Browse Topic: Jackknife crashes
In-phase rear-wheel steering, where rear wheels are steered in the same direction of front wheels, has been widely investigated in the literature for vehicle stability improvements along with stability control systems. Much faster response can be achieved by steering the rear wheels automatically during an obstacle avoidance maneuver without applying the brakes where safe stopping distance is not available. Sudden lane change movements still remain challenging for heavy articulated vehicles, such as tractor and semitrailer combinations, particularly on roads with low coefficient of adhesion. Different lateral accelerations acting on tractor and semi-trailer may cause loss of stability resulting in jackknifing, trailer-swing, rollover, or slip-off. Several attempts have been made in the literature to use active steering of semi-trailer’s rear wheels to prevent jackknifing and rollover. However, loss of stability in an articulated vehicle is usually caused by an oversteered tractor, and
Vehicle jackknifing is generally associated with the loss of yaw stability, and is one of the most common cause of serious traffic accidents involving tractor-semitrailer combinations. In this paper, an active braking control strategy is proposed for jackknifing prevention of a tractor-semitrailer combination on a low friction road. The proposed control strategy is realized via upper-level and lower-level control structures considering braking of both the units. In the upper-level control, the required corrective yaw moments for tractor and semitrailer are generated using a PID controller aiming to reduce errors between the actual yaw rates of tractor-semitrailer and the target yaw rates deduced from a reference model. The corrective yaw moments are achieved through brake torque distribution among the tractor and semitrailer axle wheels in the lower-level control. The effectiveness of the proposed jackknifing prevention control is evaluated in a co-simulation environment involving
In this research the differential braking design for articulated vehicle jackknife prevention is investigated. To handle the variations in the semi-trailer loading condition, a self-organizing fuzzy control that can update its control law through a set of learning algorithms is employed. Two different types of driving scenarios are investigated, namely the constant speed step steering and a fish hook maneuver. Computer simulations, both using a linearized vehicle model and the TruckSim® vehicle model, indicate that the SOFC performs consistently well in tracking the desired fifth wheel angle under different loading conditions
Heavy trucks are involved in many accidents every year and Electronic Stability Control (ESC) is viewed as a means to help mitigate this problem. ESC systems are designed to reduce the incidence of single vehicle loss of control, which might lead to rollover or jackknife. As the working details and control strategies of commercially available ESC systems are proprietary, a generic model of an ESC system that mimics the basic logical functionality of commercial systems was developed. This paper deals with the study of the working of a commercial ESC system equipped on an actual tractor trailer vehicle. The particular ESC system found on the test vehicle contained both roll stability control (RSC) and yaw stability control (YSC) features. This work focused on the development of a reliable RSC software model, and the integration of it into a full vehicle simulation (TruckSim) of a heavy truck
The widely used Extended Kalman Filter (EKF) is applied to a planar model of an articulated vehicle to predict jackknifing events. The states of hitch angle and hitch angle rate are estimated using a vehicle model and the available or “measured” states of lateral acceleration and yaw rate from the prime mover. Tuning, performance, and compromises for the EKF in this application are discussed. This application of the EKF is effective in predicting the onset of instability for an articulated vehicle under low-μ and low-load conditions. These conditions have been shown to be most likely to render heavy articulated vehicles vulnerable to jackknife instability. Options for model refinements are also presented
Restraining devices continue to be the most effective means of lessening injuries in automobile collisions. Evidence from the Trauma Research Group's case files illustrates how injury is avoided or minimized by use of lap, shoulder, and diagonal seat belts in several types of crashes, under various angles of impact. Prevention of fatal ejection, the improved chances a restrained driver has of retaining control of his car, and the attenuation of interior collision forces, such as result in jackknifing, are topics discussed, as well as the contribution of major automobile design improvements
A review of benefits to be gained by automatically controlling the slip properties of truck tires indicates that up to 40% shorter stops and complete jackknife control when braking is possible. A simple all-mechanical device is described for use with air brakes which, from the data, shows 7-30% shorter stops, no tire degradation, and full steering control. Data is presented from full sized semi-trailer truck skid tests
A CONTROL system is described that has been successfully preventing premature rotation stoppage of airplane wheels when too much braking is used. The system has now been applied to a truck in a series of tests conducted on an icy roadway. It is shown that wheels exert their greatest braking effect when the brakes are applied almost to the point where the wheels lock. Thus, when used on airplanes, the device (1) detects when a brake is about to lock the wheel, (2) releases the brake pressure to allow the wheel to pick up speed, and (3) again permits brake application. This cycle is then repeated until a stop is attained. Similarly, when used on ground vehicles, the device functions by sensing the impending wheel lock, and then relays a signal to actuate the brake valve. The tests showed that individual wheel control devices can prevent out-of-control skidding in trucks and buses, and jackknifing of tractor-trailers
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