Snaking stability of articulated frame steer vehicles with axle suspension

Rehnberg, Adam; Drugge, Lars; Trigell, Annika Stensson

doi:10.1504/ijhvs.2010.033178

Cited by 24 publications

(26 citation statements)

References 10 publications

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“…If the simulation test happens to be at a low and constant speed, the accuracy of the simulation result is much higher than if it runs with a varying speed. Since the Fiala tyre model is simple and detailed enough for most simulation cases, it has been used in many studies [17][18][19][20][21][22] where the road inclination angle is not a major factor and where longitudinal and lateral slip effects may be considered unrelated. However, the Fiala tyre model is not obviously applicable for soft soil simulations.…”

Section: Tyre Modelmentioning

confidence: 99%

Development of dynamic base model of a bogie suspended forwarder

Ismoilov

Sellgren

Andersson

2016

Proceedings of the Institution of Mechanical Engineers, Part K:

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A forwarder is an off-road working machine that is used to transport logs from logging sites to a landing area that is accessible by trucks. Soil damage and operator comfort, especially whole-body vibrations when operating on hard and rough terrain, are crucial issues when developing novel forest machines. Most forwarders on the market are heavy machines with articulated steering and they are equipped with pairs of wheels mounted on bogies. For such bogie machines, only the flexibility and the dynamic dissipation in the tyres contribute to the ''chassis damping''. The roll and lateral motions are the most severe components of the whole-body vibrations. So, developing new traction units, chassis suspensions and/or cabin suspension are in focus. Model-based design relies on focused models that are as simple as possible, but not too simple. This paper presents a 12 degrees-of-freedom multi-body dynamics simulation model of a standard eight-wheeled bogie type of medium-sized forwarder. The presented model is targeted for assessing and comparing different design solutions. It is shown that a configuration of seven rigid subsystems and eight flexible tyres represented with the simple and computer efficient Fiala tyre model enables the forwarder dynamic simulation model to be used to predict the roll and lateral motions of a forwarder operating on hard and rough terrain.

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Section: Tyre Modelmentioning

confidence: 99%

Development of dynamic base model of a bogie suspended forwarder

Ismoilov

Sellgren

Andersson

2016

Proceedings of the Institution of Mechanical Engineers, Part K:

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“…11 A number of studies have investigated the yaw stability of the ASV based on the free-yaw-oscillation responses, while simplifying the AFS system using the equivalent articulation stiffness and the damping, and neglecting contributions due to its kinematics. 1,9,12…”

Section: Introductionmentioning

confidence: 99%

“…The eigenvalue analysis, however, is limited to only linear or linearized models, which are considered to be valid in the vicinity of the linearization point. 1,6 Alternatively, Rhenberg et al 9 and Pazooki et al 11 have assessed the snaking behaviour in terms of the rate of decay of free oscillations in the articulation angle response following a lateral perturbation of the vehicle. The rate of decay, however, may not accurately describe the essential yaw-oscillation characteristics of the non-linear vehicle model such as the natural frequency and the damping ratio, because of its sensitivity to the magnitude and the duration of the pulse.…”

Section: Introductionmentioning

confidence: 99%

“…The equivalent torsional stiffness of AFS system is generally linearized about zero articulation angle and can range from 1.1 × 10 5 N m/rad to 2 × 10 8 N m/rad, taking into account the compliance of the hydraulic fluid, the connecting pipes and the entrapped air. 9,12,14,19 The instantaneous effective stiffness of the AFS system, however, varies with the orientations of the struts and the actuating forces of the steering struts in a non-linear manner, which was widely ignored in the aforementioned studies.…”

Section: Introductionmentioning

confidence: 99%

“…12,20,21 Higher leakage flows and a higher fluid bulk modulus were believed to increase the damping coefficient and the stiffness of the steering system respectively and have been reported to attenuate the free oscillations of the articulation angle and to increase the critical speed of the vehicle. 1,9,11,12 Horton and Crolla 1 , Pazooki et al 11 and He et al 12 always assumed that the leakage flows within the struts are proportional to the pressure difference across the seal. The leakage flows, however, depend on the relative velocity between the cylinder and the rod, which affects the seal clearance in a non-linear manner.…”

Section: Introductionmentioning

confidence: 99%

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Effect of articulated frame steering on the transient yaw responses of the vehicle

Yin

Rakheja

Yang

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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The directional performance characteristics of articulated frame steering vehicles are known to be strongly coupled with the kinematic characteristics and the dynamic characteristics of the steering system. The reported studies on articulated frame steering generally focus on the yaw divergence behaviour or the snaking tendency of the vehicle based on its free-yaw-oscillation response, while neglecting important contributions due to the kinematics and the dynamics of the steering system. This study characterizes both the free-yaw-oscillation response and the transient steering response of an articulated frame steering mining vehicle, considering the kinematics of the steering struts together with the dynamics of the flow volume-regulated steering valve and the actuating system. The validity of the analytical vehicle and steering system model is demonstrated using the measured data acquired for the vehicle. The free-oscillation behaviour of the articulated frame steering is characterized in terms of the yaw-mode natural frequency and the yaw damping ratio. The transient responses of the articulated frame steering are assessed in terms of the steering gain, the rate of articulation and the articulation overshoot. The effects of the variations in the various articulated frame steering parameters on the free response and the transient response are subsequently investigated and discussed so as to seek guidance for the design of the articulated frame steering system. It is shown that a higher bulk modulus of the hydraulic fluid and longer steering-arm lengths yield a higher yaw stiffness of the articulated frame steering system and thereby a higher frequency of the yaw oscillations. Higher leakage flows and higher viscous seal friction cause a higher yaw damping coefficient but decrease the steering gain and the articulation rate of the vehicle.

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