Papers by Keyword: Input Shaping

Abstract: The objective of this research work is to model a dynamical system that can undergo flexible deformations along with the general rigid-body motions. For the system to be able to provide precise outputs when excited by an input, the modal shapes need to be examined and a suitable control strategy is required to make the manipulator adapt to a particular use. The input shaping parameters have been analyzed for specific modes of vibrations. The model uses a Gaussian input torque and power spectral density plots are developed with suitable sampling frequency to show the variation of PSD for the modes of vibration under consideration, thereby providing an insight into the shaping parameters of the Gaussian input.

Abstract: Input shaping is a feedforward control technique for improving the settling time and positioning accuracy, while minimizing residual vibrations. Shaped command profiles are generated by convolving a sequence of impulses. To design an input shaping controller, estimates of the system natural frequency and damping ratio are required. However, real systems cannot be modeled exactly, making the robustness to modeling errors an important consideration. Many robust input shapers have been developed, but robust shapers typically have longer durations that slow the system response. This creates a compromise between shaper robustness and rise time. This paper analyses the compromise between shaper duration and robustness for several robust input shapers

Abstract: Input shaping is an effective method for suppressing residual vibration of flexible system. In this paper, the design processes of Zero Vibration (ZV), Zero Vibration and Derivative (ZVD) shapers are deduced. Based on the idea of the robustness input shaper, the Multi-stage Optimal Arbitrary Time-delay Filter (MOATF) is proposed. The proposed control method is implemented on the second-order linear time-invariant system. Simulation results show that the residual vibration can be reduced effectively and the proposed method have great robustness in system parameter uncertainty.

Abstract: The methodologies and application of multiple-mode negative impulses input shaping of a 3-DOF parallel manipulator with flexible intermediate linkages are presented in this paper. First, the structural system and the dynamic equations are expressed for a 3-DOF manipulator. Second, the multiple-mode negative impulses input shaping is introduced to reduce the residual vibration of the multiple-mode system and decrease the delay time of the system response at the same time. Finally, the theory of the multiple-mode ZV, ZVD and EI negative impulses input shapers are presented, and the two-mode negative impulses input shapers of a 3-DOF manipulator are established and compared with the positive impulses input shapers.

Abstract: A poorly designed control system can lead to excessive residual vibration and long setting time. This paper investigates the effect of input shaping on control efficiency. To perform this investigation, we design a PD controller combined with input shaping for an inertia plant. We then subject it to four standard types of inputs. The responses of the control systems are described by analytical expressions. The performances of PD control and PD combined with input-shaping control are thoroughly analyzed and compared. Simulation results show that PD feedback control enhanced with input shaping minimizes overshoot and setting time.

Abstract: Most motion control systems are designed to satisfy the performance requirement in transient and frequency domain. The actuator effort of the control system is rarely considered during the design process. This paper investigates the effects of input shaping on actuator effort of PD combined with input shaping control for an inertial plant subject to four standard types of inputs. The actuator efforts of the control systems are described in general fomula. The acting regulation of PD controller parameters on the oscillatory frequency and damping ratio of actuator effort is investigated and the effect of input shapping on the magnitude of actuator effort is thoroughly analyzed. The research results show that PD feedback control enhanced with input shaping can effectively reduce actuator effort compared with PD control.

Abstract: A new hybrid control scheme combining input shaping technique with robust sliding mode control is proposed for a gantry crane system. A cascade sliding-mode controller is designed to control the trolley position and eliminate the sway of load. The transient vibration is reduced further for safety problems by the input shaping technique which utilizes zero-vibration-derivative (ZVD) robust input shapers. This method can not only realize the accurate position of the trolley and eliminate the sway of the load and residual vibration, but also completely eliminate the chattering of conventional sliding mode control and improve the robustness of system. The simulation results proved its effectiveness.

Abstract: Input shaping has been demonstrated to be a simple method of reducing vibration in many types of controlled machines. The method is implemented by convolving a command signal with an impulse sequence of input shaper to produce a shaped input that is then used to command the system. Designing the input shaper involves determining the amplitudes and timing of the impulses such that the resulting shaped commands lead to desired levels of vibration reduction. Up to now, to the best knowledge of the authors, it is known only few special types of input shapers (ZV, ZVD, ZVDk, EI, SI,...). This paper presents two general approaches for parametrization of all three impulse zero vibration input shapers.

Abstract: Chatter is one of the unwanted noise and vibration phenomenon which are generated during the wiper operation. It is a low frequency and self-excited vibration that is often generated before and after the wiper reverses its direction. This leads to a poor visibility and annoying sound to the driver and passengers. Therefore, this paper is aimed to propose a technique that can be apply to tackle this problem. Hence, an existing two-dimensional mathematical model of a wiper system available in the open literature is adopted. Firstly, the baseline model is simulated in order to observe its vibration response. Then, an input shaping control scheme is introduced into the baseline model. It is found that the input shaping control scheme can reduce the vibration level approximately by 30 percents from the baseline model.

Abstract: 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.