extruder: Allow dynamic adjustment of pressure advance (#6635)

Signed-off-by: Dmitry Butyugin <[email protected]>

Author: dmbutyugin

klippy/chelper/__init__.py

@@ -142,8 +142,9 @@
 
 defs_kin_extruder = """
     struct stepper_kinematics *extruder_stepper_alloc(void);
+    void extruder_stepper_free(struct stepper_kinematics *sk);
     void extruder_set_pressure_advance(struct stepper_kinematics *sk
-        , double pressure_advance, double smooth_time);
+        , double print_time, double pressure_advance, double smooth_time);
 """
 
 defs_kin_shaper = """

klippy/chelper/kin_extruder.c

@@ -9,9 +9,15 @@
 #include <string.h> // memset
 #include "compiler.h" // __visible
 #include "itersolve.h" // struct stepper_kinematics
+#include "list.h" // list_node
 #include "pyhelper.h" // errorf
 #include "trapq.h" // move_get_distance
 
+struct pa_params {
+    double pressure_advance, active_print_time;
+    struct list_node node;
+};
+
 // Without pressure advance, the extruder stepper position is:
 //     extruder_position(t) = nominal_position(t)
 // When pressure advance is enabled, additional filament is pushed
@@ -52,17 +58,25 @@ extruder_integrate_time(double base, double start_v, double half_accel
 
 // Calculate the definitive integral of extruder for a given move
 static double
-pa_move_integrate(struct move *m, double pressure_advance
+pa_move_integrate(struct move *m, struct list_head *pa_list
                   , double base, double start, double end, double time_offset)
 {
     if (start < 0.)
         start = 0.;
     if (end > m->move_t)
         end = m->move_t;
-    // Calculate base position and velocity with pressure advance
+    // Determine pressure_advance value
     int can_pressure_advance = m->axes_r.y != 0.;
-    if (!can_pressure_advance)
-        pressure_advance = 0.;
+    double pressure_advance = 0.;
+    if (can_pressure_advance) {
+        struct pa_params *pa = list_last_entry(pa_list, struct pa_params, node);
+        while (unlikely(pa->active_print_time > m->print_time) &&
+                !list_is_first(&pa->node, pa_list)) {
+            pa = list_prev_entry(pa, node);
+        }
+        pressure_advance = pa->pressure_advance;
+    }
+    // Calculate base position and velocity with pressure advance
     base += pressure_advance * m->start_v;
     double start_v = m->start_v + pressure_advance * 2. * m->half_accel;
     // Calculate definitive integral
@@ -75,35 +89,36 @@ pa_move_integrate(struct move *m, double pressure_advance
 // Calculate the definitive integral of the extruder over a range of moves
 static double
 pa_range_integrate(struct move *m, double move_time
-                   , double pressure_advance, double hst)
+                   , struct list_head *pa_list, double hst)
 {
     // Calculate integral for the current move
     double res = 0., start = move_time - hst, end = move_time + hst;
     double start_base = m->start_pos.x;
-    res += pa_move_integrate(m, pressure_advance, 0., start, move_time, start);
-    res -= pa_move_integrate(m, pressure_advance, 0., move_time, end, end);
+    res += pa_move_integrate(m, pa_list, 0., start, move_time, start);
+    res -= pa_move_integrate(m, pa_list, 0., move_time, end, end);
     // Integrate over previous moves
     struct move *prev = m;
     while (unlikely(start < 0.)) {
         prev = list_prev_entry(prev, node);
         start += prev->move_t;
         double base = prev->start_pos.x - start_base;
-        res += pa_move_integrate(prev, pressure_advance, base, start
+        res += pa_move_integrate(prev, pa_list, base, start
                                  , prev->move_t, start);
     }
     // Integrate over future moves
     while (unlikely(end > m->move_t)) {
         end -= m->move_t;
         m = list_next_entry(m, node);
         double base = m->start_pos.x - start_base;
-        res -= pa_move_integrate(m, pressure_advance, base, 0., end, end);
+        res -= pa_move_integrate(m, pa_list, base, 0., end, end);
     }
     return res;
 }
 
 struct extruder_stepper {
     struct stepper_kinematics sk;
-    double pressure_advance, half_smooth_time, inv_half_smooth_time2;
+    struct list_head pa_list;
+    double half_smooth_time, inv_half_smooth_time2;
 };
 
 static double
@@ -116,22 +131,45 @@ extruder_calc_position(struct stepper_kinematics *sk, struct move *m
         // Pressure advance not enabled
         return m->start_pos.x + move_get_distance(m, move_time);
     // Apply pressure advance and average over smooth_time
-    double area = pa_range_integrate(m, move_time, es->pressure_advance, hst);
+    double area = pa_range_integrate(m, move_time, &es->pa_list, hst);
     return m->start_pos.x + area * es->inv_half_smooth_time2;
 }
 
 void __visible
-extruder_set_pressure_advance(struct stepper_kinematics *sk
+extruder_set_pressure_advance(struct stepper_kinematics *sk, double print_time
                               , double pressure_advance, double smooth_time)
 {
     struct extruder_stepper *es = container_of(sk, struct extruder_stepper, sk);
-    double hst = smooth_time * .5;
+    double hst = smooth_time * .5, old_hst = es->half_smooth_time;
     es->half_smooth_time = hst;
     es->sk.gen_steps_pre_active = es->sk.gen_steps_post_active = hst;
+
+    // Cleanup old pressure advance parameters
+    double cleanup_time = sk->last_flush_time - (old_hst > hst ? old_hst : hst);
+    struct pa_params *first_pa = list_first_entry(
+            &es->pa_list, struct pa_params, node);
+    while (!list_is_last(&first_pa->node, &es->pa_list)) {
+        struct pa_params *next_pa = list_next_entry(first_pa, node);
+        if (next_pa->active_print_time >= cleanup_time) break;
+        list_del(&first_pa->node);
+        first_pa = next_pa;
+    }
+
     if (! hst)
         return;
     es->inv_half_smooth_time2 = 1. / (hst * hst);
-    es->pressure_advance = pressure_advance;
+
+    if (list_last_entry(&es->pa_list, struct pa_params, node)->pressure_advance
+            == pressure_advance) {
+        // Retain old pa_params
+        return;
+    }
+    // Add new pressure advance parameters
+    struct pa_params *pa = malloc(sizeof(*pa));
+    memset(pa, 0, sizeof(*pa));
+    pa->pressure_advance = pressure_advance;
+    pa->active_print_time = print_time;
+    list_add_tail(&pa->node, &es->pa_list);
 }
 
 struct stepper_kinematics * __visible
@@ -141,5 +179,22 @@ extruder_stepper_alloc(void)
     memset(es, 0, sizeof(*es));
     es->sk.calc_position_cb = extruder_calc_position;
     es->sk.active_flags = AF_X;
+    list_init(&es->pa_list);
+    struct pa_params *pa = malloc(sizeof(*pa));
+    memset(pa, 0, sizeof(*pa));
+    list_add_tail(&pa->node, &es->pa_list);
     return &es->sk;
 }
+
+void __visible
+extruder_stepper_free(struct stepper_kinematics *sk)
+{
+    struct extruder_stepper *es = container_of(sk, struct extruder_stepper, sk);
+    while (!list_empty(&es->pa_list)) {
+        struct pa_params *pa = list_first_entry(
+                &es->pa_list, struct pa_params, node);
+        list_del(&pa->node);
+        free(pa);
+    }
+    free(sk);
+}

klippy/kinematics/extruder.py

@@ -18,7 +18,7 @@ def __init__(self, config):
         self.stepper = stepper.PrinterStepper(config)
         ffi_main, ffi_lib = chelper.get_ffi()
         self.sk_extruder = ffi_main.gc(ffi_lib.extruder_stepper_alloc(),
-                                       ffi_lib.free)
+                                       ffi_lib.extruder_stepper_free)
         self.stepper.set_stepper_kinematics(self.sk_extruder)
         self.motion_queue = None
         # Register commands
@@ -71,11 +71,14 @@ def _set_pressure_advance(self, pressure_advance, smooth_time):
         if not pressure_advance:
             new_smooth_time = 0.
         toolhead = self.printer.lookup_object("toolhead")
-        toolhead.note_step_generation_scan_time(new_smooth_time * .5,
-                                                old_delay=old_smooth_time * .5)
+        if new_smooth_time != old_smooth_time:
+            toolhead.note_step_generation_scan_time(
+                    new_smooth_time * .5, old_delay=old_smooth_time * .5)
         ffi_main, ffi_lib = chelper.get_ffi()
         espa = ffi_lib.extruder_set_pressure_advance
-        espa(self.sk_extruder, pressure_advance, new_smooth_time)
+        toolhead.register_lookahead_callback(
+            lambda print_time: espa(self.sk_extruder, print_time,
+                                    pressure_advance, new_smooth_time))
         self.pressure_advance = pressure_advance
         self.pressure_advance_smooth_time = smooth_time
     cmd_SET_PRESSURE_ADVANCE_help = "Set pressure advance parameters"

test/klippy/commands.test

@@ -40,7 +40,7 @@ SET_VELOCITY_LIMIT ACCEL=100 VELOCITY=20 SQUARE_CORNER_VELOCITY=1 ACCEL_TO_DECEL
 M204 S500
 
 SET_PRESSURE_ADVANCE EXTRUDER=extruder ADVANCE=.001
-SET_PRESSURE_ADVANCE ADVANCE=.002 ADVANCE_LOOKAHEAD_TIME=.001
+SET_PRESSURE_ADVANCE ADVANCE=.002 SMOOTH_TIME=.001
 
 # Restart command (must be last in test)
 RESTART

test/klippy/pressure_advance.cfg

@@ -0,0 +1,68 @@
+# Config for extruder testing
+[stepper_x]
+step_pin: PF0
+dir_pin: PF1
+enable_pin: !PD7
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^PE5
+position_endstop: 0
+position_max: 200
+homing_speed: 50
+
+[stepper_y]
+step_pin: PF6
+dir_pin: !PF7
+enable_pin: !PF2
+microsteps: 16
+rotation_distance: 40
+endstop_pin: ^PJ1
+position_endstop: 0
+position_max: 200
+homing_speed: 50
+
+[stepper_z]
+step_pin: PL3
+dir_pin: PL1
+enable_pin: !PK0
+microsteps: 16
+rotation_distance: 8
+endstop_pin: ^PD3
+position_endstop: 0.5
+position_max: 200
+
+[extruder]
+step_pin: PA4
+dir_pin: PA6
+enable_pin: !PA2
+microsteps: 16
+rotation_distance: 33.5
+nozzle_diameter: 0.500
+filament_diameter: 3.500
+heater_pin: PB4
+sensor_type: EPCOS 100K B57560G104F
+sensor_pin: PK5
+control: pid
+pid_Kp: 22.2
+pid_Ki: 1.08
+pid_Kd: 114
+min_temp: 0
+max_temp: 210
+
+[extruder_stepper my_extra_stepper]
+extruder: extruder
+step_pin: PH5
+dir_pin: PH6
+enable_pin: !PB5
+microsteps: 16
+rotation_distance: 28.2
+
+[mcu]
+serial: /dev/ttyACM0
+
+[printer]
+kinematics: cartesian
+max_velocity: 300
+max_accel: 3000
+max_z_velocity: 5
+max_z_accel: 100

test/klippy/pressure_advance.test

@@ -0,0 +1,38 @@
+# Extruder tests
+DICTIONARY atmega2560.dict
+CONFIG pressure_advance.cfg
+
+SET_PRESSURE_ADVANCE ADVANCE=0.1
+# Home and extrusion moves
+G28
+G1 X20 Y20 Z1 F6000
+G1 E7
+G1 X25 Y25 E7.5
+
+# Update pressure advance for my_extra_stepper
+SET_PRESSURE_ADVANCE EXTRUDER=my_extra_stepper ADVANCE=0.02
+G1 X30 Y30 E8.0
+
+# Unsync my_extra_stepper from extruder
+SYNC_EXTRUDER_MOTION EXTRUDER=my_extra_stepper MOTION_QUEUE=
+
+# Update pressure advance for primary extruder
+SET_PRESSURE_ADVANCE ADVANCE=0.01
+G1 X35 Y35 E8.5
+
+# Update pressure advance both extruders
+SET_PRESSURE_ADVANCE EXTRUDER=my_extra_stepper ADVANCE=0.05
+SET_PRESSURE_ADVANCE ADVANCE=0.05
+# Sync my_extra_stepper to extruder
+SYNC_EXTRUDER_MOTION EXTRUDER=my_extra_stepper MOTION_QUEUE=extruder
+G1 X40 Y40 E9.0
+
+# Update smooth_time
+SET_PRESSURE_ADVANCE SMOOTH_TIME=0.02
+SET_PRESSURE_ADVANCE EXTRUDER=my_extra_stepper SMOOTH_TIME=0.02
+G1 X45 Y45 E9.5
+
+# Updating both smooth_time and pressure advance
+SET_PRESSURE_ADVANCE SMOOTH_TIME=0.03 ADVANCE=0.1
+SET_PRESSURE_ADVANCE EXTRUDER=my_extra_stepper SMOOTH_TIME=0.03 ADVANCE=0.1
+G1 X50 Y50 E10.0