I have a requirement for application of accurate torque (with a velocity limit), velocity (with a torque limit), and position in sequenced steps for a motion simulator and test rig. Equipment list is an AKD drive and AKM servomotor with an external torque transducer and encoder to give precise feedback to the drive. Control is by a cRIO box over Ethercat, LV2014 and Softmotion.
Having never used the AKD drives or ethercat before I am finding detailed information on this setup quite scarce and would appreciate a sanity check or any advice.
I am not sure with the Softmotion and Ethercat control exactly where the control loops are closed - I assume they will be closed on the drive and the cRIO will simply send set points and limits to the drive over ethercat, and read back torque, velocity, etc. over ethercat for logging etc. Is this how Softmotion works, or will that require lower level ethercat functions (and do such things exist)?
I am equally unsure how entering an external torque controller into the loop will affect things (I think that normally in 'torque' mode the drive is really controlling the internal current which is only an approximation of the actual torque, and hence the use of an external torque transducer so we can get specific actual torques applied). The subbie building the rig will set up and program the drive as required, but I'm not sure if the 'unusual' setup with external transducers will upset the way Softmotion routines will work.
On the surface, the Softmotion and AKD combination seems to promise 'plug-n-play heaven' - could this be as simple as I would like it to be, or are there pitfalls ahead I should be wary of?