Navigation Module
The Navigation Module (NM) is an electronic schematic board, designed to supply recent changes in physical position and orientation of the Robot based on information, supplied by inertial MEMS sensors.
<stub_page>
Contents |
Analog sensors
3 axis gyro
Model: SOC Robotics, RG30, Three Axis Rate Gyro.
Sensor: Epson Toyocom XV-3500CB.
Source voltage: 3.3V
Output zero level: 1.75 V
Output range after amplification: 1.75 V ± 1.47 V = [0.28V min; 3.22V max]
Measurement range: ±100 deg/sec = ±1.745329252 radians/sec
Frequency response: 200 Hz (90 deg delay)
Temperature range: -20 .. +80 °C
Current consumption: 6.0 mA max
Dimensions: 2.54 cm x 2.463 cm = [1.00 x 0.97 in]
Weight: 8 grams
Usable calculations
- Gyro signal:
- 1.47V = 100 [deg/s] => 0.0147 [V] = 1 [deg/s]
- 1 [rad] = 180/PI [deg] => 0.0147 [V]* 180 [deg] / PI [rad] = 0.84224796[V] = 1 [rad/s]
- 1.0 [V] = 1.187298809 [rad/s]
- ADC conversion:
- ADC model: AD7327 - 12bit + sign @ 500kSPS
- selected range: -5..0..+5V => sign ignored => 0..+5V
- 12bits (sign ignored) = 2^12 LSB = 4096 LSB
- +5V = 4096 LSBs
- 1 [bit LSB] = 4096 [bits LSB] / 5 [V] = 0.001220703 [V]
- 1 [bit LSB] = 0.001220703 [V] * 1.187298809 [(rad/s)/V] = 0.001449339 [rad/s]
- Example:
- Given:
- adc_result = 2192
- adc_zero_offset = {1.65/5 * 4096} = 1352
- sensitivity = 0.001449339 [(rad/s)/bit_LSB]
- Goal:
- rate-?
- Solution:
- delta = adc_result - adc_zero_offset = 2192-1352 = 777 [bits LSBs]
- rate = delta*sensitivity = 777*0.001449339 = 1.126136403 [rad/s]
3 axis accelerometer
Model: Sure Electronics, DC-SS009, Ver 2.0.
Sensor: Freescale Semiconductor MMA7260QT
Source voltage: 3.3V
Output zero level: 1.65 V (typical) = [1.485 V min, 1.815 V max]
Output range: 1.65 V ± 1.2 V = [0.45V min; 2.85V max]
Sensitivity (Range = ±1.5 g): 0.800 V/g. Sensitivity <x,y,z> = <±0.02,±0.01,±0.00> (typical)
Sensitivity (Range = ±2.0 g): 0.600 V/g
Sensitivity (Range = ±4.0 g): 0.300 V/g
Sensitivity (Range = ±6.0 g): 0.200 V/g
Bandwidth response: <x,y,z> = <350 Hz, 350 Hz, 150 Hz>
Internal sampling frequency: 11 KHz
Current consumption: 800 uA max
Temperature range: -40 .. +105 °C
Temperature sensor output deviation (max value): <x,y,z> = <3.8, 5.9, 1.0> mg/°C
Schematic capture
Schematic capture of the Navigation Module
PCB
Two-sided PCB is shown below:
PCB image of the Navigation Module
Device photo
Photo of the completely soldered and mounted Navigation Module
