P13375: Hydraulic Nanomanipulator
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Systems Design

Table of Contents

Benchmarking

This project is a third phase building upon P12371 and P13371 The device resulting from these projects will be used to benchmark the success of new versions.

Concept Development (generation, improvement, selection)

 Software Pugh Matrix

Software Pugh Matrix

The main mechanical areas of focus will be decreasing backlash and increasing speed. The previous design team performed pugh matrix analysis on a variety of friction reduction options which P13375 reviewed on their Edge site. Team P13375 agrees with Team P13371 that friction sliders are most likely the best option for manipulator movement, considering also ball bearings and sleeve sliders. Ball bearings show some promise and will be considered further, however their increased cost does not appear to provide sufficient increased performance.

Ideas for speed improvement include new lead screw pitch, changing the manipulator cylinder, adjusting gear ratio, or replacing the motor. Resolution would most likely have to be sacrificed to increase speed.

The table below shows ideas for sources of mechanical losses that may be causing the system backlash. The most likely causes are listed first. Corresponding corrective actions are listed in the next column.

 Mechanical Losses

Mechanical Losses

 Piston Backlash Fishbone Analysis

Piston Backlash Fishbone Analysis

Functional Decomposition

 Functional Decomposition

Functional Decomposition

Functional Decomposition

Systems Architecture

 System Flowchart

System Flowchart

 Software Flowchart

Software Flowchart

Risk Assessment

ID Risk Item Effect Cause Likelihood Severity Importance Action to Minimize Risk Owner
Describe the risk briefly What is the effect on any or all of the project deliverables if the cause actually happens? What are the possible cause(s) of this risk? | L*S What action(s) will

you take to prevent, reduce the impact of, or transfer the risk of this occurring?

Who is responsible for following through on mitigation?
1 Hydraulic leak No manipulator movement Rupture in pipe, improper seal 3 3 9 Ensure system is properly sealed Beth F/ Ryan D/ David A
2 Hydraulic fluid compresses/unresponsive to mechanical input Backlash and reduced manipulator movement Air introduced into system and sealing issues 3 3 9 Be sure system is properly bled,

seal hydraulics properly

Beth F/ Ryan D/ David A
3 Chips burn out Can’t control the system Programming errors, wiring errors, feedback, unisolated contacts 3 3 9 Make sure we buy extra chips Rob M
4 Video Latency too High Unreliable user experience Poor network connection(s), Poor/improper encoding 3 3 9 Consider multiple encoding options, Benchmark use cases Bryon E
5 Bugs in UI Code Improper control of system Inexperience with programming language 3 2 6 Debug UI and ask for more experienced help Rob M
6 Part/equipment availability Delay entire project Back order 2 3 6 Check availability ahead of time Team
7 Networking Solution too Complex Delay software implementation Unforeseen incompatibilities or obstacles, Poor design selection 2 3 6 Early development of proof of concept, Have simpler

alternatives

Bryon E
8 Motors don’t respond to user input Can’t control system Programming/control/ wiring issues 2 2 4 Debug the software, and check wiring diagrams Rob M
9 Too much friction on lead screw Backlash introduced into system Contaminated threads, Machining defects 2 2 4 Better machining, Replace lead screw Beth F/ Ryan D/ David A
10 Too much friction within manipulator Too much backlash Choice of carriage and lubrication 2 2 4 Order carriages with low friction coefficient Beth F/ Ryan D/ David A
11 Improper manipulator movement Backlash, chatter, vibration Misaligment 2 2 4 Make sure parts are machined properly, proper consideration for mount parts Beth F/ Ryan D/ David A
12 Controls have a delay or slow response time Unreliable user experience Unoptimized control and system components unable to respond, high network latency 2 2 4 Optimize control program and

network architecture

Bryon E/ Rob M
13 Manufacturing tolerances Parts won’t fit properly Supplier issue and improper design 2 2 4 Fit tolerances to solid modeling during planning phase Team
14 Ability to manufacture Backlash, vibration Machining limitations, experience on machine 2 2 4 Plan ahead of time what parts will be machined vs purchased Team
15 Parts don’t arrive on time Delays entire project Supplier problems 1 3 3 Find lead time and give adequate time for parts to arrive. Team
16 Electronic Failure Delay entire project, Need replacement parts Various 1 3 3 Guarantee insulated surfaces, Stay within operating limits Rob M
17 Mechanical Failure Delay entire project, Need replacement parts Various 1 3 3 Know and operate within device limits Team
18 Dramatic reduction in resolution Customer spec not met System modifications 1 2 2 Thorough calculations with safety factors Beth F/ Ryan D/ David A
19 Break/deform attachment Need to replace attachment Too much force, Improper manipulation 2 1 2 Enact system limitations David A/ Rob M
20 Imaging Processing is too Complex Complex Calibration Unclear image 1 2 2 Early development Ryan D
Likelihood Scale Severity Scale
1 - This cause is unlikely to happen 1 - The impact on the project is very minor. We wil still meet deliverables on time and within budget, but it will cause extra work.
2 - This cause could conceivably happen 2 - The impact on the project is noticeable. We will deliver reduced functionality, go over budget, or fail to meet some of our Engineering Specifications.
3 - This cause is very likely to happen 3 - The impact on the project is severe. We will not be able to deliver, or what we deliver will not meet the customer's needs.

Risk Assessment XLSX File

Systems Design Review

Presentation, notes, actions

System Design Review Presentation

System Design Review Notes and Feedback

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