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Prototyping of automated systems
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
The rack and pinion, as shown in Figure 8.56, can also be used to convert energy between rotary and linear motions. A good example is the auto-steering system, which rotates a rack and pinion. As the gear turns, it slides the rack either to the right or left, depending on which way to turn the wheel. A rack and pinion can convert motion from rotary to linear and from linear to rotary. A rack and pinion is commonly used in the steering system of cars to convert the rotary motion of the steering wheel to the side-to-side motion in the wheels. Rack and pinion gears give a positive motion, especially compared to the friction of a wheel driving on tarmac. For example, in the rack and pinion railway, a central rack between the two rails engages with a pinion on the engine allowing the train to be pulled up very steep slopes.
Automotive Chassis Components
Published in Don M. Pirro, Martin Webster, Ekkehard Daschner, Lubrication Fundamentals, 2017
Don M. Pirro, Martin Webster, Ekkehard Daschner
Most cars today are equipped with power-assisted rack-and-pinion steering (Figure 12.8). In this design, a small pinion on the end of the steering shaft meshes with a rack mounted in a guide tube. The tie rods are connected directly to the rack through a mounting bracket. This simple linkage produces better “road feel” for the driver and may reduce steering effort. Power steering, or power-assisted steering, is now widely applied to all types of automotive equipment. In addition to the rack-and-pinion steering systems, there are two other types generally used: the linkage type (Figure 12.5) and the integral type (Figure 12.9). Although these illustrations show passenger car applications, the principles are applicable to systems used on other equipment.
Design of Steering Torque Feedback in a Fixed-base Driving Simulator and Its Validation
Published in Marcelo M. Soares, Franscisco Rebelo, Advances in Usability Evaulation, 2013
In this study, the feedback model includes speed and angular position as variables. In reality, the feedback on a steering wheel is more complex. In modern passenger cars and commercial cars, the steering wheel is the connection between a driver and a car. The feedback that a driver feels from the steering wheel includes vibration and torque resistance, the former of which reflects the road surface condition and the latter contains more information than normally understood. The driver comprehends the information from steering wheel and other channels and instantly makes driving maneuver decisions. As modern cars are usually equipped with power steering unit, the torque feedback characteristic becomes more complicated. In order to find the relationship between the feedback torque and its determining factors, we could either build a steering system model and perform calculation or use key values to build up a regression model. The former approach would produce a precise function but takes much effort. The latter one allows us to quickly establish an approximate relationship. As the objective of this study is to provide an effective torque feedback to the users of the simulator, the regression method is adopted.
Development and implementation of a time- and computationally-efficient methodology for reconstructing real-world crashes using finite element modeling to improve crash injury research investigations
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Casey Costa, James P. Gaewsky, Joel D. Stitzel, F. Scott Gayzik, Fang-Chi Hsu, R. Shayn Martin, Anna N. Miller, Ashley A. Weaver
To quantify the alignment between reconstruction and case kinematics, a novel metric, the Contact Kinematic Score (CKS), was developed and calculated for each case using Eq. (2): where binary variables represent whether the given contact occurred (C = 1) or not (C = 0) in the reconstruction (CR) or case (CC), and CL is the confidence level for the given contact (unknown = 0, possible = 1, probable = 2, certain = 3). Since CC represents case contacts, it always equals 1. Eq. (2) weighs each contact based on its confidence level. The resulting CKS is a value between 0 and 1, with 0 representing no matches between case and reconstruction and 1 representing that the M50-OS contacted all known case contacts. In the reconstructions, case contacts were positive if the M50-OS contacted the reported section of the vehicle in the same location. For the steering wheel assembly, steering column collapse and physical contact were both considered positive for contact. The same approach is used to determine steering wheel contact in CIREN since the absence of direct contact does not mean the steering assembly did not contribute to injury through the airbag.
Two Nash-equilibrium-based steering control models for representing a driver’s interaction with vehicle automated steering
Published in Vehicle System Dynamics, 2022
Xiaoxiang Na, David J. Cole, Gang Li
In the experiment, the AFS control law (4) has been programmed into the driving simulator. The AFS system, as described in [11,12], can superimpose a steering angle on the steering column independently of the driver’s steering wheel angle. As a result, the steering action applied to the vehicle is a blend of the driver’s and the AFS controller’s steering angles. The influence of these two sources of steering angles on vehicle dynamics is illustrated in Figure 1, and numerically implemented via (1). Note that the steering control performed by the AFS system is powered by the AFS actuator. Hence, the driver is less likely to perceive extra steering effort when the AFS system is in operation. However, the driver may recognise the intervention of the AFS control as it does affect the vehicle’s directional response, e.g. in terms of pulling the vehicle in a direction opposite to the driver’s target path. The vehicle parameters and AFS controller parameters used by the driving simulator are the same as those employed in the simulation study, as described in Section 3.
A system optimisation design approach to vehicle structure under frontal impact based on SVR of optimised hybrid kernel function
Published in International Journal of Crashworthiness, 2021
Xianguang Gu, Wei Wang, Liang Xia, Ping Jiang
Vehicle crashworthiness can be evaluated by parameters such as the peak acceleration, absorbed energy and firewall intrusion [28,31,32]. The peak acceleration indicates the motion characteristics of vehicle in a frontal impact. The smaller the peak value is, the smoother the vehicle crash process is, and the smaller the impact damage to passengers is. The capacity of the energy absorption of the vehicle body plays an important role in occupant protection. The kinetic energy that is not absorbed during the impact is transmitted to the compartment, causing it to be severely deformed and leading serious injuries to the occupants. The firewall is located in the front of the cab, and its intrusion must be strictly controlled. Over-deformation of the firewall will lead to large displacement of steering column and steering wheel, endangering the safety of passengers. Meanwhile, the structure lightweight also needs to be considered in the optimisation design in order to decrease the fuel consumption and make the products environmentally friendly.