• Proceedings of the KSME Conference
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• 2001.06b
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• pp.127-133
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• 2001

The flexibility of long reach manipulators presents a difficult control problem when accurate end-point position is required. Input shaping by convolving system commands with impulse sequences has been shown to be an effective method of reducing residual vibrations in flexible systems. However, existing shapers has been considered robustness for only frequency uncertainty. However, this paper presents new multi-hump convolution(CV) input shaper that could accommodate with the simultaneous variation of natural frequency and damping ratio. Comparisons with previously proposed input shapers are presented to illustrate the qualities of the new input shaper. These new shapers will be shown to have better robustness for the variation of frequency and damping ratio.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1423-1428
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• 2011

This paper proposes a learning input shaper with nonlinear actuator dynamics to reduce the residual vibration of flexible systems. The controller is composed of an estimator of the time constant of the nonlinear actuator dynamics, a recursive least squares method, and an iterative updating algorithm. The updating mechanism is modified by introducing a vibration measurement function to cope with the dynamics of nonlinear actuators. The controller is numerically evaluated with respect to parameter convergence and control performance by using a benchmark pendulum system. The feasibility and applicability of the controller are demonstrated by comparing its control performance to that of an existing controller algorithm.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.255-260
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• 2009

This paper presents an experimental result of virtual mode input shaping for positioning stage. Input shaping is liable to increase the rise time of the system, which often degrades the performance of system. The virtual mode input, shaping is an input shaper design method to improve this problem. Experiments are performed with a precise positioning stage with a flexible beam of which natural frequency is adjustable. The experimental results show that the virtual-mode shaper is useful to reduce the rise time as well as the residual vibration of precise positioning stages.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.26-31
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• 2008

본 논문은 정밀 위치결정 시스템의 잔류진동을 효과적으로 제거할 수 있는 입력성형기법을 소개하고, 실시간 입력성형기법을 적용하는 방법을 설명하였다. 또한 두 가지 응용 분야에 대한 실험결과를 바탕으로 입력성형기법의 성능을 고찰하였다. 일반적으로 입력성형기법은 정밀 위치결정 시스템에 대해 동작 완료시간을 단축시키는 효과가 있을 뿐만 아니라 위치결정 정밀도를 향상시키는 효과가 있다. 그리고 되먹임제어 방법에 비해 적용방법도 간단하며 저렴하게 구성할 수 있다는 장점이 있으므로 많은 정밀 위치결정 시스템에 유용할 것으로 생각된다.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.4
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• pp.100-106
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• 2009

The current tendency toward light weight and fast machines has lead to a need to suppress vibration of flexible dynamic systems. Input shaping is an efficient tool to eliminate transient and residual vibration caused by motion of these systems. This paper proposes a new formulation of the design method for multi-mode input shapers to eliminate residual vibration in flexible dynamic systems. The essence of the proposed method is to minimize the number of impulses to be n+1 for n-mode input shapers. This paper also suggests a solution procedure to solve the complex-valued nonlinear matrix equation for the input shapers. The proposed method is applied to two-mode input shapers. This paper discusses characteristics of several input shapers obtained under the same condition. Simulations and experiments show that the proposed method is very useful for designing multi-mode input shapers.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.83-90
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• 2008

Input shaping is an efficient tool to eliminate transient and residual vibration caused by motion of mechanical systems. However, the rise time of the systems tends to increase due to the presence of input shapers. This paper is concerned with the rise time reduction when using input shaping. To this end, this paper proposes an input shaper design method for an undamped single mode vibration system using a virtual mode, which is not an actual mode but reflected in the design process. The essence of the proposed method is to design a three-impulse input shaper as if a single mode system has two modes: one actual mode and one virtual mode. The natural frequency of the virtual mode is a design parameter to change the rise time of the system. This paper discusses the performance of the proposed input shapers by simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.67-73
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• 2002

The flexibility of long reach manipulators presents a difficult control problem when accurate end-point position is required. Input shaping by convolving system commands with impulse sequences has been shown to be an effective method of reducing residual vibrations in flexible systems. However, existing shapers have been considered robustness fur only frequency uncertainty. However, this paper presents new multi-hump convolution(CV) input shaper that could accommodate with the simultaneous variation of natural frequency and damping ratio. Comparisons with previously proposed input shapers are presented to illustrate the qualities of the new input shaper. These new shapers will be shown to have better robustness fur the variation of frequency and damping ratio.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.164-169
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• 1995

Fictitious experiment to control extrusion process was carried out using the fuzzy theory. Algorithm of the fuzzy logic controller(FLC) was made based on the general principles of extrusion. In the simulation, at first, thickness of extrudate was measured as feedback input variable. Secondly, a set point of screw speed was determined as output variable of extruder operating condition through FLC. Finally, the thickness of extrudate was controlled as a given set point. Barrel heater was simply controlled as on/off state, which was not fuzzy controlled.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.181-188
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• 2000

Input shaping is a method fur reducing residual vibration. Vibration is eliminated by convolving an input shaper, which is a sequence of impulses, with the desired system command. It has been applied to robot with a flexible manipulator. But it can be applied to the reduction of residual vibration far overhead crane. In this paper, input shaping shows good performance for anti-sway of overhead crane. In the z-domain, we designed an input shaper and calculated the sensitivity of it. If sensitivity is calculated in the z-domain, the shapes of sensitivity curves are expected easily. Accordingly, it is easy to design an input shaper in the z-domain. We compared the response of a system with shaper to it without that. Also, we compared El shaper to ZV shaper in view of robustness.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.7
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• pp.717-724
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• 2013

Industrial cranes are indispensable equipment in heavy industry. However, unwanted vibrations in cranes often cause accidents. Input shaping is widely accepted as a useful tool for removing residual vibration in cranes. A unity magnitude zero vibration (UMZV) input shaper is often used for cranes driven by on-off-type motors. However, although a UMZV input shaper minimizes residual vibration, the input shaper cannot prevent the crane from moving slightly further than expected from the original command. This paper describes an improved method of input shaping that can compensate for position inaccuracies, as well as remove the residual vibration of cranes. Experiments were performed to validate the proposed input-shaping method, illustrated through numerical simulations.