Six-Axis Stewart Platform
Overview:
What follows is part 1 of 2 for the build of a 6-Axis hexpod robot inspired by the work of D. Stewart, and implemented to be built by off the shelf parts and controlled via Arduino. This first instructable includes the design files for rapid prototyping (via laser cutting and 3D printing), a list of material and hardware links for sourcing parts, and an introduction to the electronics setup for PWM control. This platform was developed to precisely control heavy loads therefore choosing linear actuators over a converted servo design. Not locating an instruction guide for a design of this kind anywhere online, I hope this instructable provides a starting off point for anyone with similar robotic needs.
The second installation of this instructable will outline the inverse kinematics and control interface.
Parts - Electronics Hardware
Disclaimer: All hardware images are courtesy of Servocity unless otherwise noted.
- Arduino Uno (other models will work as well as long as 6 digital outputs are available)
- Breadboard
- Jumper Wires (example)
- 12VDC Power Supply (x6)
- 12V, 25 lb. Thrust Linear Actuators (x6)
- DC Barrel Power Jack (x6)
With the linear actuator rigged for PWM control snip the wire off after the control box before the supply end and re-wire the power & ground to the DC Barrel Power Jack. The actuators with PWM control have a built in resistor to stop any power overloading on the board. Therefore the Barrel Jack goes straight to the actuator and the digital input is powered by the Arduino board 5V power.
Parts - Robotic Hardware
Disclaimer: All hardware images are courtesy of Servocity unless otherwise noted.
- Lightweight Mounting Bracket for Linear Actuator (x9)
- Bushings and basic hardware come with
- Swivel Hub (x9)
- 6-32 Screws (Get prescribed length for your material of choice)
- These are for attaching robot hardware to laser cut design and mounting of your needs
Design Laser Files + Gimbal Joint Design
Note: All laser files were optimized to be cut on a bed of 32in x 18in, and 3D Printed parts optimized for a bed of 8in x 8in x 10in.
Materials:
- 0.125in Acrylic
- 0.25in Acrylic
- ABS Filament for Gimbal Print
Attached and available for download are the laser cut files and gimbal joint that connects two separate actuators to a single point at the bottom of the platform. This eases the computation during control maintaining a triangular platform and parallel lengths of connected actuators.
The 3d model attached outlines the assembly steps and illustrates how each parts relates. Please contact with any questions, issues, or suggestions!