366 lines
15 KiB
Python
366 lines
15 KiB
Python
# -*- coding: utf-8 -*-
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# *****************************************************************************
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# Module authors:
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# M. Zolliker <markus.zolliker@psi.ch>
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#
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# *****************************************************************************
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"""use transducer and motor to adjust force"""
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import time
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import math
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from secop.core import Drivable, Parameter, FloatRange, Done, \
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Attached, Command, PersistentMixin, PersistentParam, BoolType
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from secop.errors import BadValueError
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from secop.lib.statemachine import Retry, StateMachine, Restart
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class Error(Exception):
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pass
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class Uniax(PersistentMixin, Drivable):
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value = Parameter(unit='N')
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motor = Attached()
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transducer = Attached()
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limit = Parameter('abs limit of force', FloatRange(0, 190, unit='N'), readonly=False, default=150)
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tolerance = Parameter('force tolerance', FloatRange(0, 10, unit='N'), readonly=False, default=0.1)
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slope = PersistentParam('spring constant', FloatRange(unit='deg/N'), readonly=False,
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default=0.5, persistent='auto')
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pid_i = PersistentParam('integral', FloatRange(), readonly=False, default=0.5, persistent='auto')
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filter_interval = Parameter('filter time', FloatRange(0, 60, unit='s'), readonly=False, default=1)
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current_step = Parameter('', FloatRange(unit='deg'), default=0)
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force_offset = PersistentParam('transducer offset', FloatRange(unit='N'), readonly=False, default=0,
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initwrite=True, persistent='auto')
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hysteresis = PersistentParam('force hysteresis', FloatRange(0, 190, unit='N'), readonly=False, default=5,
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persistent='auto')
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adjusting = Parameter('', BoolType(), readonly=False, default=False, initwrite=True)
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adjusting_current = PersistentParam('current when adjusting force', FloatRange(0, 2.8, unit='A'), readonly=False,
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default=0.5, persistent='auto')
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safe_step = PersistentParam('max. motor step when adjusting force', FloatRange(0, unit='deg'), readonly=False,
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default=5, persistent='auto')
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safe_current = PersistentParam('current when moving far', FloatRange(0, 2.8, unit='A'), readonly=False,
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default=0.2, persistent='auto')
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low_pos = Parameter('max. position for positive forces', FloatRange(unit='deg'), readonly=False, needscfg=False)
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high_pos = Parameter('min. position for negative forces', FloatRange(unit='deg'), readonly=False, needscfg=False)
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substantial_force = Parameter('min. force change expected within motor play', FloatRange(), default=0)
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motor_play = Parameter('acceptable motor play within hysteresis', FloatRange(), readonly=False, default=10)
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motor_max_play = Parameter('acceptable motor play outside hysteresis', FloatRange(), readonly=False, default=70)
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pollinterval = 0.1
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_mot_target = None # for detecting manual motor manipulations
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_filter_start = 0
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_filtered = False
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_cnt = 0
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_sum = 0
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_cnt_rderr = 0
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_cnt_wrerr = 0
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_in_cnt = 0
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_zero_pos_tol = None
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_state = None
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def earlyInit(self):
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super().earlyInit()
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self._zero_pos_tol = {}
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def initModule(self):
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super().initModule()
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self._state = StateMachine(logger=self.log, threaded=False, cleanup=self.cleanup)
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def doPoll(self):
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self.read_value()
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self._state.cycle()
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def drive_relative(self, step, ntry=3):
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"""drive relative, try 3 times"""
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mot = self.motor
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mot.read_value() # make sure motor value is fresh
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if self.adjusting and abs(step) > self.safe_step:
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step = math.copysign(self.safe_step, step)
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self.current_step = step
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for _ in range(ntry):
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try:
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self._mot_target = self.motor.write_target(mot.value + step)
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self._cnt_wrerr = max(0, self._cnt_wrerr - 1)
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return True
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except Exception as e:
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self.log.warning('drive error %s', e)
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self._cnt_wrerr += 1
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if self._cnt_wrerr > 5:
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raise
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self.log.warning('motor reset')
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self.motor.reset()
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return False
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def reset_filter(self, now=0.0):
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self._sum = self._cnt = 0
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self._filter_start = now or time.time()
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def motor_busy(self):
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mot = self.motor
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if mot.isBusy():
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if mot.target != self._mot_target:
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raise Error('control stopped - motor moved directly')
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return True
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return False
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def zero_pos(self, value):
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"""get high_pos or low_pos, depending on sign of value
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:param value: return an estimate for a good starting position
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"""
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name = 'high_pos' if value > 0 else 'low_pos'
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if name not in self._zero_pos_tol:
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return None
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return getattr(self, name)
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def set_zero_pos(self, force, pos):
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"""set zero position high_pos or low_pos, depending on sign and value of force
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:param force: the force used for calculating zero_pos
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:param pos: the position used for calculating zero_pos
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"""
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name = 'high_pos' if force > 0 else 'low_pos'
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if pos is None:
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self._zero_pos_tol.pop(name, None)
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return None
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pos -= force * self.slope
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tol = (abs(force) - self.hysteresis) * self.slope * 0.2
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if name in self._zero_pos_tol:
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old = self.zero_pos(force)
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if abs(old - pos) < self._zero_pos_tol[name] + tol:
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return
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self._zero_pos_tol[name] = tol
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self.log.info('set %s = %.1f +- %.1f (@%g N)' % (name, pos, tol, force))
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setattr(self, name, pos)
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return pos
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def find(self, state):
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"""find active (engaged) range"""
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if state.init:
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state.prev_direction = 0 # find not yet started
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direction = math.copysign(1, self.target)
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if self.value * direction > self.hysteresis or self.value * direction > self.target * direction:
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if self.motor_busy():
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self.log.info('motor stopped - substantial force detected: %g', self.value)
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self.motor.stop()
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elif state.prev_direction == 0:
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return self.adjust
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if abs(self.value) > self.hysteresis:
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self.set_zero_pos(self.value, self.motor.read_value())
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return self.adjust
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if self.value * direction < -self.hysteresis:
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state.force_before_free = self.value
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return self.free
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if self.motor_busy():
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if direction == -state.prev_direction: # target direction changed
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self.motor.stop()
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state.init_find = True # restart find
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return Retry()
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zero_pos = self.zero_pos(self.target)
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if state.prev_direction: # find already started
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if abs(self.motor.target - self.motor.value) > self.motor.tolerance:
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# no success on last find try, try short and strong step
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self.write_adjusting(True)
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self.log.info('one step to %g', self.motor.value + self.safe_step)
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self.drive_relative(direction * self.safe_step)
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return Retry()
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else:
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state.prev_direction = math.copysign(1, self.target)
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side_name = 'negative' if direction == -1 else 'positive'
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if zero_pos is not None:
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self.status = 'BUSY', 'change to %s side' % side_name
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zero_pos += direction * (self.hysteresis * self.slope - self.motor.tolerance)
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if (self.motor.value - zero_pos) * direction < -self.motor.tolerance:
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self.write_adjusting(False)
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self.log.info('change side to %g', zero_pos)
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self.drive_relative(zero_pos - self.motor.value)
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return Retry()
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# we are already at or beyond zero_pos
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return self.adjust
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self.write_adjusting(False)
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self.status = 'BUSY', 'find %s side' % side_name
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self.log.info('one turn to %g', self.motor.value + direction * 360)
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self.drive_relative(direction * 360)
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return Retry()
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def cleanup(self, state):
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"""in case of error, set error status"""
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if state.stopped: # stop or restart
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if state.stopped is Restart:
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return
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self.status = 'IDLE', 'stopped'
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self.log.warning('stopped')
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else:
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self.status = 'ERROR', str(state.last_error)
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if isinstance(state.last_error, Error):
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self.log.error('%s', state.last_error)
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else:
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self.log.error('%r raised in state %r', str(state.last_error), state.status_string)
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self.motor.stop()
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self.write_adjusting(False)
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def free(self, state):
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"""free from high force at other end"""
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if state.init:
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state.free_way = None
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if self.motor_busy():
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return Retry()
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if abs(self.value) > abs(state.force_before_free) + self.tolerance:
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self.stop()
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self.status = 'ERROR', 'force increase while freeing'
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self.log.error(self.status[1])
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return None
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if abs(self.value) < self.hysteresis:
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return self.find
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if state.free_way is None:
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state.free_way = 0
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self.log.info('free from high force %g', self.value)
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self.write_adjusting(True)
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direction = math.copysign(1, self.target)
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if state.free_way > (abs(state.force_before_free) + self.hysteresis) * self.slope:
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self.stop()
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self.status = 'ERROR', 'freeing failed'
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self.log.error(self.status[1])
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return None
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state.free_way += self.safe_step
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self.drive_relative(direction * self.safe_step)
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return Retry()
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def within_tolerance(self, state):
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"""within tolerance"""
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if self.motor_busy():
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return Retry()
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if abs(self.target - self.value) > self.tolerance:
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return self.adjust
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self.status = 'IDLE', 'within tolerance'
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def adjust(self, state):
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"""adjust force"""
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if state.init:
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state.prev_force = None
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if self.motor_busy():
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return
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if abs(self.target - self.value) < self.tolerance:
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self._in_cnt += 1
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if self._in_cnt >= 3:
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return self.within_tolerance
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else:
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self._in_cnt = 0
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if state.prev_force is None:
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state.prev_force = self.value
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state.prev_pos = self.motor.pos
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self.write_adjusting(True)
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self.status = 'BUSY', 'adjusting force'
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elif not self._filtered:
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return
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else:
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if abs(self.value - state.prev_force) > self.substantial_force:
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state.prev_force = self.value
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state.prev_pos = self.motor.value
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else:
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motor_dif = abs(self.value - state.prev_pos)
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if abs(self.value) < self.hysteresis:
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if motor_dif > self.motor_play:
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self.log.warning('adjusting failed - try to find zero pos')
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self.set_zero_pos(self.target, None)
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return self.find
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elif motor_dif > self.motor_max_play:
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raise Error('force seems not to change substantially')
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force_step = (self.target - self.value) * self.pid_i
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self.drive_relative(force_step * self.slope)
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return Retry()
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def read_value(self):
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try:
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force = self.transducer.read_value()
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self._cnt_rderr = max(0, self._cnt_rderr - 1)
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except Exception as e:
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self._cnt_rderr += 1
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if self._cnt_rderr > 10:
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self.stop()
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self.status = 'ERROR', 'too many read errors: %s' % e
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self.log.error(self.status[1])
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return Done
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now = time.time()
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if self.motor_busy():
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# do not filter while driving
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self.reset_filter()
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self._filtered = False
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else:
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self._sum += force
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self._cnt += 1
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if now < self._filter_start + self.filter_interval:
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return Done
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force = self._sum / self._cnt
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self.reset_filter(now)
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self._filtered = True
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if abs(force) > self.limit + self.hysteresis:
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self.motor.stop()
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self.status = 'ERROR', 'above max limit'
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self.log.error(self.status[1])
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return Done
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if self.zero_pos(force) is None and abs(force) > self.hysteresis and self._filtered:
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self.set_zero_pos(force, self.motor.read_value())
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return force
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def write_target(self, target):
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if abs(target) > self.limit:
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raise BadValueError('force above limit')
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if abs(target - self.value) <= self.tolerance:
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if not self.isBusy():
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self.status = 'IDLE', 'already at target'
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self._state.start(self.within_tolerance)
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return target
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self.log.info('new target %g', target)
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self._cnt_rderr = 0
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self._cnt_wrerr = 0
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self.status = 'BUSY', 'changed target'
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if self.value * math.copysign(1, target) > self.hysteresis:
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self._state.start(self.adjust)
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else:
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self._state.start(self.find)
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return target
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@Command()
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def stop(self):
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if self.motor.isBusy():
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self.log.info('stop motor')
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self.motor.stop()
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self.status = 'IDLE', 'stopped'
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self._state.stop()
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def write_force_offset(self, value):
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self.force_offset = value
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self.transducer.write_offset(value)
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return Done
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def write_adjusting(self, value):
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mot = self.motor
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if value:
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mot_current = self.adjusting_current
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mot.write_move_limit(self.safe_step)
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else:
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mot_current = self.safe_current
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mot.write_safe_current(mot_current)
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if abs(mot_current - mot.maxcurrent) > 0.01: # resolution of current: 2.8 / 250
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self.log.info('motor current %g', mot_current)
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mot.write_maxcurrent(mot_current)
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return value
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