TAILIEUCHUNG - Servo Plant Compensation Techniques

Servo compensation usually implies that some type of filter network such as lead/lag circuits or proportional, integral, or differential (PID) algorithms will be used to stabilize the servo drive. However, there are other types of compensation that can be used external to the servo drive to compensate for other things in the servo plant (machine) that can, for example, be structural resonances or nonlinearities such as lost motion or stiction. These machine compensation techniques are shown in Figure 1 and are valid for either hydraulic or electric servo drives. DEAD-ZONE NONLINEARITY Stiction, sometimes referred to as stick-slip, occurring inside a positioning. | 11 Servo Plant Compensation Techniques Servo compensation usually implies that some type of filter network such as lead lag circuits or proportional integral or differential PID algorithms will be used to stabilize the servo drive. However there are other types of compensation that can be used external to the servo drive to compensate for other things in the servo plant machine that can for example be structural resonances or nonlinearities such as lost motion or stiction. These machine compensation techniques are shown in Figure 1 and are valid for either hydraulic or electric servo drives. DEAD-ZONE NONLINEARITY Stiction sometimes referred to as stick-slip occurring inside a positioning servo can result in a servo drive that will null hunt. The definition of a null hunt is an unstable position loop that has a very low periodic frequency such as 1 Hz or less with a small a few thousandths peak-to-peak amplitude limit cycle . The most successful way to avoid stiction problems is to use antifriction machine way rollers or hydrostatics or use a way linear material that has minimal stiction properties. If stiction-free machine slide ways cannot be provided the use of a small dead-zone nonlinearity placed inside the position loop preferably at the input to the velocity servo has Copyright 2003 by Marcel Dekker Inc. All Rights Reserved SERVO PLANT COMPENSATION TECHNIQUES RESONANCES PROB LEMS ELIMINATED ELIMINATED BY BY NOTCH FREQUENCY FILTERS SELECTIVE FEEDBACK FRICTION LOSTI NON-L SOLU1 STICTION MOTION NEAR DONS CHANGE IN GAIN DEAD ZONE TO OVERCOME TO OVERCOME POOR DRIVE AND A NULL HUNT RESOLUTION RESULTING IMPROVE FROM A SURFACE FINISH STICK-SLIP AND SPRING RATE MACHINE NONLINEARITY Fig. 1 Servo plant compensation techniques. had some success in overcoming a null hunt problem. However the dead zone must be very small . in. otherwise the servo drive will have an instability from too much lost motion. A simple analog dead-zone nonlinear circuit is shown in

• Cơ sở dữ liệu
• servo drive
• stick sli
• positioning servo
• antifriction machine
• velocity servo
• industrial servo drives
• drive sizing
• sufficient load thrust
• acceleration
• brushless DC motors
• torque regulation requirements
• Ứng dụng PLC
• Bộ điều khiển bám tín hiệu
• Tín hiệu mô phỏng hàng hải
• Tổ hợp drive/động cơ servo
• Chuyển động tàu thủy ba bậc tự do
• machine drive
• machine feed servo drive
• analysis techniques
• Classical control system
• Laplace Transform
• Describing functions
• servo drives
• torque requirements
• sizing the drive
• software sizing
• drivesizing programs
• Machine design
• thủ thuật máy tính
• công nghệ thông tin
• tin học
• quản trị mạng
• define performance
• DC servo drive
• diagram algebra
• general block
• Equations
• position loop equations
• Machine Feed
• Drive Considerations
• soft servo
• lowest resonance
• frequency
• Marcel Dekker
• performance
• troubleshooting techniques
• discusses system
• block diagrams
• engineering problems
• drive components