64 lines
2.8 KiB
Python
64 lines
2.8 KiB
Python
#!/usr/bin/env python3
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# Suggestion: implement odometry as class that is not using the ev3dev.ev3 package
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# establish value exchange with main driving class via getters and setters
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import time
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from planet import Direction
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'''
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Documentation:
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good and simple explanation on how odometry works:
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https://www.youtube.com/watch?v=qsdiIZncgqo
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Summary:
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axis a (measure distance where wheels have most friction)
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calibration factor c = diameter/ticks_per_turn
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distance d = ticks wheel * c (calculate for each wheel individually)
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vector_length = (d_l + d_r)/2
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vector_angle ~= (d_l + d_r)/a (only applicable for small distances)
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Functionality that should be implemented in this class:
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- tracking of relative distances
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- track the roboters orientation
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- maybe have seperate functions for vector length and orientation (only if it is beneficial)
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- closest coordinate to relative distance estimation/calculation
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'''
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class Odometry:
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def __init__(self, planet):
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self._wheel_axis = 11
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self._distance_per_tick= 0.0488
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self._pi = 3.141
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self.distance = 0
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#worked fine outside the class as function in nano, maybe we must fix it a bit :)
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def degree(self, delta_rotation_l, delta_rotation_r,star_Direc): #delta_rotation_l/r should work with getmovement method
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self.alpha = 0 #should be start_Direc
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self.alpha=star_Direc
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while True:
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self.alpha = ((self.delta_rotation_l * self._distance_per_tick - self.delta_rotation_r * self._distance_per_tick)/self._wheel_axis) + self.alpha
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self.distance=(self.delta_rotation_r * self._distance_per_tick + self.delta_rotation_l * self._distance_per_tick)/2 + self.distance
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if self.alpha % (2 * self._pi) >=0 and self.alpha % (2 * pi) <pi*0.25 or self.alpa % (2 * pi ) >= 7/4*pi and self.alpha %(2 * pi) <2*pi:
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return(Direction.NORTH)
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elif self.alpha % (2 * self._pi) >= self._pi*0.25 and self.alpha % ( 2 * pi ) < self._pi*0.5 or self.alpha % (2 * self._pi ) >= self._pi * 0.5 and self.alpha % (2 * self._pi ) < self._pi *0.75:
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return(Direction.EAST)
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elif self.alpha % (2 * self._pi)>=self._pi * 0.75 and self.alpha % (2* self._pi)< self._pi or self.alpha % (2 * self_pi) >=self._pi and self.alpha < self.alpha * 5/4 pi :
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return(Direction.SOUTH)
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else:
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return(Direction.WEST)
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def coordinates(self,delta_rota_l,delta_rota_r,Y_koord,X_koord): # worked as function outside the class
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self.y= self.Y_koord
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self.x= self.X_koord
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self.wheel_center = (delta_rota_r + delta_rota_l) /2
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self.alpha = ((self.delta_rotation_l * self._distance_per_tick - self.delta_rotation_r * self._distance_per_tick)/self._wheel_axis) + self.alpha
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self.y = self.y + wheel_center * math.cos(alpha)
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self.x = self.x + wheel_center * math.sin(alpha)
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return(self.x,self.y)
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