Who& s Afraid Of Electric Power Steering? The Truth About Cars

6 Июн 2014 | Author: | Комментарии к записи Who& s Afraid Of Electric Power Steering? The Truth About Cars отключены
SMART ed cabrio Electric Cars

Who s Afraid Of Electric Power

Here s a challenge: try to find a of the Toyota Corolla that t bemoan its numb steering. Now try a Chevy Cobalt. Or a Venza, or Or Rav4, or Equinox.

What do vehicles have in common? electric power steering from JTEKT. a Toyota supplier which has done a business in these fun-eliminating systems. And though the motor has been bashing electric assist steering (EPAS or for its deleterious effect on handling, the growth in these systems may put at risk than mere steering feel.

This of steering systems has not taken because manufacturers appreciate the of words like numb and in reviews of their products. EPS improved efficiency due to its reduction of losses, and is cheaper to manufacture traditional hydraulic systems. killer combination offers a combination of improvements that proven near-impossible to resist, in the broad proliferation of EPS systems.

And if steering feel were the casualty of the switch, it would be a that any manufacturer would be to run.

But as EPS has exploded onto the a number of troubling issues has the system. The National Highway Safety Administration has opened into the Chevy Cobalt and Corolla. which share the JTEKT EPS system. Cobalt, moved to an EPS system for the 2005 year has been haunted by an number of failures since the while the Corolla investigation on Corollas built since the model-year switch to EPS.

In both of these vehicles, down exact steering is proving to be difficult. Many of the complaints are related to sudden particularly at speeds above 40 The Cobalt, meanwhile, seems to complete EPS failure, causing loss of steering and/or the for drastically increased steering

Again, the inability to stay in a set lane is being targeted as the dangerous symptom of the possible

These symptoms fit conveniently a category that an early (by Amit Rohidas Bendale of the Institute of Technology, publication unknown) on EPAS technology at college-seminars.com calls auto a term the paper asserts has into the lexicon as an adjunct to the of EPAS system. Bendale to explain this phenomenon in his s section on the disadvantages of EPS thusly:

technical and product liability have precluded the introduction of systems in the U.S. market it is expected that niche may be expected in the near-to-mid term mix of vehicles. Such system have yet to prove themselves reliable and safe to prevent “auto steer” events. steer” has crept into the as an adjunct to the development of EPAS As the name implies “auto denotes an uncontrolled steering neither commanded nor stoppable by the driver due to catastrophic failure in the hardware or software. In truth, systems are control servo similar in function to aircraft servo systems, and must multiple redundancy. Although new EPAS systems are said to multiple redundancy. their and broad application within the industry have been, and continue to be, subject to economic more extreme then in the aircraft industry.

For instance one obvious safety item has been universally from such system a clutch for physically disengaging the gear box and drive motor assembly from the host system in the event of system This means that a encountering an EPAS system will have to exert force to “back drive” manually over ride) the reduction gear box and drive assist assembly while to maintain control of the vehicle in the of normal power steering

Already, the parallels between EPS issues (which are admittedly but reflect NHTSA complaints) and s gas pedal issues are plain to The first is the issue of economic towards cost-cutting, which to the reduction of fail-safes and redundancy. parallel is the fragility of by-wire systems: in Toyota gas pedals, amounts of moisture was enough to the pedals to stick.

In the case of EPS steering, there s to suggest that even phone interference could system failure. This is not to say these two situations are directly but both cases indicate earlier mechanical systems few clues as to possible malfunctions of systems. Finally, the most parallel between Toyota s acceleration and EPS unintended veering is the dynamic between the driver and the at the moment of malfunction or failure. continues:

Unlike the manual described above, PAS with the of supplementary steering force to provided solely by the operator additional engineering challenges in of maintaining the desired steering described previously. In fact, respect to steering linearity, a designed power steering system may have almost no between the hand wheel applied by the operator and the actual steering force imposed by the or tires. There no longer may the uniform, consistent and predictable between the “input and outputs” to “tactile reference driving.” the tactile sense of the driver to directional control, and the magnitude and of the “input” force may not bear a proportional relationship to the required force delivered by the steering Tactile reference steering is not possible with such Rather their drivers continuously engage in “visual steering” to maintain directional

The result is that such are very tiring to drive for any of time or distance. Further drivers are constrained to continuously at the road. If such driver look away even (i.e. to check a rearview or a child in the car), he or she has minimal reference as to the actual position of the during that period of

SMART ed cabrio Electric Cars

This is dangerous because, upon the road topography and the vehicle may have moved in significant amount relative to the driver thought his or her vehicle was This can and often does to serious trouble.

This explain the varying accounts of veering, as the ability to handle changes in steering response greatly from driver to Like unintended acceleration, makes the task of narrowing the primary causes of EPS failure or impossible based on recorded alone.

More importantly, helps explain the link numb, overboosted and uncommunicative and safety. At highway speeds, any or malfunction would be registered and to by touch (tactile feedback) the brain would be able to visual cues that control has been compromised. of EPS s deficits in tactile feedback, and between wheel and steering positions, that all-important tactile feedback would be difficult for even a well-trained to interpret, making a crash likely even if the unassisted system were still (as has been reported in certain incidents).

This is clearly an issue companies like JTEKT known about, as a 2008 on EPS [PDF ] by a JTEKT engineer that making EPS feel the hydraulic systems the buying is used to has been a major Another paper from the Engineering Journal [PDF ] that on higher-power versions of EPS,

sensitivity to such inputs as flutter and brake has become higher. J-ISM EPS assist control algorithm] has a suppression system that can inverse input vibration as differentiation value, and by providing in the direction of canceling the vibration, the is not transmitted to the steering wheel.

In tactile feedback is actively not only reducing the driver s to respond to an emergency based on feel, but also further the EPS system with compensation in addition to pure steering

The point of all this is not to merely unwarranted fears about Improved efficiency and lower are the very definition of a successful system, and as long as EPS offers benefits, its use will continue to As this trend continues, it be important for safety watchdogs to pay attention to these systems. pressure to include redundancy, and extremely robust sensor suppliers will continue to cut the of these systems to remain with the growing number of that offer similar Just as importantly, these new systems require a new approach to that pays as much to driver reaction to malfunctions as to the themselves.

Only in this way can we be sure relatively minor malfunctions don t an epidemic of inexplicable accidents and

SMART ed cabrio Electric Cars
SMART ed cabrio Electric Cars
SMART ed cabrio Electric Cars
SMART ed cabrio Electric Cars
SMART ed cabrio Electric Cars
SMART ed cabrio Electric Cars
SMART ed cabrio Electric Cars

Interesting articles

Other articles of the category "SMART":

Our partners
Follow us
Contact us
Our contacts



About this site

For all questions about advertising, please contact listed on the site.

Catalog ALL Electric Cars and hybrid/ News and Information about Electric Car and Electric Vehicle Technologies, batteries for vehicle catalog with specifications, pictures, ratings, reviews and discusssions about Electric and Hybrid cars - Green energy