In Progress

Groch Link Autonomous Shuttle Prototype

Status: In Progress (2025– ) | Scale: ~10 in tall prototype representing a ~2 m full-scale shuttle (~1:8 scale)
Robotics Autonomous Systems GPS Navigation Sensor Fusion Embedded Systems 3D Printing Mechanical Design Python Arduino Raspberry Pi

Project Summary

The Groch Link Autonomous Shuttle Prototype is a small-scale engineering platform exploring how a future 2 m tall autonomous shuttle concept could behave in the real world. This first physical iteration is a scaled-down prototype approximately 10 inches tall, built to test structure, packaging, and control before committing to larger, more complex builds.

The prototype combines a custom EMT conduit frame, 3D-printed joints, and a mixed electronics stack built from both purchased and repurposed modules. Its long-term goal is to achieve GPS-guided autonomous movement over varied terrain, serving as a practical testbed for navigation, sensor fusion, and mobility system design.

Objective

Design and build a scale prototype that can:

  • Represent the proportions and structural intent of a ~2 m tall shuttle in a compact, 10 in physical model
  • Navigate between GPS waypoints, using real-world position data rather than fixed tracks
  • Operate on different surfaces (smooth indoor flooring, concrete, light outdoor terrain)
  • Integrate multiple sensors and modules (GPS, IMU, distance sensing, repurposed vehicle electronics) into a coherent control architecture
  • Provide a platform for iterative experimentation in autonomy, stability, packaging, and systems integration

Project Timeline

2025

  • Defined initial shuttle concept and approximate full-scale dimensions
  • Chose a ~10 in scale to keep the prototype manageable while preserving proportions
  • Designed and assembled the EMT conduit frame with 3D-printed joints
  • Selected Raspberry Pi + Arduino as core compute/control pair
  • Began integrating GPS and basic sensor modules

2026 (planned)

  • Expand sensor suite (IMU, upgraded GPS, additional distance sensors)
  • Implement and refine GPS waypoint navigation
  • Conduct structured terrain tests and tuning
  • Explore enclosure concepts mirroring the full-scale shuttle form

Design & Development

1. Scaled Structural Frame

Full-scale conceptual size: ~2 m tall shuttle body.

Prototype size: ~10 in tall, scaled to roughly preserve proportions and design intent.

The frame:

  • Uses EMT conduit for a rigid but modifiable skeleton
  • Utilises custom 3D-printed joints to connect members and allow quick geometry changes
  • Keeps the centre of gravity low to better handle uneven surfaces at small scale
  • Includes dedicated mounting points for electronics, batteries, and sensor modules

Designing at this scale allows experiments with:

  • mass distribution
  • wheelbase and stance
  • internal volume for hardware
  • potential full-scale packaging decisions, in miniature

2. Electronics Architecture

The electronics are deliberately modular, centred around two main boards:

  • Raspberry Pi 4 Model B
    • Runs high-level navigation logic
    • Parses GPS data and handles waypoint management
    • Logs data from sensors for later analysis
  • Arduino Uno R3
    • Handles real-time motor control (PWM)
    • Reads sensors needing deterministic timing
    • Implements basic safety behaviours and low-level checks

Repurposed components include:

  • Motors and electronics from small vehicle platforms (e.g., salvaged from toy/consumer devices)
  • Power distribution parts adapted from previous builds
  • Reused cabling, mounts, and housings where suitable

This architecture allows you to swap and upgrade modules without rebuilding the entire system.

3. Sensor & Module Suite

The shuttle is intended as a multi-sensor platform. Current and planned modules include:

  • GPS module – global positioning and waypoint navigation
  • IMU (Inertial Measurement Unit) – heading and attitude stabilisation; supports dead-reckoning between GPS updates
  • Distance / proximity sensors (e.g., ultrasonic or infrared) – for obstacle detection in front of the shuttle
  • Repurposed IR/line sensors – reused from previous vehicle projects where useful
  • Power monitoring modules – to track voltage and current draw

Over time, the sensor stack will be tuned to balance complexity, size constraints, and real-world performance on a small chassis.

4. Drive & Mobility System

The drive system is designed to be simple, robust, and easy to iterate:

  • Differential drive layout using DC motors for left/right wheels
  • Motor drivers controlled via the Arduino
  • Wheel and tyre selection focused on handling both indoor and mild outdoor surfaces
  • Power system matched to expected run time and current demands

The small scale allows quick testing of:

  • traction on different surfaces
  • impact of centre-of-gravity changes
  • effects of speed and steering profiles

As the project matures, the drivetrain can be upgraded (motor torque, wheel type, potential suspension elements) without discarding the entire frame.

5. Autonomy & Navigation Logic (In Progress)

Autonomy is being built in layers:

  1. Manual and basic control
    • Straight-line motion tests
    • Turning response and stability checks
    • Validation of motor control and power system
  2. GPS waypoint navigation
    • Reading GPS data on the Raspberry Pi
    • Converting waypoints into heading and distance targets
    • Steering the shuttle between points and verifying real-world accuracy
  3. Sensor-assisted navigation
    • Using distance sensors to prevent collisions
    • IMU input to stabilise heading and correct for drift
    • Logging sensor data and trajectories for iteration
  4. Terrain-aware behaviour (planned)
    • Adjusting speed and control parameters based on observed surface conditions
    • Comparing performance indoor vs. outdoor and refining accordingly

Tools & Technologies

  • EMT conduit and mechanical fittings
  • 3D-printed ABS/PETG joints and mounts
  • Raspberry Pi 4 Model B
  • Arduino Uno R3
  • GPS module
  • IMU sensor
  • Ultrasonic/IR distance sensors
  • DC motors and motor drivers
  • Battery packs and power distribution hardware
  • Python (navigation & logging)
  • Arduino C++ (low-level control)
  • Hand tools, soldering equipment, test rigs

Reflection & Next Steps

By working first at 10 in scale, this project makes it possible to:

  • test structural and mobility ideas cheaply and safely
  • learn how GPS and sensor noise behave in the real world
  • refine how electronics and mechanics are packaged together
  • build up a library of tested approaches before moving toward larger, more ambitious hardware

Planned next steps include:

  • completing a robust GPS waypoint-following loop
  • adding and tuning the IMU and distance sensors for more reliable behaviour
  • systematic terrain testing indoors and outdoors
  • exploring version 2 of the chassis to better reflect the proportions and design language of the conceptual 2 m shuttle

This prototype is designed not as a finished product, but as the first serious iteration in a long-term exploration of autonomous shuttle systems.