That somebody was 4 decades failing, does not mean that at some point it won‘t be possible. In the last 4 decades the prices have lowered and the quality is much better in the RC world, if you know where to buy.
I did not mean to criticize a hobbyist project for existing.
I meant to say "There is a reason there is no standard hobbyist-grade robotic arm."
^Modifying cheap servos so that a robot arm can repeatedly insert a pencil lead. It's a lot of work though.
Most interesting application though fall out of the scope of old-fashioned robotic arms, i.e. when you need to sense the real world in a non controlled context. For instance to develop a robot that can trim wilted flowers, you'll need to measure the real world, and as soon as you do that, you can just sense your robot arm too, no need for fancy, ultra-precise actuators.
Look at this BOM: https://docs.google.com/document/d/1_3yhWjodSNNYlpxkRCPIlvIA...
Do you really need the $6,129.95 & $3,549.95 robot arms for the kind of application described ? I doubt it. I'm not a robotician, and would love some feeback on this idea.
People think they can build their own robotic arms for leas than a "real" robotic arm costs, but the do not account for wobble or repeatability.
With all due respect to the person who posted a design for a robotic arm made with RC servos on HN, I would like measurements of the repeatability. Have it draw the same pattern on a piece of paper every day for a week. Show me how closely the 7 lines overlap. I doubt that it can draw such a thing; it will tear the paper or get jammed without the strength to tear the paper.
Source: I've been building hobbyist robots since the 1980's, researched robots in the 1990's including a masters thesis, and teaching robotics for most of the last decade.