P17027: Starfish Gripper
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Integrated System Build & Test

Table of Contents

Team Vision for Integrated System Build & Test Phase

Planned to Complete

Completed

Systems Integration

Outer Housing

Panels for Outer Housing assembly were completed via water-jet cutting, allowing for system-level assembly of the following sub-assemblies and components:

Completed & Assembled Outer Housing Unit

Completed & Assembled Outer Housing Unit

System-Level Assembly

System-Level Assembly

Extension Mechanism Drive Redesign

After the aftermarket aluminum long arm servo horn stripped while operating the servomotor, the decision was made to alter the approach for driving the extension mechanism. A belt-driven system was chosen due to simplicity and ability to be easily integrated into the system without major changes. Prior to this change, the extension mechanism was to be driven by a series of linkages, and only from one side, which presented multiple issues with binding of the extension mechanism and torque from the servomotor.

Note components in green. The small rounded-triangular component, located vertically between both idler pulleys that are attached directly to the extension mechanism, allows the belt to be spliced together, and moves with the belt to cause the mechanism to extend when the servomotor is rotated.

Belt Drive Subsystem CAD Model

Belt Drive Subsystem CAD Model

Belt Drive Subsystem CAD Model

Belt Drive Subsystem CAD Model

Belt Drive Fully Integrated CAD Model

Belt Drive Fully Integrated CAD Model

Hydraulic System

Test with Full Hydraulic System Setup

Test with Full Hydraulic System Setup

While building the full hydraulic system, the team reviewed the proposed layout for the system. In doing so, we realized that we would not need the original first valve whose job was to eliminate back flow into the pump. The pump supplies sufficient pressure to keep this from happening by itself. As a result, we were able to eliminate one valve from the system. A subsequent test verified our theory.

During the hydraulics test, we realized that when first priming the system, there is a lot of air present within the tubes. Some repositioning of the tubes was attempted to try to evacuate the air, but we are waiting to do testing in the tow tank and pool to see how the system behaves in regards to air in the tubes.

Electrical System

Control Panel

Control Panel

According to previous design review, the broken toggle switch had been replaced and re-soldering the wire had been completed which included power switch(ON/OFF), toggle switch (Pump/Valve) and other switch to control the servo motor. All switches had been tested and working full functionality as expected.

ProtoShield

ProtoShield

So far all the electrical components such as resistor, transistors and diodes had been soldering to the protoshield and wired instead of using breadboard. The protoshield had been testing with control panel, pump, vale, also with hydraulic system and test with gripper. All electrical working properly as desired. Most of Electrical parts almost done and ready to final testing at this point.

Final Electrical Housing

Final Electrical Housing

All electrical parts will be placed and tie properly in the water proof container to make sure no components moving during testing and the wire will be clean up for final testing.

Test Results Summary

Complete Actuator Assembly test

A full array of soft body limbs were fabricated and fitted to the flow manifold, The following criteria were looked at in this sub-assembly test:

Complete Limb Assembly Actuation Test - Video

With the manifold assembly verified, integration into the rest of the system's hydraulic line was completed, and testing on system integration with the other sub-assemblies and valves were performed. The following aspects were components of testing:

Assembly Actuation Test with Release Valve Integration

Assembly Actuation Test with Release Valve Integration

Assembly Actuation Test with Release - Video

Complete Hydraulic System with Pressure Sensor

Pressure Sensor Test Results

Pressure Sensor Test Results

The internal pressure sensor was tested inline with the gripper as it was being actuated. The above graph shows the rise of pressure over time. The sensor reports absolute pressure. The maximum gauge pressure reached within the gripper was 13.7 psi. Even though the gripper did not fail at this pressure, it appeared to be under undue stress at maximum actuation. Therefore, the team decided that 12 psi would be the target inflation pressure as the gripper was more than fully actuated at that pressure. 13 psi has been chosen as the absolute maximum desired pressure. When this pressure is reached, the release valve will open and deflate the gripper. Under normal operation, 13 psi should not be reached, but this second limit is being included for fail safe purposes.

Testing Control of Electronics with Control Panel

During this phase, the control panel and Arduino proto-shield were soldered and tested. Code bugs were discovered during this testing, and are currently being worked on. No electronic hardware issues have been found.

Actuator Assembly Grip Test

With completed assembly, integration and testing of the actuator subsystem, hydraulic subsystem, and controls subsystem, the gripping capability of the system was tested, to furher investigate the ability to adequately grab and secure objects of appropriate size. The follow aspects of the system were examined during testing:

Securely Captured Target Object

Securely Captured Target Object

Actuator Grip Test - Video

Problem Tracking

public/Integrated System Build and Test Documents/ProblemTracking_IntegratedSystem.PNG

Plans for next phase

Individual Plans

Individual 3 Week Plans - Integrated System Build and Test w/ Customer Demo

Home | Planning & Execution | Imagine RIT

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Build & Test Prep | Subsystem Build & Test | Integrated System Build & Test | Integrated System Build & Test with Customer Demo | Customer Handoff & Final Project Documentation