Introduction

 

Background:

During recent years, the use of robots as a novelty in hospitality has significantly increased, with robots initially being used in industrial settings. These robots were used for placing orders, however, this expanded to serving and delivering items, in particular food. Hotel delivery robots are efficient as they are a 24/7 service allowing for room service to improve a guests stay, without requiring specific overnight hotel staff. 

Goal:

Overall, the vision for the Hotel Food Delivery Robot project is for the robot car  to be able to move from a starting point, manoeuvring itself along an ideal path, through any potential obstacles in the way, using the sensors that will be integrated into the robot. The 'map' for the robot will be referred to as a standard two-dimensional graph, where the X-axis represents horizontal movement and the Y-axis is the vertical translation of the car. The total length of the room determines the maximum value for the Y-axis and the total width of the room determines the maximum value for the X-axis. The final destination for the robot will be entered in as a co-ordinate which is depending on the user's desired location. 

Schematic Diagram of the Robot:


Where the components list is as follows:

  • L298N Dual Bridge DC & Stepper Motor Controller Board for Arduino
  • Arduino Uno Board and Enclosure
  • 5V Ultrasonic Distance Sensor
  • Infra Red (IR) Transmitter Module
  • AA Battery Holder Black Coil Spring Contact and 12V Transmitter Batteries, although these were replaced with a Rechargeable Battery Pack
  • Storage Box 
  • A variety of Jumper Cables; Female-Female, Female-Male and Male-Male
  • DC Motors and Wheel Mechanism
Schematic Diagrams of the Modules:


- Arduino

 


When the Arduino is connected to a computer through using USB connection, the code that is written in C++ is transferred to the Integrated Development Environment, which allows for it to be processed and compiled so that its uploaded to the memory on the board.

 

-IR Sensor

 

 

In the Infra Red Transmitter Module, the resistance of the photo-diode and the output voltage change depending on the Infra Red light that is received. When the IR LED emits radiation, this will be reflected back to the IR receiver once it hits the object, which is sensitive to the same wavelength that comes from the emitter.

-Motor Mechanism

The wheel mechanism relies on the usage of the motors, in order for the main gear to rotate, the DC motor spins. In this case, a stepper motor controller is used so that the motor can spin with precision, allowing for the position to be held when necessary. It works by using open-loop control where the controller will generate electrical pulses which supply the drive current to the motor. When one gear turns, it causes the track wheel to also turn.

-Ultrasonic Distance Sensor

The Ultrasonic Distance Sensor works through high frequency sound waves (ultrasound) being emitted and listening for the signal (echo)  being reflected back. The distance is calculated based on the time that this process takes. The Arduino board will send a pulse to trigger for the detection, and when a pulse occurs on the same pin, where the duration of this is the same as the distance. This allows for the robot to stop if necessary for obstacle avoidance, as a short time period for the pulse means short distance.

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