toolhead: Replace max_accel_to_decel with minimum_cruise_ratio

The user facing max_accel_to_decel setting is complicated and
confusing.  Replace it with a new minimum_cruise_ratio parameter.
Internally this user-facing parameter will calculate the existing
low-level "accel_to_decel" mechanism.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 29 insertions, 18 deletions

diff --git a/klippy/toolhead.py b/klippy/toolhead.py
index ce014365..d386ec8e 100644
--- a/klippy/toolhead.py
+++ b/klippy/toolhead.py
@@ -217,12 +217,19 @@ class ToolHead:
         # Velocity and acceleration control
         self.max_velocity = config.getfloat('max_velocity', above=0.)
         self.max_accel = config.getfloat('max_accel', above=0.)
-        self.requested_accel_to_decel = config.getfloat(
-            'max_accel_to_decel', self.max_accel * 0.5, above=0.)
-        self.max_accel_to_decel = self.requested_accel_to_decel
+        self.min_cruise_ratio = config.getfloat('minimum_cruise_ratio', None,
+                                                below=1., minval=0.)
+        if self.min_cruise_ratio is None:
+            self.min_cruise_ratio = 0.5
+            req_accel_to_decel = config.getfloat('max_accel_to_decel', None,
+                                                 above=0.)
+            if req_accel_to_decel is not None:
+                config.deprecate('max_accel_to_decel')
+                self.min_cruise_ratio = 1. - min(1., (req_accel_to_decel
+                                                      / self.max_accel))
         self.square_corner_velocity = config.getfloat(
             'square_corner_velocity', 5., minval=0.)
-        self.junction_deviation = 0.
+        self.junction_deviation = self.max_accel_to_decel = 0.
         self._calc_junction_deviation()
         # Input stall detection
         self.check_stall_time = 0.
@@ -561,7 +568,7 @@ class ToolHead:
                      'position': self.Coord(*self.commanded_pos),
                      'max_velocity': self.max_velocity,
                      'max_accel': self.max_accel,
-                     'max_accel_to_decel': self.requested_accel_to_decel,
+                     'minimum_cruise_ratio': self.min_cruise_ratio,
                      'square_corner_velocity': self.square_corner_velocity})
         return res
     def _handle_shutdown(self):
@@ -600,8 +607,7 @@ class ToolHead:
     def _calc_junction_deviation(self):
         scv2 = self.square_corner_velocity**2
         self.junction_deviation = scv2 * (math.sqrt(2.) - 1.) / self.max_accel
-        self.max_accel_to_decel = min(self.requested_accel_to_decel,
-                                      self.max_accel)
+        self.max_accel_to_decel = self.max_accel * (1. - self.min_cruise_ratio)
     def cmd_G4(self, gcmd):
         # Dwell
         delay = gcmd.get_float('P', 0., minval=0.) / 1000.
@@ -615,29 +621,34 @@ class ToolHead:
         max_accel = gcmd.get_float('ACCEL', None, above=0.)
         square_corner_velocity = gcmd.get_float(
             'SQUARE_CORNER_VELOCITY', None, minval=0.)
-        requested_accel_to_decel = gcmd.get_float(
-            'ACCEL_TO_DECEL', None, above=0.)
+        min_cruise_ratio = gcmd.get_float(
+            'MINIMUM_CRUISE_RATIO', None, minval=0., below=1.)
+        if min_cruise_ratio is None:
+            req_accel_to_decel = gcmd.get_float('ACCEL_TO_DECEL',
+                                                None, above=0.)
+            if req_accel_to_decel is not None and max_accel is not None:
+                min_cruise_ratio = 1. - min(1., req_accel_to_decel / max_accel)
+            elif req_accel_to_decel is not None and max_accel is None:
+                min_cruise_ratio = 1. - min(1., (req_accel_to_decel
+                                                 / self.max_accel))
         if max_velocity is not None:
             self.max_velocity = max_velocity
         if max_accel is not None:
             self.max_accel = max_accel
         if square_corner_velocity is not None:
             self.square_corner_velocity = square_corner_velocity
-        if requested_accel_to_decel is not None:
-            self.requested_accel_to_decel = requested_accel_to_decel
+        if min_cruise_ratio is not None:
+            self.min_cruise_ratio = min_cruise_ratio
         self._calc_junction_deviation()
         msg = ("max_velocity: %.6f\n"
                "max_accel: %.6f\n"
-               "max_accel_to_decel: %.6f\n"
+               "minimum_cruise_ratio: %.6f\n"
                "square_corner_velocity: %.6f" % (
                    self.max_velocity, self.max_accel,
-                   self.requested_accel_to_decel,
-                   self.square_corner_velocity))
+                   self.min_cruise_ratio, self.square_corner_velocity))
         self.printer.set_rollover_info("toolhead", "toolhead: %s" % (msg,))
-        if (max_velocity is None and
-            max_accel is None and
-            square_corner_velocity is None and
-            requested_accel_to_decel is None):
+        if (max_velocity is None and max_accel is None
+            and square_corner_velocity is None and min_cruise_ratio is None):
             gcmd.respond_info(msg, log=False)
     def cmd_M204(self, gcmd):
         # Use S for accel