Path-Following Steering Control for Articulated Vehicles

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
B. A. Jujnovich ◽  
D. Cebon
Keyword(s):  
High Speed ◽  
Path Following ◽  
Steering Control ◽  
Active Steering ◽  
High Speeds ◽  
Wide Range ◽  
Articulated Vehicles ◽  
Speed Range ◽  
Heavy Goods Vehicles ◽  
Low Speeds

Passive steering systems have been used for some years to control the steering of trailer axles on articulated vehicles. These normally use a “command steer” control strategy, which is designed to work well in steady-state circles at low speeds, but which generates inappropriate steer angles during transient low-speed maneuvers and at high speeds. In this paper, “active” steering control strategies are developed for articulated heavy goods vehicles. These aim to achieve accurate path following for tractor and trailer, for all paths and all normal vehicle speeds, in the presence of external disturbances. Controllers are designed to implement the path-following strategies at low and high speeds, whilst taking into account the complexities and practicalities of articulated vehicles. At low speeds, the articulation and steer angles on articulated heavy goods vehicles are large and small-angle approximations are not appropriate. Hence, nonlinear controllers based on kinematics are required. But at high-speeds, the dynamic stability of control system is compromised if the kinematics-based controllers remain active. This is because a key state of the system, the side-slip characteristics of the trailer, exhibits a sign-change with increasing speeds. The low and high speed controllers are blended together using a speed-dependent gain, in the intermediate speed range. Simulations are conducted to compare the performance of the new steering controllers with conventional vehicles (with unsteered drive and trailer axles) and with vehicles with command steer controllers on their trailer axles. The simulations show that active steering has the potential to improve significantly the directional performance of articulated vehicles for a wide range of conditions, throughout the speed range.

Measurement of Wet cornering Traction of Tires

1971 ◽  
Vol 44 (4) ◽  
pp. 962-995 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Elastohydrodynamic Lubrication ◽  
Speed Test ◽  
High Speeds ◽  
Wide Range ◽  
Low Speeds ◽  
Test Variability ◽  
Traction Testing ◽  
Tread Rubber

Abstract We have shown that the cornering wet traction performance of tires, as measured with a special cornering trailer, is influenced by a number of factors and their interaction with each other. Unlike conventional low speed “spin-out” wet cornering traction testing, we have evaluated tire traction over the range 30–60 mph. Over this range there is a marked speed dependence in the rating of various tread rubbers and tread patterns. In general, tread rubbers show a wide range of performance ratings at the lower speeds (30–35 mph) and a narrower range at high speeds (55–60 mph). Various tread patterns on the contrary show similar behavior at low speeds but a wide divergence in traction level at high speeds. Higher durometer tread compounds show improved high speed traction for any given rubber. Tread hardness cannot be used as an omnibus indicator of wet traction performance, however, as each rubber has its own separate correlation line. Low coefficient pavement can have either low or high degrees of macrotexture, but the lack of microtexture or harshness (asperities in the fraction of a millimeter range) produces this type of pavement. Tires must perform safely on such pavement sections of public highways and the testing reported here was done on such test surfaces. Evaluations of four types of tread rubber show that they rank from high to low traction level in the order: SBR, Butyl, NR and BR (solution type) on smooth, low microtexture surfaces. Although BR gives low traction when used alone it is not so used in commercial tread compounds. When properly blended with SBR or NR, tread compounds containing BR give satisfactory traction performance and improved wear performance. The overall behavior of tires can be explained in terms of the concepts of hydrodynamic and boundary layer lubrication. At low speeds boundary layer lubrication predominates on all but the smoothest pavements. This accounts for the marked influence of tread rubber at low speeds. At high speeds both thick and thin film elastohydrodynamic lubrication predominate. In this speed range tread materials play a lesser role and tread pattern or geometry plays a larger role. The relative softness and deformability of tread compound, compared to pavement aggregate, accounts for the importance of elastohydrodynamic lubrication. Drawing on the work of many previous investigators and the data of this work it is postulated that the fraction of the tire contact area of a cornering tire that is in the elastohydrodynamic mode of lubrication is a linear function of speed. This accounts for the good linearity of the plots of traction as a function of speed. Test variability is discussed and steps taken to measure and control such relevant factors as water depth are outlined. The use of statistically designed testing programs with their inherent averaging character are advocated for those doing this work. In addition to their power at averaging test results, such designs uncover the strong interaction between tire and test variables that underlie all wet traction testing.

The Measurement and Analysis of Ball Motion in High Speed Deep Groove Ball Bearings

1975 ◽  
Vol 97 (3) ◽  
pp. 341-348 ◽  
Author(s):  
R. J. Boness ◽  
J. J. Chapman
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Complete Analysis ◽  
Ball Speed ◽  
Rolling Axis ◽  
High Speeds ◽  
Deep Groove ◽  
Wide Range ◽  
Ring Mode ◽  
Ball Motion

This paper reports on a study of ball motion, including the measurement of ball rolling axis, in deep groove bearings operating at high speeds under thrust load conditions. The technique employed relies on viewing the test bearing, operating in the conventional fixed outer ring mode, through a rotating prism which eliminates optically the gross rotation of the separator. Videotape recordings of a selected ball, distinctively marked and illuminated stroboscopically, allows a complete analysis of ball bearing kinematics. Experimental results of separator speed, ball speed and rolling axis together with separator slip, ball slip and spin velocities at both the inner and outer raceway contacts are presented for a wide range of loads and shaft speeds up to 12,000 rev/min. These results are compared with the existing theory of Jones. Discrepancies between predicted and actual ball motion are due to the assumption made by Jones in neglecting bearing element slip. A further analysis of the experimental results including both gyroscopic torques and slip based on elastohydrodynamic traction values for the test lubricant explains actual ball motion more fully.

Genetic Optimization of Geometrical Parameters of High Speed Rotor

2015 ◽  
Author(s):  
Behnam Ghalamchi ◽  
Adam Kłodowski ◽  
Jussi T. Sopanen ◽  
Aki M. Mikkola
Keyword(s):  
High Speed ◽  
Turbine Rotor ◽  
Optimization Techniques ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Campbell Diagram ◽  
Critical Speeds ◽  
Operation Speed ◽  
Wide Range ◽  
Speed Range

The main scope of this paper is optimization of high speed rotor systems by using Evolutionary Algorithm. The target of the optimization is finding geometrical parameters of the shaft, in such a way that the critical speeds are not occurring in the operation speed range. Rotating machines have a wide range of applications in industrial machinery and applying numerical optimization techniques helps engineers to improve the performance of rotor bearing systems. A schematic of a turbine rotor system is studied. The rotor is modeled using finite element method and Timoshenko beam elements having four degrees of freedom (DOF) per node — two translational and two rotational. Critical speeds are identified using Campbell diagram. The outcome of the simulation is looking to find the widest safe margin for operation speed range without any critical speed in Campbell diagram within the operation range. Design parameters for optimization are overhang shafts lengths and diameters. Several simulation runs with different variables shows a significant effect of these parameters in dynamic behavior of the system. Comparison of the results with the basic design of turbine rotor reveals that all constraints are satisfied.

Active Command-Steering Control of Tractor and Three Full Trailers for Tractor-Track Following

2006 ◽  
Author(s):  
Krishna Rangavajhula ◽  
H.-S. Jacob Tsao
Keyword(s):  
High Speed ◽  
Control Strategies ◽  
Linear Quadratic Regulator ◽  
Cost Effective ◽  
Steering Control ◽  
Linear Quadratic ◽  
Amplification Ratio ◽  
High Speeds ◽  
Lqr Controller ◽  
Optimal Linear

A key source of safety and infrastructure issues for operations of longer combination vehicles (LCVs) is off-tracking, which has been used to refer to the general phenomenon that the rear wheels of a truck do not follow the track of the front wheels and wander off the travel lane. In this paper, we examine the effectiveness of command-steering in reducing off-tracking during a 90-degree turn at low and high speeds in an articulated system with a tractor and three full trailers. In command steering, rear front axles of the trailers are steered proportionately to the articulation angle between the tractor and trailing units. We then consider several control strategies to minimize off-tracking and rearward amplification of this system. A minimum rearward amplification ratio (RWA), as a surrogate for minimum off tracking, has been used as the control criterion for medium to high speeds to arrive at an optimal Linear Quadratic Regulator (LQR) controller. As for low speeds, the maximum radial offset between the tractor and trailer 3 is minimized in the design of the controller. Robustness of the optimal controller with respect to tyre-parameter perturbations is then examined. Based on the simulation results, we find that, active command steering is very effective in reducing off tracking at low- as well as high-speed 90-degree turns. To achieve acceptable levels of RWA and off tracking, at least two of the three trailers must be actively command-steered. Among the three two-trailer-steering possibilities, actively steering trailers 1 and 2 is most cost-effective and results in the lowest RWA for medium- to high- speeds (at which RWA is important), and off-tracking is practically eliminated for all speed regimes considered.

Active steering control strategy for articulated vehicles

2016 ◽  
Vol 17 (6) ◽  
pp. 576-586 ◽  
Author(s):  
Kyong-il Kim ◽  
Hsin Guan ◽  
Bo Wang ◽  
Rui Guo ◽  
Fan Liang
Keyword(s):  
Control Strategy ◽  
Steering Control ◽  
Active Steering ◽  
Articulated Vehicles ◽  
Active Steering Control

Implementation of Trailer Steering Control on a Multi-Unit Vehicle at High Speeds

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Richard Roebuck ◽  
Andrew Odhams ◽  
Kristoffer Tagesson ◽  
Caizhen Cheng ◽  
David Cebon
Keyword(s):  
Control System ◽  
High Speed ◽  
Tracking Error ◽  
Path Following ◽  
Stability Control ◽  
Substantial Improvement ◽  
Lateral Acceleration ◽  
Steering Control ◽  
Stability Margins ◽  
Stability Control System

A high-speed path-following controller for long combination vehicles (LCVs) was designed and implemented on a test vehicle consisting of a rigid truck towing a dolly and a semitrailer. The vehicle was driven through a 3.5 m wide lane change maneuver at 80 km/h. The axles of the dolly and trailer were steered actively by electrically-controlled hydraulic actuators. Substantial performance benefits were recorded compared with the unsteered vehicle. For the best controller weightings, performance improvements relative to unsteered case were: lateral tracking error 75% reduction, rearward amplification (RA) of lateral acceleration 18% reduction, and RA of yaw rate 37% reduction. This represents a substantial improvement in stability margins. The system was found to work well in conjunction with the braking-based stability control system of the towing vehicle with no negative interaction effects being observed. In all cases, the stability control system and the steering system improved the yaw stability of the combination.

Stability Control on Tractor Semi-Trailer during Split-Mu Braking

2011 ◽  
Vol 230-232 ◽  
pp. 549-553 ◽  
Author(s):  
Shu Wen Zhou ◽  
Si Qi Zhang ◽  
Guang Yao Zhao
Keyword(s):  
High Speed ◽  
Stability Control ◽  
Integrated System ◽  
Road Surface ◽  
Lateral Stability ◽  
Steering Control ◽  
Emergency Braking ◽  
Stopping Distance ◽  
Articulated Vehicles ◽  
Multi Body

Handling behaviour of articulated vehicles combination is more complex and less predictable than that of non-articulated vehicles. It is usually difficult for drivers to maneuver a tractor semi-trailer during high speed emergency braking on split-mu road surface. Braking on this type of road surface, the conventional anti-lock braking systems will cause the vehicle deviate from the desired direction, or overmuch stopping distance. In this paper, a 3-dof of tractor semi-trailer model was used to produce desired yaw rates which were compared with actual yaw rates. An active front steering control and four-channel ABS were integrated to improve the tractor semi-trailer lateral stability while braking on split-mu road surface, which will produce maximum braking force. A full function tractor semi-trailer model was built and assembled in multi-body dynamics software, and the dynamic analysis was performed on split-mu road surface. The simulation results show that the integrated system can improve the tractor semi-trailer lateral stability under braking on split-mu road surface.

Vibration Properties of High-Speed Planetary Gears With Gyroscopic Effects

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker
Keyword(s):  
High Speed ◽  
Eigenvalue Problems ◽  
Planetary Gear ◽  
Vibration Modes ◽  
Planetary Gears ◽  
High Speeds ◽  
Wide Range ◽  
Modal Property ◽  
Gyroscopic Effects ◽  
Complex Valued

This study investigates the modal property structure of high-speed planetary gears with gyroscopic effects. The vibration modes of these systems are complex-valued and speed-dependent. Equally-spaced and diametrically-opposed planet spacing are considered. Three mode types exist, and these are classified as planet, rotational, and translational modes. The properties of each mode type and that these three types are the only possible types are mathematically proven. Reduced eigenvalue problems are determined for each mode type. The eigenvalues for an example high-speed planetary gear are determined over a wide range of carrier speeds. Divergence and flutter instabilities are observed at extremely high speeds.

scholarly journals Active steering control based on preview theory for articulated heavy vehicles

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252098
Author(s):  
Jie Tian ◽  
Qingkang Zeng ◽  
Peng Wang ◽  
Xiaoqing Wang
Keyword(s):  
High Speed ◽  
Single Point ◽  
Path Tracking ◽  
Lateral Stability ◽  
Steering Control ◽  
Linear Quadratic ◽  
Low Speed ◽  
Active Steering ◽  
Simulation Results ◽  
Active Steering Control

This paper investigates the active steering control of the tractor and the trailer for the articulated heavy vehicle (AHV) to improve its high-speed lateral stability and low-speed path following. The four-degree-of-freedom (4-DOF) single track dynamic model of the AHV with a front-wheel steered trailer is established. Considering that the road information at the driver’s focus is the most clear and those away from the focus blurred, a new kind controller based on the fractional calculus, i.e., a focus preview controller is designed to provide the steering input for the tractor to make it travel along the desired path. In addition, the active steering controllers based on the linear quadratic regulator (LQR) and single-point preview controller respectively are also proposed for the trailer. However, the latter is designed on the basis of the articulation angle between the tractor and trailer, inspired by the idea of the driver’s single-point preview controller. Finally, the single lane change maneuver and 90o turn maneuver are carried out. And the simulation results show that compared with the single-point preview controller, the new kind preview controller for the tractor can have good high speed maneuvering stability and low speed path tracking ability by adjusting the fractional order of the controller. On this basis, three different AHVs with the same tractor are simulated and the simulation results show that the AHV whose trailer adopts the single-point preview controller has better high-speed lateral stability and low-speed path tracking than the AHV whose trailer adopts the LQR controller.

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