volunteer work both at school and in her community,
and other accomplishments, Ploy successfully applied to Shad.
The Ontario university program for high school students combines
programming, mechanical engineering and business.
https://www.shad.ca/

Ronald Ho, 2018–2019

For his graduating project in Robotics 12, Ronald Ho implemented
several improvements to the design and operation of the robotic arm.
New bearings were fitted to the base. Hitec HS-805BB servos replaced
the underpowered HS-311 on the first and second articulations.
The larger servo has an output torque of 19.8 kilograms at a radius
of one centimeter compared with 3.0 kilogram per centimeter for
the 311. Thicker 14 gauge aluminum sheet metal was used to
fabricate new parts. Extensive rewiring was done. A Pololu mini
maestro twelve channel controller was adapted to guide the
eight servos. New software was written to direct the arm through
its six degrees of freedom. For the first time the robotic arm was
fully functional! Ronald conducted additional experiments with
an Actuonix L16 micro linear actuator.

Photographs

  1. Servo Controller
  2. Controller Closeup
  3. Jaws Open
  4. Gripper Holds Calculator
  5. Calculator Tilted
  6. Empty Gripper

(Photo credit: Ronald Ho, 2018)