Application of magneto-rheological devices for impact loads rejection

This thesis discusses the performance of magneto-rheological (MR) devices in cancelling out the effect of impact energy from the gun system of an armoured vehicle during firing, specifically the performance of magneto-rheological elastomer isolator devices (MREID) and magneto-rheological fluid (MRF) dampers. The main focuses of this work are to implement the MR devices in the recoil rejection system of an armoured vehicle, to develop a model of the MR devices and to develop a control strategy to enhance MR device performance. The aim of this work is to develop and validate MR device behaviour, to develop a basic control strategy and an adaptive mechanism to improve MR device performance under various impact energies and to evaluate the performance of MR devices in real applications. The first step of the methodology was to characterise the proposed MREIDs and MRF dampers in the impact pendulum test rig. The MR device was then modelled using an adaptive neuro-fuzzy inference system (ANFIS), which demonstrated the capability of the ANFIS model to predict the force-velocity and force-displacement characteristics of MR devices. With this, a hybrid skyhook active force control (HSAFC) was proposed to achieve the optimum target force by rejecting unwanted impact force from the gun system. Gravitational Search Algorithm (GSA) was used to optimize the proposed controller‟s parameters for both MR devices under various impact energies from low (195.94 J) to high (391.88 J). A single-degree-of-freedom (SDOF) gun recoil test rig was installed on an experimental armoured vehicle in order to evaluate the effectiveness of the proposed controller. The mechanism for HSAFC to adapt to various impact energies was also formulated. Unlike a passive damper, the proposed controller was found to effectively absorb impact energies and to reduce the force response consistently up to 45.95% for MREID and 44.64% for MRF damper, when compared against a basic controller. Furthermore, agreement was found between the simulation and the experimental results with a minor percentage of error at 3.53%. Experimental results of the two MREIDs and a single MRF damper with an adaptive H-SAFC controller resulted in a substantial reduction in the firing force of up to 63.22%, which reaffirmed MR devices‟ potential to mitigate firing impact.