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原理
About PIDs
The term PID refers to a particular method of control. A PID loop has three gains and each of the letters P, I, and D refer to one of these three gains. PID feedback is one of the most common forms of feedback loops. There is a substantial amount of literature describing this type of feedback loop beyond that included in this manual.
PTerm
The P stands for proportional and refers to the gain that acts directly on the difference between the desired value and the actual value of the system being controlled.
For example in the elevator from pitch feedback loop, the P term is applied to the difference between the actual pitch and the desired pitch. This gain is referred to as Kp. The mathematical expression for the P term contribution to the elevator from pitch feedback loop is shown below.
ITerm
The I stands for integral and refers to the gain that acts on the sum of all the errors since the feedback loop was started. This gain is referred to as Ki.
For example, in the elevator from pitch feedback loop, the I term is applied to the sum of all pitch errors. This gain trims the aircraft in the same way as the trim on your RC transmitter is adjusted. Over time, your MicroPilot Autopilot adds all of the pitch errors together and this total, when multiplied by the I gain, will trim the aircraft. The mathematical expression for the I term contribution to the elevator frompitch feedback loop is shown below.
The D term stands for differential and acts on the rate of change of error. This gain is referred to as Kd.
In our example using the elevator from pitch feedback loop the D term acts on the rate of change of pitch. The mathematical expression for the D term contribution to the elevator from pitch feedback loop is shown below.
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