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heater: Report PID tuning results via the g-code terminal 

Determine the median period from the pin tuning tests and use that to
recommend a set of PID parameters.  Report the results over the g-code
terminal.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2018-01-10 22:38:05 -05:00
parent 5a68c636da
commit 5caff594c5
1 changed files with 20 additions and 5 deletions
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25
klippy/heater.py
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@ -105,6 +105,7 @@ class error(Exception):
class PrinterHeater:
error = error
def __init__(self, printer, config):
self.printer = printer
self.name = config.section
sensor_params = config.getchoice('sensor_type', Sensors)
self.sensor = sensor_params['class'](config, sensor_params)
@ -303,23 +304,37 @@ class ControlAutoTune:
self.peak = -9999999.
if len(self.peaks) < 4:
return
temp_diff = self.peaks[-1][0] - self.peaks[-2][0]
time_diff = self.peaks[-1][1] - self.peaks[-3][1]
self.calc_pid(len(self.peaks)-1)
def calc_pid(self, pos):
temp_diff = self.peaks[pos][0] - self.peaks[pos-1][0]
time_diff = self.peaks[pos][1] - self.peaks[pos-2][1]
max_power = self.heater.max_power
Ku = 4. * (2. * max_power) / (abs(temp_diff) * math.pi)
Tu = time_diff
Kp = 0.6 * Ku
Ti = 0.5 * Tu
Td = 0.125 * Tu
Kp = 0.6 * Ku * PID_PARAM_BASE
Ki = Kp / Ti
Kd = Kp * Td
logging.info("Autotune: raw=%f/%f Ku=%f Tu=%f Kp=%f Ki=%f Kd=%f",
temp_diff, max_power, Ku, Tu, Kp * PID_PARAM_BASE,
Ki * PID_PARAM_BASE, Kd * PID_PARAM_BASE)
temp_diff, max_power, Ku, Tu, Kp, Ki, Kd)
return Kp, Ki, Kd
def final_calc(self):
cycle_times = [(self.peaks[pos][1] - self.peaks[pos-2][1], pos)
for pos in range(4, len(self.peaks))]
midpoint_pos = sorted(cycle_times)[len(cycle_times)/2][1]
Kp, Ki, Kd = self.calc_pid(midpoint_pos)
logging.info("Autotune: final: Kp=%f Ki=%f Kd=%f", Kp, Ki, Kd)
gcode = self.heater.printer.objects['gcode']
gcode.respond_info(
"PID parameters: pid_Kp=%.3f pid_Ki=%.3f pid_Kd=%.3f\n"
"To use these parameters, update the printer config file with\n"
"the above and then issue a RESTART command" % (Kp, Ki, Kd))
def check_busy(self, eventtime):
if self.heating or len(self.peaks) < 12:
return True
self.final_calc()
self.heater.finish_auto_tune(self.old_control)
return False