The Research on Dynamic Friction Tester of Pavement

2010 ◽  
Vol 40-41 ◽  
pp. 711-716
Author(s):  
Deng Feng Li ◽  
Li Min Guan ◽  
Qi Ming Zhang ◽  
Cai Xia Zhao
Keyword(s):  
Friction Coefficient ◽  
System Design ◽  
Control Method ◽  
High Reliability ◽  
Low Cost ◽  
Skid Resistance ◽  
Dynamic Friction ◽  
Slip Ratio ◽  
Measuring Device ◽  
Friction Tester

As to the pavement test, with the slip-based control method, a new pavement mobile type of measuring device was designed to obtain the continuous friction coefficient parameters in this paper. The operation principles and the concrete completion methods of slip ratio control were introduced in detail. 89C52 was adopted as the center chip to achieve the system design of hardware and software. After the pavement tests, the prototype is of high reliability, low cost, and simple operation, meanwhile, meets the requirements of pavement skid resistance.

Co-Simulation Study of Synchronous Control Technology for Independent Electric Drive Vehicle

2014 ◽  
Vol 536-537 ◽  
pp. 1069-1077
Author(s):  
Heng Zhong ◽  
Wei Zhao ◽  
Yu Sun
Keyword(s):  
Electric Drive ◽  
Control Method ◽  
High Reliability ◽  
Low Cost ◽  
Control Process ◽  
Threshold Value ◽  
Motor Speed ◽  
Wheel Wear ◽  
Synchronous Control ◽  
Relationship Of

The slip-judgment method of threshold value was made for all-wheel independent electric drive vehicle through the analysis of the relationship of steering kinematics, which based on detecting speed and current of wheel-motor. The speed coordinated control of motor was used as synchronous control method. Models of vehicle dynamics and synchronous control were respectively constructed in Adams and Matlab/Simulink, which composed the model of mechanical-electric collaborative simulation. The synchronous control process of vehicle that running on bisectional road was analyzed, the result shows that synchronous control based on power control strategy reduces slip-wheel motors power consumption and increases other motors output power and torque through reducing the motor speed to average speed of normal wheel-motor. Improves the traction performance and stability of vehicle, also reduces the wheel wear and drivers control difficulty. The method has advantages of low cost, wide applicability, good controllability, high reliability etc., provide the reference of synchronization technology for independent electric drive military vehicle.

Directional Skid Resistance Characteristics of Road Pavement: Implications for Friction Measurements by British Pendulum Tester and Dynamic Friction Tester

2019 ◽  
Vol 2673 (10) ◽  
pp. 793-803 ◽  
Author(s):  
L. Chu ◽  
X. Cui ◽  
K. Zhang ◽  
T. F. Fwa ◽  
S. Han
Keyword(s):  
Test Point ◽  
Circular Path ◽  
Skid Resistance ◽  
Dynamic Friction ◽  
Estimation Errors ◽  
Road Pavement ◽  
Friction Tester ◽  
Safety Studies ◽  
Friction Measurements ◽  
Resistance Performance

The British pendulum tester (BPT) and the dynamic friction tester (DFT) are commonly used to evaluate the polishing effect of traffic on pavement skid resistance. The present study was conducted to answer two questions: (i) whether the directional moving traffic action results in significant directional differences in skid resistance of the pavement, and (ii) if so, whether BPT and DFT are effective tools for evaluating the skid resistance performance of polished pavements with significant directional skid resistance characteristics. Five in-service pavement sections with different degrees of polishing were examined in this study. The following findings were obtained from the study: (a) There were statistically significant differences between the longitudinal and transverse skid resistance of the polished pavements tested; (b) there were no statistically significant differences between the longitudinal and transverse skid resistance of the newly paved unpolished pavement tested; (c) BPT was able to differentiate the directional skid resistance differences of the polished pavements tested; and (d) DFT was unable to differentiate the directional skid resistance differences of the polished pavements tested. DFT produces one skid resistance value for a circular path at each test point. The test results found that DFT over-estimated the traffic-direction skid resistance of in-service pavements. The over-estimation errors ranged from 0.001 to 0.023 DFT units, and the corresponding percent errors were from 0.4% to 11.1%. This finding suggests that the over-estimation effect of skid resistance directionality of polished pavements on DFT measurements should be recognized in pavement skid resistance evaluation and pavement safety studies.

Novel cylinder positioning system realised by using solenoid valves

2011 ◽  
Vol 2 (1) ◽  
pp. 142-151
Author(s):  
L Földi ◽  
Z. Béres ◽  
E. Sárközi
Keyword(s):  
System Design ◽  
Control Method ◽  
Low Cost ◽  
Pressure Sensors ◽  
Pneumatic Actuator ◽  
Positioning Systems ◽  
Position Errors ◽  
Cost System ◽  
Switching Dynamics ◽  
Air Compression

This paper presents a novel control design, developed to realise fast and accurate positioncontrol of a pneumatic actuator using inexpensive on/off solenoid valves. In contrast to conventional controlmethods, the proposed control method operates chatter free, based on air compression. The controlprinciple was developed by investigating the dynamics of a pneumatic actuator with an identifiedmathematical model. This new approach is applied to a pneumatic double acting cylinder, controlled by apair of 5/3 way directional single solenoid valves. The described closed-loop circuit copes with thediscontinuities associated with the valve’s switching dynamics, and relatively long response time. Theexperimental apparatus uses an analogue displacement encoder for metering the piston’s position andvelocity, and doesn’t incorporate pressure sensors thus ensuring a low cost system design. The results ofexperiments with various step responses show that the proposed control method performs well. Themeasured steady-state position errors are equal to the used potentiometer’s travel resolution, which is 0,01mm. Therefore this novel control and the related pneumatic system design could be a cost effectivealternative to the servo-pneumatic positioning systems.

Preparation of C/C-SiC Brake Materials with Low Cost and High Friction Performance

2009 ◽  
Vol 620-622 ◽  
pp. 421-424 ◽  
Author(s):  
Yong Hui Zhang ◽  
Zhi Chao Xiao ◽  
Jian Feng Yang ◽  
Ji Ping Wang ◽  
Zhi Hao Jin
Keyword(s):  
Friction Coefficient ◽  
Low Cost ◽  
Matrix Composition ◽  
Linear Wear ◽  
Dynamic Friction ◽  
Linear Wear Rate ◽  
Frictional Properties ◽  
Dynamic Friction Coefficient ◽  
The Matrix ◽  
Friction Performance

C/C-SiC brake materials were prepared by improved chemical liquid vaporized infiltration (CLVI) combined with liquid silicon infiltration (LSI) process, which needed less than thirty hours. The microstructure and frictional properties of the material were investigated. The density and porosity of the C/C-SiC brake material were 2.05 g/cm3 and 4.8%, respectively. The average dynamic friction coefficient of the materials was about 0.36, and the friction coefficient was stable. The average linear wear rate was less than 4.7 µm cycle-1 for rotating and stationary disk. The matrix composition and microstructure resulted in the high frictional performances.

The School Bus Safety System Design for Preventing Children Forgotten in the Car

2014 ◽  
Vol 610 ◽  
pp. 549-551
Author(s):  
Xiao Ming Zhang ◽  
Bin Peng ◽  
Jian Min Liu ◽  
Xin Yong Qiao
Keyword(s):  
System Design ◽  
High Reliability ◽  
Low Cost ◽  
Safety System ◽  
Rfid Technology ◽  
Uhf Rfid ◽  
School Bus ◽  
Bus Driver ◽  
Accident Injury ◽  
Bus Safety

In recent years, the frequent occurrence of kindergarten school bus driver or teacher left children in the car, which leads to the accident, injury and even death. Based on UHF RFID technology has developed a safety system which can effectively prevent child being forgotten in school bus. After testing, the system is high reliability, low false alarm rate and with easy installation, low cost and so easy to put on the market.

scholarly journals Optimization of Multi-Way Valve Structure in Digital Hydraulic System of Loader

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 700
Author(s):  
Chunshuang Li ◽  
Xinhui Liu ◽  
Xin Wang ◽  
Jinshi Chen ◽  
Yuqi Wang
Keyword(s):  
Simulation Model ◽  
Hydraulic System ◽  
Control Method ◽  
High Reliability ◽  
Low Cost ◽  
Significance Test ◽  
Test Method ◽  
Pump System ◽  
Displacement Pump ◽  
Saving Effect

In this paper, a digital hydraulic variable control method based on multi-way valve spool displacement feedback is proposed, which combines the advantages of low cost and high reliability of the loader fixed displacement pump hydraulic system, and the distinguished energy saving effect of the loader variable pump hydraulic system. Based on the principle of hydraulic resistance, the mathematical model of flow-pressure of multi-way valve was established. Meanwhile, the theoretical structure of a valve spool suitable for digital hydraulic system was deduced. On this basis, an improvement scheme of the valve spool was proposed in combination with machining feasibility. The simulation model of multi-way valve was established, the correctness of which was verified by experiment with the significance test method, and the valve port parameters of the multi-way valve were optimized by genetic algorithm. The simulation model before and after optimization was analyzed by AMESim software. The simulation results showed that the digital hydraulic system can basically realize the function of a variable system, and the energy consumption was significantly reduced compared with the fixed displacement pump hydraulic system. The optimized valve spool structure of the digital hydraulic system had more stable load characteristics than the fixed displacement pump system and a larger speed range. The increase range accounts for about 27% of the total stroke.

scholarly journals Friction Coefficient of Load-Bearing Elements of Building Technical Facilities

2021 ◽  
Vol 1203 (2) ◽  
pp. 022008
Author(s):  
Leopold Hrabovský ◽  
Peter Michalik
Keyword(s):  
Friction Coefficient ◽  
High Reliability ◽  
Circular Cross Section ◽  
Vertical Movement ◽  
Friction Coefficients ◽  
Measuring Device ◽  
Load Bearing ◽  
Construction Design ◽  
Wide Range ◽  
Compression Springs

Abstract The engineering activities in construction are a set of a wide range of activities that are performed, for example, for the purpose of the installation or mandatory replacement or modernisation of lifts. On the territory of the Czech Republic, there are standards that strictly prescribe what is required to repair and replace on an existing lift in order to ensure the greatest possible safety when riding the lift, but also the high reliability and dependability of the lift. Polyurethane lift belts were developed and used for the vertical movement of lifts at the turn of the millennium. Due to patent rights, they were reserved solely for selected manufacturers of lifts. The classic ropes with a circular cross-section are currently being replaced more and more frequently in construction engineering by flat ropes or belts due to their undisputed advantages. This paper describes the construction design and implemented equipment on which it is possible to determine, in the laboratory, the value of the rope friction coefficient in the given type of traction disc grooves. To be specific, this paper describes the friction coefficient determined in a laboratory, in dry and clean conditions, of a flat rope with a polyurethane sheath on the circumference of the traction disc. The friction coefficient values were acquired indirectly, i.e. by measuring the tractive forces in the approaching and receding rope branches on the rotating traction disc powered by an electric drive. The friction coefficient was determined from the measured values of both tractive forces during the course of a single experimental measuring through a calculation from Euler’s relation. The value of the receding force was obtained using two methods that differ from each other in the manner of attachment (by a screw or compression springs) of the end of the rope to the load-bearing construction of the measuring device. The information obtained from the experimental measurements made it possible to compare the measured values of the rope friction coefficients with the values given by the manufacturers and to make the conclusion that the method used to determine the friction coefficients and the set of laboratory activities and procedures for determining the friction coefficients on the testing equipment is suitable and usable in practice.

Sign in / Sign up

Export Citation Format

Share Document