P17421: Robocomposter 2.0
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Subsystem Build & Test

Table of Contents

Team Vision for Subsystem Level Build & Test Phase

Frame Construction

To fit the grinder, compost input, holding bin, and reactor bin, the frame needed to be adjusted. After deconstruction of the original Robocomposter 1.0's grinder and bin placement, there was a need to reconstruct to properly place each piece. Problems occurred however due to improper documentation of the previous build so much of the new reconstruction took time on understanding how the grinder must be placed so that every piece would fit.

After moving each piece around the first iteration of the construction has been built. The grinder now sits upon two brackets which are now 3 inches lower than before to better match with the holding bin. The holding bin is now locked in with two L-brackets which leaves room for the motor. The reactor bin was shifted down by about 3 inches leaving no more room for a 5 gallon bin, which was the original plan. Here are pictures of the result.

Front view of frame

Front view of frame

Top view of frame

Top view of frame

Grinder

The grinder fabrication has been completed during this phase and testing completed. To finish the fabrication, a face place was made based off of designs in MSDI. Additionally, new bolts were purchased for the motor and threaded so that the motor could be safely secured to the grinder mount.
Top View of Grinder without Motor Attached

Top View of Grinder without Motor Attached

With the fabrication completed, the grinder could go into testing phase. The motor was attached to an Arduino and testing began.

Snapshot of Grinder Test 1

Snapshot of Grinder Test 1

Auger Coupler

The auger motor mount was completed during this phase. With this, the auger motor could be attached as seen in the photo below.

Snapshot of Grinder Test 1

Snapshot of Grinder Test 1

Arduino Update

The Arduino in it previous case was not able to receive a asynchronous stop from the Raspberry Pi. Due to the newest changes, whenever a new command is sent to the Arduino the motors will stop what they are doing. This allows for more safety on the users end.

The Arduino now has a better implementation of the jam command which was found during grinder testing. When a JAM command is received, the Arduino will send signals to grinder motor to reverse its grinders for 0.5 seconds and then resume grinding for 0.8 seconds. Doing this helps the motor to more easily grind tough material that is causing the grinder to jam.

GUI RPI

Created a development environment on a Testing Raspberry Pi.

Created prototype Graphical User Interface

GUI running on Liiliput touchscreen (Main menu)

GUI running on Liiliput touchscreen (Main menu)

Motor controls page

Motor controls page

Plans for the future

Test Results Summary

Grinder

The grinder during testing showed that during a certain amount of torque, an internal slip clutch engages which limits the amount of power output; the current, from the slip clutch, is then limited. In experiments, the max current found was 7.668 A shown in the following picture. The video of the occurrence is is Here.
Current at slip clutch

Current at slip clutch

The grinder however after adjusting disk grinding locations preformed a lot better. The quality of the wood chips was medium, with certain concerning pieces which may affect auger performance.

Wood chip quality from grinder

Wood chip quality from grinder

Concerning Large wood chip pieces

Concerning Large wood chip pieces

Auger

The auger test provided some insight on the type of problems we will face moving wood chips through the robocomposter. Troubles arose from when the wood chips were squeezed between the auger pushing upwards and the PVC pipe that separates the compost going up from the compost in the bin. This ultimately caused the Auger to fail and stop working. The video of the occurrence is is Here.
Auger Break

Auger Break

Risk and Problem Tracking

Risk Management Phase 2

Risk Management Phase 2

Functional Demo Materials

Include links to:

Plans for next phase

 Completed Tasks from last review

Completed Tasks from last review

 Tasks starting from this review

Tasks starting from this review


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