Electric servo system

• Official Post

The servo has the benefit of creating a smooth polynomial function which in this case also sets the upper and lower deflection range which are not symmetrical.

When you replace this with an actuator with a range of -1.0 to 1.0 then the servo no longer deflects the elevator by 30ish degrees but at an insane 57°. I would recommend using a polynomial object after the actuator with the same coefficients as the servoclassic.

As far as I know the actuators in the CRJ are hydraulic and not electric. So not sure why you would want to use electric actuators here.

Regards,

Jan

• The servo has the benefit of creating a smooth polynomial function which in this case also sets the upper and lower deflection range which are not symmetrical.

When you replace this with an actuator with a range of -1.0 to 1.0 then the servo no longer deflects the elevator by 30ish degrees but at an insane 57°. I would recommend using a polynomial object after the actuator with the same coefficients as the servoclassic.

As far as I know the actuators in the CRJ are hydraulic and not electric. So not sure why you would want to use electric actuators here.

Thank you for your suggestion. Since the hydraulic system is not modeled, it can only be simulated with the electric system

• The servo has the benefit of creating a smooth polynomial function which in this case also sets the upper and lower deflection range which are not symmetrical.

When you replace this with an actuator with a range of -1.0 to 1.0 then the servo no longer deflects the elevator by 30ish degrees but at an insane 57°. I would recommend using a polynomial object after the actuator with the same coefficients as the servoclassic.

As far as I know the actuators in the CRJ are hydraulic and not electric. So not sure why you would want to use electric actuators here.

Can you help demonstrate how to add a polynomial object, I am getting a crash after adding like this

"<[electrical_actuator][ServoLeftElevator][]

<[string8][Input] [Autopilot.OutputElevator]>

<[string8][InputVoltage] [DCBatteryBus.Output]>

<[float64][Speed] [ -0.1 0.1 ]>

<[float64][MinimumVoltage][12.0]>

<[float64][RatedCurrent] [0.1]>

<[float64][Position] [0.0]>

<[float64][P0][0.0]>

<[float64][P1][0.3665]>

<[float64][P2][-0.04538]>

<[float64][P3][0.0]>

>”

• Official Post

Just copy paste it from somewhere else. For example the ASG 29 uses polynomial objects for aileron differential. You then need to rename the object to the name of your actuator and your actuator needs to be renamed to something else and the output of the actuator needs to be the input of the polynomial.

When you see a red box then you made a mistake and the tm.log file usually contains the cause of the issue.

Regards,

Jan

• Just copy paste it from somewhere else. For example the ASG 29 uses polynomial objects for aileron differential. You then need to rename the object to the name of your actuator and your actuator needs to be renamed to something else and the output of the actuator needs to be the input of the polynomial.

When you see a red box then you made a mistake and the tm.log file usually contains the cause of the issue.

success! Since I'm using an Android device, the emulator may not be able to output the log file. I used another method. I directly adjusted the scaling value in the servo system control parameters to limit its angle to 30 degrees, and the electric servo system is currently running well!

<[string8][InputID][ServoLeftElevator.Output]>

<[tmvector3d][Axis][ 0.408197 -0.909028 0.083929 ]>

<[tmvector3d][Pivot][ -16.79079 3.968564 4.013117 ]>

<[float64][Scaling][0.3665]>

• Official Post

Thats not correct though. This only affects the visual angle of the elevator. The physical reaction is still way too much and the value on the flight controls display is probably also off scale. And the elevator then only deflects symmetrical which it doesn't do in the real aircraft...

Regards,

Jan

• Thats not correct though. This only affects the visual angle of the elevator. The physical reaction is still way too much and the value on the flight controls display is probably also off scale. And the elevator then only deflects symmetrical which it doesn't do in the real aircraft...

Yes, the trajectory on the display exceeds the original range, but I really don't know how to use polynomial functions. It may be that the input and output objects are wrong. After adding them, they either have no effect or crash

• When I connected the landing gear and spoilers to the electric servos, I noticed that the animation became noticeably smoother and it felt like the hydraulics were working in the background

• Official Post

If you add more electric actuators you could run into issues with the batteries and you can no longer simulate a dual engine failure for example...

Both the servo and electric actuator are updated at the same physics simulation rate of over 100x per second. What you perceive as smooth is probably just the slower actuator speed. Keep in mind that there are also certification requirements for this, that's why they are usually somewhat fast. Making them slow causes a delayed response and this can lead to pilot induced oscillations or uncontrollable aircraft behavior.

You could also just make the servo slower, no need to add an electrical actuator just for that...

Regards,

Jan

• If you add more electric actuators you could run into issues with the batteries and you can no longer simulate a dual engine failure for example...

Both the servo and electric actuator are updated at the same physics simulation rate of over 100x per second. What you perceive as smooth is probably just the slower actuator speed. Keep in mind that there are also certification requirements for this, that's why they are usually somewhat fast. Making them slow causes a delayed response and this can lead to pilot induced oscillations or uncontrollable aircraft behavior.

You could also just make the servo slower, no need to add an electrical actuator just for that...

Yes, when I increase the electric load, I can see that the trim, elevators and ailerons on the flight control board will vibrate obviously and quickly, so I have to reduce the load. I am going to remove these electric servos and only keep the landing gear and spoilers