class PID:
    def __init__(self, kp, ki, kd, integral_limit=10.0, alpha=1.0, output_limit=(0.0, 1.0)):
        self.kp = kp
        self.ki = ki
        self.kd = kd
        self.prev_error = 0.0
        self.integral = 0.0
        self.integral_limit = integral_limit
        self.alpha = alpha
        self.prev_output = 0.0
        self.output_limit = output_limit

    def update(self, error, dt):
        if dt <= 0:
            dt = 1e-6
        self.integral += error * dt
        self.integral = max(-self.integral_limit, min(self.integral_limit, self.integral))
        derivative = (error - self.prev_error) / dt
        output = self.kp * error + self.ki * self.integral + self.kd * derivative
        self.prev_error = error
        # 一阶滤波
        output = self.alpha * output + (1 - self.alpha) * self.prev_output
        self.prev_output = output

        # 输出限制
        output = max(self.output_limit[0], min(self.output_limit[1], output))

        return output

    def reset(self):
        self.prev_error = 0.0
        self.integral = 0.0
        self.prev_output = 0.0