High-speed and High-precision Motion Controller

Transcription

1 High-speed and High-precision Motion Controller - KSMC -

2 Definition High-Speed Axes move fast Execute the controller ( position/velocity loop, current loop ) at high frequency High-Precision High positioning accuracy Small following errors during moving

3 CPU ( SH4 ) KSMC Board SICPU RSMC PCC Programmable Combo Chip Encoder, PWM Driver Interface

4 KSMC-PCI

5 KSMC Board Specification Number of Axes Controllable Motor Type Output Signal Type Number of Encoder Channels Quadrature decode of Encoder Input Maximum 8 Axes Sinusoidal Communication for Synchronous AC Motor PWM & DAC Maximum 12 channels 1, 2, 4 quadrature decode Maximum Encode Count Rate 55 MHz (1/2, 1/4, 1/8) Available Encoder Type ADC-Input Resolution PWM Frequency PWM Count Frequency INC-Encoder, Analog Encoder (optional), Endat (optional) Up to 16 bit Maximum 50 khz Typical 55 MHz

6 KSMC Board Specification (cont.) DAC resolution Number of DAC channel Sin-Wave Table Size 4096 Processor Type & Speed ASIC Bus Interface PCI-Common memory size Additional Communication Maximum 16 bit 2 channel Digital Output (requires DAC board) 167MHz / SH4R@240MHz PWM-Circuit, Encoder Counter, DAC, I/O, Bus Controller PCI 16MB RS-232C, H-UDI Port (Hitachi User Debugging Interface : JTAG )

7 Programmable Combo Chip ( PCC ) 4 circuits of PWM - pulse generator 6 circuits of Encoder Counter 16 bit output data for DAC 1/T Extension registers ( sub-count compensation ) Hardware capture of the Encoder Counter ( source signal is selectable ) Typically, 2 PCCs are used on a KSMC Board

8 I/O Interface Controller Provides interface control for: PWM Pulse Generators Encoder Counters Serial A/D Converter Interface PCI Bus Interface RS232C Serial Interface Main job: Control AC Servomotor Interferes with Amplifiers: sinusoidal input, velocitymode, torque-mode, voltage-mode

9 Sodick Servo Interface (SI) Software This motion control firmware for KSMC board is developed by Sodick America Corporation.

10 Sodick Servo Interface Software Features Servo Control Algorithm Observer Current Loop Period Min. 20µs Conventional PID Control, Modern Control (Sliding Mode), Notch Filter, Feed Forward, Disturbance Observer Full-state ( Identity ) observer, Minimal order observer Position & Velocity Loop Period Min. 100µs Segment Time Min. 500µs Move Mode Error Management JOG (Feed), Homing( Origin Point Search) SPLINE, LINEAR, CIRCLE, PVT Following Error, Amplifier Fault, IIT Compensation Table Lead-screw Compensation: 1D, 2D, Backlash, Torque Compensation

11 RDI ( Real-time Motion Debugging Interface ) To tune the gains for the motors ( for the PID, Sliding Mode Controller, Disturbance Observer ). To help users design the Notch Filter, Sliding Mode Controller, Disturbance Observer, etc. even though they do not understand how to design them well. To show the internal status of the KSMC board. To send a command directly to the KSMC ( SI part ) through the PCI bus without any controller such as CNC on the host PC.

12 RDI Features PCI Configuration Register Reference Parameter Setting Command-line Interface Motor Setting ( Phasing, Gain Tuning, etc.) System Identification Notch Filter Design Disturbance Observer Design Modern Controller Auto Design (Sliding Mode Controller) Observer Design ( Full-state, Minimal order ) Data Gathering & Plotting Motion Programming Updating Firmware & ASIC configuration Data

13 RDI Screenshot - 1 Watch Window Command-Line Interface Speed Button Motion Programming Window Real-time Plotting

14 RDI Screenshot - 2 Motor Tuning Window Plot Window Gathering Feature Window

15 Motor Control Technology For a high-speed milling machine, a robust controller is necessary because the disturbance level is known to be higher than the slower speed milling machine. In order to put more control into the placement of the motor, the most advanced control theories have been introduced. Sliding Mode Controller Disturbance Observer Full-state observer, Minimal order observer Conventional PID controller is also available for use. Each axis can be controlled by either PID or Sliding Mode controller independently.

16 Sliding Mode Controller One of the most advanced modern control theories. Designable in time domain, well-suited to the motor control. Easy to design.

17 Advantages & Disadvantages of Sliding Mode Advantages Easy to design. Good robust performance Excellent when matching condition is met. Designable in time domain. Non-oscillatory transient response. Disadvantages Cannot design in frequency domain. Cannot define the frequency characteristic response because the controller is a nonlinear system. Complexity in frequency shaping.

18 Kinds & Features of Current Control Theory

19 Sliding Mode Control Current point Basic line ideal Sliding Target point

20 Sliding Mode Control Phase plane action α Gain K = β : σ > 0 : σ < 0

21 Sliding Mode Control

22 Sliding Mode Control Robustness Ambient reaction Θ σ L α Gain K = β : σ > 0 : σ < 0

23 Quick-follow Sliding Mode Control Patent pending

24 Step Response ( PID )

25 Step Response ( SLM )

26 Parabolic Reaction Circular move reaction [R=20mmF=3000mm/min]

27 Roundness on Actual Cutting Machine :MC430L Workpiece : R20mmF=3000(mm/min)S=29000(rpm), Material: Aluminum

28 Conclusion KSMC with Servo Interface software can provide high-speed and highprecision motion control by introducing the most advanced motor control technology.