Papers by Author: Lei Zhang

Abstract: The dynamic tilting of high-precision turntable has a very significant impact on the parameters of measurement and processing during the operation.In order to achieve long-term stability and control the turntable’s dynamic tilting angle at the second level, only improving the mechanical precision of the turntable is not realistic, and it may greatly enhance the cost of the turntable. A precision turntable dynamic tilting test method based on laser and CCD technology is put forward in this paper. The system uses laser as the light source, and uses CCD image sensor to receive the reflected signal of the turntable. According to the amount movement of the laser spot on the CCD target surface and the corresponding geometric relationships, we can measure the inclination error of the turntable. During debugging analysis and practical application, it proves that the system can achieve differentiate accuracy at the second level and meet the needs of online measurement.

Abstract: Nowadays, most of continuously variable transmissions (CVT) adopt hydraulic system to exert pressure on the cone-plate, in order to realize variable speed control. Electronic Mechanical Continuously Variable Transmission (EMCVT) studied in this paper, however, used rolling screw mechanism instead of the energy-hungry hydraulic system. Mechanical speed governor controlled by electro was adopted in EMCVT to regulate speed, which not only reduced the automobile’s fuel consumption, but also brought down the transmission’s manufacturing cost and failure rate obviously. Further study on the ratio control strategy of EMCVT was made and digital PID control algorithm with target ratio tracing was raised. Moreover, an improved PID control algorithm, that was integral separation and differential precession algorithm, was given. Platform experiment of EMCVT was finished, thus, the functionality and rationality of this transmission’s mechanical structure was proved, so was the feasibility and rationality of the speed ratio control strategy.

Abstract: Due to the complexity of the car running condition, the differences of the subjective intention of the driver, and Continuously Variable Transmission control system itself existed nonlinear, time delay, interference, variable parameter factors, the traditional control arithmetic based on scale model is hard to meet the clutch control requirements. This article through to design the drive mechanism of the dry friction clutch on a new, without hydraulic pump, pure electronic control car continuously variable transmission, and analyze its mechanical properties and control target, the clutch control model was established, according to the fuzzy control theory, driving experience and developers’ technical experience, the corresponding fuzzy language rules were formed, and intelligent control of the clutch on the single-chip control system was realized. At present, the pure electronic control continuously variable transmission has been tested on the experimental bench and car operation, and has passed the inspection by the national vehicle quality supervision and inspection center (Chongqing) and the identification by China Machinery Industry Federation .

Abstract: This paper introduces the algorithm structure, principle and method of the evaluation of the flatness error based on genetic algorithm. Detailedly describes how to use genetic algorithm based on real number encoding to evaluate the flatness error and gives algorithm process.MATLAB’s GA algorithm toolbox is used to evaluate the flatness error. Describes and explains the parameter setup of every step detailedly and compiles M-file used of algorithm of fitness function. The structure which is carried out by the simulation is satisfying. Simulation process and the results prove that it’s right to use genetic algorithm based on real number encoding to evaluate the flatness error to calculate convergence.It can get the result rapidly and ideally.

Abstract: The active academic basic of the shape tolerance and shape error assessment is a geometrical problem which is based on the shape tolerance zone. The research puts forward the probability distribution of the statistical roundness error on the condition of the researching about roundness error of rotor parts and does experimental measurement and data collection. In order to prove that it complies with certain probability distribution law, the fitted roundness error should gain the statistical distribution result by using mathematical statistics.

Abstract: Nowadays, the variable speed function of metal belt CVT assemblied on vehicle is completely based on hydraulic system which is driven by the engine. The extra energy consumption is obvious and the reliability is low during the speed-change process of system because of low efficiency of hydraulic components such as pump and valve. In this paper, Electronic-Mechanical CVT (EMCVT) that is a new kind of metal belt CVT is proposed, which uses DC motor driving system to implement the variable speed function. The model of speed ratio control and the clamping force of cone-plates control is established and the PID algorithm of speed ratio control is presented while the transmission principle and mechanical structure of EMCVT is introduced through the study of artificial characteristic of DC motor and dynamics of the system.

Abstract: On the foundation of the analysis of the working mechanism of the GL160C continuously variable transmission (CVT), the mathematical model of the axial clamping force of the driving and driven pulleys are constructed. The relationship between the pressure of the driving and driven cylinders and the speed ratio of the CVT are derived while the CVT is transmitting the unit torque. The control method of the axial clamping force between the driving and driven pulleys, the control model of the CVT speed ratio are given. The following conclusions are drawn from the bench test and integral vehicle test: the acceleration performance and the stability of the speed ratio of the GL160C CVT are good, the power output is stable and reliable, the controller could achieve every functional requirement, all of which could guarantee that the output of the engine could run as the designed ideal dynamic curve and the ideal economical curve.

Abstract: The theoretical and experimental studies of statistical evaluation method for flatness error are conducted thoroughly, and evaluation parameters and corresponding practicable data processing model are provided. Furthermore, a large number of experiments have been done and statistical analysis has been conducted. The results show that the distribution of extract elements of almost 90 percent of the measured planes is accordant with censored normal distribution, which proves that statistical flatness error obeys normal distribution. The characteristic that sample points are random variables is taken full advantage of in the statistic method, and the flatness error can be calculated without the influence of gross error and therefore the rate of waste parts can be reduced effectively.

Abstract: Theoretical analysis of existing evaluation method of gap roundness error and existing evaluation model of full roundness error is provided. Mathematical model of gap roundness error’s evaluation with least square method is founded based on the evaluation model of full roundness error, which gives a solution of gap roundness error. The results of the simulation analysis and measuring experiment show that mathematical model of gap roundness error’s evaluation with least square method is correct for computing gap roundness error.