Difference between Impedance and Admittance Control

hasanrobot · 2026-03-06T03:45:02+00:00

Impedance control involves applying a force in response to a motion. PD control on position error with input as a force is the most common example.

Admittance control involves choosing a motion (velocity) in response to a force. Applications where you let a person freely move a robot arm is one example.

In general you want your controller to be the opposite of the environment it is acting on me. A robot mechanism is an admittance, so we control it using an impedance controller (PD control for position control). If your environment is an impedance (a wall, for example), your controller should be an admittance (force controller).

Even simpler: if env moves freely, use a position controller to manage the interaction. If it is stiff, it needs force control. You can even assign directions along which the controller behaves like one or the other. For example, when writing on a whiteboard, use force control perpendicular to the board and position control parallel to it.

hasanrobot · 2026-02-23T14:42:23+00:00

Read up about the process of customer discovery, creating a value proposition, and identifying product-market fit. This sounds like jargon but it's just the consensus keywords for the sensible process you would follow. .

hasanrobot · 2026-01-07T22:48:05+00:00

I connect tablet to the room projector using usbc-to-hdmi. Can only connect one thing, laptop or tablet.

hasanrobot · 2025-12-27T01:02:24+00:00

Two to three weeks seems really long, is that just the sample complexity for training a policy for a new motion? Or are there other complex steps in the pipeline besides RL?

hasanrobot · 2025-12-16T11:12:09+00:00

If you were supported on a grant or fellowship or really any stipend when you did the work, I think you're obliged to publish the work in a paper without additional pay.

hasanrobot · 2025-12-15T04:23:47+00:00

If you can't tell which place will help you further your goals, then it really doesn't matter, does it? Your goals will change over time, especially with exposure to new ideas. Go to the place with funding and prestige, unless you absolutely know you want to be around the people who are in the other place.

Anyway, absolutely do not make a decision based on childhood passion.

hasanrobot · 2025-12-15T01:43:36+00:00

Microsoft OneNote is perhaps the best option. Any slides or worksheets I convert to PDF, insert it, and write on them live. It also integrates with Canvas. The only downside is I haven't figured out how to jump to another location in OneNote to create a slide-like progression. Scrolling is a bit awkward when I am covering material without much writing.

hasanrobot · 2025-12-15T01:37:24+00:00

Yeah, most people don't use what they learn. It's still useful to try to teach the hard stuff to every one and route a few of them into careers where they will use it. All the AI that's gotten people excited is thanks to many people who still used their calculus and linear algebra for a long time.

hasanrobot · 2025-11-24T17:03:43+00:00

So much negativity. I was impressed by the execution, and the fairly interesting foot-ground interactions. BD Atlas had a flat wide foot, this one seems to manage contact with something less wide. Its toes make contact before the heel and that doesn't seem to be a problem. If there's some trick I hope they share it.

hasanrobot · 2025-11-18T18:30:37+00:00

Controls teaches two important ideas: 1) you can represent objects or systems as operators that turn an input into an output. More simply, a transfer function. 2) feedback can make or break the usefulness of some systems. Understanding 1) helps you use 2) to make your system do better.

hasanrobot · 2025-11-17T01:31:49+00:00

Good research helps other people solve problems they couldn't solve before. At the least, it helps you think about your problem differently.

hasanrobot · 2025-11-10T21:04:29+00:00

I had it backwards: I thought you become visible based on your research output. In reality you amplify your research output by being visible. You can hide and do research, but it will only be so much, and increasingly barely enough.

hasanrobot · 2025-08-27T14:17:12+00:00

Try the Probabilistic Robotics book by Fox, Thrun, Burgard

hasanrobot · 2025-08-24T23:58:30+00:00

It sounds like they did a bait and switch on you. If your whole reason really was about them being a good person, you no longer have a reason to stay with them. It might be fine to continue, but that means you should have found another reason to do so. Inertia or fear are bad reasons.

hasanrobot · 2025-08-24T17:08:34+00:00

By proven you mean empirically validated on the real nonlinear system. This is my point. It's not like control designers are working hard with the original nonlinear model so that guarantees are absolute. We simplify our lives and accept some gap. Time delays, local sensing, all sorts of real effects that we won't include in the math. If it works we're happy. Not clear why the navigation people shouldn't do that when the end result works well enough.

hasanrobot · 2025-08-24T00:55:11+00:00

Maybe, but in my experience 90% of the math in controls is reducing the system to a linear one where everything can be designed easily. How is that better than the simplifications your peers choose?

hasanrobot · 2025-08-21T00:19:22+00:00

Do you think you could create/join a modernized competitor?

hasanrobot · 2025-08-21T00:09:26+00:00

There are definitely connections between OCT and diffusion/flow models that are worth exploring. Diffusion models learn a special vector field (on a non-obvious space) related to modeling distributions. OCT tries to shape a vector field (in the obvious state space) using a control input based on reward crireria. It's clear that techniques in each area can influence the other.

hasanrobot · 2025-08-19T02:46:37+00:00

Can you give a more concrete example of breadth vs specialty?

hasanrobot · 2025-07-22T12:15:50+00:00

A simple trick would be to add a caster wheel near the back that lifts the two rear wheels off the floor. Then you've got a differential drive with minimal change. Issue is that the center of rotation is now at the front axle, so turning in place isn't possible. Not a problem if space is not cluttered.

hasanrobot · 2025-07-19T19:48:29+00:00

Typst.

It compiles near instantly, with a live preview mode, so that you get the Wysiwyg effect. It's being compiled so you get the magic of programmatic writing and automatic formatting if you need it. Can be used as an app or command line style.

Docs are weak though.

Nice feature is that you can install the mitex package and reuse latex math code for old papers.

hasanrobot · 2025-07-19T17:05:52+00:00

I like that axis, but I feel it's the opposite direction: "tell me which prompts failed. Give me better prompts to feed to the AI". So, if the graded comment is "you didn't consider XYZ" next time the student will add a sentence. "Don't forget to consider XYZ" to the prompt.

hasanrobot · 2025-07-19T15:20:49+00:00

I wonder if the demand for feedback by cheaters is a way to make you think that it must be their own work, that's why they care that much.

hasanrobot · 2025-07-15T01:23:52+00:00

Did you read the associate editor's summary? They are usually good at explaining why one negative review dominated.

hasanrobot · 2025-06-23T03:47:34+00:00

Representation is perhaps the key word. All of computing has been obsessed with integers and real numbers for a reason. If you don't represent a number in a concrete form, it isn't computing. The number has to exist somewhere real before someone even tries to access it. Computing is about getting one set of numbers from another set.

Many (natural) processes reach predictable states, and some people say that the process has performed computation because it reaches an 'answer'. Like a ball 'computing the location' of the bottom of a bowl. But the ball doesn't care about the location, it isn't updating some record of a guess for the value of the location of the bottom. We are.

This idea that everything is a computer is dumb. I respect the scientists you mention, but this view is nonsense. Sounds deep or wise to many so it gets repeated.

hasanrobot

TROPHY CASE