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Include dc_motor example, a simulation not in realtime.
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‎examples/dc_motor/README.md‎

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This simulation is a simplification of gtoonstra/bldc-sim, made by Gerard Toonstra and available at https://github.com/gtoonstra/bldc-sim.

‎examples/dc_motor/dc_motor_open.py‎

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https://github.com/gtoonstra/bldc-sim
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import utime
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import math
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from machine import Timer
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class DCMotor(object):
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def __init__ (
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self,
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Ra=0.52,
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La=0.000036,
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B=0.00001,
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J=0.000012,
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Kbemf=0.0137,
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STATIC_FRICTION=0.01,
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FRICTION_S=0.01
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):
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self.bemf = 0.0
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# omega = rpm ( w )
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self.omega = 0.0
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# theta = electrical angle normalized to 2*pi
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self.theta = 0.0
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self.ia, self.va = 0.0, 0.0
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self.Pelec, self.Te, self.Tl = 0.0, 0.0, 0.0
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# La here is La subtracted by mutual inductance M.
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self.Ra, self.La, self.B, self.J = Ra, La, B, J
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self.Kbemf = Kbemf
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self.STATIC_FRICTION, self.FRICTION_S = STATIC_FRICTION, FRICTION_S
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self._last_time = 0.0
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# The simulator
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def sim( self, load, va, dt):
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now = utime.ticks_us()
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# Set the load
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sign = math.copysign( 1, self.omega )
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self.Tl = sign * load
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self.va = va
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# Calculate bemf
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self.bemf = self.Kbemf * self.omega
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# Calculate change in current per di/dt
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dot_ia = (1.0 / self.La) * ( self.va - (self.Ra * self.ia) - self.bemf )
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# Apply changes to current in phases
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self.ia += dot_ia * dt
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# Electrical torque. Since omega can be null, cannot derive from P/w
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self.Te = self.Kbemf * self.ia
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# Electrical power
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self.Pelec = self.bemf * self.ia
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# Mechanical torque.
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# mtorque = ((etorque * (p->m->NbPoles / 2)) - (p->m->damping * sv->omega) - p->pv->torque);
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self.Tm = ((self.Te) - (sign * self.B * abs(self.omega)) - self.Tl)
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# Friction calculations
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if abs(self.omega) < 1.0:
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if abs(self.Te) < self.STATIC_FRICTION:
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self.Tm = 0.0
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else:
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self.Tm -= self.STATIC_FRICTION
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else:
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self.Tm = self.Tm - sign * ( self.STATIC_FRICTION * math.exp( -5 * abs( self.omega )) + self.FRICTION_S )
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# J is the moment of inertia
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dotOmega = (self.Tm / self.J)
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self.omega = self.omega + dotOmega * dt
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self.theta += self.omega * dt
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self.theta = self.theta % ( 2.0 * math.pi )
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self._last_time += dt
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return self.omega
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def variables( self ):
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ret = {}
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ret[ "va" ] = self.va
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ret[ "ia" ] = self.ia
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ret[ "omega" ] = self.omega
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ret[ "theta" ] = self.theta
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ret[ "bemf" ] = self.bemf
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ret[ "torque" ] = self.Te
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ret[ "loadtorque" ] = self.Tl
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return ret
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dcmotor = DCMotor()
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omega = dcmotor.omega
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load = 0.3
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step = 15
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# how much time do you spend simulating
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sim_time=10
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#how much elapsed simulated time do you want to keep
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print_interval=1000e-6
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last_time=0
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deadline4 = utime.ticks_add(utime.time(), sim_time)
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while utime.ticks_diff(deadline4, utime.time()) > 0:
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omega = dcmotor.sim(load, step, 32e-6)
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if ((dcmotor._last_time - last_time) > print_interval):
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print(dcmotor._last_time,",",omega)
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last_time = dcmotor._last_time

‎examples/dc_motor/dc_motor_pid.py‎

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import utime
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import math
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from control import PID
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from machine import Timer
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class DCMotor(object):
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def __init__ (
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self,
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Ra=0.52,
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La=0.000036,
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B=0.00001,
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J=0.000012,
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Kbemf=0.0137,
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STATIC_FRICTION=0.01,
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FRICTION_S=0.01
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):
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self.bemf = 0.0
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# omega = rpm ( w )
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self.omega = 0.0
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# theta = electrical angle normalized to 2*pi
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self.theta = 0.0
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self.ia, self.va = 0.0, 0.0
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self.Pelec, self.Te, self.Tl = 0.0, 0.0, 0.0
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# La here is La subtracted by mutual inductance M.
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self.Ra, self.La, self.B, self.J = Ra, La, B, J
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self.Kbemf = Kbemf
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self.STATIC_FRICTION, self.FRICTION_S = STATIC_FRICTION, FRICTION_S
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self._last_time = 0.0
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# The simulator
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def sim( self, load, va, dt):
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now = utime.ticks_us()
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# Set the load
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sign = math.copysign( 1, self.omega )
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self.Tl = sign * load
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self.va = va
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# Calculate bemf
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self.bemf = self.Kbemf * self.omega
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# Calculate change in current per di/dt
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dot_ia = (1.0 / self.La) * ( self.va - (self.Ra * self.ia) - self.bemf )
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# Apply changes to current in phases
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self.ia += dot_ia * dt
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# Electrical torque. Since omega can be null, cannot derive from P/w
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self.Te = self.Kbemf * self.ia
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# Electrical power
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self.Pelec = self.bemf * self.ia
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# Mechanical torque.
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# mtorque = ((etorque * (p->m->NbPoles / 2)) - (p->m->damping * sv->omega) - p->pv->torque);
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self.Tm = ((self.Te) - (sign * self.B * abs(self.omega)) - self.Tl)
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# Friction calculations
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if abs(self.omega) < 1.0:
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if abs(self.Te) < self.STATIC_FRICTION:
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self.Tm = 0.0
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else:
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self.Tm -= self.STATIC_FRICTION
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else:
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self.Tm = self.Tm - sign * ( self.STATIC_FRICTION * math.exp( -5 * abs( self.omega )) + self.FRICTION_S )
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# J is the moment of inertia
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dotOmega = (self.Tm / self.J)
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self.omega = self.omega + dotOmega * dt
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self.theta += self.omega * dt
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self.theta = self.theta % ( 2.0 * math.pi )
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self._last_time += dt
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return self.omega
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def variables( self ):
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ret = {}
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ret[ "va" ] = self.va
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ret[ "ia" ] = self.ia
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ret[ "omega" ] = self.omega
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ret[ "theta" ] = self.theta
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ret[ "bemf" ] = self.bemf
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ret[ "torque" ] = self.Te
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ret[ "loadtorque" ] = self.Tl
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return ret
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dcmotor = DCMotor()
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omega = dcmotor.omega
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load = 0.3
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step = 230
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# how much time do you spend simulating
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sim_time=10
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#how much elapsed simulated time do you want to keep
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print_interval=500e-6
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power = 0
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last_time=0
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pid = PID(1.0634, 0.0082041, 0, setpoint=step)
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deadline4 = utime.ticks_add(utime.time(), sim_time)
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while utime.ticks_diff(deadline4, utime.time()) > 0:
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omega = dcmotor.sim(load, power, 32e-6)
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power = pid(omega, 32e-6)
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if ((dcmotor._last_time - last_time) > print_interval):
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print(dcmotor._last_time,",",omega,",",pid.setpoint,",",power)
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last_time = dcmotor._last_time

‎examples/water_boiler/water_boiler.py‎

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This file was deleted.

‎examples/water_boiler/water_boiler_open.py‎

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import utime
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from machine import Timer
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class WaterBoiler:
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"""
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Simple simulation of a water boiler which can heat up water
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and where the heat dissipates slowly over time
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"""
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def __init__(self, dissipation=0.2):
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self.water_temp = 20
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self.ambient = 20
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self.dissipation = dissipation
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self._last_time = utime.ticks_ms()
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def update(self, boiler_power):
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now = utime.ticks_ms()
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dt = utime.ticks_diff(now,self._last_time) if (utime.ticks_diff(now,self._last_time)) else 1e-16
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if boiler_power > 0:
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# Boiler can only produce heat, not cold
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self.water_temp += 1 * boiler_power * dt / 1000
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# Some heat dissipation
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self.water_temp -= (self.water_temp - self.ambient) * self.dissipation * dt
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self._last_time = now
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return self.water_temp
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boiler = WaterBoiler(0.001)
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water_temp = boiler.water_temp
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step = 40
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#Timer Function Callback
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def timerFunc0(t):
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global water_temp
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# step of 20
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water_temp = boiler.update(step)
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def timerFunc1(t):
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global water_temp
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print(boiler._last_time,",",water_temp)
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def timerFunc2(t):
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tim0.deinit()
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tim1.deinit()
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tim0=Timer(0)
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tim0.init(period=100, mode=Timer.PERIODIC, callback=timerFunc0)
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tim1=Timer(1)
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tim1.init(period=200, mode=Timer.PERIODIC, callback=timerFunc1)
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tim2=Timer(2)
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tim2.init(period=10000, mode=Timer.ONE_SHOT, callback=timerFunc2)
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‎examples/water_boiler/water_boiler_pid.py‎

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import utime
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from PID import PID
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from machine import Timer
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class WaterBoiler:
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"""
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Simple simulation of a water boiler which can heat up water
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and where the heat dissipates slowly over time
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"""
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def __init__(self, dissipation=0.2):
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self.water_temp = 20
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self.ambient = 20
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self.dissipation = dissipation
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self._last_time = utime.ticks_ms()
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def update(self, boiler_power):
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now = utime.ticks_ms()
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dt = utime.ticks_diff(now,self._last_time) if (utime.ticks_diff(now,self._last_time)) else 1e-16
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if boiler_power > 0:
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# Boiler can only produce heat, not cold
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self.water_temp += 1 * boiler_power * dt / 1000
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# Some heat dissipation that depend on the difference of temperature
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self.water_temp -= (self.water_temp - self.ambient) * self.dissipation * dt
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self._last_time = now
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return self.water_temp
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boiler = WaterBoiler(0.001)
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power = 0
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water_temp = boiler.water_temp
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pid = PID(3.7293, 0.9540, 0, setpoint=51, sample_time=200, scale='ms')
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pid.output_limits = (0, 100)
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#Timer Function Callback
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def timerFunc0(t):
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global power, water_temp
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water_temp = boiler.update(power)
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power = pid(water_temp)
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def timerFunc1(t):
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global power, water_temp
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print(pid._last_time,",",water_temp,",",pid.setpoint,",",power)
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def timerFunc2(t):
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tim0.deinit()
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tim1.deinit()
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tim0=Timer(0)
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tim0.init(period=100, mode=Timer.PERIODIC, callback=timerFunc0)
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tim1=Timer(1)
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tim1.init(period=200, mode=Timer.PERIODIC, callback=timerFunc1)
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tim2=Timer(2)
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tim2.init(period=10000, mode=Timer.ONE_SHOT, callback=timerFunc2)
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