Research On Ride Comfort And Road Friendly Of ISD Suspension For Heavy Vehicle Based On Dynamic Inertia Effect

Vehicle damage to the road is mainly due to the impact of dynamic tire load on the road surface in the course of driving.In the case of road conditions cannot be greatly improved,the road friendly can be improved by reducing the dynamic tire load.Inerter as a mass element with two ends,compensates for the lack of mass impedance in the traditional passive suspension "spring-damper" structure system,and forms an ISD suspension structure consisting of "Inerter-Spring-Damper",which has the dynamic inertia effect of improving the vertical motion characteristics for the system.Therefore,aiming at the problem of road damage caused by heavy vehicle driving process,this paper applied ISD suspension with inerter to heavy vehicle suspension system,used the dynamic inertia effect of ISD suspension to coordinate the vertical motion inertia of vehicles,and studied the coordination mechanism of ISD suspension to ride comfort and road friendly of heavy vehicles.At the same time,a new type of ball screw type mechatronic inerter was developed.The equivalent inerter was realized by external capacitive elements and a test prototype of ISD suspension for heavy vehicles was built.The method of combining theoretical analysis with experimental verification was used to provide theoretical support and practical experience for the study of ride comfort and road friendly of heavy vehicles based on dynamic inertia effect of ISD suspension.Firstly,the dynamic inertia effect was defined according to the relative motion process of ISD suspension between sprung and unsprung mass,which changes the vertical inertia of the system without increasing the weight for the system.The dynamic models of ISD suspension for one quarter and half of heavy vehicles were constructed respectively.The dynamic models of ISD suspension for one quarter and half of heavy vehicles were constructed,and the initial parameters of ISD suspension for heavy vehicles were optimized by using multi-objective genetic algorithm,aiming at improving ride comfort and road friendly of heavy vehicles.Compared with the traditional suspension,the simulation analysis was carried out under different driving speed and road grade conditions,meanwhile,the mechanism of vehicle ISD suspension dynamic inertia under parameter perturbation was studied.The results showed that the ride comfort and road friendly of heavy vehicles with ISD suspension are improved synergistically under the action of dynamic inertia effect.It revealed that the change of front wheel suspension parameters has more significant impact on ride comfort and road friendly,and that the damage of heavy vehicles to the road surface increases with the increase of load.It provided a theoretical basis for the study of ISD suspension of heavy vehicles.Secondly,a new type of ball screw mechatronic inerter device was innovatively designed,which is coupled by a one-way roller clutch,a rotating motor and a ball screw inerter.The working principle of the ball-screw inerter and a rotating motor was analyzed in detail.In order to reduce the device size,according to the new mechatronic similarity theory,the equivalent inerter was realized by external capacitor elements,and the equivalent mechatronic network model of the device was established and simulated in time domain and frequency domain.When the vehicle speed is 20 m/s under random road input conditions,the RMS values of body acceleration,suspension deflection and dynamic tire load of suspension system are improved by 0.26%,12.8% and 11.91% respectively.The peak value in frequency domain is significantly reduced,and the road damage coefficient representing road friendly is improved by 9.25%.The results showed that under the action of dynamic inertia,the vertical inertia of ISD suspension system with mechatronic inerter is reasonably distributed and has excellent vibration isolation performance.Then,a new type of mechatronic inerter device with ball screw was developed and its mechanical properties are tested.The structure selection and parameter design of the new ball screw inerter and rotary motor were carried out and the mechanical properties of the traditional ball screw inerter,the new ball screw inerter without circuit load and the new ball screw inerter with circuit load were tested respectively.The experimental results showed that the new ball screw type inerter can effectively eliminate the inertial impact effect caused by the change of flywheel rotation direction,and verify the effectiveness of the steady-state switching design of the new ball screw type inerter.The difference between the amplitude of the circuit load and that of the non-circuit load is about one time,which proves the feasibility of the equivalent inertial capacitance of the external circuit.The mechatronic inerter with ball screw meets the design requirements.Finally,a prototype of vehicle ISD suspension system based on a new type of ball screw mechatronic inerter was built.On the INSTRON 8800 single channel hydraulic servo excitation platform,the performance tests of the traditional passive suspension with equal stiffness were carried out under sinusoidal and random road input conditions respectively.The results showed that under sinusoidal road input conditions,the RMS of suspension deflection and dynamic tire load of heavy vehicle ISD suspension are significantly improved;under random road input conditions,when the vehicle speed is 20 m/s,the RMS of suspension deflection and dynamic tire load of vehicle ISD suspension with new mechatronic inerter are reduced by 11.16% and 9.96%,and the road damage coefficient is reduced by 8.26%.The test proves that the ride comfort and road friendly of ISD suspension system with mechatronic inerter were obviously improved under the action of dynamic inertia.It was noted that,the dynamic inertia effect of ISD suspension can enhance the vertical stability of heavy vehicles,realize the effective distribution of motion inertia between the body and wheel mass,absorb and adjust the transmission of vibration energy,reduce the road damage caused by the dynamic load of heavy vehicles tires,significantly improve the ride comfort and road friendly of heavy vehicles,and it has obvious advantages of vibration isolation.The mechatronic inerter device developed in this paper has simple structure and is easy to be realized in engineering.It has accumulated valuable experience for the engineering realization of ISD suspension of heavy vehicles.