Sensors are everywhere...
...running to the order of many, many billions of devices inside of millions of applications from autonomous vehicles to medical devices to aircraft. Over many years, a tiny percentage of the total number of sensors have failed, leading in some cases to loss of life and resulting fallout with government inquiries, lawsuits and an overall public relations nightmare for all the parties involved.
When a bunch of sensors are not to blame
Sometimes the failures of sensor-equipped devices are not the fault of the sensors that operate within a sophisticated computerized system. That’s apparently the case with Waymo robotaxis seen illegally passing stopped school buses with red lights flashing, stop arms extended and filled with children. The infractions, at least 19 of them, were sometimes recorded by cameras mounted on school buses in the Austin (Texas) Independent School District. An investigation by the National Highway Traffic Safety Administration is underway.
Waymo told ABC News the robotaxi infractions were the result of a software problem that was quickly addressed with a software update. “I don’t think people should expect perfection,” Vishay Nihalani, director of product management operation for Waymo, told ABC News. “What’s really important, though, is that we’re learning from all the different scenarios that we encounter.”
In a statement provided to Fierce Sensors, Waymo said it believes the software updates implemented by Nov. 17 “have meaningfully improved performance to a level better than human drivers in this important area. We will continue to track and implement more updates as needed and we are committed to continuous improvement.”
As a point of reference: Waymo robotaxis have plenty of sensors, with 32 external sensors on their 5th generation vehicles, consisting of 29 cameras, 5 lidars, and 6 radars. The 6th generation Waymo vehicles are more streamlined, with 13 cameras, 4 lidars, and 6 radars, plus external audio receivers. The cameras provide 360-degree vision, while the lidars are for depth perception, mainly, and the radars detect an object’s distance and speed.
Perhaps, only perhaps, the software problem with the school buses related to how an optical sensor that detected a stop sign on the side of a school bus was misinterpreted by the connected software: Could it have been seen as a stop sign on an intersecting street that could be ignored or perhaps a sign angled awkwardly? This is the kind of question an NHTSA investigation might address. NHTSA started addressing Waymo vehicle behavior near school buses in October stemming from a similar infraction in Georgia.
Waymo has 1,500 robotaxis in major US cities and had surpassed 100 million miles of autonomous driving as of July. Many of the trips are handled without a hiccup, as I discovered on a short trip to the grocery store a year ago in Phoenix.
What about medical devices?
A recent case involving suspected faulty sensors shows how serious things can get, even causing deaths. Abbott announced in November it is replacing some of its FreeStyle Libre 3 continuous glucose monitors following reports of hundreds of injuries and seven deaths worldwide.
Some sensors showed they may provide incorrect readings that could prompt users to skip insulin doses.
The company traced the problem to a manufacturing defect linked to a single production line of 3 million Libre 3 and Libre 3 Plus CGMs distributed in the US, although half have either passed their expiration date or have been used by patients.
The company received reports of 736 severe complications potentially associated with the problem with 57 in the US and seven deaths outside the US. Fierce Medtech reported Abbott's announcement in November.
Abbott has referred customers to a website that describes the sensor concern and a link to verify if a customer’s serial number is among those products affected.
As an illustration of how complex the fallout from a sensor failure might be, the US FDA will take comments while Abbott is taking questions via live chat and phone at 833-815-4273.
Abbott made the announcement Nov. 24, and the FDA issued an Early Alert on Dec. 2.
Abbott would not comment when asked by Fierce about why some sensors appear to have provided incorrect low glucose readings or what actions it is taking into the cause.
The Boeing 737 Max crashes and that errant angle-of-attack sensor
Boeing has spent years trying to recover from two fatal crashes of its 737 Max aircraft that killed 346 people in 2018 and 2019, the first diving into the Java Sea and the second into the ground in Ethiopia.
A faulty angle-of-attack sensor was quickly blamed for sending false information to the Max’s software system which pushed the nose of the aircraft down when it sensed an imminent stall. That led pilots to frantically try to make corrections before they crashed in both disasters.
A former National Transportation Safety Board managing director described the AOA sensor as a “fairly simple external device that can get damaged on a regular basis” which was important because Boeing had relied on the AOA as a single source for streams of data.
In years following the crashes, Boeing corrected the MCAS software to not rely on a message from a single, possibly faulty, AOA in order to make automated adjustments to the aircraft’s guidance. Ethiopian government officials had said the malfunctioning AOA sensor on Ethiopian Airlines flight 302 fed false data to the MCAS, which forced, repeatedly, the nose of the plane down as pilots fought to regain control.
So, obviously, properly scripted software can be written to handle the eventuality of damaged sensors, if engineers recognize that the damage or malfunction of a single sensor can be predicted.
While each of these three cases if very different, they show how integral sensors are to modern systems and applications. Without sensors, none of these applications would have come into existence, although they are part of a much larger system where other components can fail.
In the case of Waymo, an abundance of sensors has not prevented problems in software. In the case of the Abbott glucose monitors, it is not clear how much a faulty sensor could have been corrected by software oversight or even diligence by patients wearing the monitors. And with the Boeing Max, well, those planes are still flying with multiple corrections to software and hardware alike.
The financial fallout for the 737 Max crisis has been massive, not to mention the impact on Boeing’s reputation. Total overall losses are put at $35 billion since 2019, including direct losses related to production shutdowns, compensation to airline and legals fees. Some victims’ families have sued and one family won a $28 million in a jury award in late July, according to various sources including Simple Flying.
In each case, Boeing, Abbott and Waymo have expended tremendous time and resources to catch the problems and make adjustments or corrections. You might say these flubs and even disasters are what engineering projects require to achieve progress. Or, some engineers will ask: How can these problems be avoided in the first place?