An active oscillation reduction method for off-highway front loaders

Abstract

Cabin vibration in construction machines is a known issue affecting both comfort and safety of the operators, and it also induces losses in machine productivity. The solution offered in commercial machines, known as the passive ride control, has the drawbacks of limited performance on a wide range of operating conditions and component costs, which has motivated research toward “active” alternatives that utilize electro-hydraulic systems without additional components. Nonetheless, the nonlinearities and the dynamic response of these systems constraint the performance of such alternatives, when compared to the commercial solution and therefore, their diffusion on the market. To address the challenges mentioned above, this article proposes an alternative hydraulic system layout to perform the ride control function based on connecting the boom lift actuators of the front-end loader in differential mode. This article describes the development of two active control strategies for this new ride control system that utilizes pressure and acceleration information to suppress cabin oscillations and presents the experimental tests on a full-size wheel loader. The results show a similar capability for reducing the oscillations achieved by the commercial solution and the one proposed in this research. In certain scenarios, the proposed formulation offers up to 10% of further improvement in terms of cabin oscillation reduction.

A Model of an Extending Front Loader

“…The introduction of shock absorbers to the boom system limits the momentary sudden increase in stress and enables more smooth control of the loader's movement [16]. In [17], an analysis of reducing the vibrations of a front loader moving over uneven terrain was carried out, and an alternative hydraulic system was proposed to perform the driving control function. Pump leaks and leaks resulting from damage play a key role in the safety and functioning of hydraulic drives.…”