Archive:Data acquisition system

A data acquisition system is a device designed to measure and log some parameters. The purpose of the data acquisition system is generally the analysis of the logged data and the improvement of the object of measurements. The data acquisition system is normally electronics based, and it is made of hardware and software. The hardware part is made of sensors, cables and electronics components (among which memory is where information are stored). The software part is made of the data acquisition logic and the analysis software (and some other utilities that can be used to configure the logic or to move data from data acquisition memory to a laptop or to a mainframe computer). An example: Data logging, carried out by a data acquisition system (DAS), can be used to measure parameters such as temperature and humidity in storage facilities with perishable products; the measurement data are then stored for analysis to improve quality assurance. Another example: a data acquisition system can be placed on a race car to measure RPM and vehicle speed to analyze car's behaviour once it's back to pits and improve the car setup.

Data logging systems

Data logging systems consist of four elements:

1. Measuring output (sensors around the vehicle)
2. Recording output signals (logger unit)
3. Uploading/accessing recorded data (telemetry)
4. Analysis of recorded data. (DAQ software)

The 4 elements above have specific requirements which need to physically present and included in the design process. Sensors to measure selected parameters must meet certain specifications, and the routing of the sensor cables ensures they will not suffer from electromagnetic interference from other electronic systems. The DAQ unit (including memory) and the link from the DAQ unit to the operating platform to upload the acquired data via a hardwire cable or telemetry also must conform to requirements.

Most race cars use two types of telemetry. The first is sent to the engineers in the pits every time the vehicle acquires more than 50Mb of data, containing an insight into the state of the vehicle. The second is transferred each time the vehicle is in the pit lane, providing information on every part of the vehicle. With the most advanced telemetry, the data are sent constantly for analysis through a transmitter as long as a good connection is present usually through a hovering helicopter (not always possible in parts of certain raceways due to an overpass obstruction).

The operating platform acquisition system are broken into three generic categories, which are also interlinked due to system requirements and the complexity of major components (for example, a wheel speed sensor not only monitors the wheel speed but also the speed of the vehicle, location on the track and an input to traction and launch control systems):

1. Engine: Revs per minute, fuel and oil pressure, water and oil temperature, turbo charger boost pressure, exhaust gas temperature, battery voltage, inlet air temperature and throttle position sensor.
2. Chassis: Wheel speed, steering angle, lateral and longitudinal G-force (applied from braking and cornering), Brake line pressure, damper movement and gear position.
   • Advanced Chassis DAS: Ride height, drive shaft or prop shaft torque, suspension loads, tyre pressure and compound temperature, and brake disk temperature. Optional: aerodynamic parameters, including air speed and local air pressures.
3. Driver: Both engine and chassis-related factors which are controlled by the driver, such as throttle position, gear position, steering angle and brake line pressure or directly controlled parameters such as engine revs per minute, speed and G-force.

The accurate information provided by telemetry sent by DAS in a practice run takes significant fine tuning, such as ensuring the correct gear ratios are present according to track layout, or that the engine acceleration speed according to throttle position and sensitivity is set to the required conditions of a race. The engine control system will be programmed with suitable engine maps giving the driver more control of the throttle input. On a track with a large number of corners, the first part of pedal movement would be made very sensitive in order to effectively negotiate the course. On other courses, however, the vehicle might be required to come out of the chicanes and directly to peak power levels, thus less sensitivity required on the pedal.

The DAS during race time is monitored by engineers in the pit and garage area, who diagnose any faults which may occur. In this case, the DAS is used as an early warning system of potential mechanical failure, allowing the designers and material analysis team to easily distinguish the cause of the fault. This can result in a significant decrease of the danger to a driver.

Race strategists and engineers can use DAS with telemetry in real time for making more informed decisions pertaining to vehicle performance and driver technique. Information about other vehicles on the track can also be captured and added to the data analysis process. Total data from a motor sport event may exceed 80 gigs of storage space. A new technology born from Associate Systems research or artificial intelligence (AI) has increased the safety factor for spectators, drivers, and officials

A good example for critical data acquisition systems in motor sports can be taken from the 2003 British Grand Prix, when engineers in the pits observed the loss of pressure from one of Coulthards tyres. The DAS allowed the team to recall him from his practice, resolving the fault before a dangerous situation occurred, likely saving property and life.

“Formula 1 telemetry is the technological lifeblood of the sport, helping the drivers and engineers to better understand how a car functions and how they can optimise its set-up.”