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The Equations of Motion. Euler angle rate equations:. Sensors. Acceleration Measurement ADXL105EM-3 (Triple axis accelerometer) Range = ± 4g Sensitivity ~ 500mv/g Operating Voltage = 5 V DC. Rate Measurement Microgyro 100 (Dual axis rate gyroscope) Range = ± 100°/sec
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The Equations of Motion • Euler angle rate equations:
Sensors • Acceleration Measurement • ADXL105EM-3 (Triple axis accelerometer) • Range = ± 4g • Sensitivity ~ 500mv/g • Operating Voltage = 5 V DC • Rate Measurement • Microgyro 100 (Dual axis rate gyroscope) • Range = ± 100°/sec • Sensitivity = 1.1 x 10-3 mV/ degree / sec • Operating Voltage = 5 V DC
Electronics • TFX -11 (DATA LOGGER AND ADC) • 12 bit ADC • Non-Hold and Sample type • 11 12-bit channels and 8 8-bit channels • Operation Voltage = 0~5 V • 24 Digital I/O ports • 512 K Data storage memory (SFLASH) • Other Electronics Used • Salen-Key Filter (Low Pass) - 5 Hz • Non-Inverting Amplifier to increase sensitivity of rate gyros
Accelerometer Salen-Key filter 12 bit ADC Data logger ( TFX-11) Integration Routines Gyroscope Amplifier Trajectory INS System Description
Sensitivities, Ranges and Calibrations • Acceleration Measurement • Sensitivity : - 1 g corresponds to around 500 mV • ± 4g is mapped 0.5 ~ 4.5 V (for mean = 2.5 V) • Rate Measurement • Sensitivity : - 1 degree/sec corresponds to 1.1 mV • ± 100°/sec is mapped to a band of 220 mV about mean Operable region by data logger constraint = 0 ~ +5 V
Quantization and resolution error simulation. Sensor Model Noise Model Calibration Integration Routines Mean by Averaging Stationary data Trajectory Simulation Structure INPUTS ax , ay , az p , q , r
Effect of Resolution Amplification of rates = 20 Amplification of accel. = 1 All the parameters set to 0
Proposed Changes • Amplification of rate sensor signals by around 20. • Amplification of accelerometer signal by around 2.5 • Increasing resolution of ADC from 12-bit to 16-bit
REALIZATION • Stepping down to zero. Can it be done accurately? • Amplification. Will it add noise? • Possibility of alteration of accelerometer range online. • Other problems or aspects.