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Open Access Publications from the University of California

Scholarly Works (3 results)

  • Article
  • Peer Reviewed
ACCESS Magazine (1992)
Our roads are crumbling under the weight of buses and heavy truck loads. Although early researchers attributed the pavement damage to a fixed, "static" factor - the vehicle's weight and design - we now know that much of the blame is owed to "dynamic" variables - the interaction between the vehicle's suspension and the road surface. Recent studies show that dynamic force can double, even quadruple, pavement damage. But by equipping trucks and buses with advanced, "semi-active" suspensions, the problem of road wear can be effectively addressed. We are anticipating an up to 20 percent reduction in tire force on pavement surfaces.
    Cover page: Pavement-Friendly Buses and Trucks
    • Article
    Earlier Faculty Research (1992)

    This paper presents a semi-active suspension control algorithm to reduce dynamic tire forces including the development and application of observers for bilinear systems with unknown disturbances. The peak dynamic tire forces, which are greatly in excess of static tire forces, are highly dependent on the dynamic characteristics of vehicle suspensions. One way to reduce dynamic tire forces is to use advanced suspension systems such as semi-active suspensions.

    Semi-active control laws to reduce dynamic tire forces are investigated and a bilinear observer structure for bilinear systems with unknown disturbances is formulated such that the estimation error is independent of the unknown external disturbances and the error dynamics are stable for bounded inputs. The motivation for the development of a disturbance decoupled bilinear observer comes from the state estimation problem in semi-active suspensions.

    An experimental study on the performance of a semi-active suspension to reduce the dynamic tire forces is made via a laboratory vehicle test rig. The semi-active suspension has been implemented by the use of a modulable damper, accelerometers and a personal computer. Experimental studies using the laboratory test rig show that the performance of the semi-active suspension is close to that of the best passive suspension for all frequency ranges in the sense of minimizing the dynamic tire forces and that the dynamic tire force can be replaced by the estimated one. The dynamic tire forces for both passive and semi-active control test cases are compared to show the potential of a semi-active suspension to reduce the dynamic tire forces.

      Cover page: Dynamic Tire Force Control By Semi-Active Suspensions
      • Article
      • Peer Reviewed
      ACCESS Magazine (1992)
      With this first issue of Access, we at the University of California Transportation Center seek to introduce our research to a diverse community of readers. By presenting our findings in a nontechnical format, we hope to make them accessible to professionals in various fields and to citizens who might find them useful or perhaps merely interesting.
        Cover page: ACCESS Magazine Fall 1992Creative Commons 'BY-NC' version 4.0 license
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