Robust Adaptive Controls of a Vehicle Seat Suspension System

This work proposes two novel adaptive fuzzy controllers and applies them to vibration control of a vehicle seat suspension system subjected to severe road profiles. The first adaptive controller is designed by considering prescribed performance of the sliding surface and combined with adaptation laws so that robust stability is guaranteed in the presence of external disturbances. As for the second adaptive controller, both the H-infinity controller and sliding mode controller are combined using inversely fuzzified values of the fuzzy model. In order to evaluate control performances of the proposed two adaptive controllers, a semi-active vehicle suspension system installed with a magneto-rheological (MR) damper is adopted. After determining control gains, two controllers are applied to the system and vibration control performances such as displacement at the driver’s position are evaluated and presented in time domain. In this work, to demonstrate the control robustness two severe road profiles of regular bump and random step wave are imposed as external disturbances. It is shown that both adaptive controllers can enhance ride comfort of the driver by reducing the displacement and acceleration at the seat position. This excellent performance is achieved from each benefit of each adaptive controller; accurate tracking performance of the first controller and fast convergence time of the second controller

Magnetorheological Fluid Based Devices Reported in 2013–2018: Mini-Review and Comment on Structural Configurations

This paper presents a mini-review of magnetorheological (MRF) fluid-based devices (MRF devices in short) including the brake, clutch, damper, and the mount reported from 2013 to 2018. MRF devices are usually designed based on three operating modes of MRF: flow mode, shear mode and squeeze mode. Each mode has its own characteristics for the high performance of application systems. Therefore, numerous design configurations of MRF devices have been proposed by many researchers. In this article, among many different MRF devices such as MRF brake, clutch, damper and MRF mount proposed over the last 6 years are examined in the sense of their structural configuration and operating principles. Certain advantages and demerits of each MRF device are also discussed. In addition, some useful design guidelines of MRF devices, which are absolutely different from developed MRF devices so far, are provided to enhance design simplicity and control performance

State of the art of control schemes for smart systems featuring magneto-rheological materials

This review presents various control strategies for application systems utilizing smart magneto-rheological fluid (MRF) and magneto-rheological elastomers (MRE). It is well known that both MRF and MRE are actively studied and applied to many practical systems such as vehicle dampers. The mandatory requirements for successful applications of MRF and MRE include several factors: advanced material properties, optimal mechanisms, suitable modeling, and appropriate control schemes. Among these requirements, the use of an appropriate control scheme is a crucial factor since it is the final action stage of the application systems to achieve the desired output responses. There are numerous different control strategies which have been applied to many different application systems of MRF and MRE, summarized in this review. In the literature review, advantages and disadvantages of each control scheme are discussed so that potential researchers can develop more effective strategies to achieve higher control performance of many application systems utilizing magneto-rheological materials

SECURE PERFORMANCE ANALYSIS OF ADAPTIVE ENERGY HARVESTING ENABLED RELAYING NETWORKS

In this paper, the impact of the jamming signal on the secrecy performance of Energy Harvesting (EH) enabled dual-hop amplify-and-forward relaying network is investigated. First, the security outage probability analysis is studied for conventional networks under a single passive eavesdropper attack. Then, the outage performance analysis in two cases regarding energy harvesting is investigated. Moreover, the proposed work enhances Physical Layer (PHY) security performance of two-hop relaying model using Cooperative Jamming Dual-Hop Techniques (CJDH). For this purpose, new closed-form expressions are derived for the outage probability of CJDH model in the presence of interference over Rayleigh fading channels. A power allocation optimization problem for energy harvesting protocol is formulated and solved for enhancing the system security. The derived analytical formulas herein are supported by numerical and simulation results to clarify the main contributions of the paper

A Novel Adaptive PID Controller with Application to Vibration Control of a Semi-Active Vehicle Seat Suspension

This work proposes a novel adaptive hybrid controller based on the sliding mode controller and H-infinity control technique, and its effectiveness is verified by implementing it in vibration control of a vehicle seat suspension featuring a magneto-rheological damper. As a first step, a sliding surface of the sliding mode controller is established and used as a bridge to formulate the proposed controller. In this process, two matrices such as Hurwitz constants matrix are used as components of the sliding surface and H-infinity technique are adopted to achieve robust stability. Secondly, a fuzzy logic model based on the interval type 2 fuzzy model which is featured by online clustering is established and integrated to take account for external disturbances. Subsequently, a new adaptive hybrid controller is formulated with a solid proof of the robust stability. Then, the effectiveness is demonstrated by implementing the proposed hybrid controller on the vibration control of a vehicle seat suspension associated with a controllable damper. Vibration control performances are evaluated on bump and random road profiles by presenting both displacement and acceleration on the seat and the driver positions. In addition, a comparative study between the proposed and one of existing controllers is undertaken to highlight some benefits of the hybrid adaptive controller developed in this work

Self-tuning fuzzy PID-nonsingular fast terminal sliding mode control for robust fault tolerant control of robot manipulators

In this work, a new robust controller is developed for robot manipulator based on an integratingbetween a novel self-tuning fuzzy proportional–integral–derivative (PID)-nonsingular fast terminalsliding mode control (STF-PID-NFTSM) and a time delay estimation (TDE). A sliding surface based on the PID-NFTSM is designed for robot manipulators to get multiple excited features such as faster transient response with finite time convergence, lower error at steady-state and chattering elimination. However, the system characteristics are hugely affected by the selection of the PID gains of thecontroller. In addition, the design of the controller requires an exact dynamics model of the robot manipulators. In order to obtain effective gains for the PID sliding surface, a fuzzy logic system is employed and in order to get an estimation of the unknown dynamics model, a TDE algorithm is developed. The innovative features of the proposed approach, i.e., STF-PID-NFTSM, is verified when comparing with other up-to-date advanced control techniques on a PUMA560 robot