Automated Data Acquisition for an Infrared Spectrometer Lauren 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. R _sensor R2R2 R3R3 R4R4 Inside Sensor DC input + DC input - Sensor out + Sensor out - PLC Terminal and 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 GE PLC Position/ Force/Speed Transducers 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 over the 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 S sensor _ V out = 0 Where R sensor 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 taken Data 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. References 1.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 Motor