Tài liệu !!! pptx

       !!! "# $"" !!! "#%    & '( ))***+% , -  .*))/012023* /$4.*))/0120(01 5 .$$"6  "# .7.//!!! "# i CONTENTS 1 About Servo System .2 1. What is “Servo System” 2 2. Positioning Mechanisms .3 3. Three Types of Control System 5 4. Configuration of the Servo System and Its Operation 7 2. About Servo Motor 11 1. Difference with Other Conventional Motor 11 2. Types and Features of Servo Motors 12 3. Construction of AC servo motor .13 3. About detector 19 1. Detector Classification According to Their Detection Method 19 2. Typical Detector .20 3. Features of Each Detector and Its Application. 22 4. About Servo Driver 23 1. Typical Servo Driver .23 5 About position Control 25 1 Two types of Positioning Systems 25 2. Speed Control and Torque Control .26 3. Response Frequency of Position Controllers 27 6 Introduction to OMRON Servo 29 6-1 System configuration and Model .29 6-2 Servo driver Nomenclature 30 6-3 Applicable Standards and Models .31 6-4 Wiring products conforming to UL/ cUL and Wiring Products Not Conforming to Any standards 32 6-5 Using Parameter Units .33 6-6 Initial Settings: Setup Parameters 36 7 Hands-On 42 7-1 Preparations for Operation .42 7-2 Auto-tuning 45 7-3 Manually Adjusting Gain .47 8 Servo Driver Specifications .49 8-1 General Specifications .49 8-2 Specifications .50 8-3 I/ O Specifications .51 8-4 Parameter Specifications 56 9 Performance Specifications .62 10 Connection Examples of C200H-MC221 & R88D-UA .64 1 Servo Section 1 1 About Servo System .2 1. What is “Servo System” 2 2. Positioning Mechanisms .3 3. Three Types of Control System 5 4. Configuration of the Servo System and Its Operation 7 Servo Section 1 2 1 About Servo System 1. What is “Servo System” “Servo” derives from the Greek “Servus (servant).” The system is called “Servo System” as it responds faithfully to a command. It is a system to control mechanical instruments in compliance with variation of position or speed target value (designated value, command value). Servo Section 1 3 2. Positioning Mechanisms The servo system is not the only alternative to control positioning and feed speed of mechanical facilities. Beside simple mechanical devices, however, the servo system is now the major control system to positioning and feed speed. Simple positioning Simple. Low cost. Available high speed operation. Flexible positioning by servo motor Precise. High speed. Easy to change target position and feed speed. No maintenance. High speed response Direct driving system Simple mechanism. No backlash. No trouble bout gear life. Stopper Cylinder Clutch & brake Motor Clutch & brake Cam system Position controller M Stepping motor Position controller M E Servo motor Position controller M Servo motor Change to AC servo motor Open loop Semi-closed loop Full-closed loop Position controller Linear motor Direct drive Stator (coiling side) Rotor Position controller Servo Section 1 4 Mechanical backlash and its correction Almost all mechanical devices have neutral zone between forward and reverse rotations. For example, when you change rotation direction of a mechanism from forward to reverse, an additional amount of rotation is required to cover a gap (free zone) between forward and reverse rotations. This gap or allowance is called “backlash”. The servo system has a function to compensate for this backlash. As shown above, the servo system sends command pulse adding correction amount of pulses. In this case, a current position value counter does not count this correction amount. Forward direction Forward /stop Start reverse rotation/ Send compensation pulses N amount of pulses Reverse (command pulse)/stop Start forward rotation Send compensation pulses N amount of pulses Forward command pulse/ stop (N-pulses) (N-pulses) Servo Section 1 5 3. Three Types of Control System At present, there are three major control system: 1) open loop, 2) semi-closed loop, and 3) full- closed loop systems System Configuration Open loop Semi-closed loop Full-closed loop Features of each system Open loop Semi-closed loop Full-closed loop Control system Simple Little complicated Complicated Detection method None Not required as installed in motor Required Against load fluctuation Week Strong Strong Precision Mechanical difference Mechanical difference By precision of detector Difference (backlash pitch difference) Difficult to correct Correction available Correction not required Motor Stepping motor AC servo DC servo AC servo DC servo Feed rate Low High High Cost Cheap Little expensive Expensive Complicity of system configuration Simple Little complicated Complicated Position controller (NC controller) Stepping Table Ball screw (Reduction gear) Position controller (NC controller) Stepping Ball screw (Reduction gear) Linear scale Table Position controller (NC controller) Stepping Table Ball screw (Reduction gear) Rotary encoder Servo Section 1 6 • Servo motor Major difference of the servo motor compared with general use induction motors is that it has a detector to detect rotation speed and position • Driver (analog input type) The driver controls servo motor rotation speed to rotate with a designated number of rotations in proportion to analog speed command voltage. Thus, it monitors motor rotation speed all the time • Positioner The positioner controls servo motor positioning. Thus, it monitors motor rotation position all the time Speed feedback signal Configuration example of servo system Output power shaft Motor section Detector (encoder etc.) Current Analog Command voltage (Ex.) Analog command Voltage +10V -5V Forward direction Reverse direction 3,000 rpm 1,500 rpm Number of rotation Position feedback signal Speed feedback signal Analog command voltage Position data setting Speed data setting Analog Command voltage Speed feedback signal Servo motor Position feedback signal Analog command voltage Servo Section 1 7 4. Configuration of the Servo System and Its Operation These sections are same as the above configuration. Position controller OMNUC N515 ONNUC N116 TG Memory Controller Section Oscillation Oscillation Indicator Direction judgement Error counter M D/A converter Pulse Multiplication circuit A B C D E E Encoder Motor Tacho-generator Position feedback Speed feedback Current feedback + _ + _ i Position command Speed command + _ Motor Servo Driver Position controller OMNUC N115 series M Motor + _ + _ i Re Speed feedbac k Resolver R/P Motor Servo Driver Position feedback D E Position feedback M Motor + _ + _ i Speed feedback Motor Servo Driver D E E Encoder F/V Servo Section 1 8 Error counter operation and response characteristics 1) When an amount of command pulse is supplied with equivalent to command speed, the servo driver receives square shaped input. The motor, however, takes some interval to reach to the command speed as it has to overcome inertia. 2) When the motor reaches the command speed, command pulse frequency becomes return pulse frequency. The motor speed stays in the rated level. 3) When the driver stops supply of command pulse by ending number of pulse equivalent to the command position, the error counter and D/ A converter output power until stored pulses (an amount equivalent to delay pulse amount S1 at start) in the error counter are discharged, and the motor keeps rotation with this output. The motor stops rotation when number of position command pulse is equal to number of return pulses. Stored pulse amount S1 equals S2 in the figure above Note 1: Error counter (also called “deviation counter”) Command pulses are temporarily stored inside the servo driver until they turn to command voltage by the D/A converter. These pulses are called error pulses or deviation pulses. Stored section is called “error counter” or “deviation counter.” Difference after completion of positioning should theoretically become zero. However, this may vary by total amount of allowance of position detector (ex: one pulse of the encoder), allowance of the servo driver, and mechanical static friction torque. S Input command pulse Stop command pulse V (pps) ② ① This area measurement is not changed. (Stored pulse amount of the error counter) ① S .    !!!  "# $"" !!!  "#%. /$4.*))/0120(01 5 .$$"6  "# .7./ /!!!  "# i CONTENTS 1 About Servo System .2