/usr/lib/python2.7/dist-packages/sardana/util/motion/motion.py is in python-sardana 1.2.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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##############################################################################
##
## This file is part of Sardana
##
## http://www.tango-controls.org/static/sardana/latest/doc/html/index.html
##
## Copyright 2011 CELLS / ALBA Synchrotron, Bellaterra, Spain
##
## Sardana is free software: you can redistribute it and/or modify
## it under the terms of the GNU Lesser General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## Sardana is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU Lesser General Public License for more details.
##
## You should have received a copy of the GNU Lesser General Public License
## along with Sardana. If not, see <http://www.gnu.org/licenses/>.
##
##############################################################################
"""This module contains the definition for a simulated motor"""
__all__ = ["MotionPath", "Motion", "BaseMotor", "Motor", "DemoMotor"]
__docformat__ = 'restructuredtext'
import time
from math import pow, sqrt
class MotionPath(object):
"""Active motion path description"""
#: True if motion in positive direction or False otherwise
positive_displacement = True
#: True if motion is not long enough to reach maximum velocity or False
#: otherwise
small_motion = False
#: position where maximum velocity will be reached
max_vel_pos = -1
#: necessary displacement to reach maximum velocity
displacement_reach_max_vel = 0
#: necessary diplacement to reach minimum velocity
displacement_reach_min_vel = 0
#: maximum velocity possible
max_vel = 0
#: displacement at maximum velocity
at_max_vel_displacement = -1
#: time to reach maximum velocity
max_vel_time = -1
#: time to reach minimum velocity
min_vel_time = -1
#: time at maximum velocity
at_max_vel_time = -1
#: time the motion will take
duration = -1
def __init__(self, motor,
initial_user_pos,
final_user_pos,
active_time=None):
"""MotionPath constructor - creates and calculates
motion path parameters.
:param initial_user_pos: position at which constant vel
should be reached
:param final_user_pos: position at which deceleration should
start
:param active_time: if passed, will fix the constant velocity
(abs(final_user_pos - initial_user_pos)/active_time)
otherwise motor constant velocity
will be selected as high as possible"""
self.motor = motor
self.initial_user_pos = initial_user_pos
self.final_user_pos = final_user_pos
self.active_time = active_time
self._calculateMotionPath()
def setInitialUserPos(self, initial_user_pos):
self.initial_user_pos = initial_user_pos
self._calculateMotionPath()
def setFinalUserPos(self, final_user_pos):
self.final_user_pos = final_user_pos
self._calculateMotionPath()
def _calculateMotionPath(self):
motor = self.motor
initial_user_pos = self.initial_user_pos
final_user_pos = self.final_user_pos
initial_pos = initial_user_pos * motor.step_per_unit
final_pos = final_user_pos * motor.step_per_unit
displacement = abs(final_pos - initial_pos)
# in this case active_time forces that the user range
# correspond to the constant velocity
# and
if self.active_time != None:
velocity = displacement / self.active_time
self.motor.setMaxVelocity(velocity)
sign = final_pos > initial_pos and 1 or -1
accel_time = motor.getAccelerationTime()
decel_time = motor.getDecelerationTime()
base_vel = motor.getMinVelocity()
accel_displacement = accel_time * 0.5 * (velocity + base_vel)
decel_displacement = decel_time * 0.5 * (velocity + base_vel)
initial_pos -= sign * accel_displacement
final_pos += sign * decel_displacement
displacement = abs(final_pos - initial_pos)
self.initial_user_pos = initial_pos
self.final_user_pos = final_pos
if displacement == 0:
positive_displacement = False
small_motion = True
accel = 0
decel = 0
displacement_reach_max_vel = 0
displacement_reach_min_vel = 0
max_vel = 0
min_vel = 0
max_vel_pos = initial_pos
at_max_vel_displacement = 0
max_vel_time = 0
min_vel_time = 0
at_max_vel_time = 0
duration = 0
else:
positive_displacement = final_pos > initial_pos
displmnt_not_cnst = motor.displacement_reach_max_vel + motor.displacement_reach_min_vel
small_motion = displacement < displmnt_not_cnst
if positive_displacement:
accel = motor.accel
decel = motor.decel
else:
accel = -motor.accel
decel = -motor.decel
if not small_motion:
# necessary displacement to reach maximum velocity
displacement_reach_max_vel = motor.displacement_reach_max_vel
# necessary diplacement to reach minimum velocity
displacement_reach_min_vel = motor.displacement_reach_min_vel
if positive_displacement:
max_vel = motor.max_vel
min_vel = motor.min_vel
# position where maximum velocity will be reached
max_vel_pos = initial_pos + displacement_reach_max_vel
else:
max_vel = -motor.max_vel
min_vel = -motor.min_vel
# position where maximum velocity will be reached
max_vel_pos = initial_pos - displacement_reach_max_vel
# displacement at maximum velocity
at_max_vel_displacement = displacement - (displacement_reach_max_vel + displacement_reach_min_vel)
else: # Small movement
# position where maximum velocity will be reached
max_vel_pos = initial_pos * accel - final_pos * decel
max_vel_pos /= accel - decel
# necessary displacement to reach maximum velocity
displacement_reach_max_vel = abs(max_vel_pos - initial_pos)
# necessary diplacement to reach minimum velocity
displacement_reach_min_vel = abs(final_pos - max_vel_pos)
# maximum velocity possible
cnst = 2 * accel * decel * displacement / (decel - accel)
max_vel_2 = pow(motor.min_vel, 2) + cnst
max_vel = sqrt(abs(max_vel_2))
if positive_displacement:
min_vel = motor.min_vel
else:
max_vel = -max_vel
min_vel = -motor.min_vel
# displacement at maximum velocity
at_max_vel_displacement = 0.0
delta_vel = abs(max_vel - min_vel)
# time to reach maximum velocity
if accel == 0 or delta_vel == float('inf'):
max_vel_time = 0
else:
max_vel_time = abs(delta_vel / accel)
# time to reach minimum velocity
if decel == 0 or delta_vel == float('inf'):
min_vel_time = 0
else:
min_vel_time = abs(delta_vel / decel)
# time at maximum velocity
if abs(max_vel) == float('inf'):
at_max_vel_time = 0
else:
at_max_vel_time = abs(at_max_vel_displacement / max_vel)
# time the motion will take
duration = max_vel_time + at_max_vel_time + min_vel_time
self.initial_pos = initial_pos
self.final_pos = final_pos
self.displacement = displacement
self.positive_displacement = positive_displacement
self.small_motion = small_motion
self.accel = accel
self.decel = decel
self.displacement_reach_max_vel = displacement_reach_max_vel
self.displacement_reach_min_vel = displacement_reach_min_vel
self.max_vel = abs(max_vel) #velocity must be a positive value
self.min_vel = abs(min_vel)
self.max_vel_pos = max_vel_pos
self.at_max_vel_displacement = at_max_vel_displacement
self.max_vel_time = max_vel_time
self.min_vel_time = min_vel_time
self.at_max_vel_time = at_max_vel_time
self.duration = duration
def info(self):
print "Small movement =",self.small_motion
print "length =",self.displacement
print "position where maximum velocity will be reached =",self.max_vel_pos
print "necessary displacement to reach maximum velocity =",self.displacement_reach_max_vel
print "necessary displacement to stop from maximum velocity =",self.displacement_reach_min_vel
print "maximum velocity possible =",self.max_vel
print "time at top velocity =",self.at_max_vel_time
print "displacement at top velocity =",self.at_max_vel_displacement
print "time to reach maximum velocity =",self.max_vel_time
print "time to reach minimum velocity =",self.min_vel_time
print "time the motion will take =",self.duration
print ""
print "For long movements (where top vel is possible), necessary displacement to reach maximum velocity =",self.displacement_reach_max_vel
print "For long movements (where top vel is possible), necessary displacement to stop from maximum velocity =",self.displacement_reach_min_vel
class Motion(object):
"""Active motion description"""
#: instant this motion started
start_instant = -1
#: instant when maximum velocity should be reached
max_vel_instant = -1
#: instant when should start decelerating
min_vel_instant = -1
#: instant the motion will end
final_instant = -1
def __init__(self, motor, initial_user_pos, final_user_pos, start_instant=None):
self.motion_path = mp = MotionPath(motor, initial_user_pos, final_user_pos)
start_instant = start_instant or time.time()
max_vel_instant = start_instant + mp.max_vel_time
min_vel_instant = max_vel_instant + mp.at_max_vel_time
final_instant = start_instant + mp.duration
self.start_instant = start_instant
self.max_vel_instant = max_vel_instant
self.min_vel_instant = min_vel_instant
self.final_instant = final_instant
assert(final_instant >= start_instant)
assert(start_instant <= max_vel_instant)
assert(final_instant >= min_vel_instant)
if self.motion_path.small_motion:
assert(max_vel_instant == min_vel_instant)
else:
assert(max_vel_instant <= min_vel_instant)
def __getattr__(self, name):
return getattr(self.motion_path, name)
class BaseMotor(object):
# base velocity (<units length>/s)
min_vel = 0
# top velocity (<units length>/s)
max_vel = float('+inf')
# acceleration time (s)
accel_time = 0
# deceleration time (s)
decel_time = 0
# acceleration (<units length>/s^2)
accel = float('+inf')
# acceleration (<units length>/s^2)
decel = float('+inf')
#: steps per unit
step_per_unit = 1
#: lower limit switch position
lower_ls = float('-inf')
#: upper limit switch position
upper_ls = float('+inf')
#: True if motor is powered or False otherwise
power = True
#: True if motor is enabled or False otherwise
enabled = True
#: necessary displacement to reach maximum velocity from minimum velocity
displacement_reach_max_vel = 0
#: necessary displacement to reach minimum velocity from maximum velocity
displacement_reach_min_vel = 0
#: internal member describing current motion
current_motion = None
current_position = float('nan')
def __init__(self):
pass
def setMinVelocity(self, vi):
pass
def getMinVelocity(self):
return self.min_vel
def setMaxVelocity(self, vf):
pass
def getMaxVelocity(self):
return self.max_vel
def setAccelerationTime(self, at):
"""Sets the time to go from minimum velocity to maximum velocity in seconds"""
pass
def getAccelerationTime(self):
return self.accel_time
def setDecelerationTime(self,dt):
"""Sets the time to go from maximum velocity to minimum velocity in seconds"""
pass
def getDecelerationTime(self):
return self.decel_time
def setAcceleration(self, a):
"""Sets the acceleration in ms^-2"""
pass
def setDeceleration(self, d):
"""Sets the deceleration in ms^-2"""
pass
def getStepPerUnit(self):
return self.step_per_unit
def setStepPerUnit(self, spu):
self.step_per_unit = spu
def startMotion(self, initial_user_pos, final_user_pos, start_instant=None):
if not self.power:
raise Exception("Motor is powered off")
if self.isInMotion():
raise Exception("Already in motion")
initial_pos = initial_user_pos * self.step_per_unit
final_pos = final_user_pos * self.step_per_unit
if initial_pos == final_pos:
return
motion = Motion(self, initial_user_pos, final_user_pos, start_instant)
motion_path = motion.motion_path
self.current_position = motion.initial_pos
self.current_motion = motion
def abortMotion(self, curr_instant=None):
curr_instant = curr_instant or time.time()
if not self.current_motion:
return self.current_position
self.current_position = self.getCurrentPosition(curr_instant)
self.current_motion = None
return self.current_position
def isInMotion(self, curr_instant=None):
curr_instant = curr_instant or time.time()
#we call getCurrentPosition because inside it updates the current_motion flag
self.getCurrentPosition(curr_instant)
return self.current_motion is not None
def setCurrentPosition(self, curr_pos):
self.current_position = curr_pos
def getCurrentPosition(self, curr_instant=None):
curr_instant = curr_instant or time.time()
pos = None
if self.current_motion:
motion = self.current_motion
# if motion should be ended...
if curr_instant >= motion.final_instant:
self.current_motion = None
pos = motion.final_pos
else:
pos = motion.initial_pos
if curr_instant > motion.min_vel_instant:
if motion.positive_displacement:
pos += motion.displacement_reach_max_vel
pos += motion.at_max_vel_displacement
else:
pos -= motion.displacement_reach_max_vel
pos -= motion.at_max_vel_displacement
dt = curr_instant - motion.min_vel_instant
pos += motion.max_vel * dt + 0.5 * motion.decel * pow(dt,2)
elif curr_instant > motion.max_vel_instant:
if motion.positive_displacement:
pos += motion.displacement_reach_max_vel
else:
pos -= motion.displacement_reach_max_vel
dt = curr_instant - motion.max_vel_instant
pos += motion.max_vel * dt
else:
dt = curr_instant - motion.start_instant
pos += motion.min_vel * dt + 0.5 * motion.accel * pow(dt,2)
else:
pos = self.current_position
if pos <= self.lower_ls:
pos = self.lower_ls
self.current_motion = None
elif pos >= self.upper_ls:
pos = self.upper_ls
self.current_motion = None
self.current_position = pos
return pos
def setCurrentUserPosition(self, user_pos):
self.setCurrentPosition(user_pos*self.step_per_unit)
def getCurrentUserPosition(self, curr_instant=None):
return self.getCurrentPosition(curr_instant=curr_instant) / self.step_per_unit
def hitLowerLimit(self):
user_pos = self.current_position / self.step_per_unit
return user_pos <= self.lower_ls
def hitUpperLimit(self):
user_pos = self.current_position / self.step_per_unit
return user_pos >= self.upper_ls
def getLowerLimitSwitch(self):
return self.lower_ls
def setLowerLimitSwitch(self, user_lower_ls):
self.lower_ls = user_lower_ls
def getUpperLimitSwitch(self):
return self.upper_ls
def setUpperLimitSwitch(self, user_upper_ls):
self.upper_ls = user_upper_ls
def turnOn(self):
self.power = True
def turnOff(self):
self.power = False
def isTurnedOn(self):
return self.power
def hasPower(self):
return self.power
def setPower(self, power):
self.power = power
def info(self):
if self.current_motion is not None:
print self.current_motion.info()
class Motor(BaseMotor):
"""The motor definition"""
def __init__(self, min_vel=None, max_vel=None, accel_time=None, decel_time=None):
super(Motor, self).__init__()
if min_vel is not None:
self.setMinVelocity(min_vel)
if max_vel is not None:
self.setMaxVelocity(max_vel)
if accel_time is not None:
self.setAccelerationTime(accel_time)
if decel_time is not None:
self.setDecelerationTime(decel_time)
self.__recalculate_acc_constants()
def setMinVelocity(self, vi):
""" Sets the minimum velocity in ms^-1. A.k.a. base rate"""
vi = float(vi)
if vi < 0:
raise Exception("Minimum velocity must be >= 0")
self.min_vel = vi
#TODO: consult this solution with others
if self.max_vel < self.min_vel:
pass
#self.max_vel = self.min_vel (original version)
# force recalculation of accelerations
if self.accel_time >= 0:
self.setAccelerationTime(self.accel_time)
if self.decel_time >= 0:
self.setDecelerationTime(self.decel_time)
def getMinVelocity(self):
return self.min_vel
def setMaxVelocity(self, vf):
""" Sets the maximum velocity in ms^-1."""
vf = float(vf)
if vf <= 0:
raise Exception("Maximum velocity must be > 0")
self.max_vel = vf
#TODO: consult this solution with others
if self.min_vel > self.max_vel:
pass
#self.min_vel = self.max_vel #accel set to zero (original version)
#self.setMinVelocity(0) another solution could be to set it to 0
# force recalculation of accelerations
if self.accel_time >= 0:
self.setAccelerationTime(self.accel_time)
if self.decel_time >= 0:
self.setDecelerationTime(self.decel_time)
def getMaxVelocity(self):
return self.max_vel
def setAccelerationTime(self, at):
"""Sets the time to go from minimum velocity to maximum velocity in seconds"""
at = float(at)
if at < 0:
raise Exception("Acceleration time must be >= 0")
self.accel_time = at
try:
self.accel = (self.max_vel - self.min_vel) / at
except ZeroDivisionError:
self.accel = float('inf')
self.__recalculate_acc_constants()
def getAccelerationTime(self):
return self.accel_time
def setDecelerationTime(self,dt):
"""Sets the time to go from maximum velocity to minimum velocity in seconds"""
dt = float(dt)
if dt < 0:
raise Exception("Deceleration time must be >= 0")
self.decel_time = dt
try:
self.decel = (self.min_vel - self.max_vel) / dt
except ZeroDivisionError:
self.decel = float('inf')
self.__recalculate_acc_constants()
def getDecelerationTime(self):
return self.decel_time
def setAcceleration(self, a):
"""Sets the acceleration in ms^-2"""
a = float(a)
if a < 0:
raise Exception("Acceleration must be >= 0")
self.accel = float(a)
if a > 0:
self.accel_time = (self.max_vel - self.min_vel) / a
else:
self.accel_time = float('INF')
self.__recalculate_acc_constants()
def setDeceleration(self, d):
"""Sets the deceleration in ms^-2"""
d = float(d)
if d > 0:
raise Exception("Deceleration must be <= 0")
self.decel = d
if d < 0:
self.decel_time = (self.min_vel - self.max_vel) / d
else:
self.decel_time = float('INF')
self.__recalculate_acc_constants()
def __recalculate_acc_constants(self):
"""precomputations assuming maximum speed can be reached in a motion"""
if self.accel_time == 0:
self.displacement_reach_max_vel = 0.0
else:
self.displacement_reach_max_vel = 0.5 * self.accel * pow(self.accel_time,2)
self.displacement_reach_max_vel += self.min_vel * self.accel_time
if self.decel_time == 0:
self.displacement_reach_min_vel = 0.0
else:
self.displacement_reach_min_vel = 0.5 * self.decel * pow(self.decel_time,2)
self.displacement_reach_min_vel += self.max_vel * self.decel_time
@staticmethod
def fromMotor(motor):
try:
import taurus.core.tango.sardana.pool
if isinstance(motor, taurus.core.tango.sardana.pool.PoolElement):
min_vel = motor.getBaseRate()
max_vel = motor.getVelocity()
accel_time = motor.getAcceleration()
decel_time = motor.getDeceleration()
return Motor(min_vel=min_vel, max_vel=max_vel,
accel_time=accel_time, decel_time=decel_time)
except Exception,e :
print e
return Motor._fromTangoMotor(motor)
@staticmethod
def _fromTangoMotor(motor):
import PyTango
attrs = "base_rate", "velocity", "acceleration", "deceleration"
attr_values = motor.read_attributes(attrs)
v=[]
for attr_value in attr_values:
if attr_value.has_failed:
raise PyTango.DevFailed(*attr_value.get_err_stack())
v.append(attr_value.value)
return Motor(min_vel=v[0], max_vel=v[1], accel_time=v[2], decel_time=v[3])
class DemoMotor(Motor):
def __init__(self):
super(DemoMotor, self).__init__(2, 100, 2, 2)
self.setCurrentPosition(0)
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