YASKAWA E-S Series Product Manual

Contents

8.8 Manual Tuning8.8.1 Tuning the Servo Gains8-38 Decimal Points in Parameter SettingsDecimal places are given for the settings of parameters in the manual. For example with Pn100(Speed Loop Gain), Pn100 = 40.0 is used to indicate a setting of 40.0 Hz. In the followingadjusted value guidelines, the decimal places are also given.Model Following ControlYou can use model following control to improve response characteristic and shorten position-ing time.Normally, the parameters that are used for model following control are automatically set alongwith the servo gains by executing autotuning or custom tuning. However, you must adjust themmanually in the following cases.• When the tuning results for custom tuning are not acceptable• When you want to increase the response characteristic higher than that achieved by the tun-ing results for custom tuning• When you want to determine the servo gains and model following control parameters yourselfThe block diagram for model following control is provided below.• Speed Loop Gain (Pn100 [Hz]) and Speed Loop Integral Time Constant (Pn101 [ms])Stable gain: Pn101 [ms] ≥ 4,000/(2π × Pn100 [Hz]), thereforeIf Pn100 = 40.0 [Hz], then Pn101 = 4,000/(2π × 40.0) ≈ 15.92 [ms].ExampleModel followingcontrolmKp, mVFF, mTFF+ MPG++TfSpeed Speed patternTimeMovementreferenceTorque feedforwardSpeed control loopServomotorPowerconverterCurrentcontrolsectionSpeed loopSpeed controlsectionKv and TiSpeedreferencePositionloop gainKpDeviationcounterPosition loopCurrent loopEncoderKp: Position loop gain (Pn102)Kv: Speed loop gain (Pn100)Ti: Speed loop integral time constant (Pn101)Tf: First stage first torque reference filter time constant (Pn401)mKp: Model following control gain (Pn141)SpeedfeedforwardmTFF: Model following control bias in the forward direction (Pn143)Model following control bias in the reverse direction (Pn144)mVFF: Model following control speed feedforward compensation (Pn147)Position control loop