R

Rainier Lamers

Well Known Member
I am getting a lot of queries regarding our autopilot developments so please allow me to write where we are and where we are going.

Originally we started with the development of our own servos which has progressed to early prototype stage. During my visit to the U.S. and Oshkosh in particular I had opportunety to have a chat to the great folks at Trio at their stand not far from ours.
As a result we decided to support and back Trio's servos and put our own servos on the backburner.
We will be supporting Trio's digital servos as well as PWM servos (i.e. any servo that can be contolled using a standard PWM 1-2mS signal such as Navaid etc).

This means we are moving away from the CAN interface for this so for all our current panels you will need our COM extender unit which gives you an additional 4 RS232 serial ports as well as 4 PWM servo signals plus servo power control. It's an inexpensive add-on though at around $150.

We delayed submission of the COM extender for production until the servo issue was sorted out (as it might have needed a CAN interface for Enigma). But now we have given the go-ahead for this unit.

After having had a very good look at the Trio servos internals and general usability and build quality and further coupled to Trio's preparedness to offer these at a competitive price the choice to back these units was quite simple and I think it was a good one.

Rainier
CEO MGL Avionics
 
Rainier Lamers said:
I am getting a lot of queries regarding our autopilot developments so please allow me to write where we are and where we are going.

Originally we started with the development of our own servos which has progressed to early prototype stage. During my visit to the U.S. and Oshkosh in particular I had opportunety to have a chat to the great folks at Trio at their stand not far from ours.
As a result we decided to support and back Trio's servos and put our own servos on the backburner.
We will be supporting Trio's digital servos as well as PWM servos (i.e. any servo that can be contolled using a standard PWM 1-2mS signal such as Navaid etc).

This means we are moving away from the CAN interface for this so for all our current panels you will need our COM extender unit which gives you an additional 4 RS232 serial ports as well as 4 PWM servo signals plus servo power control. It's an inexpensive add-on though at around $150.

We delayed submission of the COM extender for production until the servo issue was sorted out (as it might have needed a CAN interface for Enigma). But now we have given the go-ahead for this unit.

After having had a very good look at the Trio servos internals and general usability and build quality and further coupled to Trio's preparedness to offer these at a competitive price the choice to back these units was quite simple and I think it was a good one.

Rainier
CEO MGL Avionics
Click to expand...

Renier, can you give us a comparison on the TRIO vs TRUTRAK servos as concerns design and functionality. I am not asking which is better, rather the design differences. They look very different.
Thanks.
 
I just had an email exchange with Jerry at Trio, and I was told that the servo's will be offered thru MGL once the system interface and firmware changes are made. Hopefully soon...:)

Is this correct Rainier? I'm assuming it is, coming straight from Trio...:cool:
 
cjensen said:
I just had an email exchange with Jerry at Trio, and I was told that the servo's will be offered thru MGL once the system interface and firmware changes are made. Hopefully soon...:)

Is this correct Rainier? I'm assuming it is, coming straight from Trio...:cool:
Click to expand...

I know this is Trio's current stance. Trio is assuming that we want to change the servos due to our involvement with a UAV project.
I prefer using the Trio servos as is as the additional effort to change firmware or make other mechanical changes is not going to be effective and for the applications in mind, the servos are just fine.

I have had an e-mail exchange with Trio this morning so I think the picture will be clearer now.

Rainier
CEO MGL Avionics
 
rv72004 said:
Renier, can you give us a comparison on the TRIO vs TRUTRAK servos as concerns design and functionality. I am not asking which is better, rather the design differences. They look very different.
Thanks.
Click to expand...

Yes, they are very different.
It is difficult to state if one design is better than the other. Each has specific advantages and disadvantages.

Our own servo development was based on a system similar to Trutrak.

Trio servos:

Based on a DC motor driving output shaft via gear reduction. This solution gives constant torque but needs a slip coupling (clutch) to enable overdrive by the pilot. It also needs a mechanical means of disengaging the gears when the servo is not in use - but this gives the advantage of near zero residual torque. Current consumption for a given amount of torque can be lower.
Weight can be reasonably low with this design. Model aircraft servos tend to be constructed like this (minus the clutch and disengage).

Trutrak servos:

Based on a stepper motor with a single stage reduction drive. This design has the advantage of being mechanically very simple. It is simple to set the required torque electrically by adjusting the current used. This design can also be much faster than the competing system but that does not really matter much for our typical applications. Possible disadvantage might be a slight residual torque when not in use but that is not really a big factor either. The stepper motor will weigh much more to get similar torque figures so these servos are heavier. Also, due to the nature of stepper motors, the torque is applied uneven as the shaft rotates. You could have a system with a good holding torque yet unable to actually apply a lot of torque when turning.

This is basically it in a nutshell. In practise, both systems tend to work well and there is no clear advantage for any one of the types that I am aware of. When looking for an autopilot - the real guts is in the software that drives the servos based on various sensor inputs. This is really where good and bad (or not so good) comes in. And even this is never a clear cut thing either. A particular system might work very well in a particular class of aircraft but may perhaps be less suitable for others.

Rainier
CEO MGL Avionics
 
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