01 February 2003
Learning on the road
Sensory and data acquisition technology moves information collection from factory to the road.
By Matthew Lamoreaux
Since the onset of mass-produced automobiles, auto manufacturers have tested the endurance and failures of individual components and whole cars.
But traditional testing techniques are time-consuming, expensive, and limited to a simulated environment that cannot replace real-world road tests.
With increasing market pressure to reduce product development time and expense, auto manufacturers have begun moving data collection from the shop to the road. And these new data collection techniques promise to improve both the quality and safety of automobiles in years to come.
They also provide permanent data recording capabilities that could have unprecedented influence on crash investigations and even crime investigations involving automobiles.
EQUIPMENT DURABILITY FAILURE
For automobile manufacturers, the reliability of their systems is a major concern. Recent advancements such as telemetry, wireless computing and data transmission, and the ability to tap into onboard controller area network (CAN) bus systems greatly reduce and simplify sensor requirements, according to a Society of Automotive Engineers paper by Bob Davis and Jon Garner of HBM, Inc., a manufacturer of mobile automotive data acquisition systems.
In today's CAN bus networked automobiles, a data acquisition system can use inputs from permanent sensors for engine speed, oil and engine temperatures, oil pressure and consumption, and current and voltage throughout the vehicle electrical system.
Additional types of sensors, including torque and pressure transducers, provide a variety of specialized measurements to meet specific engineering requirements.
Microelectromechanical systems accel er ometers are also becoming widely used, due to their small size and high level of sophistication. Custom-mounted strain gauges offer inexpensive, reliable solutions for tight areas and special applications that would preclude the use of typical packaged sensors.
A basic mobile data acquisition system offered by HBM provides a choice of single- to 8-input modules (maximum of 128 channels per housing). The system can have its own Ethernet address, just like a conventional office network.
A more advanced system reads data from a global positioning satellite receiver and enables test engineers to precisely assign the measured quantities recorded in the vehicle to the traveled route.
OBJECTIVELY IDENTIFY DRIVERS
Test engineers are not the only users of onboard data acquisition systems. Black box data recorders are becoming increasingly popular as a driver monitoring tool for fleets of commercial and emergency vehicles.
Such systems count events such as excessive speed or acceleration, slamming on the brakes, and quick turns that are normally associated with accidents or near misses.
One such system manufactured by Thousand Oaks, Calif.-based Road Safety International, Inc. rates drivers on a score derived from average (miles) between counts (ABCs). The system's on board computer transmits data via a wireless radio transceiver to the system administrator's desktop computer.
Database reports allow the administrator to look at all vehicle and driver information, including the driver's ABC performance individually or in comparison to others.
Data collected from these systems allows fleet operators to objectively identify which drivers should undergo additional safety or defensive driving training, hopefully before an accident occurs.
This preventive strategy promises to save companies money on insurance premiums, deductibles, and downtime resulting from accidents. But most importantly, it prevents injuries and loss of life.
RECORD CRASH EVENT DATA
More than 6 million traffic accidents are reported annually in the U.S., resulting in a cost of $150.5 billion. In many cases, having a permanent record of a crash event can be an invaluable asset in determining the cause of the accident.
To meet this need, some vehicle owners are installing crash cameras. San Francisco-based DriveCam Systems Inc. offers the DriveCam video event data recorder.
This palm-sized video recorder mounts behind a vehicle's rearview mirror. The device monitors driving activity by continuously recording video, audio, and four directions of g forces into a digital looping memory. The recorder saves events activated by g forces resulting from hard braking, rapid acceleration, harsh cornering, or collisions. Drivers can also manually activate the recorder.
But accessible data recorders may soon become standard equipment on most cars. According to Russell Lindsay, principal engineer at Asheville, N.C.-based PARC Engineering Associates, many newer cars actually do have something close to a black box.
SENSE DIAGNOSTIC MODULE
General Motors (GM) installed sophisticated crash data recorders on Indy cars in the early 1990s, said Lindsay. While still impractical in production cars, these early devices provided valuable information on human tolerance to collision forces.
In the mid-1990s, GM cars with air bags were equipped with a solid-state accelerometer in the sensing and diagnostic module (SDM) that stored the change in longitudinal vehicle velocity (delta V) during an impact. Newer GM vehicles record data such as wheel speed, engine revolutions per minute (rpm), throttle position, and brake switch status at the time of a deployment or near deployment of the air bag system.
With the proper equipment, electronic data can extract from the SDM and various other electronic devices in a car after a collision. Santa Barbara, Calif.-based Vetronix Corp. makes one such crash data retrieval device that will extract crash data from the SDM of most GM cars for the 2000 model year or later.
Ford and DaimlerChrysler also have recorders similar to GM's SDM in their newer cars, but as of the writing of this article, the data is not readily retrievable.
Most heavy trucks now record vehicle parameters in the engine electronic control module (ECM), said Lindsay. The ECM records engine rpm, wheel speed, throttle, and brake conditions.
GREATER MANUFACTURING VALUE
The rapid advancement of sensory and data acquisition technology has made it possible for auto manufactures to collect more and more data on the road, reducing labor and equipment costs in manufacturing test facilities.
As these technologies mature, the cost of acquiring data will come down, leading to greater efficiencies in the auto manufacturing process.
The possibilities for putting such data to good use are endless. We can expect cars to become more reliable and cheaper to maintain. At the same time, much like the PC, automobiles will increasingly record many aspects of people's daily lives, giving rise to privacy concerns. Yet this same data could be very useful to law enforcement, especially as global positioning technol ogy more commonly integrates with onboard automotive systems. IT
Behind the byline
Matthew Lamoreaux is a freelance writer who covers the instrumentation and automation market. Contact him at firstname.lastname@example.org.