2014-03-12 00:35:01 -03:00
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#!/usr/bin/env python
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'''
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simple antenna tracker simulator core
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'''
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from aircraft import Aircraft
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import util, time, math
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from math import degrees, radians
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from rotmat import Vector3
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class Tracker(Aircraft):
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'''a simple antenna tracker'''
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def __init__(self,
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rate_controlled=False,
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pitch_range = 45,
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yaw_range = 180,
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zero_yaw = 270, # yaw direction at startup
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zero_pitch = 10, # pitch at startup
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2014-03-12 17:30:41 -03:00
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turn_rate=90 # servo max turn rate in degrees/sec
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2014-03-12 00:35:01 -03:00
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):
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Aircraft.__init__(self)
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self.rate_controlled = rate_controlled
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self.turn_rate = turn_rate
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self.last_time = time.time()
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self.pitch_range = pitch_range
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self.yaw_range = yaw_range
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self.zero_yaw = zero_yaw
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self.zero_pitch = zero_pitch
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self.verbose = False
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self.last_debug = time.time()
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self.pitch_current = 0
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self.yaw_current = 0
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def slew_limit(self, current, target, range, delta_time):
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'''limit speed of servo movement'''
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dangle = self.turn_rate * delta_time
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dv = dangle / range
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if target - current > dv:
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return current + dv
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if target - current < -dv:
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return current - dv
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return target
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def update(self, state):
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# how much time has passed?
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t = time.time()
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delta_time = t - self.last_time
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self.last_time = t
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self.pitch_current = self.slew_limit(self.pitch_current, state.pitch_input, self.pitch_range, delta_time)
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self.yaw_current = self.slew_limit(self.yaw_current, state.yaw_input, self.yaw_range, delta_time)
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pitch_target = self.zero_pitch + self.pitch_current*self.pitch_range
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yaw_target = self.zero_yaw + self.yaw_current*self.yaw_range
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while yaw_target > 180:
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yaw_target -= 360
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(r,p,y) = self.dcm.to_euler()
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pitch_current = degrees(p)
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yaw_current = degrees(y)
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roll_current = degrees(r)
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pitch_rate = pitch_target - pitch_current
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pitch_rate = min(self.turn_rate, pitch_rate)
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pitch_rate = max(-self.turn_rate, pitch_rate)
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yaw_diff = yaw_target - yaw_current
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if yaw_diff > 180:
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yaw_diff -= 360
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if yaw_diff < -180:
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yaw_diff += 360
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yaw_rate = yaw_diff
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yaw_rate = min(self.turn_rate, yaw_rate)
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yaw_rate = max(-self.turn_rate, yaw_rate)
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# keep it level
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roll_rate = 0 - roll_current
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if time.time() - self.last_debug > 2:
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self.last_debug = time.time()
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print("roll=%.1f/%.1f pitch=%.1f/%.1f yaw=%.1f/%.1f rates=%.1f/%.1f/%.1f" % (
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roll_current, 0,
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pitch_current, pitch_target,
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yaw_current, yaw_target,
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roll_rate, pitch_rate, yaw_rate))
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self.gyro = Vector3(radians(roll_rate),radians(pitch_rate),radians(yaw_rate))
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# update attitude
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self.dcm.rotate(self.gyro * delta_time)
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self.dcm.normalize()
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accel_earth = Vector3(0, 0, -self.gravity)
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self.accel_body = self.dcm.transposed() * accel_earth
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# new velocity vector
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self.velocity = Vector3()
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self.update_position(delta_time)
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