Tuesday, October 8, 2019

AMC-AASD15A servo controller development - Completed

AMC-AASD15A and 150mm stroke actuator

After a few months of developing and beta testing the AMC-AASD15A servo controller is now the most safe and comprehensive motion controller for servomotors using direct  Step/DIR control method. At this point it not only support the AASD-15A (and AASD-20A) servo drives, but also Syntron HS servo drives and Dorna M1 Servo drives with custom wiring for 44pin cables.

It features great safety features like, automatic home calibration on power up or hot-plug data cable connection, or Platform Check to constantly check the state of each actuator for failures from over-current or over-torque and if any of the actuators fail and gets disabled, will safely park the rest active actuators to home position to prevent motion with less actuators until the issue is resolved. Additionally there are inputs to hook up emergency stop switch, manual park/standby button and force offline switch to pause the motion without interrupting the simulation game.

While the AMC-AASD15A is plug and play regarding the wiring, you may need to adjust a few parameters in the LCD user menu regarding the actuator model. The control panel has a few controls to allow navigation of the user menu, as well to manually test the motion of the actuators without motion software connection:

The latest firmware v2.07 allows use of actuators of any stroke length, and calculates and sets the model of the servo internally using a few simple parameters by the user that can be set differently for each actuator if needed:
*Leadscrew size (4mm/rev, 5mm/rev, 10mm/rev and 25mm/rev supported)
*Belt Ratio (1:1, 1:1.5 , 1:2 ratios suported)
*Inline or Foldback motor actuator mount methods
*Actuator Stroke

The max actuator stroke calculation depends on the Leadscrew size used and the belt ratio (if belt is used, usually only on Foldback type actuators). See a chart of the possible combinations and their effect on the max available stroke length that the AMC-AASD15A controller can handle.

LeadscrewRatioMax Stroke

If you are looking for custom size actuators, you could inquiry on PT-ACTUATOR, they do custom actuators except the listed stroke sizes on their website.

AMC-AASD15A menu walkthrough - Firmware 2.06

All the recent firmware update history as well additional information can be seen here:

Apart from that, the AMC-AASD15A servo controller now supports 7 servos by adding an extra DB25 connector on the side. Easy to replicate PCB was created and available to order from OSHPark. You can now order that allows easy attachment of the BD25 connector without wiring, just a 2.54mm header (male and female): https://oshpark.com/shared_projects/pSGlJpx4

The 3D printed enclosure was updated to accommodate for this extra servo port as well.

3D printed enclosure with Servo7-aux DB25 

Regarding the motion software support, Simtools 2.4 release has now included a "AMC" interface plugin that includes the AMC-AASD15A in the supported devices allowing to use 7 axis. Also there is available a AMC config tool to access and modify the parameters in the AMC-AASD15A that you can download here:

There is an expensive playlist on YouTube with all videos regarding the AMC-AASD15A, that includes tutorials and many demonstrations on actual motion platforms:

If you are interested in the AMC-AASD15A Servomotor Motion controller please visit:

And feel free to join my Discord for latest news, or ask questions!


San Diego, California
USA, 2019

Monday, May 27, 2019

New firmware for easy AASD-15A Servomotor interfacing


After years to integrating many different type of motors in the AMC1280USB, in 2017 I added support for servomotors via Servo signal conditioner and Encoder2position modules. These worked good converting the complex signals required for the servomotors to simple inputs/outputs that the standard AMC1280USB firmware can handle (speed control, PID position feedback etc).

But recently I had inquiries from SFX100 users for possibility to use the AMC1280USB to be able to have Simtools compatibility. The SFX100 system is using AASD-15A servo drives that lack some extra outputs that can be used for limit switches so it didn't seem easy to be adapted using the standard AMC1280USB + Servo circuitry. It is too expensive too anyways and complex to make.

So I followed a new route. I decided to completely rebuild the firmware to control the AASD-15A drives via Pulses and implement local position index in the memory of the AMC1280USB controller. But I needed a way to also be able to calibrate the actuators on power up so I can properly set the position of the index to match the actuator position otherwise, if the actuator is powered in middle position it might exceed the total stroke and damage possibly the actuator mechanics and even damage the servo drive electronics if torque limits does not catch it.

So I went above and beyond and made it so it will automatically detect the presence of a AASD-15A drive connection and calibrate it without using limit switches. As soon its detected it will move slowly the motor until a hard stop is detected. It will then set that as home position and will calculate automatically the position index for all the rest functions. The new functions include Automatic Park position and Automatic Standby position that will move to slowly when needed. No more jumping to center on power up.

So to keep it short, you can now interface the AASD-15A servos on the AMC1280USB main board using the standard PWM outputs and some extra inputs on the analog connectors. A few resistors and capacitors are needed to filter out some noise from the servo drives, but the rest of the wiring is simple:

See below example wiring to a DB25 Breakout. I soldered the resistors/capacitors on two little protoboards on the analog input headers to save space:

If you want to follow the development of this and more information behind it have a read here:

Here are some videos of the early testing and development:

The new firmware that supports the AASD-15A servos has now different menu options:

Here is a performance test with Simtools:

So after implementing all in the AMC1280SUB controller, I decided I wanted a single board that you can plug these AASD-15A servos directly without having to make custom wiring and breakout connectors etc... Thus the AMC-AASD15A servo controller was born:

The unique design allows direct plug of these AASD-15A servos using off the shelve DB25 male-male cables (Straight). A truly plug and play system at last!

Closer look of the AMC-AASD15A servo controller:

Plug and play calibration feature:

Here is testing two servos:

Some explanation of the new options for the LCD menu:

And how to set individual strokes/screw lead pitch/Inline and Foldback actuator types...

3D printed enclosure was also designed for the AMC-AASD15A servo controller:

The latest firmware for this is same for both AMC1280USB and the AMC-AASD15A boards and can be found here:


San Diego, California
USA, 2019