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Force Feedback for i.e. Logitech Yoke

Hellmut1956

Aug 11, 2014
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I use to fly myself single-engine airplanes and today I am into flight simulation. I use the Logitech peripherals for the MSFS2020. What I find as being a serious weakness is that the yoke does not reflect how it is on a real general aviation single-engine plane.

An example is the landing process. You make your touch-down in a stall the moment you touch the runway. During the final approach, you feel the pressure on the yoke and this is important feedback when landing a plane.

Being an aficionado of stepper motors you can manage the torque of a stepper motor by controlling the amount of current flowing through the stepper motor. So if the yoke would include a stepper motor an electronic would require information of the flying generated inside an airplane simulator to adjust the amount of current so that the force feedback on the yoke would reflect real-life airplane behavior.

Does anybody know how to get that information so that the electronics compute the torque of the stepper motor in a yoke?

Best regards
Hellmut
 

kellys_eye

Jun 25, 2010
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Lots of people are into flight simulation and youtube has many, many examples of DIY cockpits and yokes etc. What I do know is that you need to either write or have access to a DLL file in the simulator to read or write code to activate the yoke (of your own design). I'm quite sure this has already been done by an aficionado of the art so a lot of googling might help in this case.

Indeed, here is one of the first I came across that has all the mechanicals and code for such a device http://bffsimulation.com/FFB-yoke-1.php
 

Hellmut1956

Aug 11, 2014
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Thx for the link. I will investigate further and will try to give an update here if I have news to share.
 

Hellmut1956

Aug 11, 2014
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Thx for the link. I will investigate further and will try to give an update here if I have news to share.
I am impressed with the work you have done so far. I use to fly single-engine GA airplanes in California, Arizona, and Texas where my work got me to About 4 times a year. Now I am retired and my health adds to the financial limitations I have to keep my license current. So a good friend of mine with whom I use to fly frequently decided to use the FS2020 to go back to where we Hand Wonderful flying experiences.


Starting to practice the sim I found out that the yoke mainly is a Problem as it misses the Forces you feel i.e. doing a Landing. As I did learn Long ago, the best landing procedure lets the plane stall when it touches the runway and so to get slower as fast as possible. Here in Germany, DEMJ, Jesenwang, used to be my home Airport and it has a very short runway to proper Landing process is key. I use to work in the semiconductor industry, first as a field application engineer and later moving into managerial positions. So thinking along the path of using electronics is my way. I have some experience with stepper motors and drivers from Trinamic, now part of Analog Devices. I have recently started to occupy myself with stepper motors as those and the Trinamic Drivers are used in popular 3D Printers.


Stepper motors, as I am sure you are aware of, by the way, they operate have the Position Information. The second piece is that the torque of a stepper motor is proportional to the amount of current that flows through ist Coils and PWM is the mode to Control the amount of current.


So if The current is set i.e. at 45° plus and minus to a free definable current and 5° plus and minus to the lowest and apply a curve to the amount of current between 45° +/- and 5° +/-, the torque and in consequence, the amount of force the user sees on the yoke controls, a normal yoke, like the Logitec yoke I am using would generate a force Feedback on the user operating the yoke. The curves can be modified so that the force Feedback is as a user wants to have it.

So the difference between the normal yoke Operation and the sim is None existent, but the force feedback is given.

Stepper motors Nema17 can be purchased at 10 Euros or less, same Price range for a StepStick Driver TMC2208. Man DIY projects using Arduino ONE i.e. are available for 3D Printers and for CNC online. This way the programming is limited to a G-code script.

The project would only generate the force Feedback but cost 10% of your solution. I have the Controller board that came with my Ender 5 Plus that I replace with another board, so the cost is 0 Euros for the board that could also be used to generate force Feedback for other control surfaces.

Here the email I sent to Ian
Rgds
Hellmut
 

Harald Kapp

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I'm not convinced that a stepper motor is the right tool for the trade in this situation.
A stepper motor is designed to hold its position or move by defined steps. Increasing torque by increasing current will mean in these situations:
- more force to hold the motor's position.
- or more torque for moving the motor.

I have no experience flying an airplane but i take it from your description that what you want is that the yoke can still be moved (otherwise you wouldn't generate the necessary movement of flaps etc.), but that the force required tpo move the yoke depends on the actual flight situation of the plane.
If you were to use the stepper motor to hold the yoke's position, you'll lose the movement of the yoke :(
if you were to use the stepper motor to actually move the yoke against your manual movement, it will either pull back too strongly against your manual movement, or it will not pull strong enough. In the latter case your manual force will let the stepper motor slip giving you a jerky motion.

What I imagine would be a spring that pulls on the yoke. This would give you a linear feedback of force versus position. Now add the motor (be it stepper, servo or whatever) to the end of the spring opposite to where the spring is mounted to the yoke. By pulling on the spring you can increase the tension and thus the force feedback without losing control over the manual movement of the yoke. Equivalently by releasing the pull on the spring you can reduce the force feedback. Like so:
upload_2022-3-11_10-41-30.png
You could even create "negative" torque by pushing on the yoke.
 

Martaine2005

May 12, 2015
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Adding to Haralds spring idea for feedback, have you considered a radio controlled helicopters gyro plus a servo?
The gyro puts opposite force on the yaw and can be adjusted from 0% to 100%. The older mechanical gyros can be bought very cheaply now as newer ones are solid state. That coupled with an arduino or similar could be programmed to give opposite feedback with varying force.

Martin
 

Hellmut1956

Aug 11, 2014
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First of all: What high-value feedback you are giving to me! Thx a lot.

The ideas for the spring are very interesting. I will reflect on it. The same is true for the concept Martin is presenting. Whoww!

I am now even more motivated to advance the work on my workshop and my PC to do experiments for both approaches.

Rgds Hellmut

P.S. I will give you the feedback as soon as I have it!
 

Alec_t

Jul 7, 2015
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On a small single-engined plane I imagine air turbulence results in fairly random small variations in yoke pressure? For extra realism in your sim you might want to replicate that effect.
 

Hellmut1956

Aug 11, 2014
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Dear Alec. You are right. But sadly I do not consider myself being capable to integrate a solution so that it gets information from the sim. So the idea is kind of quick and dirty. I find it especially disturbing during the final stage of a landing. I learned to fly in Germany, Jesenwang, a very short runway. So it is mandatory to decelerate the plane as fast as possible. To eat speed the best is to force the plane to lift and to have it stall the moment the wheels touch the runway. It means that after such a touch-down the plane is unable to lose contact with the ground as the speed is too low. Of course, it demands a soft touch-down!
So at that step in the landing operation, you pull the yoke requiring quite a lot of force. So using the spring concept of the motor-based approach you would have a U form line as to the force required to move the yoke.
 

Bluejets

Oct 5, 2014
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In my experience, aircraft are trimmed to fly, even on landing (especially on landing approach)
The only time there is pressure on the yoke is if it is not trimmed, and this would be during the flare.
It is well known aircraft will stall at a given stick position as it is the angle of attack of the wing to the direction of flight.
Stick a micro switch on your leg and a stall warning buzzer on the dash.
Whether slow or high speed, same applies.
 

Hellmut1956

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Dear Bluejets, there is an important difference between GA airports in Europe and the ones in the USA. Runway in Jesenwang, EDMJ, 1437 ft x 39 ft (438 m x 12 m), displaced threshold 98". To land with a CESNA 172 demands to have a very low speed of the plane. Landing a PA-28R i.e. where the ground effect keeps the plane in the air, it is essential to eat up as much speed as possible and to touch the runway where it begins, Speed is reduced by the energy a lift of the plane requires and this consumption is taken by reducing the speed. So yes, in the USA runways are so long that you can land balancing the engine and trimming the plane so that it touches the runway where you wish it to do. In Germany you reduce the speed of the plane pulling the yoke and when you are well trained the plane touches the runway at the moment it stalls and has so consumed all the energy in the speed to make it impossible to climb off the runway. Also, I remember y check out the flight in the north of Phoenix where the safety pilot was impressed that doing such a steep approach my touchdown was perfectly smooth.
 

Bluejets

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Most would be taught to have an aiming point on the runway with correct safe approach speed.
Any stall condition would be after the aiming point is passed and the flare initiated at the correct height.
Either way, much easier and safer to have aircraft trimmed and speed correct all the way into the aiming point.
Point being, no joystick pressure until the last moments which is what this was about.
 

Hellmut1956

Aug 11, 2014
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Yeap! My purpose is to have the MSFS airplane work like I was used to and what is required to be able to land in Jesenwang. In Jesenwang by your procedure, you are prone to have an accident by moving over the end of the runway.
 

hevans1944

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This is a very interesting thread. Realism from a simulation! What will they think of next?

Years ago (in another century) we were tasked with finding out how a real pilot would control a "joy stick" if he or she was tasked to use it to keep a "tracking dot" centered on a circular target. The circular target was a computer-controlled circle with a variable diameter (under computer control) and the tracking dot was just that... a small dot on the screen whose position could be moved up/down and left/right using the joy stick. To make matters interesting, the computer would know the joy stick position at all times and would (depending on how strenuous to make the task that day) sometimes move the target circle away from the position of the joy stick. The closer the dot cursor got to the circular target, the faster the target moved away. Pilots seemed to handle this situation without a problem, keeping the dot cursor centered on the circular target seemingly without conscious effort. If that's what it takes to be a fighter pilot, I failed miserably when I was allowed to try it.

Part of this research was to discover what kind of joy stick pilots would perform best with in actual combat. A modern jet fighter experiences combat-close conditions in an aerial dog-fight for just a very few seconds, at the most. At the end of that short period of time, they are either dead or victorious. There are very few survivable ejections in a supersonic dog-fight.

Much to my surprise (not being an aviator myself), the "best" joy sticks for fighting are very stiff "force sticks" with torque motor feedback to let the pilot know the effect of air flowing along the control surfaces of the (imaginary) airplane. Some joy sticks in some aircraft may even have mechanical linkages to the control surfaces, which of course provides a very realistic feedback, especially under stall conditions, with our without ground effect. Unfortunately, "fly-by-wire" with remote sensors and actuators appears to have overtaken the military aircraft designs, but I think civilian aviation still has a long way to go to catch up... assuming that is even desirable.

One task on my "bucket list" is to learn how to fly an acrobatic bi-plane and do some fancy maneuvers a safe ten or twelve thousand feet or so above the ground. Ummm. I think I would practice first in a realistic trainer sim for a few sorties, after I get my private pilot's license, and maybe sit behind an instructor pilot who knows how to fly acrobatics really, really, well.. There used to be a guy like that who flew out of a little airfield in Moraine OH. He went by the name Red Baron when he was doing his stuff at the annual Dayton Air Show, but his real name was Harold Johnson and he was a former mayor of Moraine. I never got to meet him, and it's now too late to drive north for flying lessons. He died here in Florida on January 12, 2011.

Anyhoo, we had two kinds of joy sticks to play with. The original allowed a large amount of pitch and yaw movement of the stick, which may be good for learning how to fly an airplane, but is waaaay too slow for high-speed maneuvering. So most of our research was directed at the force-sticks, very stiff joy sticks that used strain-gauge instrumentation to determine stick "movement". Real pilots did well with these, but we did not have any means to adjust the joy stick output as a function of force applied to the stick, other than by scaling the strain gauge signal... which of course is what we did, but it would have been nice to have some sort of mechanical adjustment too. And amazing as all this was to a young technician in the 1970s, it was all over much too soon, and I then had to learn how to play nice with CO2 lasers for the Air Force Weapons Laboratory in Albuquerque, NM. These were high-powered diagnostic lasers, not the "weapons grade" chemical lasers the Air Force installed in the Airborne Laser Laboratory or ALL The ALL program has since been de-commissioned, but the ALL aircraft was once placed on static display outside at the Air Force Musuem. These static displays are changed often, so it is prudent to call ahead if there is a particular aircraft you want to see.

It would be interesting (and expensive) to introduce the simulation into a real airplane cockpit, like the commercial airlines use to train crews. There are one or two of these open and available to the the public at the Air Force Museum, located in Area B at Wright-Patterson Air Force Base, Dayton, OH. Admission to the museum is free, but there is always a line of kids (and sometimes adults) waiting their turn at flying the simulator.
 
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roughshawd

Jul 13, 2020
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I grew up in a heavy equipment shop. I have always wanted to build a hydraulic yoke, and I think using stepper motors for force feed back is old news what do you think? Kids toys? overkill?? the object is to make the computer which is just kind of guessing where the yoke is, to understand that landing and take offs are special parts of the simulation that require more focus on the controls, basically fake the takeoffs and landings part by building scenarios for different conditions. The designers decided to go with the body of the sim, extra planes, more fields, longer flights, special yokes... and other important sim stuff.. However the hydraulic could be turned on if the climb angle was to steep, or the air speed dropped... or the pilot passed out.
 

CircutScoper

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I'm not convinced that a stepper motor is the right tool for the trade in this situation.

Ditto. Better (and simpler and probably cheaper) than a stepper would be a brushed DC motor, in which both the magnitude and direction of torque are determined by the amplitude and polarity of applied armature current. Then a screw & nut assembly could convert torque from the armature into linear force on the control yoke, with useful mechanical advantage to enable a smaller (cheaper) motor with smaller (cheaper) drive current to generate realistic force.

Bipolar drive is important for simulator realism, because an airplane's control yoke can require the application of force either way.

Push to speed up and/or descend -- trading altitude for airspeed -- ultimately limited by ground contact (!). Hence the utility of engines.
Pull to slow down and/or ascend -- trading airspeed for altitude -- ultimately limited by the stall -- often followed (shortly thereafter) by ground contact. Ditto.

Actually, of course, pulling on the yoke does one thing only -- increases angle of attack. Pushing decreases it.
 
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Hellmut1956

Aug 11, 2014
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So, I have made my decision which I want to share with you. Here is the link to the device I bought and which is scheduled to arrive on Monday:

52721493895_8498a8df8e_c.jpg


As you can see the yoke is very expensive and yes, it is done using brushless motors. Flying with MSFS2020 is the best left for me after health and finances make it impossible to fly real GA planes. I have only been flying real GA planes and the technique learned to land in airports in Germany and specially in my former home airport EDMJ, Jesenwang, this yoke I hope will make it possible to regain the old "feeling" when flying in the sim
 
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