The Study On Steering Technology Of Independently Rotating Wheels Based On Active Differential Mechanism

Independently rotating wheels can be low floor, but also makes its automatic performance in a straight line and guide performance on the curve disappeared. That two function are referred to as independently rotating wheels steering function.Analyzed its development status at home and abroad, Reference guide principle of tanks and other armored tracked vehicle, In the thesis, aiming at the problem of independently rotating wheels steering questions Expanding the following research:Through in-depth studying and analyzing the steering mechanism and influence factors of the rigid guide wheel in the straight line and the curve,, resulting that independently rotating wheels steering function can be further controlled by controlling the speed of the left and right wheels of independently rotating wheels. According to theory of the speed-control, designed a planetary gear wheel of an mechanical differential which is independently rotating wheels mechanical coupling used, through studying and analyzing the structure and driving principle, achieved the output shaft can run with differential speed.Analyzed its active-oriented control methods of the independently rotating wheels when it running, established an independently rotating wheels model based on active differential mechanism in SIMPACK, and established the control way of the parameter module in SIMULINK, Thereby established a joint simulation SIMAT model, Implement the Model data-connection, parameters-obtain and real-time control. Simulating the running motion in straight line and the curve of the model, Compared the simulation results to rigid wheels model and independent rotating wheels model, then the conclusions can be drawn as follows:(1)The rigid wheels having a straight line automatic centering function on a straight track; and it mainly rely on restoring force of gravity and the wheel-rail creep forceto obtain curve-guiding function on curved track;The independently rotating wheels don’t have a straight line automatic centering function on a straight track; and it lacking of initiative guiding function on a curved track, prone to derailments.(2)The movement on straight track of the differential independently rotating wheels bogie model, its wheels lateral offset gradually decreases until it is zero over time, so differential independently rotating wheels having a straight line automatic centering function on a straight track as same as rigid wheels; on curved track, its wheel offset value of the first wheels is less than the independently rotating wheels, its second wheels which mounted active differential gear device,its wheel lateral offset value is small, the absolute value of the amount remained at about 2.7mm,which is in the wheel-rail contact range and far less than the independently rotating wheels, therefore differential independently rotating wheels having a curved track certain active guiding function, compared to rigid wheels and independently rotating wheels, its active guiding function better, and it also has a good performance in a small radius curve by the wheel rail wear less, higher security, meet the design requirements.(3)Through the study of the structure design and control strategy of the differential independently rotating wheels model, completed the physical production, installation and testing of the differential independently rotating wheels based on active differential mechanism according to test results,the main conclusions include:The differential independently rotating wheels model which studied and designed in the thesis, can be controlled through the inner ring rotation angular velocity of the wheel to control the speed-difference of the left and right wheel, the rotational motion of the wheel or the distance between the arc is proportional to the control input terminal of the angle of rotation of the worm, it can be implemented on a curved track active guiding function, with good reliability and value.In summary, the differential independent rotating wheels model having a rigid wheel unique a straight line automatic centering function on a straight track; and better than the curve of the independent rotating wheels active steering function, effectively combines the advantages of the both, to achieve the active steering function of the smaller wheel radius and linear automatic centering function is automatically integrated in the demand for capacity, it promoted that the theory of the independently rotating wheels used to low-floor urban rail vehicles can transformation to practical use.