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The demand for increased performance of heavy earthmoving equipment has spurred the development of computer control for machinery using fluid power systems. Application of standard automatic control components to these systems provides the opportunity to implement advanced control approaches that reduce the operator workload and improve performance. In this work, closed-loop control is applied to the joints of a typical three-link digging device. Because the changing configuration of the device greatly changes the dynamic characteristics, an adaptive control algorithm is introduced to modify the control parameters to maintain consistent performance of the implement.

An analysis has been conducted on the hydrostatic drive system for driving a soil bin. A comparison of the bin velocity was made between the pure inertia load and inertia plus disturbance. Also, the pressure fluctuations that are predicted are quite sensitive to the leakage values chosen. A low leakage value predicts an oscillatory pressure response. Although no feedback was employed for the velocity output, the load disturbance changed the output velocity very little.

The differences between courses offered agricultural and mechanical engineers are examined. The topics in the courses are reviewed in some detail. The students start with a review of basic fluid mechanics followed by an introduction to bulk modulus. Governing equations for pumps motors and valves are introduced next. Course emphasis then diverges. The agricultural engineers cover the basics of control theory to cover a deficiency in their undergraduate curriculum. The mechanical engineers embark on more rigorous examination of the simulation of fluid power components. Students in both departments may elect to take a 1 cr. laboratory course. The laboratory exercises are discussed.

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.

The political and economic pressures of creating employment opportunities and providing higher standards of living for individuals have resulted in intense examinations of economic growth stimulators. These studies have shown the international attractiveness of encouraging, developing, and utilizing advanced technologies. The result is that government and education have focused their efforts on research, technology transfer to industry, and the encouragement of new enterprises. While research parks and incubators hold some immediate attraction, longer term efforts are toward developing university research with industrial applications, accelerating knowledge transfer, and providing technical assistance, Iowa's new efforts using advanced technologies as an economic development tool began in 1982 and have expanded rapidly. These efforts include venture capital, incentives for research, education and training, and direct grants for research.