Alternative to inverse kinematics (?)

Hacker News

Hi HN, This was my M.A. thesis, and I would appreciate some feedback from HN. It is a robot arm with a visual system. It did a tracking task - looking at a computer screen, following a red dot by moving a mouse. https://www.youtube.com/watch?v=wQ6FGeSjN9c The interesting thing is it doesn't use traditional inverse kinematics, instead there are multiple cascades of feedback loops, no internal models. First level are just standard position control loops, just like any servo. Second level loops are controlling relationships between arm points, they operate in parallel, simultaneously. For example - one of the loops maintains distance from fingertip to base (reach), and another one maintains the height from the fingertip to the surface. If the setpoint for reach changes, then the arm will start extending the elbow. That will disturb the height control system, and it will compensate to maintain its setpoint. Third level is the visual system, it was used to maintain distance of cursor marker to target marker. If the target moves up, then the control system maintaining vertical distance sets a new setpoint for the height control system, which sets the shoulder servo to move, and that disturbs the reach system which then starts the elbow servo and so on. It is actually an M.A. in psychology, on theories of motor control, testing perceptual control theory. It was very low budget and my mechanics skills are not yet polished. Hopefully, next one will be better. I was gonna record it doing the tracking task, but a couple of gears broke, and now I need to replace the gearbox. Anyway.. anyone here read about perceptual control theory? There are some interesting simulations of arms with 14 degrees of freedom, also not using traditional inverse kinematics. I'm kinda weirder out by the lack of people who have heard about the theory, it's been around for quite a while, and seems like a pretty interesting approach.

Visit product View on Hacker NewsJun 11, 2015

Share card

Actual performance

4points

2comments

Did not reach leaderboard

Launch Intel predictions

Analyze your own launch →

Product HuntOn track for Day 1 leaderboard · Strong signals: cursor, model, computer · Missing: mac, agents, macos

89%89% predicted probability of success on Product Hunt, based on ML models trained on real launch data.

best fitHighest predicted score across all platforms for this description.

Indie HackersFits the IH revenue-focused audience · Strong signals: para · Missing: supports, reddit linkedin, podcasting

83%83% predicted probability of success on Indie Hackers, based on ML models trained on real launch data.

Hacker NewsStrong engagement from HN community · Strong signals: io · Missing: https docs, excited, just released

56%56% predicted probability of success on Hacker News, based on ML models trained on real launch data.

nativeThis product was originally launched on this platform.

TrustMRRLess likely to generate early MRR · Strong signals: way, para · Missing: mobile apps, ios, personal

42%42% predicted probability of success on TrustMRR, based on ML models trained on real launch data.

AppSumoMay struggle as an AppSumo deal · Missing: plus, platform, intuitive

37%37% predicted probability of success on AppSumo, based on ML models trained on real launch data.

Acquire.comPre-revenue stage for this audience · Missing: arr, mrr, revenue

12%12% predicted probability of success on Acquire.com, based on ML models trained on real launch data.

BetaListMay not resonate with beta-testers · Missing: web3, chat, crypto

0%0% predicted probability of success on BetaList, based on ML models trained on real launch data.

Incorrect prediction on native model

Similar products

frozen - Storm alternative without Java43%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

frozen - Storm alternative without Java

Hacker News2

Diffboard, a pastebin alternative with diffs56%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Diffboard, a pastebin alternative with diffs

Hacker News5

dump_r() - print_r() and var_dump() alternative58%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

dump_r() - print_r() and var_dump() alternative

Hacker News12

developing a techmeme alternative.56%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

developing a techmeme alternative.

Hacker News3

an alternative to AdSense59%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

an alternative to AdSense

Hacker News112

A BBS alternative59%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

A BBS alternative

Hacker News3

suchjs - a terse alternative to jQuery55%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

suchjs - a terse alternative to jQuery

Hacker News4

An alternative to strong_parameters in Rails: parameters_schema50%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

An alternative to strong_parameters in Rails: parameters_schema

Hacker News1

Mantis BT Alternative from Usersnap59%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Mantis BT Alternative from Usersnap

Hacker News2

Okfans41%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

OnlyFans alternative.

TrustMRREntertainment

Browse all products Analyze your launch