76 lines
2.2 KiB
Python
76 lines
2.2 KiB
Python
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# Simulation of a PID-controller
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import matplotlib.pyplot as plt
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class PIDController:
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def __init__(self, Kp, Ki, Kd, setpoint):
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self.Kp = Kp
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self.Ki = Ki
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self.Kd = Kd
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self.setpoint = setpoint
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self.prev_error = 0
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self.integral = 0
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def update(self, measured_value):
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error = self.setpoint - measured_value
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self.integral += error
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derivative = error - self.prev_error
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output = self.Kp * error + self.Ki * self.integral + self.Kd * derivative
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self.prev_error = error
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return output
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def set_setpoint(self, setpoint):
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self.setpoint = setpoint
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# Simulation parameters
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Kp = 4 # Proportional gain
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Ki = 1/4 # Integral gain
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Kd = 1/2 # Derivative gain
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setpoint = 100.0
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initial_value = 0.0
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simulation_time = 100
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time_step = 0.1
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# Create PID controller
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pid_controller = PIDController(Kp, Ki, Kd, setpoint)
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# Initialize lists to store data for plotting
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time_points = []
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control_signals = []
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current_values = []
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# Simulate PID controller
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current_value = initial_value
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for t in range(simulation_time):
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if t == simulation_time // 3:
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pid_controller.set_setpoint(50.0)
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if t == 2 * simulation_time // 3:
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pid_controller.set_setpoint(150.0)
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time_points.append(t)
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control_signal = pid_controller.update(current_value)
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control_signals.append(control_signal)
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# Apply control signal (simulate process)
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current_value += control_signal * time_step
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current_values.append(current_value)
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# Plotting
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plt.figure(figsize=(10, 6))
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plt.subplot(2, 1, 1)
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plt.plot(time_points, current_values, label='Current Value')
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plt.plot([0, simulation_time // 3], [100, 100], 'r--', label='Setpoint 100')
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plt.plot([simulation_time // 3, 2 * simulation_time // 3], [50, 50], 'r--', label='Setpoint 50')
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plt.plot([2 * simulation_time // 3, simulation_time], [150, 150], 'r--', label='Setpoint 150')
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plt.xlabel('Time')
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plt.ylabel('Value')
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plt.title('PID Controller Simulation')
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plt.legend()
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plt.subplot(2, 1, 2)
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plt.plot(time_points, control_signals, 'g', label='Control Signal')
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plt.xlabel('Time')
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plt.ylabel('Control Signal')
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plt.legend()
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plt.tight_layout()
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# plt.savefig('pid_simulation.png') # Save to file
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plt.show() # Show immediately
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