Joystickless Powered by the GelForce Sensor

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Joystickless Powered by the GelForce Sensor

• Engineered at University of Tokyo
• Transparent deformable gel measures forces
• Magnitude
• Direction

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GelForce Sensor Composition

• Composed of a transparent elastic body in two
  layers of red and blue markers.
• A CCD camera captures the movements.

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Video of GelForce Application
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Application Examples

• Joystick controller for equipment usage.
• Bullet-proof vest engineering.
• Fabricate a robotic hand that has tactile feeling
  similar to human hand.

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What is it composed of?(cont)

• The markers are simply small colored balls
  imbedded in the gel.
• The balls are evenly spaced (distance known).
• One layer of balls are red the other is blue.
• This is so the camera underneath can determine
  the depth.

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How does it work?

• When the user presses on the pad the gel conforms
  to users touch.
• This action causes the embedded markers to shift
  from their original location.
• This is viewed by the CCD camera below, which
  streams the information to a computer.
• The computer tracks the changing states of the
  markers and uses elastic theory to calculate
  movement of the markers.

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How does it work?(cont)

• The camera sees the markers as they 2
  dimensionally shift away from the center of
  depression.
• The computer calculates the center which provides
  the x,y for the action.
• The separation of the markers on the 2 layers
  tells the computer how hard the gel was pressed
  (or the z).

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Internal Calculations

• The computer knows the initial state of the
  markers in the gel.
• Once the gel is pressed this information is used
  along with the magnitude of the directional shift
  to create a matrix.
• This matrix is what creates the computer print
  out of force vectors.

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Why this design?

• The designers desired 3-dimensional force
  vectors, but the movement of markers captured by
  a CCD camera is 2-dimensional.
• If only one layer of markers is prepared, only
  the magnitude of force can be measured with
  accuracy, otherwise two cameras (for stereoscopic
  vision) would be necessary to measure the
  3-dimensional movement. Using an additional
  camera would bring about calibration and space
  problems. These issues would make scaling the
  sensor unrealistic in practical applications.
• To solve this problem, they used two layers of
  markers at different depths. Using the two layers
  is the same as measuring 2 times 2 dimensional
  movement of markers. This provides sufficient
  measurement to obtain a force vector.

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Sensor Characteristics
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Sensor Characteristics
Cylinder Experiment

• Setup
• 5mm diameter cylinder
• 910g Force
• Radial variation is generated around the force
  application point
• The force vectors are observed in the x y plane
  and in 3D space

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Sensor Characteristics
This graphs shows a simulation of both the red
and blue markers.

• Setup
• Given a force distribution
• 100g force in z-direction
• 50g force in y-direction
• Error added to the movement vectors
• Mean 0 pixel
• Standard Deviation 0.1 pixel

Conclusion The difference between the two layers
of markers needs to be between 2mm and 3mm
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Sensor Characteristics
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Sensor Characteristics

• Computational time
• Equipment used
• 1.8GHz Intel P4 processor
• Windows 2000
• Accuracy 10µsec
• Computational time was calculated 300 times
• Time to obtain forces 2.9 msec
• Time untilled displayed 1.9 msec

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Joystickless Demand

• Construction, Maintenance, and Mining Equipment
• Wheel Chair, Robotic arm, and Receiver Dish
  control

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Joystickless Competitors

• None that operate in the same way or provide the
  same type of control
• Conventional Joysticks use switches,
  potentiometers, or optics translate direction

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What is the Joystickless?

• Allows operator simultaneous control of direction
  and speed
• Two Possible Setups
• With D-Pad or Joystick
• Easier transition
• Sensor Protection
• W/out D-Pad or Joystick
• Greater Flexibility
• Quicker RT
• Multiple Operation Options

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Joystickless Benefits to Society

• Simple design allows for more operational time
  and less downtime due to repairs
• Allows for more accurate control of equipment
• Comparable installation ease to conventional
  joysticks.

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GelForce Sensor JoysticklessPotential Profit
Cost To Produce

• 50 to 100 CCD Camera
• 20.00 Gel Markers
• 25.00 Housing D-Pad Controller
• 20.00 Wiring Misc.
• 165.00 Total Cost
• 200 Selling Price
• 35.00 Profit/Unit

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Questions/Comments
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