Active Ride Control for Construction Machines Based on Pressure Feedback

Abstract

Typically, off-road construction machines are not equipped with suspensions at the wheel axles. This has led to alternative concepts that uses the working implement to mitigate the vibration transmitted to the cabin. The most common solutions are based on passive ride control (PRC) methods. A PRC usually requires a hydraulic accumulator and dissipating valves properly connected to the working hydraulics. In this way, the PRC is able to dissipate the fluid energy and damp the oscillations of the pressure inside the hydraulic actuators, with clear benefits on the machine vibration. This paper focuses instead on an active ride control (ARC) methodology, which controls the working hydraulic motion to counter-reach the machine vibrations, avoiding the use of an accumulator. The paper addresses the main challenge of designing the controller for the ARC for the reference case of a wheel loader. A high pass pressure filter control with pressure feedback is proposed for this application. The controller is first studied in a simulation model and then validated through experiments on a stock machine. The bandwidth limitation of the standard hydraulic system does not permit to achieve the same performance of a state-of-art PRC system considered as baseline. Notwithstanding, the experimental results on the proposed ARC shows significant improvements with respect to a case where no controller is used. Moreover, the proposed method could be applied with more effectiveness in hydraulic systems with higher dynamic response.

A Comprehensive Review of Electronically Controlled Implement Architectures for Mobile Machinery Using Secondary Control

“…Most mobile machines, like wheeled loaders and wheeled excavators are not equipped with suspensions at the wheel axles. Instead, passive (PRC) and active ride control (ARC) modules are used [3]. The PRC typically use an accumulator and a hydraulic restriction to dampen the oscillation.…”

An active oscillation reduction method for off-highway front loaders

“…Such study was validated experimentally by several research groups on different machines. [15][16][17] Cheng et al 18 compare the two strategies investigating their effectiveness through the motion of a robotic manipulator. The pressure feedback induces a higher overshoot, and an increased settling time can be observed during the motion of the actuator, as Padovani 16 also confirms.…”

“…For this purpose and to further validate the effectiveness of the proposed ARC, this article also presents the results of the two alternatives when implemented on a different size wheel loader, the 15 tons CASE 721 F. Specifically, the proposed CP approach is compared with the baseline ARC described by Madau and Vacca. 15 The past study presents a pressure feedback control strategy on the analyzed 15 tons vehicle. The vehicle was instrumented with a proper DAQ system, as presented in section ''Reference machine and instrumentation'' for the reference 621G, and an Eaton CMA valve was also included in the hydraulic system to reproduce the proposed ARC on the bigger size machine.…”