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Entry 2 - The waterfall computer

10 June 2019, 10 AM

As an example of an alternate computer architecture, take the waterfall. It's input is the physical configuration of water flowing into it, it's 'information manipulation parameters' is the shape of the rocks that comprise the static element of the waterfall, and it's output is the configuration of the falling water. In terms of efficiency in computing the output as a function of the input given specific parameters, nothing beats the waterfall itself. Sure, you could find a way to represent all that information in terms of bits and input it into a traditional PC, and it would be able to crunch the numbers and spit out the output configuration of the water after it has passed over the simulated waterfall, but it would take much longer and use much more energy. Moral of the story: be more like the waterfall computer.



Entry 1 - What are passive mechanisms?

10 June 2019, 9 AM

I've been reading a lot of articles recently about walking dynamics in robots. The idea of adding compliance to systems seems to be really hot right now. I noticed a trend in the academic literature towards passive mechanisms in robotics that allow the natural dynamics of the robot to influence it's motion, with the actuators placed so that they can apply torques and forces (in essence, suggesting a direction in which to move). When it comes down to it, though, passive mechanisms are really computers that have been optimized for a specific task. For input, they take all relevant physical information about the system, and for output, they produce forces and torques. To program this computer, it only takes tuning of the physical parameters (spring constants, damping coefficients, etc.). The trend towards replacing actuators with passive mechanisms is really a trend towards replacing unnatural computers (ones where the representation of information is not aligned with how the system itself naturally represents information) with natural ones.