Project update 5 of 21
We’re excited to announce that we made our goal of $5,000 in the first two days! On the request of many potential backers, we’ve completed a thorough datasheet for the IQ Speed Module, which is now available.
We’re looking forward to seeing the kinds of vehicles and machines our backers build. One of our earliest customers, bunnie Huang, started messing around with our prototype motors a few months ago. He posted a blog post yesterday that highlights a few unique capabilities. Here are a few excerpts and videos:
Because of the microcontroller on the inside, the IQ Position Module can emulate a range of behaviors, from a simple stepper to a range of BLDC drive standards, but the real magic happens when you tell it where you want it to go and how fast, and it figures out the best way to get there.
“But wait”, you say, “my servos and brushed DC motors can do that just fine, I just control the pulse width!” This is true for crude and slow motion control applications, but if you really want to run at high speeds – like the ones achievable by a BLDC – you have to consider things like acceleration and deceleration profiles.
The video below shows what I mean. Here is a pre-production IQ Position Module that’s being commanded to turn once in two seconds; then twice, three times, and finally ten times in two seconds. The motor can go even faster, but the figurine I attached on top isn’t balanced well enough to do that safely. Notice how the speed “ramps up” and back down again, so that the motor stops with the figurine in precisely the same position at the end of every cycle, regardless of how fast I commanded the motor to turn.
There’s more. Because this is a “direct drive” system, there’s no gears to shear. Anyone who has busted a geared servo motor by stalling or back-driving it knows what I mean. IQ Position Modules don’t have this problem. When you stop driving the IQ module – put it in a “coast” mode – it turns freely and without resistance.
This means the IQ motor doesn’t just “write” motion – it can “read” motion as well. Below is a video of a simple motion copy demo I cooked up in about an hour (including time spent refactoring the original API), where I implement bidirectional read/write of motion between two IQ Position Modules.