Question: How many point locations in a typical scene?
Answer: At minimum, 12 points or nodes would be monitored; however, capability to acquire 3D dynamic data at higher densities is very desirable.
Question: How much time does the typical crash take?
Answer: 150-175 ms
Question: What is the maximum time that must be recorded during a crash?
Answer: 350 ms
Question: Will we be tracking point locations or objects?
Answer: Either, depending upon technology proposed and consistent with the requirement that the intruding surface be accurately mapped.
Question: Any statistics of the typical vibration (frequencies and amplitudes), impact forces, and shock experienced by the in vehicle monitoring equipment?
Answer: Please see the attached Excel spreadsheet for typical acceleration data at floorpan and vehicle cg locations, from offset crash tests of two vehicles.
Note: acceleration is given in g units, time in seconds.
offsetaccel.xls(1.56mb)
Question: What system is currently used to monitor objects inside the vehicle during a collision?
Answer: Mechanical measurements; e.g., string potentiometers.
Question: Is there a spec sheet or white paper on the currently used technology?
Answer: No.
Question: Is there a physical space limitation for the sensor and associated data capture devices. If so, what is it?
Answer: For the case of measurement of dynamic floorpan intrusion, and if a vehicle seat must be removed to accommodate the measurement system, the system should occupy no more vehicle floor space than was previously occupied by the seat assembly. In this case, system form factor and mass should be controlled so as to utilize existing vehicle seat track hardware for mounting purposes. In addition, minimal alteration of vehicle c.g. is desirable.
Question: The 2 to 3 inch surface spacing of points is very coarse. Are you interested in being able to manually place markers at points of interest with that spacing, or are you interested in a evenly spaced grid of points?
Answer: Tracking of either markers placed on the surface or grid nodes would be acceptable, depending upon the technology proposed and consistent with the guiding requirement that the intruding surface be accurately mapped. At minimum, our requirement is to track a minimum of 12 points or nodes; however, capability to acquire 3D dynamic data at higher spatial densities is very desirable.
Question: Could the grid or markers be placed on the surface(s) of interest or would it be better if the pattern was projected onto the surface?
Answer: We do not have a preconceived preference with regard to technical approach.
Question: Orientation of the X and Z axis?
Answer: The information on coordinate system used by NHTSA is in the following document (page 71) located in the NHTSA website http://www-nrd.nhtsa.dot.gov/pdf/software/vehdb_v5.pdf Positive x axis is along the longitudinal axis of the vehicle (back to front). Positive z axis is along the vertical axis (top to bottom) of the vehicle.
Question: What is the significance of t=0.0 sec as the accelerometers appear to have started measuring significant g's before that point on the '96 Toyota Camry?
Answer: t=0 is established via a contact switch at the front bumper of the vehicle. Occasionally, a small delay may occur due to switch placement or variability in contact.
SOLICITATIONS