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The Serpentine Drive Analysis Program (SDAP) is developed for designing flexible member (i.e. roller chain, synchronous belt, and V-belt) serpentine drives. The program, based on industry standard design procedures, provides the user with a design tool for investigating alternative configurations. SDAP calculates driver sizes, geometrical relationships, and force transmission characteristics. Basic design methodology is discussed, and two examples illustrate the usage and flexibility of the program.

Data envelopment analysis (DEA) is used to examine the efficiency of 74 front wheel assist agricultural tractors from three U.S. manufacturers. The outputs of drawbar horsepower and power takeoff horsepower are modeled in a constant returns-to-scale framework using three productive performance inputs (fuel consumption, slip, and center of gravity), and one price input, namely, retail tractor price. The results suggest that by and large, John Deere tractors are more DEA efficient than their competitor's tractors. However, competitor's tractors that are DEA efficient are most often the top benchmarks for DEA inefficient tractors. These results suggest that while John Deere appears to produce many quality tractors, competitor's like CNH and AGCO produce a few tractors that may be of even higher quality.

An exploratory concept for a chassis suspension system for improving the operator ride comfort of an agricultural tractor is presented in this paper. The first section of the paper describes the criteria and concepts that have been incorporated into the design of a hybrid leading and trailing arm chassis suspension system. The second section of the paper discusses the evaluation of this suspension system and its parameters by simulating nine (9) different tractor and nine (9) different tractor-plow models, derived from the various combination of suspension configurations and operator cab locations. A generalized mechanical system simulation program is utilized to predict the dynamic linear transfer function behavior of each vehicle model. With frequency domain analysis techniques and the Fast Fourier Transform (FFT) algorithm, the dynamic vehicle response to the ISO 5007 Smooth Track excitation is computed.

European and American suspension systems are described for improving the operator ride comfort on off-road vehicles. Analytical methods are then described to predict the dynamic behavior of a vehicle and human ride response criteria. The approach includes the selection of a terrain input to excite the vehicle model formulated by the generalized mechanical system simulation programs. An example involving an agricultural tractor-plow system is presented to illustrate the techniques.

An analytical study of the dynamic behavior of agricultural tractor-trailer combinations is conducted to investigate the stability and handling characteristics. Equations of motion reflecting the characteristics and parameters of the combination in terms of stability and handling are developed. The influence of changing the combination operating and design parameters on the lateral stability of the system is investigated with an eigenvalue analysis technique and a time-domain integration technique. The simulation results showed that forward speed of the combination and the properties of the trailer substantially affect the lateral stability of the tractor-trailer combination.

A kinematic model for studying the maneuverability of an off-road tractor/double-axle trailer combination has been formulated. The influence of steering inputs from the tractor and the trailer front axles on the system's maneuverability in terms of lateral displacement and rotational motion during the turning process is studied by conducting computer simulations using the LOTUS spreadsheet program. A lane-change problem is presented to demonstrate the computational procedure and to illustrate the application of the kinematic model.

Applications of active suspension control for both on-highway and off-highway vehicles are reviewed. Suspension design is evaluated in terms of ride vibration exposure and road/terrain handling. Active, semi-active, and slow-active suspension types are described in terms of their performance capabilities. Finally, numerous design concepts and their application to a wide range of ground vehicle types (i.e, truck, automotive, agricultural, and construction) are described.

The purpose of this paper is to describe and demonstrate a computer program to interactively design roller-chain and synchronous-belt drives. The program allows the user to optimize the power-transmission drive system and has graphics capability to assist in design visualization. The paper discusses the analysis procedure, design criteria, and the program data base. The analysis procedure and design criteria are based on accepted methodology by the roller-chain and synchronous-belt manufacturers. Governing equations and flow charts are included in the discussion, and three examples are presented to demonstrate the program capabilities and features.

Computer simulation modelling techniques are basic engineering tools to investigate and predict the performance and mobility of agricultural tractors. Analytical methodologies developed by researchers to simulate and evaluate the terrain-operator-agricultural vehicle system and its subsystems are described. The techniques are classified as models and methods describing the subsystem interactions and relationships and the overall tractor-soil-implement system. The subsystem models and methods include: soil mechanics) the soil-wheel interactions, the soil-track interactions, the vehicle mechanics relationships, the soil-implement interactions, and the power train and hitching relationships. These models and methods were developed by various researchers as a means to optimize the tractive performance of the tractor by parameter sensitivity analyses.