| Suspension system is an important assembly to isolate road excitation,and plays an important role in the ride comfort and the drive stability of the vehicle.With the wide application of vehicles,higher and higher requirements for vehicle comfort,safety and off-road performance are proposed.These requirements have posed a challenge for the design of suspensions.In this paper,a double-diamond bionic kangaroo leg suspension is proposed by combining the characteristics of kangaroo legs with fast jumping speed,small footing surface,and stable movement,and its static and dynamic modeling are performed and characteristics simulation are studied.The main research works are as follows:1.Based on the study of the kangaroo leg structure and function,the three-link bionic kangaroo leg suspension structure was symmetrically arranged,the placement of components such as spring dampers are improved,a double-diamond bionic kangaroo leg suspension structure is proposed.2.The static modeling and static stiffness analysis of the a double-diamond bionic kangaroo leg suspension are analyzed and it is found that stiffness of the suspension presents the characteristics of "hardening" when it is compressed and "softening" when it is stretched,and the suspension has obvious nonlinear characteristics which is closely related with the initial attitude include initial angle,lever length ratio,and spring stiffness ratio.Based on the static analysis,the suspension system parameters are designed.3.To grasp the vertical parameter characteristics of the suspension,the dynamic modeling is performed by Lagrange Equation Method.The study found that there are strong nonlinear coupling characteristics between the suspension’s displacement,velocity,acceleration and other parameters.4.The suspension dynamic simulation modeling and analysis are carried out.The vertical performance of the double-diamond bionic kangaroo leg suspension is analyzed on pulse road,step road and random road which at different speeds(20 km/h,50 km/h,70 km/h and 100 km/h)under different pavements(class A,B,C,D and E),the results display that,(1)The vertical performance parameters of the suspension are all within a reasonable range,which indicates that the design of the suspension is reasonable and the parameters of the suspension are properly set;(2)Under the above-mentioned random road conditions,the transmissibility values the body vertical acceleration are limited in 2.8% ～ 2.9%,under pulse road excitation and step road excitation,the vertical acceleration of the body decreases by 91.09% and 92.20%,respectively,the results show that the suspension proposed has good cushioning and vibration damping performance;(3)The transmissibility value of the body vertical acceleration and the body dynamic displacement decrease with the increase of the road grade and the speed,the transmissibility values of the tire dynamic displacement fluctuates in a small range around 5.6%,shows that the suspension has good off-road performance,good high-speed comfort,road adaptability and stability,these characteristics are consistent with the superior movement characteristics of kangaroo legs,verifies the correctness and rationality of the bionic design ideas in this paper.5.The traditional two-degree-of-freedom suspension is modeled and analyzed compared with the proposed suspension under the same conditions.The results display that there is a certain improvement for the vibration damping performance of the proposed suspension.The change of the body dynamic displacement of the proposed suspension is more smoothly,and has presents obvious peak clipping and hysteresis characteristics,shows that the proposed suspension has better performance and has certain research value.In a word,the double-diamond bionic kangaroo leg suspension has good high-speed comfort,road adaptability and stability.These performances verify the correctness and feasibility of the design ideas and research methods in this paper. |
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