The previous code calculates each step time via an "exponential
search" followed by a "false position with Illinois algorithm" search.
Replace with a "secant method" with "bounds check" search. This
simplifies the code, improves the performance, and does a better job
of finding steps near a direction change.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Use a more strict check for determining if the iterative solver has
correctly found a step - the guess must be within 1 picometer of the
target or correct to within 1 nanosecond.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This prevents some cases where the iterative solver fails to converge
in a reasonable time, causing "no next step" errors.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Avoid using doubles as flags when generating steps during "lead up to
stepper activity". Instead, explicitly track how many inactive move
entries are skipped and only generate steps for those entries.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Don't assume the times passed to itersolve_gen_steps_range() are
contained within the move. It's possible the checks in
itersolve_generate_steps() may round to different values when
converting the times to a relative move time.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Some stepper motor drivers do not respond well to rapid "step +
direction change + step" events. In particular, it is believed this
can cause "over current" events on the tmc2208 drivers when they are
in "stealthchop" mode. Detect these events and remove them from the
generated step times.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Some stepper motor drivers do not respond well to rapid "step +
direction change + step" events. In particular, it is believed this
can cause "over current" events on the tmc2208 drivers when they are
in "stealthchop" mode. Detect these events and remove them from the
generated step times.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
If the stepper changes direction then the average velocity since the
last step pulse isn't a good indicator of the next step pulse.
Instead, reset the bounds checking to use a low starting guess.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
The queue_append system predates the iterative solver - it was useful
when many different kinematic functions directly added steps to the
step compression queues. With the iterative solver being the only
source of step generation, it is simpler to directly add steps from
the iterative solver code.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Add support for generating steps from kinematic functions that
calculate step times based on a range of the motion queue. It
requires scanning for step generation during the lead up to stepper
activity (when the stepper would nominally be idle). And it requires
scanning for step generation just after a stepper has nominally become
idle.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Use sentinels to make list traversal code simpler. Also add in null
moves so that there are no time gaps in the list.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Now that the only caller to set_commanded_position() is
set_position(), remove the set_commanded_position() method and pass
the set_position() call directly to the itersolve.c code.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Minor rework of the loop to reduce the chance that numerical stability
could cause an infinite loop.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Now that all callers use the trapq system to queue moves, it is no
longer necessary to individually allocate and fill a 'struct move'.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Eliminate the old gen_steps() call now that all callers have been
converted to the newer trapq based generate_steps().
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Support associating a stepper_kinematics with a trapq. Support
generating steps from a time range on the given trapq.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
If the kinematic position calculation function had an error in it (if
it produces sudden position changes) then it could lead to an infinite
loop in itersolve_gen_steps().
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Add support for an itersolve_set_position() function that sets a
stepper position from a cartesian coordinate. This eliminates the
need for both the python and C code to be able to translate from a
cartesian coordinate to a stepper position.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Kevin O'Connor