121 lines
3.8 KiB
Python
121 lines
3.8 KiB
Python
import numpy as np
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import math
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import time
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from controller import ControllerBase
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class PIDController(ControllerBase):
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def __init__(self):
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super().__init__()
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self.t = None
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self.P_angle = 0.4
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self.I_angle = 0.35
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self.D_angle = 0.1
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self.P_pos = 0.50
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self.I_pos = 0.3
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self.D_pos = 0.1
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self.mode = 'combined'
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self.e_angle_old = 0.0
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self.e_pos_old = 0.0
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self.i = 0.0
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self.i_angle = 0.0
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self.i_pos = 0.0
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def set_target_position(self, target_pos):
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super(PIDController, self).set_target_position(target_pos)
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self.mode = 'combined'
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self.e_angle_old = 0.0
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self.e_pos_old = 0.0
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self.i = 0.0
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self.i_angle = 0.0
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self.i_pos = 0.0
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def compute_control(self, state):
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# measure state
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x_pred = state[1:]
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if self.t is None:
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dt = 0.1
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else:
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dt = time.time() - self.t # time since last control was applied
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if self.mode == 'angle':
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# compute angle such that robot faces to target point
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target_angle = self.target_pos[2]
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angles_unwrapped = np.unwrap([x_pred[2], target_angle]) # unwrap angle to avoid jump in data
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e_angle = angles_unwrapped[0] - angles_unwrapped[1] # angle difference
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p = self.P_angle * e_angle
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self.i += self.I_angle * dt * (e_angle + self.e_angle_old)/2.0 # trapezoidal rule
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d = self.D_angle * (e_angle - self.e_angle_old)/dt
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u1 = p + self.i + d
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u2 = - u1
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self.e_angle_old = e_angle
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elif self.mode == 'combined':
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# compute angle such that robot faces to target point
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v = self.target_pos[0:2] - x_pred[0:2]
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target_angle = math.atan2(v[1], v[0])
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angles_unwrapped = np.unwrap([x_pred[2], target_angle]) # unwrap angle to avoid jump in data
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e_angle = angles_unwrapped[0] - angles_unwrapped[1] # angle difference
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e_pos = np.linalg.norm(v[0:2])
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if e_pos < 0.03:
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self.mode = 'angle'
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self.e_angle_old = 0
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self.e_pos_old = 0
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self.i_angle = 0
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self.i_pos = 0
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u1 = 0
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u2 = 0
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else:
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forward = abs(e_angle) < np.pi/2.0
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if not forward:
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if e_angle > np.pi/2.0:
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e_angle -= np.pi
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else:
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e_angle += np.pi
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p_angle = self.P_angle * e_angle
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self.i_angle += self.I_angle * dt * (e_angle + self.e_angle_old) / 2.0 # trapezoidal rule
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d_angle = self.D_angle * (e_angle - self.e_angle_old) / dt
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p_pos = self.P_pos * e_pos
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self.i_pos += self.I_pos * dt * (e_pos + self.e_pos_old) / 2.0 # trapezoidal rule
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d_pos = self.D_pos * (e_pos - self.e_pos_old) / dt
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if forward:
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u1 = p_angle + p_pos + self.i_angle + self.i_pos + d_angle + d_pos
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u2 = - p_angle + p_pos - self.i_angle + self.i_pos - d_angle + d_pos
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else:
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u1 = p_angle - p_pos + self.i_angle - self.i_pos + d_angle - d_pos
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u2 = - p_angle - p_pos - self.i_angle - self.i_pos - d_angle - d_pos
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self.e_pos_old = e_pos
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self.e_angle_old = e_angle
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else:
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u1 = 0.0
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u2 = 0.0
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return u1, u2
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def stop(self):
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super(PIDController, self).stop()
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self.t = None
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def apply_control(self, control):
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self.t = time.time() # save time when the most recent control was applied
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super(PIDController, self).apply_control(control)
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