scholarly journals Truck Handling Stability Simulation and Comparison of Taper-Leaf and Multi-Leaf Spring Suspensions with the Same Vertical Stiffness

2020 ◽  
Vol 10 (4) ◽  
pp. 1293 ◽  
Author(s):  
Leilei Zhao ◽  
Yunshan Zhang ◽  
Yuewei Yu ◽  
Changcheng Zhou ◽  
Xiaohan Li ◽  
...  
Keyword(s):  
Dynamic Models ◽  
Load Capacity ◽  
Lightweight Design ◽  
Steering Wheel ◽  
Leaf Spring ◽  
Slip Angle ◽  
Vertical Stiffness ◽  
Spring Suspension ◽  
Before And After ◽  
Stability Indexes

The lightweight design of trucks is of great importance to enhance the load capacity and reduce the production cost. As a result, the taper-leaf spring will gradually replace the multi-leaf spring to become the main elastic element of the suspension for trucks. To reveal the changes of the handling stability after the replacement, the simulations and comparison of the taper-leaf and the multi-leaf spring suspensions with the same vertical stiffness for trucks were conducted. Firstly, to ensure the same comfort of the truck before and after the replacement, an analytical method of replacing the multi-leaf spring with the taper-leaf spring was proposed. Secondly, the effectiveness of the method was verified by the stiffness tests based on a case study. Thirdly, the dynamic models of the taper-leaf spring and the multi-leaf spring with the same vertical stiffness are established and validated, respectively. Based on this, the dynamic models of the truck before and after the replacement were established and verified by the steady static circular test, respectively. Lastly, the handling stability indexes for the truck were compared by the simulations of the drift test, the ramp steer test, and the step steer test. The results show that the yaw rate of the truck almost does not change, the steering wheel moment decreases, the vehicle roll angle obviously increases, and the vehicle side slip angle slightly increases after the replacement. Thus, the truck with the taper-leaf spring suspension has better steering portability, however, its handling stability performs worse.

scholarly journals A Fault Tolerant Vehicle Stability Control Using Adaptive Control Allocation

2018 ◽  
Author(s):  
Ozan Temiz ◽  
Melih Cakmakci ◽  
Yildiray Yildiz
Keyword(s):  
Adaptive Control ◽  
Fault Tolerant ◽  
Stability Control ◽  
Steering Wheel ◽  
Slip Angle ◽  
Control Allocation ◽  
Control Input ◽  
Allocation Strategy ◽  
Virtual Control ◽  
Yaw Stability

This paper presents an integrated fault-tolerant adaptive control allocation strategy for four wheel frive - four wheel steering ground vehicles to increase yaw stability. Conventionally, control of brakes, motors and steering angles are handled separately. In this study, these actuators are controlled simultaneously using an adaptive control allocation strategy. The overall structure consists of two steps: At the first level, virtual control input consisting of the desired traction force, the desired moment correction and the required lateral force correction to maintain driver’s intention are calculated based on the driver’s steering and throttle input and vehicle’s side slip angle. Then, the allocation module determines the traction forces at each wheel, front steering angle correction and rear steering wheel angle, based on the virtual control input. Proposed strategy is validated using a non-linear three degree of freedom reduced two-track vehicle model and results demonstrate that the vehicle can successfully follow the reference motion while protecting yaw stability, even in the cases of device failure and changed road conditions.

scholarly journals A new dynamic model to optimize the reliability of the series-parallel systems under warm standby components

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Amir Mohammad Fakoor Saghih ◽  
Azam Modares
Keyword(s):  
Dynamic Models ◽  
Failure Time ◽  
Recursive Formula ◽  
Reliability Function ◽  
Mode Analysis ◽  
Redundancy Allocation ◽  
Failure Time Distribution ◽  
Before And After ◽  
Common Technique ◽  
Warm Standby

<p style='text-indent:20px;'>Redundancy allocation problem (RAP) is a common technique for increasing the reliability of systems. In this paper, a new model for the RAP is introduced that takes into account the warm standby and mixed strategy, the model dynamics, and the type of the strategy in redundancy allocation problems. A recursive formula is first obtained for the reliability function in the dynamic warm standby and mixed redundancy strategies that leverages the success mode analysis and works for any arbitrary failure-time distribution. Failure rates for warm standby units change before and after their replacement with a damaged unit, and, therefore, the reliability function in warm standby varies with time (i.e., the model is dynamic). Although dynamic models are commonplace in practice, they are more challenging to assess than static models, which have been mainly considered in the literature. An optimization problem is then formulated to select the best redundancy strategy and redundancy levels. Genetic algorithm and particle swarm optimization are leveraged to solve the problem. Finally, the efficiency of the presented method is verified through a numerical example. The experimental results verify that the proposed model for RAP significantly improves the system reliability, which can be of vital importance for system designers.</p>

Simultaneous Optimal Distribution of Lateral and Longitudinal Tire Forces for the Model Following Control

2004 ◽  
Vol 126 (4) ◽  
pp. 753-763 ◽  
Author(s):  
Ossama Mokhiamar ◽  
Masato Abe
Keyword(s):  
Lateral Force ◽  
Longitudinal Force ◽  
Equality Constraints ◽  
Steering Wheel ◽  
Slip Angle ◽  
Force Distribution ◽  
Distribution Method ◽  
Tire Force ◽  
Model Following Control ◽  
Tire Forces

This paper presents a proposed optimum tire force distribution method in order to optimize tire usage and find out how the tires should share longitudinal and lateral forces to achieve a target vehicle response under the assumption that all four wheels can be independently steered, driven, and braked. The inputs to the optimization process are the driver’s commands (steering wheel angle, accelerator pedal pressure, and foot brake pressure), while the outputs are lateral and longitudinal forces on all four wheels. Lateral and longitudinal tire forces cannot be chosen arbitrarily, they have to satisfy certain specified equality constraints. The equality constraints are related to the required total longitudinal force, total lateral force, and total yaw moment. The total lateral force and total moment required are introduced using the model responses of side-slip angle and yaw rate while the total longitudinal force is computed according to driver’s command (traction or braking). A computer simulation of a closed-loop driver-vehicle system subjected to evasive lane change with braking is used to prove the significant effects of the proposed optimal tire force distribution method on improving the limit handling performance. The robustness of the vehicle motion with the proposed control against the coefficient of friction variation as well as the effect of steering wheel angle amplitude is discussed.

Study of the Torsional Behavior of Aluminum Foam-Filled Galvanized Steel Tubes after High Temperature

2018 ◽  
Vol 773 ◽  
pp. 238-243
Author(s):  
Zhan Guang Wang ◽  
Yang Wang
Keyword(s):  
High Temperature ◽  
Aluminum Foam ◽  
Load Capacity ◽  
Steel Tube ◽  
Galvanized Steel ◽  
Steel Tubes ◽  
Torsional Load ◽  
Torsional Behavior ◽  
Before And After ◽  
Foam Filled

Torsional test of aluminum foam-filled galvanized steel tube before and after high temperature is performed. The influence of temperature, porosity of aluminum foam and steel ratio on torsional behavior of aluminum foam galvanized steel tubes were analyzed. Experimental results showed that torsional curves of aluminum foam-filled galvanized steel tube before and after high temperature is similar, and can be divided into four stages: the elastic torsional stage, yield platform stage, descent stage and hardening stage; Its torsional load capacity decreases with increasing porosity of aluminum foam and increases at a higher steel content and slenderness ratio; after high temperature, torsional load capacity of galvanized steel tube decreased significantly. It was found that the strength reduction factor ratio under the elevated test temperature is higher than that recommended by British ECCS, Australian AS4100 and Chinese CECS 200-2006.

Test Results: Vehicle Responses to Simulated Drag Caused by Front Tire Tread Detachment — The Effect of Scrub Radius and Speed

2018 ◽  
Author(s):  
Mark W. Arndt ◽  
Stephen M. Arndt
Keyword(s):  
Lateral Displacement ◽  
Rear Wheel ◽  
Lateral Acceleration ◽  
Steering Wheel ◽  
Slip Angle ◽  
Yaw Rate ◽  
Wheel Drive ◽  
Steady State Responses ◽  
Four Wheel Drive ◽  
Left Front

The effects of reduced kingpin offset distance at the ground (scrub radius) and speed were evaluated under controlled test conditions simulating front tire tread detachment drag. While driving in a straight line at target speeds of 50, 60, or 70 mph with the steering wheel locked, the drag of a tire tread detachment was simulated by applying the left front brake with a pneumatic actuator. The test vehicle was a 2001 dual rear wheel four-wheel-drive Ford F350 pickup truck with an 11,500 lb. GVWR. The scrub radius was tested at the OEM distance of 125 mm (Δ = 0) and at reduced distances of 49 mm (Δ = −76) and 11 mm (Δ = −114). The average steady state responses at 70 mph with the OEM scrub radius were: steering torque = −24.5 in-lb; slip angle = −3.8 deg; lateral acceleration = −0.47 g; yaw rate = −8.9 deg/sec; lateral displacement after 0.75 seconds = 3.1 ft and lateral displacement after 1.5 seconds = 13.1 ft. At the OEM scrub radius, responses that increased linearly with speed included: slip angle (R2 = 0.84); lateral acceleration (R2 = 0.93); yaw rate (R2 = 0.73) and lateral displacement (R2 = 0.59 and R2 = 0.87, respectively). At the OEM scrub radius, steer torque decreased linearly with speed (R2 = 0.76) and longitudinal acceleration had no linear relationship with speed (R2 = 0.09). At 60 mph and 70 mph for both scrub radius reductions, statistically significant decreases (CI ≥ 95%) occurred in average responses of steer torque, slip angle, lateral acceleration, yaw rate, and lateral displacement. At 50 mph, reducing the OEM scrub radius to 11 mm resulted in statistically significant decreases (CI ≥ 95%) in average responses of steer torque, lateral acceleration, yaw rate and lateral displacement. At 50 mph the average slip angle response decreased (CI = 87%) when the OEM scrub radius was reduced to 11 mm.

Function integration concept design applied on CFRP cross leaf spring suspension

2017 ◽  
Vol 3 (2/3/4) ◽  
pp. 276
Author(s):  
Andrea Airale ◽  
Alessandro Ferraris ◽  
Shuang Xu ◽  
Lorenzo Sisca ◽  
Paolo Massai
Keyword(s):  
Leaf Spring ◽  
Concept Design ◽  
Spring Suspension ◽  
Function Integration ◽  
Integration Concept

Function integration concept design applied on CFRP cross leaf spring suspension

2017 ◽  
Vol 3 (2/3/4) ◽  
pp. 276
Author(s):  
Lorenzo Sisca ◽  
Andrea Airale ◽  
Paolo Massai ◽  
Shuang Xu ◽  
Alessandro Ferraris
Keyword(s):  
Leaf Spring ◽  
Concept Design ◽  
Spring Suspension ◽  
Function Integration ◽  
Integration Concept

Nonlinear Finite Element Analysis and Experimental Study of Leaf Spring Suspension

2011 ◽  
Vol 63-64 ◽  
pp. 478-481
Author(s):  
Jin Sheng Qiu ◽  
Jie Meng
Keyword(s):  
Finite Element ◽  
Testing Machine ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Leaf Spring ◽  
Design Calculation ◽  
Element Analysis ◽  
Universal Testing ◽  
Spring Suspension ◽  
Element Theory

By the universal testing machine and special fixture, the leaf spring suspension was tested for deformation, and based on nonlinear finite element theory, the suspension was analyzed. The calculation result is coinciding with test result.The finite element model established could be applied to design calculation and parameter optimization of leaf spring suspension.

scholarly journals Design and Implementation of a Fault-Tolerant Magnetic Bearing System for MSCMG

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Enqiong Tang ◽  
Bangcheng Han
Keyword(s):  
High Speed ◽  
Fault Tolerant ◽  
Control Strategies ◽  
Load Capacity ◽  
Maximum Load ◽  
Magnetic Bearing ◽  
Before And After ◽  
Key Factor ◽  
Gyroscopic Coupling ◽  
Bearing System

The magnetically suspended control moment gyros (MSCMGs) are complex system with multivariable, nonlinear, and strongly gyroscopic coupling. Therefore, its reliability is a key factor to determine whether it can be widely used in spacecraft. Fault-tolerant magnetic bearing systems have been proposed so that the system can operate normally in spite of some faults in the system. However, the conventional magnetic bearing and fault-tolerant control strategies are not suitable for the MSCMGs because of the moving-gimbal effects and requirement of the maximum load capacity after failure. A novel fault-tolerant magnetic bearing system which has low power loss and good robust performances to reject the moving-gimbal effects is presented in this paper. Moreover, its maximum load capacity is unchanged before and after failure. In addition, the compensation filters are designed to improve the bandwidth of the amplifiers so that the nutation stability of the high-speed rotor cannot be affected by the increasing of the coil currents. The experimental results show the effectiveness and superiority of the proposed fault-tolerant system.

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