Project 1: Specification for Automail: Software Modelling and Design (SWEN30006_2024_SM2)

Project 1: Specification for Automail

Background: Automail

Delivering Solutions Inc. (DS) has recently developed and provided a Robotic Mail Delivery system called Automail to the market. Automail is an automated mail sorting and delivery system designed to operate in a large building that has a dedicated mail room. The system offers end-to-end receipt and delivery of mail items within the building and can be tweaked to fit many different installation environments.

The current version of the system supports delivery of letters using one specific delivery mode  where every robot operates with the same behaviour. DS would like the system to also handle parcel delivery, and to support exploring alternative delivery modes which specialize the robot  behaviour.

The Automail System

The building the system operates in (see Figure 1) will have a number of floors each with the same number of rooms. Below the rooms is a mailroom (row 0), to the left and right are robot tracks (column 0 and column roomsperfloor+1) respectively. 

Figure 1: Automail Building Layout (6 floors by 5 rooms) with Robots

The mail items are letters which are effectively weightless, or parcels which have a given weight. All mail items are addressed to deliver within the building to an room identified by combination of Floor and Room number.  The current system handles only delivery of letters.

The Automail system consists of two key components:

·  A MailRoom subsystem which holds mail items after their arrival at the building’s mail room. The mail roomdecides the order in which mail items should be delivered.

·  Delivery Robots which take mail items from the mail room, or from other robots, and deliver them throughout the building. The currently used robot (see Figure 2) has a backpack-like container for carrying mail items. Carrying capacity of the robot is weight limited. As such the total weight of carried items cannot exceed robot.capacity.  An installation of Automail can manage a team of delivery robots of configurable size.

Figure 2: Artistic representation of one of the DS robots

DS provides a simulation subsystem to show that Automail can operate to deliver mail items within the building. The subsystem runs a simulation based on a property file, generates an output trace of execution and outputs the average time to deliver a mail item.

The simulation subsystem uses a clock to simulate operations of the mail room and robot subsystems. Broadly speaking, for each tick of the clock (i.e. one unit of time), the mail room subsystem will load items to a robot if there are robots available at the mailroom; and the robots will either move to deliver an item (if there are items in their backpack), deliver an item, or move to return to the mailroom (if all items are delivered). Currently, the robots offered by DS will take one unit of time when

·  moving one step (i.e., moving up or down one floor in a building, or left or right one across the building).

·  delivering items at one apartment once there.

·  transferring items from one robot to another.

·  being loaded and moved out of the mailroom.

The simulation completes only after all items have been delivered.

Unfortunately, the staff who designed and implemented the Automail simulation did not consider maintainability and future enhancements.

Current operating mode: Cycling

This mode has been implemented in the current simulation.  It has the robots moving clockwise through the building delivering mail items, as illustrated in this video (https://canvas.lms.unimelb.edu.au/media_attachments_iframe/20429677? type=video&embedded=true) .

The Cycling mode (MODE=cycling) has every robot operating with the same behaviour. All items a robot carries for delivery will only ever be for a single floor at a time.

Initially: All robots (robot.number>0) start in the MailRoom.

Ongoing (each timestep):

1. If there are any items and robots in the mailroom, the mailroom will Load a robot with items for one floor (the floor with the earliest remaining delivered item), and move it to the bottom left (0, 0).

2. If a robot has items to deliver and has not reached its target floor, it will Step up.

3. If a robot has an item to deliver it will Step towards the left-most location to which its items are addressed.

4. If a robot has reached its delivery location and not yet delivered, it will Deliver.

5. If a robot has no items to deliver, it will Step towards the bottom right (0, building.roomsperfloor+1).

6. If there is a robot at bottom right (0, building.roomsperfloor+1), it will Return to the mailroom.

You can assume that the Automail Cycling mode has been well tested and performs reasonably well,though only for letters.

Proposed operating mode: Flooring

This mode has not been implemented in the current simulation; you and your team need to add this.  It involves having one robot per floor delivering on that floor, with two robots (one at each end) bringing mail items up to the other robots for delivery, as per this video (https://canvas.lms.unimelb.edu.au/media_attachments_iframe/20429779? type=video&embedded=true) .

The Levels mode (mode=FLOORING) always involves exactly building.floors+2 robots

·  one for each floor, each of which exhibits floor behaviour, and

·  one for each of the leftmost and rightmost columns, each which exhibits column behaviour.

Floor robots only ever move on their floor and column robots only ever move on their column and in/out of the mailroom.

Floor Behaviour:

·  Initially: the robot is at Room 1 on their floor. ·  Ongoing (each timestep):

1. If the robot has mail items, continue delivering them (ignore column robots).

2. If the robot is next to a waiting column robot (i.e. with items for this floor), Transfer them from the column robot to this robot and start delivering from that end of the floor towards the other end. (Note: as all robots have the same capacity and the floor robot is carrying nothing, all items will be transferable.)

3. If the robot is heading for a waiting column robot, continue moving towards that robot.

4. If a column robot is newly waiting, start heading towards it.  If two column robots are    newly waiting, move towards the one with the earliest arrival item, or the left one if the and Design (SWEN30006_2024_SM2) arrival time is the same.

5. If the robot has no items and no column robots are waiting for this floor, then do nothing. Column behaviour:

·  Initially: the robot is in the mailroom and is assigned to the left or right column (one robot to each).

·  Ongoing (each timestep):

1. If the robot is in the mailroom and the mailroom has items, Load the robot (as per Cycling) and move it to its floor 0, otherwise do nothing.

2. If the robot is loaded for delivery, and not at the destination floor move towards the destination floor.

3. If the robot is at the destination floor, and the floor robot is adjacent, Transfer from this robot to the floor robot.

4. If the robot has transferred, head towards floor 0.

5. If the robot arrived back at floor 0, enter the mail room.

All items a robot carries for delivery will only ever be for a single floor at a time. Robot Operations:

·  Step: move one floor or apartment towards the destination.  Only one robot can be on a square at a time. If the destination square is blocked, the robot does nothing.

·  Load: the load destination is the floor of the item in the mailroom with the earliest arrive

time. Load the robot with all items destined for that floor which can be transferred to the destination robot, subject to load.  All letters are transferred, and parcels are transferred in order of "earliest arrival time package which will fit within weight capacity".

·  Transfer: all items which can be transferred are move from the source robot to the

destination robot, subject to load.  All letters are transferred, and parcels are transferred in order of "earliest arrival time package which will fit within weight capacity".

·  Return: all items are transferred from the robot back to the mailroom.

·  Deliver: the item is removed from the robot and the elapsed time since arrival used in the item statistics.

Your Task

To expand the usage and trial different modes of operation, DS wants to update their Automail to support (1) parcels, and (2) the FLOORING operating mode.

The Base Package

You have been provided with a zip file containing source code for  the current version of the system, including an example property file.

(https://canvas.lms.unimelb.edu.au/courses/187398/files/20444343?wrap=1)  

(https://canvas.lms.unimelb.edu.au/courses/187398/files/20444343/download?download_frd=1)

This provides the basis for you to implement the additions described above.

Please carefully study the provided code and ensure that you are confident you understand  how it is set up and functions before continuing. Note that you do not need to understand all aspects, just those relevant to the changes you need to make. If you have any questions, please make use of the discussion board.

Note: The simulation will run and generate mail items at random times and with random weights, based on a seed. You can configure this in the property file (test.properties by default). Any integer value will be accepted, e.g. 30006.

Configuration and Project Deliverables

(1) Extended Automail: As discussed above, and for the users of Automail to have confidence that changes have been made in a controlled manner, you are required to preserve the Automail simulation’s existing behaviour. Your extended design and implementation must account for the following:

·  Preserve the existing behaviour of the system for configurations where the additional

capabilities are turned off in the configuration file (properties), i.e. mail.parcels=0 and

MODE=cycling.  Note that “preserve” implies identical output. We will use a file comparison tool to check this.

·  Add the handling and delivering behaviour for parcels (including robot capacity limitation). ·  Add the new FLOORS mode of delivery.

·  Configurable building size and number of robots (robot.number for cycling mode or building.floors+2 for flooring mode).

It's recommended that you understand the high-level design of current system so that you can effectively identify and update relevant parts. You don't need to refactor the whole system, just those parts necessary or helpful to making the required changes.

(2) Report: In addition to the extended Automail, DS also wants you to provide a report to document your design changes and justification of your design. You should also comment on how easy your changes make it to add further mail items (beyond letters and parcels), or further delivery models (beyond cycling and flooring) in the future.  Your report should include:

·  a design class diagram which shows all of the changed design elements in your submission (at least - it can show more than just the changes but doesn't need to show all unchanged elements).

·  a design sequence diagram which illustrates the behaviour of a floor-assigned robot in FLOORING mode, for appropriate scenario of your choosing.

More detail of the report is available on the LMS submission page.

Note: Your implementation must not violate the principle of the simulation by using information that would not be available in the system being simulated. For example, it would not be appropriate to use information from the simulation package (e.g., mail items which have not yet been delivered to the mail room). We also reserve the right to award or deduct marks for clever or very poor code quality on a case-by-case basis outside of the prescribed marking scheme.