of-hybrid-electrical-air-cushion-tracked-vehicle-for-swamp-p

Development of hybrid electrical air-cushion tracked vehicle

for swamp peat

Ataur Rahman a,*,A.K.M.Mohiuddin a ,Ahmad Faris Ismail a ,Azmi Yahya b ,

Altab Hossain a

a

Department of Mechanical Engineering,Faculty of Engineering,International Islamic University Malaysia,50728Kuala Lumpur,Malaysia b

Department of Biological and Agricultural Engineering,Faculty of Engineering,University Putra Malaysia,43400Serdang,Selangor,Malaysia

Received 19May 2008;received in revised form 4June 2009;accepted 5June 2009

Available online 30July 2009

Abstract

This study presents a developed hybrid electrical air-cushion tracked vehicle (HETAV)for the transportation operation of agricul-tural and industrial goods on the swamp peat terrain bearing capacity of 5kN/m 2.The vehicle’s design parameters are optimized by using the developed mathematical models which are made based on the kinematics and dynamics behaviors of the vehicle.A set of sen-sors are used with this vehicle to activate the air-cushion system and battery pack recharging system.The vehicle’s air-cushion system is protected by a novel-design auto-adjusting supporting system.The air-cushion dragging motion resistance is overcome with additional thrust which is developed by a propeller.The vehicle is equipped with the air-cushion system to make the vehicle ground contact pressure 5kN/m 2.

ó2009ISTVS.Published by Elsevier Ltd.All rights reserved.

1.Introduction

This is a custom-built light weight small-scale vehicle is made for the transportation operation of agricultural and industrial goods on swamp peat in Malaysia.The propul-sion system of the vehicle is comprised of tracks and air-cushion system as shown in Fig.1.The track mechanism is used as the driving system to overcome the rolling motion resistance and the air-cushion system is used to increase the ?oatation capacity of the vehicle.The driving force is provided to each of the tracks by an individual DC motor.The air-cushion system of this vehicle was designed in such a way that it would not slide on the terrain with the vehicle movement.It only supports the partial load of the vehicle once the vehicle sinkage is closed to 50mm and makes the vehicle ground contact pressure 5kN/m 2[12].The additional thrust (or tractive e?ort)is provided to the vehicle by using a propeller to overcome the drag motion resistance of the air-cushion system.As

the terrain is unprepared and di?erent types of decomposed materials are on the terrain,the air-cushion system was protected by using a Novel designed supporting system.It adjusts the air-cushion system on the terrain automati-cally by absorbing its longitudinal displacement with two horizontally attached shock absorbers and vertical dis-placement with four vertically attached springs.

Di?erent types of vehicles are introduced to solve the transportation problems on moderate peat terrain [1–5].But still no one o?ers any vehicle on low bearing capacity swamp peat terrain in Malaysia.The proposed vehicle could be useful for transporting the palm oil fresh fruit bunches over the swamp peat.

2.Material and methods

The mathematical model is formulated by understand-ing the terrain nature,analyzing the mechanics of track-ter-rain interaction,and simplifying the recommended mathematical models of Ataur et al.[17],Wong [18].The solutions to this set of equations de?ne the vehicle sinkage,

0022-4898/$36.00ó2009ISTVS.Published by Elsevier Ltd.All rights reserved.doi:10.1016/j.jterra.2009.06.003

*

Corresponding author.Tel.:+60336914550;fax:+60361964455.E-mail address:arat@e0d669de7cd184254a353594.my (A.Rahman).

e0d669de7cd184254a353594/locate/jterra

Available online at e0d669de7cd184254a353594

Journal of Terramechanics 47(2010)

45–54

Journal of

Terramechanics

slippage,entry and exit angle of the track.Based on the set

of equations,the vehicle ground pressure distribution,dynamic load distribution,motion resistance,and tractive e?ort are simulated.The tractive e?ort and motion resis-tance of the vehicle are formulated in this study based on two sinkage conditions:(i)sinkage,06z 670mm and (ii)sinkage,z P 70mm.Assumptions are made in order to establish the mathematical models:(i)the pressure distri-bution in the track–terrain interface is assumed to be uni-form by locating the vehicle C.G at the mid point of the track system and (ii)critical sinkage of the vehicle is con-sidered to be 70mm based on the study of Jamaluddin [12].Consider a track vehicle of total weight W,track size including track ground contact length L ,width B ,pitch T p ,and grouser height H ,radius of the rear sprocket R rs ,and radius of the road-wheels R r ,and height of the center of gravity h cg is traversing under traction on a swamp peat terrain at a constant speed of v t as soon as applying the driving torque Q at the rear sprocket.The pressure distri-bution in the track–terrain interface is assumed to be uni-form by locating the vehicle C.G at the mid point of the track system.The pressure at main straight part P ,and rear sprocket P rs ,and the sinkage of the vehicle z is as shown in Fig.2.

The traction (tractive e?ort)equation for the bottom of the vehicle’s track ground contact part on peat terrain is computed by simplifying the recommended equation of Ref.[16]:

(i)For sinkage,06z 670mm

F b ?eA t c teW t Ttan u T

K w iL e 1à1tK w iL

exp 1àiL K w

!

:e1T

where,A t =2(L YZ )(B )and L =L YZ .

In Eq.(1),F b is the traction that develops at the bottom part of the track in kN,L is the ground contact length of the track in m,A t is the area of the track ground contact area in m 2,W t is the vehicle load supported by the track system in kN,c is the cohesiveness in kN/m 2,u is the ter-rain internal friction angle in degrees,K w i …… 此处隐藏：28767字，全部文档内容请下载后查看。喜欢就下载吧 ……