Green Turtle Shell

    Hovercrafts are a near frictionless vehicle that have typically been utilized for amphibious transitions from land to water.  Because of their near frictionless nature it is difficult to control movement especially changing direction and rotation.  

 

Capabilities

  

 I am proposing an Hovercraft with one lift fan and one thrust fan that will may include some or all of the following capabilities:

 

• Detect Painted boundary (Avoid)

• Physical Obstacles (Avoid)

• Miscellaneous External forces - Picking up the aircraft (Stop all)

• Detect low battery via tachometer (Execute warning)

• Video Feedback (User Feedback)

 

Unique Technology

 

    The control system may be user defined which will utilize a base station sensor to detect hand position and gestures of the user (no direct contact of user).  This will then communicate to the hovercrafts onboard micro-controller as a users controlled input

 

     A traditional hovercraft with one lift fan and one thrust fan has been historically difficult to control and turn on a dime.  In order to make the system more stable an implementation of a  mechanical Extension/Retraction devise with a high friction/sticky spherical tip.

 

The devise will serve two purposes:

 

• Quick Stop

• Provide a pivot point for craft to turn about.

 

Sensors

 

    In order to avoid obstacles and find the base

station, sensors will be used for the

micro controller to be aware of its

surroundings.  The sensors that may be

utilized are as follows:

 

• Ultrasonic sensor - Collision avoidance

• CDS sensor - Detects Boundary

• Accelerometer/ Tilt switch - Detects if craft is removed from ground

• Microphone/ Ir Laser - Search

• Capacitive touch/touch free - allow user input

 

Strengths

 

    Several well known universities have constructed team competitions around a hovercraft.  Most, if not all, of those that compete turn off the lift fan to control the motion of the craft.  With the utilization of a pivot point located at the CG of craft, a controlled motion of the craft may be more easily achieved without turning off the lift fan.

 

Concerns - Hardware

 

    Developing hardware for a hovercraft is not straight forward.  In order to lift the aircraft off the ground a fan is used.  In the online tutorials usually use a computer case fan or propeller provides the airflow for lift.  I would like to utilize a more efficient impeller/centrifugal fan to provide the lift.  Centrifugal fans are not as easy to find and so a custom 3d printed on may be required.  

 

    The hovercraft skirt is another custom part that will be required if the surface is not uniform.  This can be cut from PPE painters drop cloth or trash bag but will require multiple attempts to get right.

 

    The remainder of the components (Mounts, Base, Fixtures, Control surface) may be constructed from wood or be 3d printed in interlocking pieces.

 

Concerns - Software

 

    The micro-controllers that will be used are Arduino Uno and Arduino Nano.  In order to connect the users input to the Arduino on the craft a wireless link will be required.  There are several methods of achieving this including a cheap 325-450mg transmitter receiver although this method is limited in its capability.

 

Conclusion

 

    A hovercraft as a platform allows for a diverse range of uses.  Although it is not depicted in the proposal a use over water may be implemented (time and courage permitted).  There are several difficult challenges with the design of the hardware and software, but with trial and error, the goals can be achieved.