0 - Torque Mode
Only the iq and id loops are involved in this mode, thus only the PID gains of these two
loops need to be tuned. The PID gains of iq and id loops should always be the same in
normal operation, thus there is actually only one set of PID gains to be tuned when BEAR is
operating in this mode.
It is recommended to start with the following settings:
i
q
/i
d
P = 0.02, I = 0.02, D = 0
which should work just fine for most applications.
BEAR with correct id/iq PID gains shows great id/iq tracking. The P gain and I gain should
not deviate from the above by a significant amount even when further tuning is needed, and
the D gain should be kept at zero(0) all the time.
1 - Velocity Mode
When operating in Velocity Mode, the velocity PID loop result feeds to iq loop, thus the
velocity PID gains are tuned on top of correct id/iq PID gains. See previous sector for how to
tune the id/iq PID gains correctly.
While the actual settings could vary depending on the application and desired dynamic per-
formance, it is recommended to start with the following settings:
Velocity P = 0.5 ∼ 1, I = 0, D = 0
A very small (0 ∼ 0.001) I gain may be needed depending on the application, but it is
recommended to keep the D gain at zero(0).
BEAR with correct id/iq PID gains and well turned velocity PID gains shows good velocity
tracking performance.
2 - Position Mode
Getting the correct PID settings for BEAR to run dynamically and accurately in Position Mode
can be a little challenging, but it is simple and straight forward once it is tuned step by step
in the correct sequence.
When in Position Mode, the position PID loop result feeds to velocity loop, and then the
velocity PID loop result feeds to iq loop, thus all PID gains of the id/iq loop, velocity loop
and position loop need to be correct. Therefore, a fairly reliable set of velocity loop gains is
required before the position gains can be tuned. Refer to previous sector for how to tune the
velocity PID gains correctly.
The actual PID setting for position loop varies dramatically between different types of BEAR
and their applications. Always get the velocity and id/iq PID gains correct BEFORE spending
time in tuning the position PID. Bad velocity and/or id/iq gains can be the reason why a BEAR
is not outputting enough torque or not tracking goal position, no matter its position gains.
3 - Direct Force Mode
When operating in Direct Force Mode, all of position, velocity and iq can be involved as
explained in section. 2.3, and eventually feeds into the internal Iq loop, thus a well tuned set
of id/iq PID gain is fundamental.
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