Abstract
The paper shows results of an experimental and theoretical study of dynamic processes in the vehicle transmission after kinematic alignment of elements during gearshifts. The purpose of the research is increasing the quality of transient processes in the vehicle transmission. Applying an analysis of experimental results obtained through looking into dynamics of a 3-ton vehicle transmission and studying literature sources it was established that dynamic loading of the transmission after the kinematic stage of shifting (i. e. synchronizing speeds of driving and driven elements in the gearbox) is influenced by oscillations which are in the single-node mode. Solving the task of increasing transient processes is achieved by applying a method of control power redistribution. By employing simulation models a number of methods were used to regulate power redistribution. Results of computations made it possible to determine that the efficiency of power redistribution are closely related to initial conditions of the process under the study. In the progress of the research a method for identifying the initial conditions was developed. This method is based determining signatures of the torque and its derivatives. In accordance with the research results it turned out that it is appropriate to apply the ZVD (zero vibration derivation) algorithm of power redistribution for low gears (below 4th) from point of view achieving better overshoot and robustness characteristics and a satisfactory response rate level. For higher gears it is recommended that the Ramp algorithm (linear increase in the control input) be used for the cases when the response rate is not longer than period of the single-node mode of oscillations occurring in the dynamic system during a gear shift. Application of the proposed algorithms allows to bring down dynamic loading of the transmission and also to improve the comfort in vehicles.
Highlights
Application of modern high-torque engines results in generating intensive vibrations in the transmissions of vehicles when they starts to move and when gears are shifted
In the process of performing the present research a method was devised for damping low-frequency oscillations in transmissions of transportation vehicles at the stage following kinematic equalization of speeds of driving and driven components; to do so an antiphase control action was developed that would operate at the natural frequency of dynamic systems which is in the lowest single-node oscillation mode
The novelty lies in synthesizing a shaper on the basis of computing parameters for redistributing in time the control action under the following algorithms: ZV (Zero Vibration), ZVD (Zero Vibration and Derivative), ZVDD (Zero Vibration and Double Derivative), RAMP, etc
Summary
Application of modern high-torque engines results in generating intensive vibrations in the transmissions of vehicles when they starts to move and when gears are shifted. Low-frequency oscillations in the transmission are quite natural; they are generated when the driving torque in a dynamic system rises sharply at its lowest natural frequency, which is the first single-node oscillation mode. This phenomenon made a full-scale manifestation as a 3-ton transportation vehicle fitted with a hybrid power plant, which contained a 650 hp eight-cylinder engine, was subjected to an experimental study. When the dynamic load of the vehicle was estimated, it was established that low-frequency torsional oscillations in the transmission initiate intense longitudinal vibrations of the vehicle’s body with the acceleration ranging from 2 to 4 m/s2.
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