Crane Tether Mechanism Cole Perrault Spring 2016 ET

Crane Tether Mechanism Cole Perrault Spring 2016 ET 493 Dr. Cris Koutsougeras

Problem � Certain work environment's may be prone to slips, trips and falls. � Releasing � Current � Personnel systems use mechanical means to automatically lock. the lock may be difficult after an STF. may get suspension trauma.

Hardware � Solenoid � Seatbelt Tether � Accelerometer � Arduino � Zig. Bee Modules � Encoder

Solenoid � Requires NPN Transistor TIP 120 � Diode for current protection � 12 -24 V up to 6 A

Encoder � Use of Arduino external interrupts � Implements function at each interrupt

Methodology Module One to measure slip, trips, falls Module Two � Accelerometer: � Encoder: � Zig. Bee: � Solenoid: to communicate STF values to measure the tethers rotational velocity to lock/unlock the tether � Zig. Bee: to communicate STF values

Flow Chart Encoder Input Accelerometer Input Velocity Conversions Set point STF Lock Tether

Encoder

Velocity � First order approximation with preset time interval � Encoder to return position based on four different possible states

Angular Velocity � Angular_Velocity() will be executed on interval � Solenoid state determined from STF and RPM set point

Angular Velocity � Determine if we are extending the tether � Determine If we are reading encoder pulses � Calculating RPM

Linear Velocity � Scale is linear correlation of voltage offset for each -/+ g felt by sensor � If free fall is detected send true value

Prototype Improvements � Addition of “super positon” sensors. � Determine for STF pattern � Use of multiple sensors � Implementation boon sweeping of

Crane Tether Mechanism Cole Perrault Spring 2016 ET 493 Ho-Hoon Lee Cris Koutsougeras