Force Feedback i.e. the Yoke from Logitech

[Hellmut1956]

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

 

[rjenkinsgb]

The problem with a stepper is the extremely limited range (less than 1' on a 200 step motor) before it slips, if there is not adequate torque to manage the load.
Once it starts to slip, it will be "cogging" and vibrating - possibly OK for a stick shaker, but not good otherwise!

For force feedback, I believe you would be far better off with a DC or BLDC motor, with very low gearing so it back-turns easily without affecting the feel of the stick when it's not supposed to.

Looking for force feedback interfacing, this place does both driver boards and the interface software for them:

Flight Sim Control Loader (force feedback)Software

Flight Sim Control Loader (force feedback) Software.

bffsimulation.com

 

[Hellmut1956]

Hi. I have some experience with stepper motors as I use them on my DIY sailboat model to control the sails.

Your comment is typical for what is a widespread lack of information about stepper motors. Please do not get offended, English is my third language and so my wording is sometimes seen as offensive when nothing is farther away from y intentions.

You can find extensive information about stepper motors at the site of Trinamic. You find also lots of videos showing the functionality given by the Trinamic stepper motor drivers in the Youtube channel of Trinamic.

Motor Control

Trinamic products offer a variety of unique features to improve accuracy and smoothness of motor operation. By using the motor as the sensor, electric feedback from the actuator is used to turn key motor characteristics to your advantage.

www.trinamic.com

youtube trinamic at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

What makes it so cheap and easy to handle is the widespread use of StepSticks TMC2208/2209 and others in 3D printers. So you get a StepStick TMC2208 for less than 10 Euros. I will use the controller board I replaced from my Ender 5 Plus to control the stepper motor and the driver. This makes it possible to run such force feedback using G-Code script.

To make it easy to find and look for the proper information at the Trinamic website or their Youtube channel here some info:

The stepper motor would be enough to use a Nema 17 that can be purchased at just less than 10 Euros. The torque available from a stepper motor is proportional to the amount of current flowing through its coils. PWM, pulse width modulation is used to limit the current to the desired amount making it possible to operate the stepper motor with voltages up to 10x the nominal voltage. That is the way the Trinamic drivers work.

The Trinamic ICs in the StepSticks offer the functionalities you can see listed on the page at the Trinamic website the link gets you to. One function i.e. can increase the available torque to up to 120% of the nominal torque to prevent losing steps.

The amount of torque/current would be the highest at the maximum push or pull of the yoke and when released or passing the central position you can control it.

Around the center position of the Yoke you would have minimal torque, i.e. 5° plus or minus. Between the max and the center point you would define a curve so the force feedback behaves like you want it. This way the force feedback is independent from inputs from the sim.

Here some feedback!
Rgds
Hellmut

 

[rjenkinsgb]

Nothing changes the fact that stepper motors such as you suggest cannot give continuous, smooth back-torque against external motion such as the aircraft control stick or yoke.

That requires the exact motor rotor position to be known and the drive current to each phase modulated to maintain the set torque; eg. electronic commutation with rotor feedback, as in a BLDC motor.

Things such as 3D printers rely on the fact that in normal operation there is never enough torque load to make a stepper "slip" - but if one does, it's then out of position until the machine is re-homed.

And it only needs the motor to be out of position by half a step before it will jump to the next step rather than holding position.

Try it yourself - block an axis on your printer with your hand as you try and jog it. It will lose position and "buzz" whilst it tries to move against an obstruction.

Steppers are used is small devices such as 3D printers as a "cheap and cheerful" method, far lower cost than closed-loop BLDC servos - not because they are better than such servos.

[I have a lot of experience with both hobby level steppers and industrial drives & control systems, over several decades].

 

[Hellmut1956]

In my project to use for the control of the sails a stepper motor I add the use of a magnetic angle decoder, also a pretty cheap tool.

I use it together with an LPCXpresso1769:

This board has a quadrature decoder peripheral on board and the software library to use that peripheral. The image shows the board with the debug interface still not broken away. So it is a pretty small and cheap board from "Embedded Artists". I must confess that I have not yet experimented to use this setup as a force feedback tool that requires allow the user to force the stepper motor to turn it mechanically from outside. As soon as I have the work of improving my workshop I will make experiments to verify its use.

But please, do not feel personally attacked over this topic.

Rgds
Hellmut

 

[rjenkinsgb]

I await the results of your experiments!