| Summary: | M.Ing. (Mechanical Engineering) === A hydromechanical traction system for a wheeled vehicle is being examined in order to generate information that will be applicable to the design of the drive system controller. The functional analysis of the drive system leads to the description of the system and component properties. A design methodology is proposed by which the system components could be dimensioned and the system layout constructed by taking into account the specified functional requirements concerning the system performance. An explicit description of power flow and manipulation of power flow in the drive system is given. The mechanisms by which the hydraulic machines are adjusted to manipulate power flow, are examined in detail so that their contribution to the dynamic behaviour of the total drive system can be described. , Experimental measurements are used to obtain a reliable description of the dynamic response of the adjustment mechanisms. An analytical model of the dynamic behaviour of the drive system is presented in block diagram format. The inherent multiple-input-multiple-output characteristic of the drive system with secondary controlled hydraulic motors is discussed. The block diagram is simplified to create linearized transfer functions that will depict the input-output-relationships. The effect of an accumulator on the dynamic response of the system is also given. Digital simulation programmes are constructed from the analytical model. The requirements of a vehicle traction system are interpreted and used as guidelines to conduct a functional design of the control system layout. The delivery of torque and the restriction of wheel spin for each of the wheel drive units, which is realised by secondary controlled hydraulic motors, are described in detail. A hypothetical drive system is considered and quantitive control system design information is generated, using the simulation programmes. Some aspects of the dynamic response of the system are discussed and it is shown that the adjustment mechanism has a big influence on the overall dynamic response of the system.
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