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Would You Let a Robot Stick You With a Needle?
An anonymous reader writes "IEEE Spectrum has a story about a robot that uses infra red and ultrasound to image veins, picks the one with best bloodflow, and then sticks a needle in. (video included). Veebot started as an undergrad project and the creators are aiming for better performance than a human phlebotimist before going for clinical trials. Robodracula anyone?"
Therac-25 is an example of the dangers of improperly tested computers with lethal equipment.
The Therac-25 was the result of layer after layer of utter incompetence. They assigned a programmer who wasn't qualified to write a javascript button-click handler, to write life-critical sofware. Then no one else even looked at his code. There was no design review, no QA or bug tracking, and very little testing. Even after the defect was reported, there was no review or followup, or realization that it could even be a software problem. But the problem went much deeper. The hardware design was just as defective. There were no interlocks, in either hardware or firmware, to prevent defective software from killing patients. Many books on mission critical embedded system design devote an entire chapter to all the stupid mistakes that made up the Therac-25. If you make a list of the rules of sane system design, the Therac-25 design will have violated nearly every one of them.
a human will be aware enough to never jab the needle all the way through your arm. If there's a bug, the computer will do that happily and quickly.
And a bit of thought to the mechanical design of the robot will prevent it ever having the physical capability to do that.
Which oddly enough, is how they've designed the robot in TFA....
"I've got more toys than Teruhisa Kitahara."
And the exact same thing could happen to any other completely mechanical device.
You design the mechanism so that it is physically impossible for the software to do something dangerous. In the case of Therac-25, there should have been a mechanical interlock that cut power to the radiator when the shield was not in place. In the case of the needle sticking robot, you use an actuator with a stroke of, say, 5mm. Then there there is no way it could "jab through your arm". You also use a weak actuator, that doesn't have enough physical strength to push into bone, even when given full power. You put a spring-loaded (not software controlled) sheath over the needle, so the needle is never exposed unless it is pressed against skin. You design the hardware assuming the software is malicious. You design away any way you can think of for the software to do harm.
Then you design the software assuming the all the mechanical interlocks have failed, and use sensors to double check everything.