Dong-Ho Yang

Hardware-in-the-loop simulation experiment for semi-active vibration control of lateral vibrations of railway vehicle by magneto-rheological fluid damper

The active lateral suspension (ALS) of a train consists of either active or semi-active technologies. However, such an active system on a real railway vehicle is not easy to test because of cost and time. In this study, a hardware-in-the-loop simulation (HILS) system is developed to test the ALS. To this end, the dynamic model of a railway vehicle is equipped with the actuator, two bogies and four-wheel sets, and the ALS is used. The proposed HILS system consists of an alternating current servo motor connected to a ball-screw mechanism and a digital control system. The digital control system implements the dynamic model and the control algorithm. The design and manufacture of the HILS system are explained in detail. Both the passive damper and the magneto-rheological (MR) fluid damper are tested using the HILS system, where the sky-hook control algorithm was applied for the MR fluid damper. Experimental results show that the proposed HILS system can be effectively used for the performance estimation of the ALS.

Active Vibration Control Experiment of Cantilever Using Active Linear Actuator for Active Engine Mount

Vibrations caused by automobile engine are absorbed mostly by a passive-type engine mount. However, user specifications for automobile vibrations require more stringent conditions and higher standard. Hence, active-type engine mount have been developed to cope with such specifications. The active-type engine mount consists of sensor, actuator and controller where a control algorithm is implemented. The performance of the active engine mount depends on the control algorithm if the sensor and actuator satisfies the specification. The control algorithm should be able to suppress persistent vibrations caused by the engine which are related to engine revolution. In this study, three control algorithms are considered for suppressing persistent vibrations, which are the positive position feedback control algorithm, the strain-rate feedback control algorithm, and the modified higher harmonic control algorithm. Experimental results show that all the control algorithms considered in this study are effective in suppressing resonant vibrations but the modified higher harmonic controller is the most effective controller for non-resonant vibrations.

Active vibration control of a submerged cylindrical shell by piezoelectric sensors and actuators

The active vibration control of a submerged cylindrical shell by piezoelectric sensors and actuators is investigated. The fluid is assumed to be inviscid and irrotational in developing a theoretical model. The cylindrical shell is modelled by using the Rayleigh- Ritz method based on the Donnell-Mushtari shell theory. The fluid motion is modelled based on the baffled shell model, which is applied to the fluid-structure interaction problem. The kinetic energy of the fluid is derived by solving the boundary-value problem. The resulting equations of motion are expressed in matrix form, which enables us to design control easily. The natural vibration characteristics of the cylindrical shell in air and in water are investigated both theoretically and experimentally. The experimental results show that the natural frequencies of the submerged cylindrical shell decrease to a great extent compared the natural frequencies in air. However, the natural mode shapes for lower modes are not different from the mode shapes in air. Two MFC actuators were glued to the shell and the positive position feedback control was applied. Experiments on the active vibration control of the submerged cylindrical shell were carried out in water tank. Both theoretical and experimental results showed that both vibrations and sound radiation can be suppressed by piezoelectric actuators.

Development of a Solenoid Control Technique for the Suppression of Noise and Vibrations of the Brake System of Elevator Traction Machine

This paper is concerned with the suppression of noise and vibrations of the brake system of elevator traction machine by means of a solenoid control technique. The solenoid is used to hold the brake shoe, which is then released by turning the solenoid off. Since the brake shoe hits the brake disk, vibrations and noise occur. We developed the solenoid control technique based on the dynamic behavior of the solenoid. The theoretical model for the solenoid is modeled by using linear magnetic principles. The solenoid model was then combined with the vibration model to simulate the vibrations of brake system. The simulation results show that the additional pulse input to the solenoid can decrease the vibrations. The timing of the applied pulse is determined by observing the current. The experimental results show that both the vibrations and noise can be substantially decreased, which validates the approach developed in this paper.

Active vibration control of structures using a semi-active dynamic absorber

This study is concerned with the theory and application of a tuneable dynamic absorber. The dynamic characteristics of the tuneable dynamic absorber are discussed in terms of the mass ratio, natural frequency of the main structure, natural frequency of a dynamic absorber and excitation frequency. We proposed a semi-active dynamic absorber with a natural frequency that can change through the use of repulsive forces produced by permanent magnets and electromagnetic forces induced by current flowing through a coil. A simple active control algorithm is implemented in the LabView software and the experimental results showed that when the proposed semi-active dynamic absorber is used with the active control algorithm, the vibrations of a structure can be more effectively suppressed than when a passive dynamic absorber with a fixed natural frequency is used.

Development of Dynamic Modeling and Control Algorithm for Lateral Vibration HILS of Railway Vehicle

This paper is concerned with the dynamic modeling for the hardware-in-the-loop simulation of lateral vibrations of a railway vehicle. The resulting dynamic model is a nine degree-of-freedom model which can describe the lateral, roll and yaw motions of the car body and two bogies. It is assumed that the external disturbances come from wheel motions. In order to test the efficacy of the model, the linear quadratic regulator and the sky-hook control algorithm were designed and applied to the model. The simulation results show that both control algorithms are effective in suppressing the vibrations of railway vehicles.

Experiments on Rope Vibrations to Validate the Dynamic Model of Elevator Rope

In this paper, the vibration characteristic of elevator rope was verified. To this end, the dynamic model of elevator rope was derived using Rayleigh-Ritz method. And the numerical simulation was carried out for theoretical predictions. To calculate the response of elevator rope, the parameters of real elevator was considered. Based on numerical simulation, the vibration experiments were carried out to validate the dynamic model of elevator rope. To measure the vibration of elevator rope, the CCD camera and the line laser was considered. And the image processing technique was applied to calculate the horizontal displacement of elevator rope. Measurement equipment was installed in elevator shaft at 3 m, 29 m, and 51 m from the base level. Shaker was equipped at the bottom of elevator rope to excite the rope. In experiments, the displacement of rope was measured when the elevator rope was subjected to each natural frequencies. Experimental results are in good agreement with theoretical predictions.

Active Vibration Control of a Hanged Rectangular Plate Partially Submerged Into Fluid by Using Piezoelectric Sensors and Actuators

This paper is concerned with the active vibration control of a hanged rectangular plate partially submerged into a fluid by using piezoelectric sensors and actuators bonded to the plate. A dynamic model for the plate is derived by using the Rayleigh-Ritz method and the fluid effect is modeled by the virtual mass increase that is obtained by solving the Laplace equation. The natural vibration characteristics of the plate in air obtained theoretically are in good agreement with the experimental results. The changes in natural frequencies due to the presence of fluid were measured and compared to the theoretical predictions. Experimental results show that the theoretical predictions are in good agreement with the experimental results. The natural vibration characteristics of the plate both in air and in water are used for the active vibration control design. In this study, the multi-input and multi-output positive position feedback controller was designed based on the natural vibration characteristics and implemented by using a digital controller. Experimental results show that the vibration of the hanged rectangular plate both in air and partially submerged into a fluid can be successfully suppressed by using piezoelectric sensors and actuators.Copyright

Maneuvering and Active Vibration Control of Slewing Flexible Beam Using Input Shaper

This research is concerned with the derivation of equations of motion for a slewing beam and the application of input shaper to the bang-bang control to achieve vibration suppression. When a uniform beam with a tip mass rotates about the axis perpendicular to the undeformed beam`s longitudinal axis, it experiences inertial loading. Hence, the beam vibrates. In this paper, we used the input shaper for the maneuvering control to suppress vibrations. The maneuvering control which can achieve a minimum-time control is a bang-bang control. The input-shaped bang-bang maneuvering is used to suppress vibrations both theoretically and experimentally. The slewing beam experiment is not an easy subject because of the inherent damping existing inside the rotor. We propose the use of a negative damping to eliminate the rotor damping. Numerical and experimental results show that the input-shaper can be effectively used for the vibration suppression of a slewing beam.