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InstaSPIN-Motion Position Resolution and Interpolation in 3 Axis

Erhan Ergun
Intellectual 270 points
Other Parts Discussed in Thread: TMS320F28075, TMS320F28377D, TMS320F28377S

Hello,

I am prepearing to design a system which will have 3 axis. I will use 3 PMSM motor in this design and system will do high precision positioning thats why i also use encoders and hall sensors. I searched and found your InstaSPIN-Motion solution.

But i want to learn something else if you can please help me:

1_There will be 3 independent motor drivers and 1 control unit in my design. Can i use your ınstaspin solution in order to generate interpolation in 3 axis?(i saw that we can do generate interpolation in 2 axis with one microcontroller)

2_Can i use analog positioning sensors with instaspin-motion?


For speed and resolution questions below i will use 3 phases and 4 pole pair or 1 pole pair PMSM motor with enough torque.

3_With a perfect mechanical design can i get 0.02 arcsec resolution with instaspin with encoder? I need high resolutions that is wy i asked for analog sensors.

4_With that maximum resolution and instaspin-motion ( i saw that supported microcontroller has 90 MHz clock speed) and without interpolation while positioning what rpm speed can i reach?

Thank You.

  • 0
    Guru 12800 points

    Erhan,

    Erhan Ergun1 said:
    1_There will be 3 independent motor drivers and 1 control unit in my design. Can i use your ınstaspin solution in order to generate interpolation in 3 axis?(i saw that we can do generate interpolation in 2 axis with one microcontroller)

    In the InstaSPIN-MOTION product you are limited to up to 2 motion axes per chip.  We are planning on offering SpinTAC (the core motion algorithm inside InstaSPIN-MOTION) on the TMS320F28377D, TMS320F28377S, and TMS320F28075 and those chips will support an unlimited number of axes.

    Erhan Ergun1 said:
    2_Can i use analog positioning sensors with instaspin-motion?

    Sure, InstaSPIN-MOTION only requires the electrical angle as feedback.  So provided that you can generate an electrical angle for use by the FOC, it can also be used as the feedback to InstaSPIN-MOTION.

    Erhan Ergun1 said:
    3_With a perfect mechanical design can i get 0.02 arcsec resolution with instaspin with encoder? I need high resolutions that is wy i asked for analog sensors.

    InstaSPIN-MOTION uses IQ24 variables for it's internal calculations, so that is really the limit in terms of precision.  Typically the limit in precision is the feedback sensing and not the control algorithm.

    Erhan Ergun1 said:
    4_With that maximum resolution and instaspin-motion ( i saw that supported microcontroller has 90 MHz clock speed) and without interpolation while positioning what rpm speed can i reach?

    The maximum speed supported by InstaSPIN-MOTION in position control is dependent on host fast the control loop is running.  Assuming that you are running your position control loop at 1ms, the maximum speed would be (1 / [sample time]) / 3 [min number of samples] in electrical hertz.  This ends up being 333.3333 Hz.  But if you were to decrease the sample time, this value goes up.