Passive Realization Of Ideal Skyhook Damping And Its Applications In Vehicle Suspension

Ideal skyhook damping requires the damper connect to the inertial reference system, however, in the vehicle suspension system, this condition can not be achieved. This is the basic reason why ideal shy hook damping can not be passively realized. For the realization of ideal skyhook damping, it used to adopt indirect methods, including active and semi-active control method. For active and semi-active control suspension, there are shortcomings such as high energy consumption, poor reliability, validity, and real-time performance, as well as, high complexity of the system, therefore, it is difficult to get in the commercial large-scale promotion and application. With the introduction of inerter and the presentation of inerter-spring-damper suspension structure system, it makes passive realization of ideal skyhook damping possible.This paper makes a study of design theory and method, system matching and optimization, manufacturing, performance testing, and other key technologies for a new generation of mechanical vibration-isolated system based on inerter-spring-damper structure system. It develops a typical application technology with independent intellectual property rights, that is, a new inerter-spring-damper vibration-isolated technology for vehicle suspension. And also, in order to substitute for active and semi-active realization system, it develops an inerter-spring-damper suspension. This kind of suspension does not require energy input, does not depend on control system, as well, can reduce energy consumption, enhance the validity and real-time performance of the system, improve system reliability, and reduce the complexity of the system. Studies help to promote the progress and development of the suspension system design theory and application technology.First, based on new electrical and mechanical analogy, the concept and principle of inerter were explained, the models and devices of inerter were systematically study, and the essential characteristics of inerter devices were revealed. Studies laid the theoretical foundation for the design and development of inerter devices.Second, the anti-resonance phenomenon of the inerter-spring-mass system was found. Based on the theory of network analysis, a passive realization method of ideal skyhook damping was presented. As a result, the technical problem that ideal skyhook-damping requires the damper connect to the inertial reference system was solved. And then, the passive realization method of ideal skyhook damping was extended to the passive realization of ideal groundhook damping. Passive skyhook, groundhook and hybrid damping vibration-isolated system models were established by application of impedance analysis method, to study the transmission characteristics of the three systems. The correctness of the passive realization methods of ideal skyhook, groundhook and hybrid damping was preliminarily verified in theory.Third, the passive realization methods of ideal skyhook and groundhook damping were applied to the vehicle suspension. The half-car and full-car models of passive skyhook, groundhook and hybrid damping suspension were built to analyze the frequency-response characteristics and dynamic performance of the suspension. The correctness, validity and feasibility of the passive realization methods of ideal skyhook and groundhook damping were further verified in theory.Fourth, a design method of inerter was proposed to design and development rotary screw ball-screw inerter. To obtain frequency-response characteristics curve, and to compare the ideal and actual performance of inerter, dynamic performance tests of inerter were carried on. Effects of the friction, inertance and other parameters on the dynamic performance of inerter. Studies provide a reliable basis for the design and improvement of inerter devices.Finally, passive skyhook-damping suspension prototype was designed, and installed in the rear suspension of test car. On four-poster tire coupled road simulator, the special and random roads were simulated to test the entire car. The frequency-response characteristics and dynamic performance of the suspension were analyzed to verify the correctness and validity of the passive realization method of ideal skyhook damping.Studies have shown that the simulation and experiment are consistent. Passive realization method of ideal skyhook damping is effective. The car whose rear suspension is passive skyhook-damping one, is compared with the car whose front and rear suspension both are traditional passive one. The peak value of vertical acceleration gain of the former’s rear body decreases by37.5%; in accordance with national standard GB5902-86, in pulse test of a long waveform bump, peak to peak values of vertical acceleration of the rear body, rear wheel, and center of mass, and body pitch acceleration, reduce by22.5%,15.8%,16.1%,13.5%, respectively; In random road test, RMS values of the vertical acceleration of the rear body, rear wheel, and center of mass, body pitch acceleration and body roll acceleration reduce by15%,6.2%,11.2%,9.4%,5.5%, respectively; Passive skyhook-damping suspension improves low-frequency response characteristics of vehicle. It not only inhibits the body resonance, but also reduces the body’s pitch and roll vibration, as a result, improves ride comfort. At the same time, both reduction of vertical acceleration of the rear wheel that reflects the dynamic tire load, and decrease of the body pitch and roll angle in the twist road test, show that the actual passive skyhook-damping suspension does not reduce ride security. Compared with active and semi-active realization method of ideal skyhook damping, passive realization method does not need energy consumption, has good reliability, real-time performance, and the effectiveness of control system. And also, passive realization system is simple, easy to spread and apply.