Project Overview
This project involved the design and development of a novel quad VTOL platform featuring 2-DOF thrust vectoring at each propulsion unit. The primary objective was to improve control authority and system efficiency by redirecting each propeller’s thrust axis, rather than relying on differential thrust to generate body moments.
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By allowing each propulsion unit to independently control both thrust magnitude and direction, the system enables the generation of artificial body moments without necessarily altering the direction of travel. This effectively decouples the vehicle’s body frame from its translational motion in the inertial frame, allowing for more efficient maneuvering and improved performance in constrained environments.
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Traditional quad-copters couple thrust generation and attitude control, limiting efficiency and maneuverability. This architecture redefines that paradigm by introducing independent thrust-vector control at each arm, creating a significantly more complex but more capable system.
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The design space introduced challenges across multiple domains:
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Multi-axis mechanical actuation at each propulsion unit
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Nonlinear system dynamics due to moving thrust vectors
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Lack of existing control frameworks for this configuration
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Tight integration between mechanical design and control performance
This required a first-principles, system-level approach combining mechanical design, dynamics, and control theory.
Mechanical Design & Controls
I led the development of the gear-driven thrust-vectoring mechanism, initially based on a 3-DOF spherical gear architecture. Early evaluation revealed limitations in stiffness, load transmission, and packaging efficiency.
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To address these issues:
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The architecture was simplified by constraining unnecessary degrees of freedom, reducing complexity while preserving required motion
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Critical gear interfaces were redesigned to improve stiffness and mitigate backdriving under load
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The actuation system was transitioned to a belt-driven architecture, allowing motors to be relocated closer to the center of the frame, significantly reducing mass and inertia at the arms
In parallel, I contributed to vehicle-level structural optimization using generative design techniques, achieving significant weight reduction while maintaining stiffness along critical load paths. This ensured structural efficiency without compromising performance or durability.
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The non-traditional architecture required a completely new control strategy. I worked closely with the electrical engineering team to develop a custom flight control framework capable of handling the coupled dynamics of thrust magnitude and vectoring direction.
Key elements of the control development included:
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Inverse kinematics to relate actuator motion to thrust vector orientation
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Application of Lagrangian mechanics and moving-frame dynamics to model how thrust vectoring translates into body forces and moments
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Development of a control allocation framework to convert desired force and moment commands into individual actuator inputs
The system coordinated 16 motors across propulsion and vectoring actuation, requiring precise mapping between high-level control commands and low-level hardware inputs.
Results and Takeaways
The project successfully demonstrated the feasibility of a thrust-vectoring quadcopter architecture, with early validation showing controlled multi-axis motion and improved flexibility in maneuvering.
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Key insights included:
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Mechanical design decisions (e.g., stiffness, backlash, actuator placement) have a direct and significant impact on control performance
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Decoupling thrust direction from magnitude enables more efficient and versatile flight dynamics
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Novel architectures require tight integration between mechanical design, system dynamics, and control logic
Key Takeaways
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System-level innovation requires rethinking fundamental assumptions in both mechanics and control
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Effective control of complex systems depends on accurate modeling and understanding of underlying physics
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Mechanical simplicity and stiffness are critical for achieving predictable and controllable behavior
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Simulation environments are essential for validating non-standard system architectures before hardware deployment