1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
System Level Design
Team Vision for System-Level Design Phase System Architecture
Functional Decomposition Benchmarking
Morphological Chart and Concept Selection Selection Criteria
Concept Selection
Feasibility: Prototyping, Analysis, Simulation Risk Assessment
Plans for Next Phase:
Team Vision for System-Level Design Phase
Plan Actual
Benchmark different conveyors systems and microcontrollers Many systems + components beyond the conveyor and microcontroller were benchmarked.
Create functional decomposition Functional decomposition was generated from engineering requirements. Refine project scope as conveyor system and microcontrollers
are researched.
Project's scope and risks were updated to reflect our findings.
Define high-level system architecture High-level system architecture was defined.
Generate and select design concepts Design concepts were generated and selected based on selection criteria and engineering requirements
Conduct feasibility analysis of design concepts Was not accomplished in this phase of the project. See Feasibility section for more info.
For this phase, the team launched an investigation into all of the subsystems needed to meet Dematic's requirements. Initially, a high-level system architecture was generated from the current design, and engineering requirements. From here, a functional decomposition was generated to show the functionality that was required for the project. For each function, concepts were generated and selected using a morphological chart in combination with selection criteria which we generated from our engineering requirements. While this was happening, the project's scope and risks were updated to reflect our research. While we planned to begin feasibility analysis and generate test plans, the real world caught up to us, and this unfortunately has been shifted into the next phase of the design process.
System Architecture
The system architecture document shown above describes the flow of power, information, material and structural forces within the system. The document provides a high-level overview of the functionality of each subsystem, and how each subsystem interfaces with the others. The key subsystems in this architecture are contained within the small dotted rectangles, which are driven by our main control panel seen in the center. Each "component" and subsequent interconnections are color coded to represent the nature of the force. Black arrows represent the transfer of low voltage power, while red arrows represent the transfer of 24V power. The green arrows represent the flow of communication between components, i.e. the microcontrollers and sensors. Finally, blue arrows represent the flow of mechanical energy. This document was constructed based on the current design, as well as the engineering requirements.
Working PDF: System_Architecture_Final.pdf Draw.io File: System_Architecture_Final.drawio
Functional Decomposition
Benchmarking
Through the functional decomposition and system architecture, major areas of the system were chosen to focus on. Within these areas, the most unknown aspects of our design were chosen to focus on and benchmark. It was decided to benchmark commercially available solutions against our engineering requirements to find an optimal solution.
24V Power Supplies:
The key electrical characteristics of the AC-DC 24V power supplies shown above were collected from each respective datasheet. Links to each power supply and datasheet can be found in the working document below. The information collected will be used to validate engineering requirements requirements surrounding the AC-DC power supply, as well as the 24V power rail.
Low Voltage Power Supplies:
The key electrical characteristics of the low voltage, DC-DC power supplies shown above were collected from each respective datasheet. As above, links to each DC-DC power supply and associated datasheet can be found in the working document below. The information collected will be used to validate engineering requirements regarding the low voltage power rails, as well as the microcontroller selection.
Framing Material:
The key physical characteristics of the frame material shown above were collected from each respective datasheet. The options for framing shown above vary greatly in pricing. T-slot aluminum is currently used for the model, and Dematic has instructed the team to continue using this material to save time and maintain the aesthetic of the model.
3D Printing Plastic:
The key physical characteristics of the 3D printing plastics shown above were collected from each respective datasheet. The 3D printing filaments compared above are relatively similar in terms of strength, weight, and cost. The team will likely move forward with PLA plastic as it is currently used on the model and supplied by Dematic. This will ultimately save the team time and money, while maintaining consistency with the current model. PLA meets all the strength and temperature requirements of the project.
Microcontroller Selection:
The key electrical and software characteristics of each viable microcontroller shown above were collected from each respective datasheet. At this time, the microcontroller selection is not definite, but will likely use a the Raspberry Pi 3B+ alongside another microcontroller to support movement, and sensor integration. Ultimately, the information collected here will be used to make a final determination into the most cost effective, robust platform to begin development on.
Electrical Stepper Motors:
The key electrical and mechanical characteristics of the stepper motors shown above were collected from each respective datasheet. At this time, the final stepper motor selection is not definite. Once an accurate power budget is completed in the next phase of design, a final decision will be made. The final decision will likely choose the stepper motor that balances power consumption with cost.
Electric DC Motors:
The key electrical and mechanical characteristics of the DC motors shown above were collected from each respective datasheet. At this time, the final DC motor selection is not definite. Once an accurate power budget is completed in the next phase of design, a final decision will be made. The final decision will likely choose a DC motor which balances power consumption with cost.
DME Devices:
The key electrical and physical characteristics of the DME devices shown above were collected from each respective datasheet. The final DME device selection is one of our largest unknowns at this time. The DME device is crucial to creating an accurate, real-world model of Dematic's AS/AR system.The team has committed extra time in the next phase of the design process to prototyping, and ultimately making a final selection.
Drive Type:
The key mechanical characteristics of the different drive types shown above were researched. The cheapest options are both the timing belt and steel mini chain. Due to the nature of the project, compactness is one of the most important characteristics in our selection process. Timing belts are extremely compact and can be woven around and through tight spaces making them the most appealing option. The only option that doesn't meet our strength requirements is the poly chain.
A working document of all benchmarking characteristics can be found here: Benchmarking.xlsx
Morphological Chart and Concept Selection
The purpose of the Morphological Chart was to document multiple concept options for the subsystems within our model. The concepts were then compared to the selection criteria in the next section and then selected using Pugh Charts.
Working document of Morphological Chart: Morphological Chart.xlsx
Selection Criteria
Criteria Description Requirement
Number
Corresponding Engineering Requirement
Ease of user interaction
Final selection to support user interaction(tablet/SW) must be easy to use, and easy to integrate
S20 Tablet to support user interaction.
Easy to assemble /setup
Components must be designed such that they are easy to assemble and debug if any issues arise.
S1,S8,S9,S10 Components must be designed such that they are easy to assemble and debug if any issues arise.
Strength of components
Components must be designed to be lightweight, and strong to support transportation and assembly. Crucial for shipping.
S8,S9,S10,S11 Weight of each subsystem must be kept in mind for transport
Compact System must be as compact as possible to ease in assemble and transportation. Crucial for shipping.
S8,S9,S10,S11 Lightweight components = Compact components.
Within budget
Total system design must come in below budget of $4000. S1, S14 Components within budget, project finished on time.
Within Timeline
Project complete in scheduled time. S1,S14 Project finished on time and within budget.
Improve accuracy
The overall system must function as closely as possible to the real-world AR /AS system.
ALL All eng. requirements contribute to improving accuracy.
Robust /Modular Design
The individual subsystems must be able to function independently of each other. Design must be robust for the addition of future subsystems.
S3,S4,S7,S13 Power needed to drive a robust design, electrical support for future designs, documentation.
Well organized design
Design must be well organized, easy to follow, and easily modifiable for future subsystem additions.
S12,S13 Reliability and documentation are key to creating an organized design.
Safety Design and component selection must keep safety of user in mind at all times. S21 Safety!
Documentati on
Chosen components must have adequate documentation and resources available.
S13 Documentation of all subsystems + system setup
Reliable System must be reliable. S12 Reliable
Working document of engineering requirements: Customer_Requirements_Final.xlsx
Concept Selection
Using a Pugh Chart analysis the concepts proposed in the Morphological Chart were rated against the Selection Criteria. A +, - and 0 rating was used to select concepts that meet out customer and engineering requirements. Concepts with higher net scores and ranks were often considered to be pursued further. In some cases multiple concepts were considered to be combined in order to create the most effective concept.
Conveyor Type
Crane Drive
Shelving for Pallet
Interconnection
Controllers
Communication
Shipping
Direction Change Method
The following concepts have been chosen to be pursued further based on the ranks they received in the Pugh Charts.
Final Selections
Conveyor Type
Crane Drive
Shelving for Pallet
Interconnection Controllers Communication Shipping Direction Change Method
Concept(s): 1 & 2 2 & 3 1 & 2 2 2 & 3 4 & 5 2 & 6 1 & 2
Feasibility: Prototyping, Analysis, Simulation
Due to circumstances beyond our control(Career fair+midterms) we have not had the opportunity to begin conducting prototyping, analysis, and simulations of our designs. The team has committed extra time as we enter the next phase of the design process.
Risk Assessment
Working document of risk assessment can be found here: Risk Management.xlsx
Plans for Next Phase:
The next phase of our project will be spent developing the preliminary detailed design of our system. We will accomplish the following deliverables: Complete a proof of concept for our selected designs by doing further analysis, prototyping and/or simulation.
Draft initial drawings/schematics for each subsystem Inital BOM for all subsystems
Expand risk assessment, mitigation plans and triggers based on system selections Draft system test plans
Complete preliminary detailed design review
