Use Case Diagram – Elevator System

A Use Case Diagram illustrates how actors interact with various functions (use cases) in the system. It shows what the system does from the user’s perspective, not how it does it. The Elevator System consists of multiple use cases that involve both users and supporting systems.


Actors Involved:

  1. Passenger – Primary actor using the elevator.
  2. Maintenance Technician – Supporting actor managing repairs.
  3. Elevator Control System – Internal system actor.
  4. Building Security System – External actor (optional).
  5. Administrator / Monitoring System – Supervisory actor.

 

Main Use Cases:

For Passenger:

  • Call Elevator (Up/Down Button)
    The user presses a button from a floor to request the elevator.

 

  • Select Destination Floor
    Once inside, the passenger chooses the desired floor.

 

  • View Floor Display / Status
    The system shows current floor and direction on display panels.

 

  • Trigger Emergency Alarm
    Passenger can press an alarm in case of emergencies.

 

  • Open/Close Door Request
    Press a button to keep the door open a little longer or to close it manually.

For Elevator Control System:

  • Process Floor Request
    Determines optimal movement and direction based on pending requests.

 

  • Control Elevator Movement
    Sends commands to move elevator up/down to the selected floors.

 

  • Manage Door Operations
    Opens/closes doors with safety checks for obstructions.

 

  • Handle Overload or Faults
    Detects and responds to system faults or passenger overload.

For Maintenance Technician:

  • Perform Diagnostics
    Connect to system for error logs and real-time status.

 

  • Manual Control Access
    Operate elevator directly during maintenance.

 

  • Service Mode Activation
    Disable elevator for public use during repair.

For Administrator / Monitoring System:

  • View System Logs
    Retrieve historical records of elevator activity and faults.

 

  • Configure Operational Settings
    Adjust timing, floor access, or peak hour logic.

 

  • Monitor Real-Time Status
    Remotely track elevator location, load, or state.

For Building Security System (Optional Use Case):

  • Activate Fire Emergency Mode
    Forces elevator to return to ground floor and stay there.

 

  • Restrict Floor Access
    Block access to certain floors unless authorized (e.g., keycard or biometric).

Diagram Elements to Include When Drawing:

  • Actors: Draw as stick figures labeled with their roles.
  • Use Cases: Draw as ovals with names of the functions.
  • System Boundary: A box enclosing all the use cases labeled “Elevator System”.

 

  • Relationships:

    • Solid lines connecting actors to use cases.

    • “Include” and “Extend” relationships where applicable (e.g., “Call Elevator” may include “Process Floor Request”).

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