Aberdeen Test Center. Non-Contact Recoil Measurements Ken McMullen ITEA Conference / Transducer Workshop 10 May 2011

Transcription

1 Aberdeen Test Center Non-Contact Recoil Measurements Ken McMullen ITEA Conference / Transducer Workshop 10 May 2011

2 Half Century of Ballistic Recoil Measurements 1950s Continuous Rotating Potentiometer System 1970s Linear Displacement Transducer System (sliding magnet) String Transducer System 1980s Optical Encoder System (analog version) 1990s - Optical Encoder System (digital version) 2000s - Linear Displacement Transducer System (Penny Giles) 2011s Non-Contact Recoil Measurements Laser Recoil System Recoil Radar System

3 3 Non-Contact Recoil Systems Radar Based System Laser Based System Manufacturer: Tyco Electronics Product: Stereo Doppler Transceiver Manufacturer: LMI Technologies Product: Laser Displacement Sensor

4 4 Radar Recoil System Features: Rugged Die cast Construction IF Bandwidth: 10Hz 5000Hz Size: 26.6mm x 19.6mm x 20.5mm Low Cost: $4k Temperature Range: -40 C to 85 C Easy to use Specifications: Frequency: GHz Output Power: 5.0mW Operating Voltage: 5.0V Operating Current: 85mA Transceiver Sen.: -103dBc

5 5 120mm Abrams Recoil Test Radar Recoil System 120mm M265 Breech Raw Response from Doppler System RD. 154 I Q

6 6 Start Time Software Data Process Full Recoil Time End Time Process: I & Q are acquired as Voltage/Time (automatic) I & Q are validated for proper response (manual) Start, Middle and End times are chosen (manual) Center of the sinusoid is chosen (manual) Zero crossings times are derived (automatic)

7 7 Software Data Process (cont.) Recoil Velocity Full Recoil Velocity = 0 Counter Recoil Velocity Process: Use the Doppler equation to calculate velocity Velocity = Speed of Light * f_doppler / 4 * f_carrier

8 8 Software Data Process (cont.) Max Travel = Improper Baseline Determination Process: Distance is calculated by integrating the velocity curve using trapezoidal approximation A virtual 0V start and end time is inserted for the calculation

9 9 Laser Recoil System SLS 6000 Displacement Laser SLS 6000 Blast with Protection Features: Rugged Construction Automatic Laser Power Control Measurement Range: 1000mm Sample Rate: 16kHz Size: 376mm x 170mm x 70mm Low Cost: $12k Temperature Range: 0 C to 50 C Specifications: Wavelength: 655nm Max Peak Power: 35mW Class 3B Operating Voltage: 18V 32V Operating Current: 350mA Max Cable Length: 100m

10 10 120mm Hard Stand Recoil Test Laser Recoil System SLS 6000 Digital Results Digital Results: Binary Count Analog Results: 0 to 20mA SLS 6000 Analog Output Results 000 Air Blast Effect

11 11 Software Data Process SLS khz Digital Stream Clock Binary Data Digital Stream Expanded Clock Binary Data Process: Clock & Data acquired as voltage/time signals Clock & Data are validated and the Binary Count is compiled

12 12 Software Data Process Peak = SLS 6000 Results Derived Distance (Inches) Peak = Penny Giles Results Linear Displacement Sensor Distance (Inches) Process: Clock & Data acquired as voltage/time signals Clock & Data are validated and the Binary Count is compiled

13 Blast Effect on the SLS 6000 SLS 6000 Digital Output SLS 6000 Analog Output Blast Mitigation: Battery Power Shield SLS6000 Secure Cables Use Digital Output 13

14 Calibration Lab Fixture Calibration fixture with LDT mounted to reflective surface. Calibration fixture with LDT mounted and the SLS 6000 positioned with proper offset. 14

15 Calibration Lab Results Specifications LDT SLS 6000 Radar Max Recoil Distance 450mm 1000mm 1300mm* Min Standoff Distance N/A 500mm N/A 76.2mm Std. Dev. Percent of Reading mm mm 0.25% mm mm 0.10% mm 5.38mm 0.33% Resolution <1.27mm <1.27mm NT Slew Velocity 10m/s max >10m/s >10m/s * Max distance tested NT Not tested 15

16 16 Acknowledgements Software Pete Thompson (ATC) Calibration Saejin Park (ATC) Hardware John Dixon (ATSS)