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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.
Time-dependent mechanism reliability analysis with imprecise probability distributions based on envelope function
Published in Mechanics Based Design of Structures and Machines, 2023
Zheng Zhang, Changcong Zhou, Qi Chang, Haihe Li, Zhufeng Yue
As shown in Table 10, we can draw similar conclusions to the above examples that errors of the upper and lower bounds of failure probability estimated by MEVF refer to the MCS procedure are less than 6%. It indicates that MEVF can guarantee the accuracy in this rack-and pinion steering linkage mechanism. As for the calls to the limit state function, that required by MEVF to estimate is 210 × 54× comparing with 106×100 × 65× by MCS. And for the upper bound of failure probability of MEVF is 210 × 111× while it is 106×100 × 106× for MCS. The results listed in Table 10 show that MEVF is reasonable and more efficient in this mechanism.
Modelling and control of a new differential steering concept
Published in Vehicle System Dynamics, 2019
First works by [3,4] utilise this principle, where Wang et al. [3] introduced the term differential drive assisted steering or generally differential steering as used in the present paper. The same authors later extended their results in [5,6] where a common feature is that differential steering only assists a conventional rack and pinion steering gear, the rear axle is driven but not steerable, and its torque differences are applied for yaw control. The steering assist and yaw controllers are designed and implemented separately and they cooperate through an additional traction controller. Investigations in [7] show the possibility of a complete steer-by-wire implementation of the differential steering principle, but still include an additional conventional steering device, and the rear axle is not utilised at all. In order to improve the steering feel, optimisation and robust control may be applied to differential drive assisted steering systems [8,9]. The differential steering principle may also be utilised as a safety fallback solution for steer-by-wire systems using separate steering angle tracking control [10]. This may also be achieved by using only friction brakes [11].
Preview-scheduled steering assistance control for co-piloting vehicle: a human-like methodology
Published in Vehicle System Dynamics, 2020
Kaiming Yang, Yahui Liu, Xiaoxiang Na, Xiangkun He, Yulong Liu, Jian Wu, Shirou Nakano, Xuewu Ji
Human drivers’ steering behaviour data were collected through an experiment using a driving simulator as shown in Figure 2. The experiment data collected will later be used to identify the parameters of the driver model (3). The vehicle dynamics model run by the driving simulator is a 27-DoF model developed by CarSim. The visualised driving scenarios were operated in real-time by NI®/Labview software in PXI hardware. The driver can apply steering control to the simulator vehicle model through the rack and pinion steering assembly. The steering resistance torque calculated by the vehicle dynamic model is fed back to the steering assembly by a Panasonic®/EXLAR® servo cylinder, which runs a feedforward-and-feedback control logic.