Comparison of Polynomial Cam Profiles and Input Shaping for Driving Flexible Systems

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Brice Pridgen ◽  
William Singhose
Keyword(s):  
Rise Time ◽  
Laplace Transforms ◽  
Experimental Results ◽  
Input Shaping ◽  
Flexible Systems ◽  
Residual Vibration ◽  
Alternative Method ◽  
Cam Follower ◽  
Low Pass ◽  
Polynomial Profiles

Polynomial profiles can be used as reference commands to limit induced vibration in flexible systems. Due to their ease of design and low-pass filtering effects, polynomial profiles are often found in cam-follower systems. Polynomial profiles have also been used as smooth reference commands for automated machines. However, despite extensive work to develop and improve such profiles, inherent tradeoffs still exist between induced vibration, rise time, and ease of design. Input shaping is an alternative method for generating motion commands that reduce residual vibration. This paper compares polynomial profiles to input-shaped commands for the application of reducing vibration in flexible systems. Analyses using Laplace transforms reveal that input shapers suppress vibration at regularly spaced frequencies. However, polynomial profiles do not share this property. Simulations and experimental results show that input shaping improves rise time and reduces residual vibration in comparison to polynomial profiles.

Hybrid input shaping to suppress residual vibration of flexible systems

2011 ◽  
Vol 18 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Hakan Yavuz ◽  
Selçuk Mıstıkoğlu ◽  
Sadettin Kapucu
Keyword(s):  
Input Shaping ◽  
Flexible Systems ◽  
Residual Vibration

Residual Vibration Reduction Using Vector Diagrams to Generate Shaped Inputs

1994 ◽  
Vol 116 (2) ◽  
pp. 654-659 ◽  
Author(s):  
W. Singhose ◽  
W. Seering ◽  
N. Singer
Keyword(s):  
Natural Frequency ◽  
Upper Bound ◽  
Vibration Amplitude ◽  
Damping Ratio ◽  
Vibration Reduction ◽  
System Model ◽  
Input Shaping ◽  
Flexible Systems ◽  
Residual Vibration ◽  
Performance Predictions

This paper describes a method for limiting vibration in flexible systems by shaping the input to the system. Unlike most previous input shaping strategies, this method does not require a precise system model or lengthy numerical computation; only estimates of the system natural frequency and damping ratio are required. The effectiveness of this method when there are errors in the system model is explored and quantified. Next, an algorithm is presented, which, given an upper bound on acceptable residual vibration amplitude, determines a shaping strategy that is insensitive to errors in the estimate of the natural frequency. Finally, performance predictions are compared to hardware experiments.

A Study on Dynamic Performance of Precise XY Stages Using Real-Time Input Shaping

2008 ◽  
Vol 381-382 ◽  
pp. 493-496
Author(s):  
Sang Won Park ◽  
S.W. Hong ◽  
H.S. Choi ◽  
W.E. Singhose
Keyword(s):  
Feedback Control ◽  
Simulation Model ◽  
Real Time ◽  
Dynamic Performance ◽  
Experimental Results ◽  
Input Shaping ◽  
Residual Vibration ◽  
The Real ◽  
Duration Time ◽  
Input Command

Reducing residual vibration is very crucial to enhance the speed and precision of XY stages which are often employed by manufacturing/measuring machines. Input shaping is known to be a very effective tool for suppressing such residual vibration without introducing any complicated sensors and feedback control. This paper investigated the effects of input command discretization parameters in real-time input shaping, such as discretizing interval and duration time, on the dynamic performance of a XY stage equipped with servo motors. A simulation model is established to investigate the dynamic performance of the XY stage. In order to evaluate the real-time input shaping parameters on the performance of the XY stage, two fundamental input shaping schemes, ZV(zero vibration) and ZVD(zero vibration and derivative), are implemented and tested with the discretizing interval and duration time varied. The experimental results provide a strategy to gain better performance.

Improving Manual Control of Two-Link Pendulum on Gantry Crane With Anti-Delay Closed-Loop Input Shaping

2017 ◽  
Author(s):  
Withit Chatlatanagulchai ◽  
Nitirong Pongpanich ◽  
Pisai Yaemprasuan
Keyword(s):  
Feedback Loop ◽  
Closed Loop ◽  
Smith Predictor ◽  
Human Operator ◽  
Manual Control ◽  
Gantry Crane ◽  
Input Shaping ◽  
Flexible Systems ◽  
Residual Vibration ◽  
Shaping Filter

This paper presents a novel and improved technique in manual control of flexible systems. Flexible systems, when subject to a rapid movement commanded by a human operator, exhibit severe oscillation, causing low positioning accuracy, high fatigue to the human operator, and unsafe accidents. Input shaping filter was proposed to reduce this oscillation by using the destructive interference principle where impulse responses cancel one another resulting in zero residual vibration. Recently, the input shaping filter was placed inside the feedback loop, so-called closed-loop signal shaping, to assist with the manual control of the flexible systems. The vibration was successfully suppressed. However, the input shaping filter also introduced time delays in the feedback loop, which limit the performance of the human operator. This paper offers a breakthrough idea by introducing an anti-delay algorithm called Smith predictor inside the feedback loop. When the plant model is perfect, it can be shown that the Smith predictor can entirely remove the effect of time delay from the feedback loop; therefore, improving the performance of the human operator. Experiments on manual control of a two-link pendulum on a gantry crane show the effectiveness of the proposed algorithm. The human operator was able to move the two-link pendulum with minimum residual vibration. Comparing to the currently world-best technique, the proposed technique could achieve faster maneuvering time, higher accuracy, and with less subjective difficulty.

Negative Input Shaping: Eliminating Overcurrenting and Maximizing the Command Space

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Khalid L. Sorensen ◽  
Aayush Daftari ◽  
William E. Singhose ◽  
Keith Hekman
Keyword(s):  
Rise Time ◽  
System Performance ◽  
Three Dimensional ◽  
Mitigation Strategies ◽  
Input Shaping ◽  
Bridge Crane ◽  
Flexible Systems ◽  
Filtering Method ◽  
Dimensional Simulation ◽  
Insight Into

Input shaping is a filtering method used for reducing oscillation in flexible systems. A class of these filters, called negative input shapers, has been developed to improve system rise-time beyond what is achievable using conventional input-shaping filters. However, negative input shapers can cause overcurrenting and subsequent system oscillation, when used with certain reference commands. This class of reference commands is examined in the context of the command space. The command space represents the space of all possible signals that may be issued to a system. It provides insight into how overcurrenting occurs, how overcurrenting can be mitigated, and the influence that mitigation strategies have on system performance. Two overcurrenting mitigation strategies are presented. The operational effects of overcurrenting and overcurrenting mitigation are evaluated using a three-dimensional simulation of a bridge crane, and experimental results from a 10ton industrial bridge crane.

Three-step input shaper for damping tubular step motor vibrations

2007 ◽  
Vol 221 (1) ◽  
pp. 1-9 ◽  
Author(s):  
S S Gürleyük ◽  
R Hacioglu ◽  
Ş Cinal
Keyword(s):  
Experimental Results ◽  
Step Motor ◽  
Input Shaping ◽  
Flexible Systems ◽  
Step Input ◽  
Shaping Technique ◽  
Input Shaper

Input shaping technique is used to improve the performance of many flexible systems. Employing specified train of impulses convolved with a reference command can effectively reduce residual vibrations. Zero vibration, zero vibration derivative and specified insensitive or extra insensitive, and zero vibration derivative-derivative shapers are wellknown types of input shapers. These shapers improve the robustness of the system with respect to modelling errors. In this article, a coherent input shaping scheme with all positive threeimpulse sequences is developed, which is preferable to derivative shaper types. The proposed method is used for damping the tubular step motor vibrations. The method allows generating the impulse amplitudes without additional derivative constraints. The technique is also evaluated by analysing the robustness. Experimental results show the efficiency of the proposed method.

Time-Optimal Negative Input Shapers

1997 ◽  
Vol 119 (2) ◽  
pp. 198-205 ◽  
Author(s):  
W. E. Singhose ◽  
W. P. Seering ◽  
Neil C. Singer
Keyword(s):  
Rise Time ◽  
The Other ◽  
High Mode ◽  
Piezo Actuator ◽  
Input Shaping ◽  
Residual Vibration ◽  
Dc Motors ◽  
Mode Excitation ◽  
Time Optimal ◽  
Computer Controlled

Input shaping reduces residual vibration in computer controlled machines by convolving a sequence of impulses with a desired system command. The resulting shaped input is then used to drive the system. The impulse sequence has traditionally contained only positively valued impulses. However, when the impulses are allowed to have negative amplitudes, the rise time can be improved. Unfortunately, excitation of unmodeled high modes and overcurrenting of the actuators may accompany the improved rise time. Solutions to the problem of high-mode excitation and overcurrenting are presented. Furthermore, a simple look-up method is presented that facilitates the design of negative input shapers. The performance of negative shapers is evaluated experimentally on two systems; one driven by a piezo actuator and the other equipped with DC motors.

A Fast Response Surface Thermocouple

1974 ◽  
Vol 16 (3) ◽  
pp. 174-177 ◽  
Author(s):  
I. S. Donaldson ◽  
R. A. Haslett
Keyword(s):  
Response Surface ◽  
Rise Time ◽  
Fast Response ◽  
Experimental Results ◽  
Fabrication Technique ◽  
Surface Thermocouple

A fabrication technique is described for a cheap, robust surface thermocouple having a rise time of the order of 5 μs. Experimental results using the thermocouple are also presented.

Sign in / Sign up

Export Citation Format

Share Document