Design of an Index Finger Force Amplification Exoskeleton

1
Design of an Index Finger Force Amplification
Exoskeleton

• Alex Birdwell
• Aaron Ferber

2
Objective

• Design and construct an
• index finger exoskeleton to
• assist in the movement of
• the proximal joint.

3
Design Concept
4
Design Components
Frame constructed of steel conduit Set Screws
Pin joints Set Screws Mechanical stops
Flex Sensors Detect users desire for
motion Brushed DC Motor Controls joint
rotation
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Flex Sensor

• Change in curvature yields a change in
  resistance
• Neutral position (flat) is 100 kO
• Small deflections (10º) yield 5 kO change

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Flex Sensor
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Motor Selection Criteria

• Easiest to use small brushed DC-motor
• High gear ratio vs. direct drive (no gearing)
• High ratio will yield speed control, but not
  torque control (always high torque)
• Direct drive will yield better torque control,
  but at a lower torque output
• Overall maximum torque output
• Size

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High Gear Ratio Motor
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Other brushed DC-motors
direct drive
low gearing, high torque
high gear, high torque
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Status and Issues

• Status
• Tested flex sensors
• Working to dimension frame

• Issues
• Motor selection
• Torque control vs.speed control
• Motor connection