Investigation of the tyre characteristics under non-steady-state conditions on the basis of road tests

2016 ◽  
Vol 231 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Hubert Sar ◽  
Andrzej Reński ◽  
Janusz Pokorski
Keyword(s):  
Steady State ◽  
Computer Simulations ◽  
Dynamic Characteristics ◽  
Slip Angle ◽  
Real Motion ◽  
Side Force ◽  
The Real ◽  
Different Types ◽  
Non Linear ◽  
The Difference

This paper presents a method of identifying the dynamic characteristics of tyres for non-steady-state conditions on the basis of road measurements on a vehicle. The side force acting on the tyre is presented as a function of not only the slip angle but also the slip angle derivative (i.e. the velocity of the change in the slip angle). Hence, the influence of the manoeuvre dynamics on the tyre characteristics and the difference between the characteristics obtained for steady-state conditions and the characteristics for non-steady-state conditions are shown. Also the results of computer simulations prepared for different types of tyre characteristics are presented in this paper. It is evident from the presented graphs that applying dynamic non-linear tyre characteristics for computer simulations instead of steady-state characteristics enables us to describe the real motion of a vehicle better.

Real-Time Engine Modelling of a Three Shafts Turbofan Engine: From Sub-Idle to Max Power Rate

2006 ◽  
Author(s):  
Sogkyun Kim ◽  
Sean Ellis ◽  
Mark Challener
Keyword(s):  
Steady State ◽  
Real Time ◽  
Partial Derivative ◽  
Normal Range ◽  
The Real ◽  
Partial Derivatives ◽  
Operating Range ◽  
Engine Model ◽  
Non Linear ◽  
Perturbation Size

Real-Time Engine Models are required for operation with engine electronic control systems and/or aircraft simulators for functional demonstration. The challenge for Rolls-Royce has been to establish the sub-idle speed behaviour of the engine. This paper covers the development steps by the Civil Aerospace Modelling and Simulation team to resolve this limitation in the models. The real-time engine model is now generated using two non-linear thermodynamic engine models. One of the thermodynamic engine models, normal range, covers the idle to max power range and the other is for sub-idle operation. Previously sub-idle operation was established by extrapolation from the normal range model. However, this method limited control system development by simulation for altitude starting adding time to altitude test programmes in high cost facilities. The requirement for the technique is to obtain the partial derivatives and steady-state data for the whole operating range. For the partial derivative estimation in sub-idle region, a variable perturbation size is introduced and changed according to the different shaft speed so that the sensitivity issue of using a fixed perturbation size in this operating range is resolved. Furthermore, the partial derivative of each parameter from the non-linear models is fine tuned by comparing with the steady-state values for each parameter. The summation of the integrated partial derivatives should be same as the steady-state value of each engine parameter. If an error exists then an adjustment of each integrated partial derivative is conducted according to the relative weight of each integrated partial derivatives contribution to the whole. It is highlighted that error sharing between the integrated partial derivative parameters results in less error during the validation process. The real-time engine model is constructed in state-space modular subsystems in SIMULINK, which include an engine shaft block to generate the engine shaft speeds, and fuel block to generate a signal of engine lit, etc. The database generated by the process of partial derivatives is then used in calculation of engine’s shaft speeds, temperatures and pressures. For the test of the real-time engine model obtained in this study, simulation of engine starting from stationary is conducted. Using a starter torque as the input to the engine model, starter-assisted starting can be achieved. In addition, engine relighting in flight is also conducted. The output of the real-time engine model has been compared with flight test data for engine relight and agreement has been demonstrated.

Paper 5: Vehicle Behaviour in Combined Cornering and Braking

1968 ◽  
Vol 183 (8) ◽  
pp. 19-34 ◽  
Author(s):  
A. J. Harris ◽  
B. S. Riley
Keyword(s):  
Steady State ◽  
Load Transfer ◽  
Equations Of Motion ◽  
Rear Wheel ◽  
Front Wheel ◽  
Slip Angle ◽  
Vehicle Model ◽  
Force Coefficient ◽  
Wheeled Vehicle ◽  
Non Linear

This paper considers first the steady-state motions of a simple two-wheeled vehicle model having non-linear sideway force relationships with respect to tyre slip angle. It is shown that any steady-state conditions may be represented and their solutions found by simple graphical means, using only the non-linear curves. The curves can be modified to take into account the influence of vehicle parameters such as compliance, roll steer, wheel camber, and load transfer. Stability boundaries are discussed and criteria are presented showing that stability of the motion depends only on the slopes of the curves and the speed of the manoeuvre at the cornering acceleration being considered. A more involved four-wheeled vehicle model is then considered when subjected to braking while cornering on a fixed radius path of 45·8 m on a wet Bridport macadam surface. Actual sideway force–slip angle curves for combined braking and cornering, as presented by Holmes and Stone (see reference (6))†, are used with the equations of motion derived for the quasi-steady state conditions of decelerating while cornering. The effects of front wheel steered angle and body slip angle on the forces necessary for the manoeuvre are also considered. An envelope of maximum cornering acceleration at various braking decelerations is presented. This shows that for those particular conditions up to about 70 per cent of maximum deceleration may be obtained before there is more than about 10 per cent loss in maximum cornering ability. Outside the envelope the vehicle fails to maintain the path. At the lower deceleration the car spins, and at higher values it continues tangentially to its original path without spinning. It is also shown that the total sideway force–slip angle curve for a pair of front or rear wheels, when one or both wheels have a high braking force coefficient, can have a sharp peak, such that for small increase in slip angle there is a rapid fall in sideway force. It is suggested that this is why a rear wheel skid which occurs while braking and cornering is more difficult to correct than one which occurs when only cornering.

Lateral Tire Forces on Wet Roads

1977 ◽  
Vol 5 (2) ◽  
pp. 75-82 ◽  
Author(s):  
A. Schallamach
Keyword(s):  
Normal Load ◽  
The Self ◽  
Experimental Results ◽  
Slip Angle ◽  
Tire Model ◽  
Side Force ◽  
Tire Forces

Abstract Expressions are derived for side force and self-aligning torque of a simple tire model on wet roads with velocity-dependent friction. The results agree qualitatively with experimental results at moderate speeds. In particular, the theory correctly predicts that the self-aligning torque can become negative under easily realizable circumstances. The slip angle at which the torque reverses sign should increase with the normal load.

ANALYTICAL INDICATOR. ANALYSIS OF THE REAL STATE OF DYNAMICS OF MORTALITY OF THE POPULATION OF RUSSIA FROM MALIGNANT TUMORS AND CHANGES IN ITS STRUCTURE

2019 ◽  
Vol 65 (2) ◽  
pp. 205-219 ◽  
Author(s):  
V. Merabishvili
Keyword(s):  
Malignant Tumors ◽  
Specific Weight ◽  
Mortality Rates ◽  
Retirement Age ◽  
Medium Term ◽  
Age Composition ◽  
The Real ◽  
Indicator Analysis ◽  
The Difference ◽  
Real State

The mortality rate is one of the most important criteria for assessing the health of the population. However, it is important to use analytical indicators correctly, especially when evaluating time series. The value of the “gross” mortality is closely linked with a specific weight of persons of elderly and senile ages. All international publications (WHO, IARC, territorial cancer registers) assess the dynamics of morbidity and mortality only by standardized indicators that eliminate the difference in the age composition of the compared population groups. In Russia, from 1960 to 2017, the share of people of retirement age has increased more than 2 times. The structure of mortality from malignant tumors has changed dramatically. The paper presents the dynamics of gross and standardized mortality rates from malignant tumors in Russia and in all administrative territories. Shows the real success of the Oncology service. The medium-term interval forecast until 2025 has been calculated.

scholarly journals Smoke recognition network based on dynamic characteristics

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092566
Author(s):  
Dahan Wang ◽  
Sheng Luo ◽  
Li Zhao ◽  
Xiaoming Pan ◽  
Muchou Wang ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
State Of The Art ◽  
The State ◽  
Detection Accuracy ◽  
Static Characteristics ◽  
Good Tool ◽  
Early Signal ◽  
Fuzzy Objects ◽  
The Difference ◽  
Smoke Recognition

Fire is a fierce disaster, and smoke is the early signal of fire. Since such features as chrominance, texture, and shape of smoke are very special, a lot of methods based on these features have been developed. But these static characteristics vary widely, so there are some exceptions leading to low detection accuracy. On the other side, the motion of smoke is much more discriminating than the aforementioned features, so a time-domain neural network is proposed to extract its dynamic characteristics. This smoke recognition network has these advantages:(1) extract the spatiotemporal with the 3D filters which work on dynamic and static characteristics synchronously; (2) high accuracy, 87.31% samples being classified rightly, which is the state of the art even in a chaotic environments, and the fuzzy objects for other methods, such as haze, fog, and climbing cars, are distinguished distinctly; (3) high sensitiveness, smoke being detected averagely at the 23rd frame, which is also the state of the art, which is meaningful to alarm early fire as soon as possible; and (4) it is not been based on any hypothesis, which guarantee the method compatible. Finally, a new metric, the difference between the first frame in which smoke is detected and the first frame in which smoke happens, is proposed to compare the algorithms sensitivity in videos. The experiments confirm that the dynamic characteristics are more discriminating than the aforementioned static characteristics, and smoke recognition network is a good tool to extract compound feature.

Analysis of Single Buffer Random Polling System With State-Dependent Input Process and Server/Station Breakdowns

2018 ◽  
Vol 9 (1) ◽  
pp. 22-50 ◽  
Author(s):  
Thomas Y.S. Lee
Keyword(s):  
Steady State ◽  
Linear Model ◽  
Repair Process ◽  
Polling System ◽  
Steady State Analysis ◽  
Relaxation System ◽  
Polling Model ◽  
State Dependent ◽  
Non Linear ◽  
State Analysis

Models and analytical techniques are developed to evaluate the performance of two variations of single buffers (conventional and buffer relaxation system) multiple queues system. In the conventional system, each queue can have at most one customer at any time and newly arriving customers find the buffer full are lost. In the buffer relaxation system, the queue being served may have two customers, while each of the other queues may have at most one customer. Thomas Y.S. Lee developed a state-dependent non-linear model of uncertainty for analyzing a random polling system with server breakdown/repair, multi-phase service, correlated input processes, and single buffers. The state-dependent non-linear model of uncertainty introduced in this paper allows us to incorporate correlated arrival processes where the customer arrival rate depends on the location of the server and/or the server's mode of operation into the polling model. The author allows the possibility that the server is unreliable. Specifically, when the server visits a queue, Lee assumes that the system is subject to two types of failures: queue-dependent, and general. General failures are observed upon server arrival at a queue. But there are two possibilities that a queue-dependent breakdown (if occurs) can be observed; (i) is observed immediately when it occurs and (ii) is observed only at the end of the current service. In both cases, a repair process is initiated immediately after the queue-dependent breakdown is observed. The author's model allows the possibility of the server breakdowns/repair process to be non-stationary in the number of breakdowns/repairs to reflect that breakdowns/repairs or customer processing may be progressively easier or harder, or that they follow a more general learning curve. Thomas Y.S. Lee will show that his model encompasses a variety of examples. He was able to perform both transient and steady state analysis. The steady state analysis allows us to compute several performance measures including the average customer waiting time, loss probability, throughput and mean cycle time.

scholarly journals Determinants of Non-Linear Effects of Fiscal Policy on Output: The Case of Bulgaria

2009 ◽  
Vol 4 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Vladimir Vladimirov ◽  
Maria Neycheva
Keyword(s):  
Fiscal Policy ◽  
Currency Board ◽  
Main Determinant ◽  
The Real ◽  
Real Gdp ◽  
Non Linear ◽  
Short Run ◽  
Linear Effects ◽  
Policy Impacts ◽  
The Government

Determinants of Non-Linear Effects of Fiscal Policy on Output: The Case of BulgariaThe paper illuminates the non-linear effects of the government budget on short-run economic activity. The study shows that in the Bulgarian economy under a Currency Board Arrangement the tax policy impacts the real growth in the standard Keynesian manner. On the other hand, the expenditure policy exhibits non-Keynesian behavior on the short-run output: cuts in government spending accelerate the real GDP growth. The main determinant of this outcome is the size of the discretionary budgetary changes. The results imply that the balanced budget rule improves the sustainability of public finances without assuring a growth-enhancing effect.

scholarly journals Investigation of Color Reproduction on Linen Fabrics when Printing with Mimaki TX400-1800D Inkjet with Pigment TP250 Dyes

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 354
Author(s):  
Tim Tofan ◽  
Rimantas Stonkus ◽  
Raimondas Jasevičius
Keyword(s):  
Mechanical Properties ◽  
Color Reproduction ◽  
Related Effect ◽  
Color Characteristics ◽  
Fabric Density ◽  
Different Types ◽  
The Difference ◽  
Printing Parameters ◽  
Linen Fabric

The aim of this research is to investigate related effect of dyeability to linen textiles related to different printing parameters. The study investigated the change in color characteristics when printing on linen fabrics with an inkjet MIMAKI Tx400-1800D printer with pigmented TP 250 inks. The dependence of color reproduction on linen fabrics on the number of print head passes, number of ink layers to be coated, linen fabric density, and different types of linen fabric was investigated. All this affects the quality of print and its mechanical properties. The change in color characteristics on different types of linen fabrics was determined experimentally. We determine at which print settings the most accurate color reproduction can be achieved on different linen fabrics. The difference between the highest and the lowest possible number of head passages was investigated. The possibilities of reproducing different linen fabric colors were determined.

Sign in / Sign up

Export Citation Format

Share Document