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Revised model for servo transit time
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@oskay
oskay committed Feb 21, 2022
1 parent c08aa61 commit 7ba774a
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Showing 2 changed files with 60 additions and 55 deletions.
100 changes: 51 additions & 49 deletions inkscape driver/axidraw.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2278,7 +2278,6 @@ def serial_connect(self):
else:
logger.debug(" Connected successfully")


def enable_motors(self):
"""
Enable motors, set native motor resolution, and set speed scales.
Expand Down Expand Up @@ -2332,15 +2331,18 @@ def pen_raise(self):
pen_down_pos = self.layer_pen_pos_down
else:
pen_down_pos = self.options.pen_pos_down
v_dist = abs(float(self.options.pen_pos_up - pen_down_pos))

# Servo travel time is estimated as the 4th power average (a smooth blend between):
# (A) Servo transit time for fast servo sweeps (t = slope * v_dist + min) and
# (B) Sweep time for slow sweeps (t = v_dist * full_scale_sweep_time / sweep_rate)
v_time = int(((self.params.servo_move_slope * v_dist + self.params.servo_move_min) ** 4 +
(self.params.servo_sweep_time * v_dist / self.options.pen_rate_raise) ** 4) ** 0.25)
if v_dist < 0.9: # If up and down positions are equal, no initial delay
v_time = 0

v_distance = float(self.options.pen_pos_up - pen_down_pos)
v_time = int(1000.0 * v_distance * self.params.servo_move_time /
self.options.pen_rate_raise)
if v_time < 0: # Handle case that pen_pos_down is above pen_pos_up
v_time = -v_time
v_time += self.options.pen_delay_up
if v_time < 0: # Do not allow negative delay times
v_time = 0
v_time = max(0, v_time) # Do not allow negative delay times
if self.options.preview:
self.update_v_charts(0, 0, 0)
self.vel_data_time += v_time
Expand Down Expand Up @@ -2368,43 +2370,47 @@ def pen_lower(self):
if not self.pen_up:
return # skip if pen is state is _known_ and is down

if not self.resume_mode and not self.b_stopped: # skip if resuming or stopped
if self.use_layer_pen_height:
pen_down_pos = self.layer_pen_pos_down
else:
pen_down_pos = self.options.pen_pos_down
v_distance = float(self.options.pen_pos_up - pen_down_pos)
v_time = int(1000.0 * v_distance * self.params.servo_move_time /
(self.options.pen_rate_lower))
if v_time < 0: # Handle case that pen_pos_down is above pen_pos_up
v_time = -v_time
v_time += self.options.pen_delay_down
if v_time < 0: # Do not allow negative delay times
v_time = 0
if self.options.preview:
self.update_v_charts(0, 0, 0)
self.vel_data_time += v_time
self.update_v_charts(0, 0, 0)
self.pt_estimate += v_time
else:
ebb_motion.sendPenDown(self.serial_port, v_time)
if self.params.use_b3_out:
ebb_motion.PBOutValue( self.serial_port, 3, 1 ) # I/O Pin B3 output: high
if v_time > 50:
if self.options.mode != "manual":
# pause before issuing next command
time.sleep(float(v_time - 30) / 1000.0)
self.pen_up = False
if self.resume_mode or self.b_stopped: # skip if resuming or stopped
return

def servo_setup_wrapper(self):
""" Utility wrapper for self.servo_setup """
#
# 1. Configure servo up & down positions and lifting/lowering speeds.
# 2. Query EBB to learn if we're in the up or down state.
#
# This wrapper is used in the manual, setup, and various plot modes,
# for initial pen raising/lowering.
if self.use_layer_pen_height:
pen_down_pos = self.layer_pen_pos_down
else:
pen_down_pos = self.options.pen_pos_down
v_dist = abs(float(self.options.pen_pos_up - pen_down_pos))

# Servo travel time is estimated as the 4th power average (a smooth blend between):
# (A) Servo transit time for fast servo sweeps (t = slope * v_dist + min) and
# (B) Sweep time for slow sweeps (t = v_dist * full_scale_sweep_time / sweep_rate)
v_time = int(((self.params.servo_move_slope * v_dist + self.params.servo_move_min) ** 4 +
(self.params.servo_sweep_time * v_dist / self.options.pen_rate_raise) ** 4) ** 0.25)
if v_dist < 0.9: # If up and down positions are equal, no initial delay
v_time = 0

v_time += self.options.pen_delay_down
v_time = max(0, v_time) # Do not allow negative delay times
if self.options.preview:
self.update_v_charts(0, 0, 0)
self.vel_data_time += v_time
self.update_v_charts(0, 0, 0)
self.pt_estimate += v_time
else:
ebb_motion.sendPenDown(self.serial_port, v_time)
if self.params.use_b3_out:
ebb_motion.PBOutValue( self.serial_port, 3, 1 ) # I/O Pin B3 output: high
if v_time > 50:
if self.options.mode != "manual":
# pause before issuing next command
time.sleep(float(v_time - 30) / 1000.0)
self.pen_up = False

def servo_setup_wrapper(self):
""" Utility wrapper for servo_setup()
1. Configure servo up & down positions and lifting/lowering speeds.
2. Query EBB to learn if we're in the up or down state.
This wrapper is used in the manual, setup, and various plot modes,
for initial pen raising/lowering.
"""
self.servo_setup() # Pre-stage the pen up and pen down positions

if self.pen_up is not None:
Expand Down Expand Up @@ -2466,28 +2472,24 @@ def servo_setup(self):
if not self.options.preview:
servo_range = self.params.servo_max - self.params.servo_min
servo_slope = float(servo_range) / 100.0

int_temp = int(round(self.params.servo_min + servo_slope * self.options.pen_pos_up))
ebb_motion.setPenUpPos(self.serial_port, int_temp)

int_temp = int(round(self.params.servo_min + servo_slope * pen_down_pos))
ebb_motion.setPenDownPos(self.serial_port, int_temp)

"""
Servo rate options (pen_rate_raise, pen_rate_lower) range from 1% to 100%.
The EBB servo rate values are in units of 83.3 ns steps per 24 ms.
Our servo sweep at 100% rate sweeps over 100% range in servo_sweep_time seconds.
Our servo sweep at 100% rate sweeps over 100% range in servo_sweep_time ms.
"""

servo_rate_scale = float(servo_range) * 0.024 / (100 * self.params.servo_sweep_time)
servo_rate_scale = float(servo_range) * 0.24 / self.params.servo_sweep_time
int_temp = int(round(servo_rate_scale * self.options.pen_rate_raise))
ebb_motion.setPenUpRate(self.serial_port, int_temp)
int_temp = int(round(servo_rate_scale * self.options.pen_rate_lower))
ebb_motion.setPenDownRate(self.serial_port, int_temp)

ebb_motion.servo_timeout(self.serial_port, self.params.servo_timeout) # Set timeout


def query_ebb_voltage(self):
""" Check that power supply is detected. """
if self.params.skip_voltage_check:
Expand Down
15 changes: 9 additions & 6 deletions inkscape driver/axidraw_conf.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -186,8 +186,8 @@
max_step_dist_hr = 0.000348 # Maximum distance covered by 1 step in Hi Res mode, rounded up, in inches. ~1/(2032 sqrt(2))
# In planning trajectories, we skip movements shorter than these distances, likely to be < 1 step.

const_speed_factor_lr = 0.25 # When in constant-speed mode, multiply the pen-down speed by this factor. Default: 0.25 for Low Res mode
const_speed_factor_hr = 0.4 # When in constant-speed mode, multiply the pen-down speed by this factor. Default: 0.4 for Hi Res mode
const_speed_factor_lr = 0.25 # In constant-speed mode, multiply pen-down speed by this factor. Default: 0.25 for Low Res mode
const_speed_factor_hr = 0.4 # In constant-speed mode, multiply pen-down speed by this factor. Default: 0.4 for Hi Res mode

start_pos_x = 0 # Parking position, inches. Default: 0
start_pos_y = 0 # Parking position, inches. Default: 0
Expand All @@ -208,11 +208,14 @@
servo_max = 27831 # Highest allowed position; "100%" on the scale. Default: 27831 units, or 2.32 ms.
servo_min = 9855 # Lowest allowed position; "0%" on the scale. Default: 9855 units, or 0.82 ms.

# Times for servo to move over full range, from servo_min to servo_max, at maximum raise/lower rate:
servo_sweep_time = 0.25 # Duration (s) to sweep servo control signal over 100% range. Default: 0.25
servo_move_time = 0.33 # Duration (s) for servo to physically move over 100% range. Default: 0.33
# Time for servo control signal to sweep over full 0-100% range, at 100% pen lift/lower rates:
servo_sweep_time = 200 # Duration, ms, to sweep servo control signal over 100% range. Default: 200

skip_voltage_check = False # Set to True if you would like to disable EBB input power voltage checks. Default: False
# Time for pen lift servo to physically move. Time = slope * distance + min, when using a fast sweep.
servo_move_min = 45 # Minimum time, ms, for pen lift/lower of non-zero distance. Default: 45
servo_move_slope = 2.69 # Additional time, ms, per percentage point of vertical travel. Default: 2.69

skip_voltage_check = False # Set to True to disable EBB input power voltage checks. Default: False

clip_to_page = True # Clip plotting area to SVG document size. Default: True

Expand Down

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