Effective Feedforward/Feedback Controller Design With Command Shaping to Reduce Residual Vibration

Manufacturing ◽  
2003 ◽  
Author(s):  
Peter H. Meckl ◽  
Young Joo Shin
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
Controller Design ◽  
High Volume ◽  
Feedback Controller ◽  
Residual Vibration ◽  
Command Shaping ◽  
Minimum Residual ◽  
High Volume Production ◽  
Point To Point

Many manufacturing devices must execute motions as quickly as possible to achieve profitable high-volume production. This paper develops a control strategy that combines feedforward and feedback control with command shaping. First, the feedback controller is designed to increase damping and eliminate steady-state error. Next, the feedforward controller is designed to speed up the transient response. Finally, an appropriate reference profile is generated using command-shaping techniques to ensure fast point-to-point motions with minimum residual vibration. The particular focus of the paper is to understand the interactions between these individual control components. The resulting control strategy is demonstrated on a model of a high-speed semiconductor manufacturing machine.

Controller Design Procedure for Two-Mass Systems With Single Flexible Mode

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Young Joo Shin ◽  
Peter H. Meckl
Keyword(s):  
Control Strategy ◽  
Controller Design ◽  
Design Procedure ◽  
High Volume ◽  
Command Shaping ◽  
Flexible Mode ◽  
Minimum Residual ◽  
High Volume Production ◽  
Pid Controller Design ◽  
Point To Point

Many manufacturing machines must execute motions as quickly as possible to achieve profitable high-volume production. Most of them exhibit some flexibility, which makes the settling time longer and controller design difficult. This paper develops a control strategy that combines feedforward and feedback control with command shaping for systems with collocated actuator and sensor. First, a feedback controller is designed to increase damping and eliminate steady-state error. Next, an appropriate reference profile is generated using command-shaping techniques to ensure fast point-to-point motions with minimum residual vibration. Finally, a feedforward controller is designed to speed up the transient response. The proposed proportional-integral-derivative (PID) controller design ensures that two important resonant frequencies nearly match, making the design of the input commands much simpler. The resulting control strategy is successfully demonstrated for a generic dimensionless system that incorporates some modeling errors to assess robustness.

Friction-Compensating Command Shaping for Vibration Reduction

2004 ◽  
Vol 127 (4) ◽  
pp. 307-314 ◽  
Author(s):  
Jason Lawrence ◽  
William Singhose ◽  
Keith Hekman
Keyword(s):  
Steady State ◽  
Coulomb Friction ◽  
Vibration Reduction ◽  
Input Shaping ◽  
Residual Vibration ◽  
Command Shaping ◽  
Point Motion ◽  
Common Operation ◽  
Point To Point ◽  
Theoretical Developments

Fast and accurate point-to-point motion is a common operation for industrial machines, but vibration will frequently corrupt such motion. This paper develops commands that can move machines without vibration, even in the presence of Coulomb friction. Previous studies have shown that input shaping can be used on linear systems to produce point-to-point motion with no residual vibration. This paper extends command-shaping theory to nonlinear systems, specifically systems with Coulomb friction. This idea is applied to a PD-controlled mass with Coulomb friction to ground. The theoretical developments are experimentally verified on a solder cell machine. The results show that the new commands allow the proportional gain to be increased, resulting in reduced rise time, settling time, and steady-state error.

scholarly journals Rest-to-Rest Motion of an Experimental Flexible Structure Subject to Friction: Linear Programming Approach

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Rajaey Kased ◽  
Tarunraj Singh
Keyword(s):  
Linear Programming ◽  
Controller Design ◽  
Open Loop ◽  
Programming Approach ◽  
Pulse Control ◽  
Test Bed ◽  
Residual Vibration ◽  
Linear Programming Approach ◽  
Point To Point ◽  
Harmonic System

A linear programming approach designed to eliminate the residual vibration of the two-mass harmonic system subject to friction and undergoing a point-to-point maneuver is proposed and implemented on an experimental test bed. Techniques for design of positive pulse control profiles for nonrobust and robust open loop controller design are explored, where the positive pulses initiate motion and the friction force brings the system to rest. It is shown that consistent results can be obtained from experiments and the robustness against frequency uncertainty results in the reduction in residual vibration as well as steady-state error.

Command Shaping Slewing Motions for Tower Cranes

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Jason Lawrence ◽  
William Singhose
Keyword(s):  
Nonlinear Dynamics ◽  
Rotational Motion ◽  
Effective Control ◽  
Input Shaping ◽  
Residual Vibration ◽  
Command Shaping ◽  
Tower Crane ◽  
Control Scheme ◽  
Point To Point ◽  
Gantry Cranes

Input shaping has been shown to be a practical and effective control scheme for reducing payload swing on industrial bridge and gantry cranes. However, when applied to tower cranes, standard input shapers will have degraded performance due to the nonlinear dynamics of rotational motion. To alleviate this problem, two new command generators for tower cranes are developed for a point-to-point slewing motion. It is shown that standard shaping techniques greatly reduce oscillation and the new tower crane command generators cause even less residual vibration. Simulations and experiments verify the results.

scholarly journals H∞Optimal Inversion Feedforward and Robust Feedback Based 2DOF Control Approach for High Speed-Precision Positioning Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Chao Peng ◽  
Chongwei Han ◽  
Jianxiao Zou ◽  
Guanghui Zhang
Keyword(s):  
High Speed ◽  
Controller Design ◽  
Feedback Controller ◽  
Linear Matrix ◽  
Positioning Error ◽  
Precision Positioning ◽  
Positioning Systems ◽  
Control Approach ◽  
Lmi Optimization ◽  
Feedforward Controller

This paper proposed a novelH∞optimal inversion feedforward and robust feedback based two-freedom-of-freedom (2DOF) control approach to address the positioning error caused by system uncertainties in high speed-precision positioning system. To minimize theH∞norm of the positioning error in the presence of model uncertainty, a linear matrix inequality (LMI) synthesis approach for optimal inversion feedforward controller design is presented. The specification of position resolution, control width, robustness, and output signal magnitude imposed on the entire 2DOF control system are taken as optimization objectives of feedback controller design. The robust feedback controller design approach integrates with feedforward controller systematically and is obtained via LMI optimization. The proposed approach was illustrated through a simulation example of nanopositioning control in atomic force microscope (AFM); the experiment results demonstrated that the proposed 2DOF control approach not only achieves the performance specification but also could improve the positioning control performance compared withH∞mixed sensitivity feedback control and inversion-based 2DOF control.

Minimizing Residual Vibration for Point-to-Point Motion

1985 ◽  
Vol 107 (4) ◽  
pp. 378-382 ◽  
Author(s):  
P. H. Meckl ◽  
W. P. Seering
Keyword(s):  
Minimum Energy ◽  
Residual Vibration ◽  
Test Fixture ◽  
Square Wave ◽  
Wave Forcing ◽  
Forcing Function ◽  
Point Motion ◽  
Minimum Residual ◽  
Order Of Magnitude ◽  
Point To Point

This paper describes an appropriately shaped forcing function for moving a dynamic system over an incremental distance with minimum residual vibration. The function is constructed by combining harmonics of a “ramped sinusoid” function so that minimum energy is introduced to the system at its resonant frequencies. A test fixture to evaluate this approach is described and experimental results are given. Residual vibration amplitudes for the ramped sinusoid function are compared with those for a square wave input and a bang-bang function. In practice, the ramped sinusoid achieves nearly an order-of-magnitude reduction in residual vibration amplitude as compared to the square wave forcing function.

Free Drawing and Polymer Coating of Silica Glass Optical Fibers

1999 ◽  
Vol 121 (4) ◽  
pp. 774-788 ◽  
Author(s):  
U. C. Paek
Keyword(s):  
Optical Fibers ◽  
High Speed ◽  
Low Cost ◽  
High Volume ◽  
Commercial Application ◽  
Fiber Drawing ◽  
Drawing System ◽  
High Volume Production ◽  
Process Mechanics ◽  
Fiber Manufacturing

The paper is primarily to highlight the current issues concerning fiber drawing and coating. The main emphasis is on high-volume production of silica-based optical fibers by using a large preform and a high-speed drawing. The commercial application of these processes has led to increasing the productivity in fiber manufacturing and resulted in a low cost of produced fibers. In order to systematically address the problems associated with the fiber manufacturing process, the fiber drawing system was divided into three major functional sections: heating, cooling, and coating zones. The governing equations at each section were formulated to describe the process mechanics and to identify the key control parameters for drawing and coating. These process parameters are the basic elements of implementing a streamline production system of optical fibers.

New Command Shaping Methods for Reduced Vibration of a Suspended Payload With Constrained Trolley Motion

2007 ◽  
Author(s):  
Aaron R. Enes ◽  
Timothy Y. Hsu ◽  
Angela A. Sodemann
Keyword(s):  
System Modeling ◽  
Small Scale ◽  
Residual Vibration ◽  
Conveyor System ◽  
Command Shaping ◽  
Common Task ◽  
Modeling Errors ◽  
Point To Point ◽  
Manufacturing Environments ◽  
Command Signal

In manufacturing environments, a common task is to quickly move a suspended payload point-to-point along a fixed overhead conveyor track without inducing significant payload vibration. Recent research in command shaping has shown remarkably effective ways to reduce the swing of a suspended payload providing the motion of the trolley is not constrained. However, the development of a command shaper where the trajectory of the trolley is constrained to follow a fixed curvilinear path has not been explored. This paper will present the development of a simple feedforward command shaper for fast, low vibration, point-to-point movement of a payload suspended from a trolley constrained to follow a fixed generalized path. The command shaping method involves modifying the command signal by convolving it with a series of impulses. Prior work has suggested command shaping to be very effective for fast, low-vibration movement of flexible systems. In this paper, command shaping methods are applied to an overhead conveyor system constrained to move along a fixed curvilinear path. Two new command shapers are presented for canceling payload vibration induced by motion of the trolley along the path. The designed Tangential Vibration (TV) shaper reduces payload vibrations induced by tangential accelerations of the trolley along the path, while the Centripetal-Tangential Vibration (CTV) shaper reduces vibrations induced by both tangential and centripetal accelerations. A key result of this study is that a command shaper having at least three impulses is required to yield zero residual vibration for motion along a curvilinear path. A simple pendulum payload attached to an actual small-scale overhead trolley following a constrained path is used to evaluate the performance of the designed command shapers. It is shown that the designed shapers significantly reduce payload swing compared to unshaped performance. An experimental sensitivity analysis shows the designed shapers are robust to system modeling errors and variations in path parameters.

The Green, Digital Clamping Device Composed of Self-Locking Power Screw Driven by the Servo Motor

2009 ◽  
Author(s):  
Yang Liu ◽  
Kangmin Zhong ◽  
Xiaoming Sheng ◽  
Mingdi Wang
Keyword(s):  
High Speed ◽  
Manufacturing Industry ◽  
High Volume ◽  
Energy Utilization ◽  
Servo Motor ◽  
High Volume Production ◽  
Volume Production ◽  
Basic Link ◽  
Clamping Device ◽  
The Cost

Fluid transmission, such as hydraulic and pneumatic, is widely used in the fixtures in modern industry. But there are some disadvantages in these fixtures. First, too much loops and turns in the hydraulic or pneumatic systems have lead to lower energy utilization ratio and complicated structure. Second, oil emission in hydraulic system may cause environment pollution, and the noise in pneumatic system may cause pollution too. Third, fluid system always needs electro-hydraulic or electro-pneumatic transform elements for digital intelligent control, which will add the cost and the complexity of system. In order to overcome this disadvantage, a new kind of mechatronics clamping device is designed innovatively, which is driven by servo motor and translated along the self-locking power screw. So it was very simple with little transmission elements and has no high-speed mechanic components. By changing the geometry shape of basic link, different requirements for clamping forces and clamping situations can be satisfied. This new kind of clamping device has prominent advantages in green and digital aspects. Moreover, it can meet perfectly the requirements of short-cycle, high-volume production in modern manufacturing industry.

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