我在网上遇到了一些代码,其中为arduino实现了PID . 我对实施感到困惑 . 我对PID如何工作有基本的了解,但是我的混淆源是为什么十六进制用于m_prevError? 0x80000000L表示的值是什么,为什么在计算速度时右移10?
// ServoLoop Constructor
ServoLoop::ServoLoop(int32_t proportionalGain, int32_t derivativeGain)
{
m_pos = RCS_CENTER_POS;
m_proportionalGain = proportionalGain;
m_derivativeGain = derivativeGain;
m_prevError = 0x80000000L;
}
// ServoLoop Update
// Calculates new output based on the measured
// error and the current state.
void ServoLoop::update(int32_t error)
{
long int velocity;
char buf[32];
if (m_prevError!=0x80000000)
{
velocity = (error*m_proportionalGain + (error - m_prevError)*m_derivativeGain)>>10;
m_pos += velocity;
if (m_pos>RCS_MAX_POS)
{
m_pos = RCS_MAX_POS;
}
else if (m_pos<RCS_MIN_POS)
{
m_pos = RCS_MIN_POS;
}
}
m_prevError = error;
}