Delta Electronics ASDA-B Series manual Kpf, Pff

Chapter 6 Control Modes of OperationASDA-B Series

of mechanical system. In PDFF control AutoMode, the value of this parameter will be changed in accordance with the setting value of parameter P2-31 automatically (Please refer Table 6.D & 6.E in Chapter 6).

P2 - 03

PFF

Smooth Constant of Position Feed Forward Gain Communication Addr.: 0203H

Default: 5	Related Section:
Applicable Control Mode: P	Section 6.2.6, P2-02
Unit: ms
Range: 2 ~ 100
Settings:

When using position smooth command, increase gain can improve position track deviation. When not using position smooth command, decrease gain can improve the resonance condition of mechanical system.

			Position Control Block Diagram
			Position Feed		Smooth Constant of
		Differentiator	Forward Gain		Position Feed
			P2-02		Forward Gain P2-03
Position		Proportional				+	Maximum Speed
						+
Command	+	Position Loop		Position Loop			Limit P1-55
		Gain P2-00
				Gain Switching		Gain Switching
				RateP2-01			Speed Command
						Control Selection
						P2-27
				Position			Encoder
				Counter

When the value of Proportional Position Loop Gain, KPP is too great, the position loop responsiveness will be increased and it will result in small phase margin. If this happens, the rotor of motor will oscillate. At this time, the users have to decrease the value of KPP until the rotor of motor stop oscillating. When there is an external torque command interrupted, over low KPP value will let the motor cannot overcome the external strength and fail to meet the requirement of reasonable position track error demand. Adjust feed forward gain, KPF (P2-02) to efficiently reduce the dynamic position track error.

Position

KPP

(3)

Position

Position

Command

KPF

(1)

Actual position curve will change from (1) to (3) following the increasing KPP value

Time Time

6-8 Revision January, 2009