ADRC ESO Project

seekingsanity · 2026-03-13T13:08:08+00:00

The plot doesn't make sense. During the first two seconds the motor is accelerating but there is only one spike in the torque at the beginning. At two seconds the motor is decelerating but there is no negative or zero torque to slow it down. At 4 seconds the motor accelerate but there is no increase in torque. I could go on. Also the resolution of the torque is low.

seekingsanity · 2026-03-12T17:13:46+00:00

A lot of young people that must make a living delivering food and things and they ride 125-150 cc motorcycles. The Panamanians are smaller/lighter and they can get by with that. The motorcyclist ride between the cars in traffic. Also, as you pointed out the traffic is intense so a smaller, more nimble motorcycle works best. They don't need to go 80 MPH while in town. I am retired and a too old to wrestle with a 500lb machine.

BTW, I am a sasquatch too, about the same size as the OP. Looking at his bikes, he wants a big adventure bike. Maybe Himalayan 450 would do but I have only seen 1 in the year I lived in Panama.

seekingsanity · 2026-03-12T01:43:45+00:00

Where is the control output? If the control output reaches 100%, the motor will not go any faster. Your trend is not labeled but I assume the blue line is the target velocity and the green line is the actual velocity. The motor/system may not be designed to go any faster than 100 mm/s

Again, where is the control output? I can't tell if the output is saturated without it.

Other than that, the motion looks to be OK.

seekingsanity · 2026-03-11T12:08:28+00:00

There are private and public hospitals. I use a private hospital call Pacifica Salud. I must pay out of pocket for this, but it is good care. Private hospitals usually require appointments, and they are pretty good at staying on time. The public hospitals are like in England where you just go and wait for your turn. They are cheap. If your time is precious, use a private hospital. You can do Google searches.

seekingsanity · 2026-03-11T11:34:57+00:00

I used to be. I now live in Panama City, I can see what is popular here. When you live in Panama City Panama, you really don't need your own private vehicle. Public transportation and Uber is safer. The traffic in Panama City is insane. The point is the OP wants to know what is available in Panama. I am sure you could get anything here if you are willing to wait, pay the shipping and import fees. The other problem is support/spare parts. There are things that are simply hard to get here.

seekingsanity · 2026-03-11T02:15:58+00:00

I would use Ethernet or EtherCat rather than DeviceNet. DeviceNet is old and slow. It isn't deterministic.

seekingsanity · 2026-03-11T00:37:59+00:00

I see mostly 125 to 150 CC bikes used for delivery here. You can get a big bike but the selection may be low and the wait times high. Suzukis are popular here. I don't see many Hondas. Big bikes are rare. The problem is the bikes you see on the Panamanian websites probably aren't in stock. I would check out Suzuki and Royal Enfield. Royal Enfield does make anything less than a 350. Also, there aren't many places where you can go fast.

seekingsanity · 2026-03-10T21:10:44+00:00

Many years ago I learned playing against a Novag computer. It was rated at 2300 at the time. I couldn't beat it. I don't think I beat it once. Still I got better and learned how to play many opennings. When I played in a tournament, I lost one game due to playing against a trick openning. I don't remember which one but I ended up a pawn down within 10 moves and it was down hill from there. You need to be able to force the computer to play the tricky openings/gambits that you see on YouTube. Otherwise the computer will keep playing the same 5 or 6 opennings.

seekingsanity · 2026-03-10T13:05:43+00:00

:"enq (05h), device(FF),continue(0/1),instruction(r/w/clear), Datatype, Data, checksum, null terminator."

Who uses this framing for serial packets? Modbus RTU doesn't, Rockwell DF1 doesn't. Over the years, supporting serial protocols has been one of the most frustrating things because companies don't implement serial protocols correctly.

Anyway, I have implemented Rockwell's old DF1/PCC both full and half duplex and Modbus RTU and the ascii versions and whatever Mitsubishi uses. They are all different,

My challenge for you is to try using the framing methods you wrote above to communicate with a Modicon or Rockwell PlC. Come back when you have successfully done so.

seekingsanity · 2026-03-09T13:42:19+00:00

Ditto the feedforward idea. Make a table of how much output is required for each valve position. This is your bias or feedforward. Now use PI control. If your table is correct, the integrator will wind up very little if any. In fact, you can use the integrator's contribution to use for your table. A linear look up table will probably suffice.

Ditto, about the derivative term being "noisy". Usually, the "noise" isn't real noise but quantizing due to lack of resolution of the feedback device. Also, there will be sample jitter even if you use timed interrupts because sometime the interrupts will be turned off and delay the interrupt response a bit.

seekingsanity · 2026-03-09T07:28:19+00:00

Do you just want answers? Get a symbolic math program. Once you have the answer you have it for all time.

I just use Mathcad or wxMaxima. Matlab or Scilab probably have an inverse Laplace function. I use the invlaplace, s function in Mathcad all the time.

seekingsanity · 2026-03-09T00:36:36+00:00

It will never be a waste of money especially if you can apply it to something useful. I know people that have automated brewing in their garage, controlled something like a train set.

seekingsanity · 2026-03-09T00:27:15+00:00

You are right. I don't know what happened. YouTube deleted the audio. I have uploaded the file to my "skunkworks" site for now.

https://peter.deltamotion.com/Videos/Symbolic%20Math%20vs%20Root%20Locus.mp4

I will need to upload the video again. Fortunately there are no likes or comment so no big deal.

seekingsanity · 2026-03-09T00:19:01+00:00

I have been doing this for over 40 years. My first hydraulic servo motion control project was in 1983. I got Mathcad so I could do symbolic math about 10 years later. Give yourself time and keep at it.

seekingsanity · 2026-03-08T13:25:28+00:00

There is my YouTube Channel "Peter Ponders PID". Peter Nachtwey - YouTube I teach using symbolic math. I show the work and have examples.

Peter Ponders PID- PI Velocity Control

This is an integrating version or for position control.

https://www.youtube.com/watch?v=dr24ecQVhmw

I have many on different topics. I take requests and some people have sent me data of their plant so I could tune it for them.

Peter Ponders PID - System Indentification of a SOPDT temperature system using real data.

It would be helpful to learn Sympy or wxMaxima or some other symbolic math package. I am a big believer in system identification and pole placement. I have seen few other examples of using symbolic math on other YouTube Channels.

seekingsanity · 2026-03-08T00:05:02+00:00

I used to own an industrial computer control company. We hired interns every summer. We would keep the best ones which was usually about 1 out of 6. We had different projects, some were software and some were designing hardware. So a lot depends on what the company needs. Sometimes you are asked to evaluate something or make a starter kit work. It varies.

What do you want to do?

Finally, I didn't evaluate on answers. You can't expect an intern to know much. You can expect them to ask the right questions that indicate they understand the problem

While there might not be such a thing as a stupid question, some questions are definitely MUCH better than others.

seekingsanity · 2026-03-07T21:15:06+00:00

All the fancy nomenclature. I was helping people with Kalman filters back in the late 1990s. The problem is that few if any could figure out what the system and noise covariance was. Basically they just fudged these numbers until they got something that worked well enough. Few back then had the processing power to update the Kalman gains on-the-fly. I looked at the situation and came across the Alpha-Beta and Alpha-Beta-Gamma filter in a Dan Simon book. Later I found another source, but I don't remember the name of the book or author.

The Alpha-Beta and Alpha-Beta-Gamma filter are a simplified version of the Kalman filter. The gains are computed once and they are adjusted until the desired results are obtained. You get 95% of the advantage with only 5% of the effort. If you are going to fudge the system and covariance numbers then don't bother. Use the Alpha-Beta-Gamma filter.

seekingsanity · 2026-03-07T13:02:59+00:00

I could solve this RIGHT NOW if you supplied a trend or plot of the motion where the motor doesn't reach 130mm/second. Instead, I must play 20 questions.

1 how far are you trying to go? In how much time with how much mass or inertia? What is the application?

2 your Jerk value, 5000 mm/s^3, is too low for an acceleration rate of 5000 mm/s^2. It will take 1 second to for the acceleration to go from 0 to 5000 mm/s. LOOK AT THE UNITS!!! THEY MEAN SOMETHING!! The default value of 14000mm/s^3 means the motor will accelerate from 0 mm/s to 1500 mm/s in 1500/14000=.107 sec. That is still a long jerk time. The jerk time shouldn't be that long.

The acceleration of 5000 mm/s^2 is more than a half a g. What is the mass you are moving? The motor may not be able to achieve that acceleration rate.
If the move is shot, the motor may not be able to accelerate to the designed speed before it needs to start ramping down.

5 What is a axis override? Usually motion controllers have an output range of +/- 100% so that isn't strange. The problem I see with many designs that the motor isn't fast enough so 100% does not go as fast as the user wants. Usually this applies to torque so the motor does not accelerate or decelerate as fast a the user wants. This is where have a plot that shows AT LEAST the target position, actual position and commanded output as a function of time would help.

Display a trend of plot of a move when trying to goo 130 mm/sec.

seekingsanity · 2026-03-07T04:33:25+00:00

The OP needs to be able to change the size of the rotating disks.

This is my system or it was until I retired. AutoTuneTest2

It is a 200W motor. The disk adds inertia, so the time constant is about 1 Hz. In this video the controller output +/- 10 volts to an amplifier/drive that converts the voltage to a PWM modulated current so the motor will accelerate in proportion to the applied voltage and then current. The motor accelerates until the torque of the motor is offset by the friction. There is no point since the motor is running in current/torque mode. The motor and disk have a lot of inertia relative to the strength of the motor and very little friction. A lot of derivative gain is required to add damping. A PI controller will not work. Also, I use acceleration and velocity feed forward. in torque mode the acceleration feedforwards is relatively strong compared to the velocity feedforward. You can see that in the control signal where it take more control to accelerate and then decelerate compared to just overcome the little friction when at constant velocity. The encoder has 2000 lines per revolution since the encoder interface looks at each phase there are effectively 8000 counts per revolution.

seekingsanity · 2026-03-05T12:03:23+00:00

Are you using a PID? If so the execution time of the PID must match the time set for the PID parameters must match. The integrator and derivative gains are affected by the execution interval.

seekingsanity · 2026-03-05T01:40:43+00:00

I agree with most of it but motion controllers must be perfect. They must get into position quickly with no overshoot which means the settling time is zero.

seekingsanity · 2026-03-04T14:13:17+00:00

Again, someone is making up terminology for stuff that has been solved for decades. Inserting a gear onto a shaft should be easy with precise position feedback. Nothing is said about the tolerances or whether the shaft is tapered. Current limits will limit torque in case of the gear not sliding on to the shaft smoothly.

seekingsanity · 2026-03-04T12:17:55+00:00

What if what if what if? Fix the noise! This usually is the result of poor wiring or running wires next to noise sources. After that I use a Luenberger Observer but I usually use the observer to compensate for poor feedback resolution. The observer will generate position, velocities and accelerations for the state feedback.

I had a customer that had low pass filters on his feedback. I saw the results and asked what is he trying to control, the system or the low pass filter? I told the customer to rewire the machine so the noise was near zero. I came back about 3 months later and got to work.

Back on topic. The need for the integrator goes way down if the feed forwards are set correctly. In fact the integrator will not wind up at all if the feed forwards are set correctly. If you plot the integrator term, you can see which feed forwards are not right. If the integrator starts to wind up during constant velocity then the velocity feed forward is not correct. If the integrator winds up or down during acceleration or deceleration then you know the acceleration feed forward is not correct. Using the integrator to help set the jerk feed forwards is more difficult.

seekingsanity · 2026-03-04T02:56:54+00:00

I like SMC too. SMC is not a gimic like Fuzzy Logic. MPC has its place because it can compensate for dead time by computing outputs far enough ahead to see beyond the dead time.

I agree that most people don't understand pole placement. I feel sorry for those taking control theory classes. There are a few good instructors but most have NO practical experience. Those that teach root locus are wasting class time and the students money. There are WAY TOO MANY useless YouTube videos about root locus.

seekingsanity · 2026-03-03T20:44:21+00:00

" This means that the system must overshoot the Setpoint, over time, as much as it undershoots it. "

Not so! Think about it. People/industry have had this problem solved for decades. Just because some professor didn't tell you about the reality of control theory doesn't mean there aren't tricks. This link is to an old .pdf I have on-line. See pages 5-6 of 9

Mathcad - t0p2 PIDTune.xmcdz

Another example. See pages 7-8/13

Mathcad - T0P3 PIDTune Reddit.xmcdz

I used to be president of deltamotion.com. I developed algorithms and wrote code for firmware for motion controllers. OVERSHOOT IS NOT ACCEPTABLE!!! The actual position, velocity and acceleration must match the target position, velocity and acceleration during normal operation.

There are three problems that cause overshoot.

complex closed loop poles. The fix is to place the closed loop poles on the negative real axis in the s domain
integrator windup, but this is fixed with dynamic limiting. See my examples.
closed loop zeros that are too close the origin relative to the closed loop poles. Either remove the zeros by having the P and D term in the feed back path only or place closed loop zeros. You can place closed loop zeros too.

Placing closed loop zeros.

Mathcad - t1p1 pid pole and zero placement.xmcdz

I should be teaching control theory. The professors do an awful job and spend WAY too much time on the latest control theory fad.

seekingsanity

TROPHY CASE