【正文】 譯 文 學(xué) 院 ： 機(jī)電與汽車工程學(xué)院 專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動化 學(xué) 號： 09455 姓 名： 吳 欣洋 指導(dǎo)教師： 張建 Semiactive hydrogas suspension system for a tracked vehicle U. Solomon, Chandramouli Padmanabhan Machine Design Section, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036, India Received 18 June 2022。 received in revised form 12 November 2022。 accepted 11 January 2022 Available online 4 March 2022 Abstract A semiactive hydrogas suspension is proposed for a tracked vehicle to improve ride fort performance, without promising the road holding and load carrying capabilities of the passive suspension. This is achieved through an active damper used in parallel with a gas spring. The suspension damper parameters are varied by a control mechanism based on skyhook damping theory, which alters the flow characteristics. A damper prototype has been developed, tested for its flow characteristics, after which it has been integrated into an existing hydrogas suspension system. An analytical model has been proposed from first principles rather than developing a phenomenological model based on experimental characteristics. This model is validated with experiments carried out on a suspension test rig. In order to pare the performance with the original passive system, an inplane vehicle model is developed and the simulations clearly show that the semiactive system performance is superior to the passive system. 2022 ISTVS. Published by Elsevier Ltd. All rights reserved. Keywords: Semiactive hydrogas suspension。 Skyhook damper。 Variable orifice damper The damping in a passive suspension system is chosen to provide optimal performance at low frequencies. However ,the higher damping chosen makes the performance to degrade at higher frequencies. A semiactive suspension ,with variable damper characteristics offers a low cost solution to improve the ride fort without promising road holding and load carrying performance of the suspension. One of the most popular semiactive damping strategies has been the “skyhook?? damper originally proposed by Karnopp et al. The performance of this damper has been investigated in detail by Karnopp and Emura et al. have highlighted the limitations in realizing such a damper in a practical scenario. Oueslati and Sankar studied the performance of passive, active and semiactive suspensions using single degreeoffreedom (DOF) and four DOF vehicle models. They proposed three types of control schemes for a semiactive suspension. The first scheme is based on the idea of modulating the passively generated damper forces using feedback control while using a small amount of external power. This alternative suspension approached the performance of an active suspension with the significant advantage that it requires only a fraction of the power used by an active suspension. The second control strategy was originally suggested by Rakheja and Sankar . They observed that, in a passive damper, the damping force increases the sprung mass acceleration when the spring and damper force have the same sign. The active damper does not provide a force during this part of the cycle. When the spring force and damper force are in opposite directions, the active damper generates a force having the same magnitude as the spring force but acting in the opposite direction, so that a zero resultant force is obtained. The attractiveness of this control scheme is the need to measure only the relative displacement and velocity across the suspension. The power requirements of this scheme depend on the choice of the gain. As desired, at higher frequencies the isolation provided by the active damper is superior to the passive damper but at frequencies around the natural frequency of the suspension system, a high root mean square (rms) acceleration transmissibility occurs, which is a significant drawback of the control strategy. To overe this a third control scheme, where a passive damper is placed in parallel with the active damper and spring, is proposed. While the introduction of the passive damper significantly reduces the rms acceleration ratio around the natural frequency, it increases the rms acceleration ratio at higher frequencies. Tseng and Hedrick demonstrated that modulated dampers can provide excellent vibration isolation at low frequencies (around 1 Hz). They also proved that optimal semiactive suspension parameters can be obtained by minimization of a quadratic performance index. Cheok showed that the clippedoptimal solution (where a quadratic performance index is minimized subject to road holding, suspension working space and damper maximum value constraints) is optimal in minimizing the “ model following error ” but not in minimizing the unconstrained quadratic performance index. Youn and Hac180。 developed a 2DOF model of a vehicle incorporating a semiactive suspension with adaptive capability. In addition to a variable damper, a spring in which the stiffness can be discretely varied among the three different levels was proposed by them. They concluded that the adaptive system showed significant improvement in controlling vehicle vibration when pared to a semiactive suspension with a modulated damper and fixed stiffness. The literature reviewed in the previous paragraphs primarily deal with control strategies for semiactive suspensions in wheeled vehicles. Use of active dampers in offroad wheeled/tracked vehicles has also been investigated by several authors. Nell and Steyn developed and experimentally evaluated a twostate semiactive translational damper on a high mobility offroad vehicle. They modified the passive