A plant control includes determining a control input into the plant to cause a control output of the plant to converge to a desired value. A value of at least one parameter for adjusting a speed of change of the control output relative to change of the desired value is determined in accordance with a plant condition. The control input is determined based on the parameter having the value thus determined. The parameter includes a first parameter for changing a speed of change of the control input relative to change of the desired value. The parameter can also include a second parameter for changing the relative speed via a corrected desired value that is determined by correcting the desired value. The second parameter can further include a gradient parameter and a gradually-approaching characteristic parameter.