A simple method of implementing a feedback control system. Basically, the amount you change your input signal by is equal to -Px, where P is a constant and x is the error at your output signal. In other words, a high positive error will produce a high negative change in signal, and a low negative error will produce a slightly positive change in signal, so that the tuning is more gradual as the error decreases.

Proportional control is usually accurate on the first order for most control systems, and it is frequently used by programmers who are savvy enough to know not to use bang-bang control. However, it has a couple of pitfalls:

  1. You may end up with a constant steady state error, if the proportional correction is not strong enough to change the output signal appreciatively. This can be reduced by fixing the value of P, but
  2. If P is too high, then any time delay in feedback is likely to cause your system to oscillate around the target value, as the system tries to adjust to error data that has already been fixed.
If you have the above problems, then consider using PD control, or PID control for your system.

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