2.5 DOF system

Project Description

Goal: Design of a motion system with 2.5 degrees of freedom (DOF) by building the mechanical and electrical sub-systems and integrate them to demonstrate the functionality of your prototype.

Learning Objectives:

To devise different ways to embody ideal joints such as revolute, prismatic, spherical and/or universal joints.
To design mechanical components with rational shapes, considering their function, mechanical loading, required accuracy, method of fabrication and assembly.
To integrate and test a product prototype with mechanical and electrical components.

Additional notes: 20 minute weekly team meetings with the professor to review designs.

Concept and Designs

Concept: Create a Zen Garden that can draw any image in a sandbox, using magnets and a magnetic ball. Half degree of freedom will come from a servo-motor activating and deactivating the magnets.

Designs: Housing (laser cut), parts to hold bars, sliders to hold Y and Z axis, arm to hold magnets on servo-motor (3D printed parts)

Individual components

X Bar Holder

X Motor Holder

Slider

Axis Assembly

Y Bar Holder

Y Motor Holder

Y Sliding mount for servo motor

Servo motor arm

The Zen Garden works by combining a few simple motion systems into one. The x-axis uses a belt built around a 1010 aluminum bar and a stepper motor. Two identical x-axis stages are synced together to support the system and keep it stable. 3D-printed x-axis parts connect the motor, belt, and aluminum bar, making it easy to put everything together using standard fasteners. The y-axis then rides on top of the x-axis, using two sliding parts that move along the bars (one supporting the structure and the other supporting both the structure and the motor) to keep motion aligned and consistent. Finally, the 2.5-DOF z-axis adds vertical control with a servo-driven sliding mount and arm that raise or lower the magnet under the sand, allowing the magnetic ball to engage or disengage during the drawing process without needing a full z-axis.

Housing

Notable Features: holes in the back for Arduino MEGA wiring and LED lights, ledges to hold up acrylic cover, storage spaces on side for sand rakes, walls to contain sand

Code

Fengrave

Image to G-Code Converter

Full coding ME360 Kinetic Sand Art.pdf

G-Code

Controls motor movement to create images in sand

IMG_9978.MOV

X-Y Movement with LEDs

Physical outcome of G-code

Controls colors of LEDs, movement of servo and stepper motors to create images in the sand. All G-Code instructions were uploaded from Marlin firmware to transcribe images into G-Code, readable by Repetier Host.

The housing allows space for the x, y, and z axis to move freely. The rectangular spaces on top frame the workspace and act as storage for the sand rakes.

The Final Product

IMG_2207.mov

2.5 DOF

Movement inside housing (Servo motor moving magnet up and down to engage magnetic ball, X and Y axis used to draw images in sand)

Final video

Final Product

Highlights use of G-code to move magnetic ball and change LED light colors

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