Input Shaping Control Scheme Research Articles

Hybrid input shaping control scheme for reducing vibration of robot based on multi-mode control

Hybrid input shaping control scheme for reducing vibration of robot based on multi-mode control

An Input Shaping Control Scheme with Application on Overhead Cranes

Abstract A new optimization technique is developed to generate a step-input acceleration function for an input shaping harmonic system. This approach is integrated into an overhead crane model for a rest-to-rest maneuver with standard and nonstandard maneuver settings. The proposed method guarantees the satisfaction of the system constraints and desired final conditions, while it minimizes the system sensitivity to crane cable-length variations. The minimal system sensitivity is achieved through an optimization algorithm that provides zero vibration and a minimum integral of system sensitivity over a continuous range of crane cable length. Numerical simulations are conducted to demonstrate the feasibility of the proposed shaper in eliminating the residual vibration at the end of a programmed maneuver. Sensitivity analyses are also performed to verify the robustness of the new shaper. In comparison to the previous shapers, the new methodology is significantly less sensitive and can effectively handle different arbitrary maneuver times.

Active sway control of a gantry crane using hybrid input shaping and PID control schemes

This project presents investigations into the development of hybrid input-shaping and PID control schemes for active sway control of a gantry crane system. The application of positive input shaping involves a technique that can reduce the sway by creating a common signal that cancels its own vibration and used as a feed-forward control which is for controlling the sway angle of the pendulum, while the proportional integral derivative (PID) controller is used as a feedback control which is for controlling the crane position. The PID controller was tuned using Ziegler-Nichols method to get the best performance of the system. The hybrid input-shaping and PID control schemes guarantee a fast input tracking capability, precise payload positioning and very minimal sway motion. The modeling of gantry crane is used to simulate the system using MATLAB/SIMULINK software. The results of the response with the controllers are presented in time domains and frequency domains. The performances of control schemes are examined in terms of level of input tracking capability, sway angle reduction and time response specification.

Robust input shaping control for multi-mode flexible structures using neuro-sliding mode output feedback control

Input shaping provides an effective method for suppressing residual vibration of flexible structure systems. However, it is not very robust to parameter uncertainties and external disturbances. In this paper, a closed-loop input shaping method is developed for suppressing residual vibration of multi-mode flexible structure systems with parameter uncertainties and external disturbances. The proposed scheme integrates both input shaping control and discrete-time neuro-sliding mode output feedback control (NSMOFC). The input shaper is designed for the reference model and implemented outside of the feedback loop to achieve the exact elimination of residual vibration. In the feedback loop, the discrete-time NSMOFC technique is employed to make the closed-loop system behave like the reference model with input shaper, where the residual vibration is suppressed. The selection of switching surface and the existence of sliding mode have been addressed. The knowledge of upper bound of uncertainties is not required. Furthermore, it is shown that increasing the robustness to parameter uncertainties does not lengthen the duration of the impulse sequence. Simulation results demonstrate the efficacy of the proposed closed-loop input shaping control scheme.

Closed-Loop Input Shaping Control of Vibration in Flexible Structures via Adaptive Sliding Mode Control

Input shaping technique is widely used in reducing or eliminating residual vibration of flexible structures. The exact elimination of the residual vibration via input shaping technique depends on the amplitudes and instants of impulse application. However, systems always have parameter uncertainties which can lead to performance degradation. In this paper, a closed-loop input shaping control scheme is developed for uncertain flexible structures. The algorithm is based on input shaping control and adaptive sliding mode control. The proposed scheme does not need a priori knowledge of upper bounds on the norm of the uncertainties, but estimates them by using the adaptation technique. This scheme guarantees closed-loop system stability, and yieldsgoodperformance androbustnessinthepresence ofparameter uncertaintiesandexternal disturbances aswell. Furthermore, it is shown that increasing the robustness to parameter uncertainties does not lengthen the duration of the impulse sequence. Simulation results demonstrate the efficacy of the proposed closed-loop input shaping control scheme.

Closed-Loop Input Shaping Control of Vibration in Flexible Structures via Adaptive Sliding Mode Control

Input shaping technique is widely used in reducing or eliminating residual vibration of flexible structures. The exact elimination of the residual vibration via input shaping technique depends on the amplitudes and instants of impulse application. However, systems always have parameter uncertainties which can lead to performance degradation. In this paper, a closed-loop input shaping control scheme is developed for uncertain flexible structures. The algorithm is based on input shaping control and adaptive sliding mode control. The proposed scheme does not need a priori knowledge of upper bounds on the norm of the uncertainties, but estimates them by using the adaptation technique. This scheme guarantees closed-loop system stability, and yields good performance and robustness in the presence of parameter uncertainties and external disturbances as well. Furthermore, it is shown that increasing the robustness to parameter uncertainties does not lengthen the duration of the impulse sequence. Simulation results demonstrate the efficacy of the proposed closed-loop input shaping control scheme.

Closed‐loop input shaping control of vibration in flexible structures using discrete‐time sliding mode

AbstractInput shaping technique is widely used in reducing or eliminating residual vibration of flexible structures. It is easy to implement and achieve the exact elimination of the residual vibration if the dynamics of the system are known accurately. However, it is not very robust to parameter uncertainties and external disturbances. In this paper, a closed‐loop input shaping method is developed for reducing or eliminating residual vibration of flexible structure systems with parameter uncertainties and external disturbances. The algorithm is based on input shaping control and discrete‐time sliding mode control. It is shown that the proposed scheme guarantees closed‐loop system stability, and yields good performance and robustness in the presence of parameter uncertainties and external disturbances as well. The selection of switching surface and the existence of sliding mode are two important issues, which have been addressed. The knowledge of upper bound of uncertainties is not required. Furthermore, it is shown that increasing the robustness to parameter uncertainties does not lengthen the duration of the impulse sequence. Simulation results demonstrate the efficacy of the proposed closed‐loop input shaping control scheme. Copyright © 2010 John Wiley & Sons, Ltd.

Increasing Robustness of Input Shaping Method to Parametric Uncertainties and Time-Delays

The input shaping technique has proven to be highly effective in reducing or eliminating residual vibration of flexible structures. The exact elimination of the residual vibration via input shaping depends on the amplitudes and instants of utilized impulses. However, systems always have parametric uncertainties, which can lead to performance degradation. Furthermore, input shaping method does not deal with vibration excited by external disturbances and time-delays. In this paper, a closed-loop input shaping control scheme is developed for uncertain flexible structure and uncertain time-delay flexible structure systems. The algorithm is based on the sliding mode control and H∞/μ techniques. This scheme guarantees closed-loop system stability, and yields good performance and robustness in the presence of parametric uncertainties, time-delays and external disturbances as well. Also, it is shown that increasing the robustness to parametric uncertainties and time-delays does not lengthen the duration of the impulse sequence. Numerical examples are presented to verify the theoretical analysis.

Performance studies of human operators driving double-pendulum bridge cranes

Oscillation of crane payloads makes it challenging to manipulate payloads quickly, accurately, and safely. The problem is compounded when the payload creates a double-pendulum effect. This paper evaluates an input-shaping control method for reducing double-pendulum oscillations. Human operator performance testing on a 10-ton industrial bridge crane is used to verify the effectiveness and robustness of the method. Fifty operators drove the crane with a standard control pendent, as well as a wireless touchscreen interface. Data from these experiments show that human operators drive the crane much faster and safer with the input-shaping control scheme. Furthermore, considerably less operator effort is required when input shaping is used to limit the oscillation. Additional tests required the operators to drive the crane numerous times over a period of eight days. These experiments show that significant learning occurred when operators did not have the aid of input shaping. However, the performance never approached that achieved by untrained operators using input shaping.

Dynamic Analysis on Noise and Vibration Study of Flexible Wiper Blade System

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.

CLOSED-LOOP INPUT SHAPER ELIMINATING RESIDUAL VIBRATION OF MULTI-MODE FLEXIBLE SYSTEMS

Though input shaping technologies are used to reduce residual vibration of flexible systems, most input shaping technologies adopt open-loop control scheme and can not handle the uncertainties such as non-zero initial conditions, external disturbances, model parameter variations and system nonlinearities. A closed-loop input shaping control scheme, which combines an input shaper with a vibration damper, is proposed for suppressing the residual oscillations of the multi-mode flexible systems. The input shaper prevents the operator from inadvertently adding energy to the system through the commands, and the vibration damper acts as energy damper to remove the energy that has entered into the system from aforementioned uncertainties, so the two controllers cooperate with each other to suppress the residual vibration. Compared with the open-loop input shaper, the robustness and disturbance resistance of the closed-loop input shaper is strengthened. The proposed control technology is used in crane experiment to suppress the residual oscillation of payload.

An adaptive input shaping control scheme for vibration suppression in slewing flexible structures

The application of an input precompensation scheme for vibration suppression in slewing flexible structures, with particular application to flexible-link robotic manipulator systems, is considered. The control from such input shaping schemes corresponds to a feedforward term that convolves in real time the desired reference input with a sequence of impulses and produces a vibration-free output. The robustness of such an algorithm with respect to modal frequency variations is not satisfactory but can be improved by convolving the input with a longer sequence of impulses, the tradeoff being a decrease in the transient response speed. An adaptive precompensation scheme that can be implemented by combining a frequency domain identification scheme, used to estimate the modal frequencies online, with a subsequent scheme for adjusting the spacing between the impulses is proposed. The combined adaptive input shaping scheme provides the most rapid slew that results in a vibration-free output. Experimental results for a single flexible link are presented to verify the technique. >