Automated Data Acquisition for an Infrared SpectrometerLauren Foster 1, Obadiah Kegege 2, and Alan Mantooth 2,3

1 Manhattan College, Bronx, NY,2 Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR.

3 Department of Electrical Engineering, University of Arkansas, Fayetteville, AR.

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Calibration• Software calibration done such that the sensor is balanced at a

given reference value

• Output scaling done from the HMI tag formulas

Automated Integrated System

Inputs: • Force (sensor) (analog input or AI)

• Depth (sensor) (AI)

• Up (sensor) (digital input or DI)

• Down (sensor) (DI)

• Data Acquisition Confirmation (DI)

Outputs: • Insertion and removal of probe (AO)• Motor direction (digital output or DO)• Trigger Data Acquisition (DO)• Brake the Motor (DO)• Sensor Excitation (analog output or AO)

Spectrometer on Rover

Spectrometer on Rover

GEPLC

Position/Force/SpeedTransducers

Desired position/ Force/speed

Position

Force

Motor

Feedback loops

Speed

Schedule Data Acq.

Control of Speed and Force of the Probe

For feedback controls:

HMI (Human to Machine Interface)

•Automated System controlling:

- insertion, withdrawal, and data acquisition

fiber optics to IR module

window overthe fiber optic illuminate and sense elements

PLC

Analog Sensor Interface• Analog sensors:

- Force, Depth, Speed

• Example:

- Wheatstone bridge is very common for design

• The circuit is balanced if Ssensor _ Vout = 0

• Where Rsensor is the resistance of an analog sensor at reference voltage

Objectives• Design, assemble and program all electrical and

mechanical parts of the automated control system

• Produce an OPRA prototype to acquire IR (infrared) data for spectrometer on a robotic arm or rover

Background of Research• OPRA

- “Optical Probe for Regolith Analysis”

• A NASA funded project currently under development by the University of Arkansas

• Current data:

- Obtained manually

- Insertion & withdrawal of a probe

in regolith (loose soil and rock)

- Data acquisition

• Future data:

- Obtained from an automated control system

- Acquire, store and analyze data

- From infrared spectrometer on a robotic arm or rover

Operating Procedure• The operator specifies operating mode:

- (1) Constant Velocity

- (2) Constant Force

• Press “start data acquisition”

• System will create relationship between:

- Regolith Strength vs. Depth

• Obtain IR data:– (1) Constant Velocity Mode:

- Probe is inserted at constant speed

to a designated depth

- Penetration Force vs. Depth recorded

- IR data taken

– (2) Constant Force Mode:

- Probe is inserted at constant force

- Probe inserted until balanced by the resistance

strength from the regolith.

- Penetration Depth vs. Time recorded

- IR data takenData Storage and Plotting

• Computer:- Force and depth data stored

- Data plotted for analysis

• IR data stored by onboard spectrometer

Conclusions• The automated system will be very helpful for

IR data acquisition, plotting, and analysis

• It will also help to characterize strength of regolith at each depth

Acknowledgements• I would like to offer my thanks to all individuals who

advised me, especially my fellow participants in the OPRA project. It is an honor to be part of a project that may one day find its way to the Moon or Mars.

References1. Ulrich et al. (2006). “Fiber Optic Spectral Array on a

Regolith Probe for Surface and Sub-Surface Mineralogical Profiling: Optical Probe for Regolith Analysis”, Arkansas Center for Space & Planetary Sciences, University of Arkansas

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