之前看到过一篇文章，分析了Toyouta的Camery车型所发生的突然加速导致的交通事故中，几位嵌入式系统专家对原因进行的分析的文章，看了之后颇多感慨，一直想找到原文看看，不可得，只找到了这个大概报道。
Embedded Expert: No Pedal Misapplication in Toyota Case
Charles Murray, Senior Technical Editor, Electronics Test
11/8/2013 31 comments
The Toyota unintended acceleration case decided by a jury two weeks ago may have hinged on the testimony of an embedded systems expert who definitively said there was no pedal misapplication. Michael Barr, CTO and co-founder ofBarr Group, told the court that the fatal accident involving a 2005 Toyota Camry was the result of a systematic software malfunction, combined with a loss of throttle control.
”The dispute in this case is related to computer software and hardware,” J. Cole Portis, attorney for the plaintiffs, said in a summation argument obtained by Design News. “That is what we have talked about; that is the issue in the case…”
The highly publicized case involved a 76-year-old driver who exited an Oklahoma freeway, sped down an off-ramp, and crashed her car. The driver was seriously injured, and her passenger died. The crash occurred in 2007, years before the Toyota “unintended acceleration” incidents became national news.
Toyota argued that the incident was caused by pedal misapplication -- in other words, the driver pushed on the accelerator when she should have stepped on the brake. The 2005 Camry did not have a black box onboard to record the driver’s actions prior to the accident.
Barr, who worked on behalf of the plaintiffs, told the court that he hunted through hundreds of thousands of lines of Toyota’s software code, spending approximately 15 months and 2,000 hours in the process. He wrote an 800-page report. He was one of a dozen engineers designated by the court to examine the car’s embedded computer system. His testimony did not rely on any previous unintended acceleration theories involving loose floor mats, sticky accelerator pedals, or so-called "tin whiskers." Instead, it drilled down into the software code, making the case that Toyota’s software “failsafes” had holes in them, which led to a system malfunction. ”The failsafes that they have contain defects or gaps,” Barr said in sworn testimony. He added that the Camry’s safety architecture was “a house of cards.”
The failsafes were significant to the case because such systems are put in place by engineers to intercede if the engine’s throttle-by-wire control is lost. Barr argued, however, that the failsafes were constructed in a way that might cause them to be unsuccessful in such a situation. ”It is possible for a large percentage of the failsafes to be disabled at the same time that throttle control is lost,” he testified.
Barr’s position seemed to fly in the face of earlier statements made by former Secretary of Transportation, Ray LaHood, in February 2011. “We enlisted the best and the brightest engineers to study Toyota’s electronics systems, and the verdict is in,” LaHood was widely quoted as saying back then. “There is no electronic-based cause for unintended high-speed acceleration in Toyotas. Period.”
Barr argued, however, that NASA scientists who studied the Toyotas had left the door open for other, unexamined possibilities, saying they couldn’t rule out the existence of a systematic software malfunction.
During the trial, Barr told defense attorneys that dynamometer tests had shown that Toyota's built-in failsafes had "gaps" in them. Moreover, he said, skid marks at the accident scene were not compatible with pedal misapplication, pedal entrapment was not an issue, and the vehicle had been inspected a dozen times for mechanical problems, such as throttle blockages. As a result, he concluded that it was more likely than not that a software malfunction had caused the throttle problem
When a Toyota defense attorney suggested that the accident could be explained by a simple pedal misapplication, Barr responded, "No, it cannot," according to court transcripts.
After a number of unintended acceleration cases came to light in the media during the past three years, the National Highway Traffic Administration stepped in and proposed a standard for a “brake-throttle override” system that would shut down the throttle in rare cases of unintended acceleration. Manufacturers enthusiastically supported the creation of a standard. Toyota did not have such a system on the 2005 Camry in the Oklahoma case, however.
Jurors in the case awarded $1.5 million to the driver and $1.5 million to the family of the passenger who died in the crash. A subsequent private settlement was reached to head off further punitive damages.
During the trial, Barr argued that Toyota could have easily saved itself all its troubles by implementing a brake-throttle override system. “It would have been very simple…” Barr said in testimony. “Toyota could have done this in 2002 without any extra cost to the vehicle.”
转载于:https://my.oschina.net/drjones/blog/176913