kureigu
Member level 2
Hey all, it's been a while since I've dealt with much DSP, so I'm a little unsure of how best to deal with a problem I've been experiencing in my system.
I'm trying to make a 3-axis stabilised platform, using stepper motors to drive it, an inclinometer for the x and y axes, and a compass for the z-axis.
Firstly, due to the stepper motors there is noise present on all axes any time a stepper motor moves. I've tried to employ a moving average in an attempt to reduce this noise and get a more stable output, however I think this is causing the motors to overshoot, and subsequently oscillate (due to compensation) since there is an inherent lag in the sensor feedback loop now.
So I was wondering, if I'm able to vary the sample rate, number of samples in the moving average and motor speeds, how best can I tweak these things avoid this oscillating behaviour and be able to still have a fast response? Is there anything else I can do?
I should note:
All the sensors give an absolute position output with respect to the surroundings, none are relative to their last position or anything.
I'm using an FPGA to deal with the signals, but I'm trying to limit the complexity of the system.
I've already got an active low-pass filter on the inclinometer (as well as moving average), but this isn't possible with the compass since it has a digital-only interface.
The compass will likely not be used for much longer, and may eventually be replaced with a rate sensor.
I'm trying to make a 3-axis stabilised platform, using stepper motors to drive it, an inclinometer for the x and y axes, and a compass for the z-axis.
Firstly, due to the stepper motors there is noise present on all axes any time a stepper motor moves. I've tried to employ a moving average in an attempt to reduce this noise and get a more stable output, however I think this is causing the motors to overshoot, and subsequently oscillate (due to compensation) since there is an inherent lag in the sensor feedback loop now.
So I was wondering, if I'm able to vary the sample rate, number of samples in the moving average and motor speeds, how best can I tweak these things avoid this oscillating behaviour and be able to still have a fast response? Is there anything else I can do?
I should note:
All the sensors give an absolute position output with respect to the surroundings, none are relative to their last position or anything.
I'm using an FPGA to deal with the signals, but I'm trying to limit the complexity of the system.
I've already got an active low-pass filter on the inclinometer (as well as moving average), but this isn't possible with the compass since it has a digital-only interface.
The compass will likely not be used for much longer, and may eventually be replaced with a rate sensor.