Patrick McGuire's Portfolio

Fleet Robotics:

Docking and Charging Station

Overview

I contributed to the development of Fleet Robotics' docking station, including mechanical design, FEA analysis, electrical system architecture, failure mode analysis, and vendor engagement for fabrication quoting. I led multiple design reviews and collaborated with team members to ensure seamless mechanical and electrical integration with the robotic system.

Full system CAD

Docking station frame

Alignment mechanism

Frame and Alignment

I designed a steel weldment frame that aligns with predefined attachment points on a ship’s deck. To ensure manufacturability, I collaborated with a local welding shop to validate the fabrication process. The frame included integrated lift points for safe and efficient hoisting onto the vessel.

An alignment mechanism was incorporated to accommodate significant placement tolerances, enabling quick and error-tolerant installation on various ships.

Technical Drawings

I created drawing packets for the frame. I worked with a local shop to improve manufacturability and get a quote for the welded frame. All components went through multiple revision cycles where changes were made based on feedback from various shops.

Viability simulation of cantilevered plate

Worst case loading of bent sheet metal part

FEA Simulation

I performed FEA simulations on key frame components to verify structural integrity and ensure adequate safety factors. These analyses accounted for shipboard acceleration profiles to estimate real-world loading conditions.

The simulation results informed iterative design improvements, enabling a structurally robust yet streamlined frame optimized for simplicity and manufacturability.

Actuation Design

The docking system’s primary actuation involved rotating a 200 lb structure that supports the robot while docked. I conducted detailed load analysis to ensure the selected linear actuators would operate reliably under expected conditions. To enable safe manual override, the system was counterbalanced using gas springs, reducing the force required by operators.

To prevent galvanic corrosion at the pivot, I designed the hardware with plastic bushings that isolate dissimilar metals, ensuring long-term durability in marine environments.

Actuator force simulations

Cross section of primary actuation joint

Electrical block diagram

Electrical System

I architected the electrical system, encompassing power management, actuator control, networking, sensor integration, computing, and mechanical interface considerations. The power system was designed to deliver multiple voltage levels and included a battery backup to maintain critical functions during outages. All electronic components were protected by circuit breakers, with power switching implemented on many devices to enable selective activation and shutdown.

Control hierarchy was established with a PLC managing low-level actuator control, while a Linux-based computer handled higher-level system coordination and external communications. I incorporated inductive limit switches for the actuators, allowing reliable adjustment of travel limits after shipboard installation. A smart industrial motor driver was selected to efficiently drive the actuators and provide overcurrent protection.

Additionally, medium-gain sector antennas were integrated and optimized to deliver broad field-of-view coverage for reliable wireless connectivity.

Cable Routing

I designed the cable routing path to ensure proper actuation and protection, strictly maintaining minimum bend radius requirements for the conduit to prevent damage. The routing was developed parametrically, enabling automatic updates to conduit paths in response to major design modifications, thereby streamlining iteration.

Conduit in the extended state

Conduit in the retracted state

Failure and hazard overview table

Failure and Hazard Analysis

Given the system’s intended long-term deployment on ships with minimal maintenance, thoroughly understanding potential failure modes was essential. I conducted failure mode analyses and developed corresponding mitigation strategies, which were integrated directly into the design. The system was engineered to “fail safely,” ensuring that any failure would not adversely affect ship operations. Additionally, manual overrides were incorporated to maintain control and safety in the event of system malfunctions.

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