浅论中职学校机电机制专业“理实一体化”教学模式的探究

“百年大计,教育为本”。国家一直高度重视并支持大力发展职业教育,把中职教育作为推动国家发展、民族振兴、社会进步的源动力,促使许多国民素质普遍得到显著的提升。从近几年的中职教育的发展来看,一些传统陈旧落后的教学模式制约及束缚着中职教育的发展,不能有效培养适合祖国振兴和跨越发展需求的新时代优秀技术人才。中职教育的学情特点决定了“理实一体化”的教学模式。中职学校的在校学习的机电机制专业的学生,他们在初中学习的基础比较薄弱或参差不齐,导致在中职学校的学习积极性不太高涨,学习效果不够理想,需要教师不断创新教学方法,将所讲授的专业理论知识与学生的实地实践有机结合,从而实现“做中学、做中教、学做合一”的显著教学效果,促使学生增长学习激情,提高学习质量,促进全面发展。

建立机电评估机制 提高现场管理水平

该文介绍了机电评估机制的内容、操作程序及效果 。

Study of Diesel Engine Management System

Aim To study the diesel engine management spstem (DEMS). The DEMS can consider many engine parameters and so it can acquire the optimum system performance. Methods On the basis of analyzing the characteristics of diesel engine electronic system, the real-time, multi-tasks system design methods were used for the heavy duty vehicular diesel engine electronic control system . The hardware and software of DEMS were developed. Results and Conalusion By the test on dieSel engine bed, the system was verified and the foundation of the fully developed DEMS was laid.

INDUCTION MOTOR SPEED CONTROL SYSTEM BASED ON FUZZY NEURAL NETWORK

A fuzzy neural network controller with the teaching controller guidance and parameter regulations for vector-controlled induction motor is proposed. The design procedures of the fuzzy neural controller and the teaching controller are described. The parameters of the membership function are regulated by an on-line learning algorithm. The speed responses of the system under the condition, where the target functions are chosen as I qs and ω, are analyzed. The system responses with the variant of parameter moment of inertial J, viscous coefficients B and torque constant K tare also analyzed. Simulation results show that the control scheme and the controller have the advantages of rapid speed response and good robustness.

EFFECTIVE DOUBLE LOOP CONTROL FOR A SQUARE WAVE BRUSHLESS DC MOTOR

A new type of brushless DC motor has been developed by using a square wave rare earth permanent magnet synchronous motor with its double loop control circuit. The double loop control scheme of the drive system yields a combination of desired characteristics including simplified control structure, small ripple torque, high speed accuracy, wide operating speed range, and fast dynamic response. Experimental results confirm excellent characteristics of the motor.

Integrated design of brushless motor drive and control system for robot joints

To meet the requirements of high performance, low cost, and easy operation of the robot, a brushless motor drive and control system for the robot joint is designed, including CAN bus, WPF upper host computer development, and magnetic encoders, and other sensors, in which the STM32 F103 chip is used as the main control chip, and the DRV8323 is a brushless motor drive chip. The principle of field-oriented control(FOC) brushless motor drive is elaborated.Meanwhile, the drive and control system design is completed from both hardware and software aspects. Finally, the PID algorithm is used for the closed-loop speed test of the robot joint. The experimental result shows that the designed robot joints and control system run smoothly and reliably, have the characteristics of modularization and miniaturization, and are suitable for the control of micro-service robots and manipulators.

Wide speed range for traction motor in braking force of electric braking control system

A vehicle stopping method using an electric brake until a traction motor is stopped is studied. At the moment of vehicle stop, electric brake is changed to control mode where torque is reduced at a low speed. Gradient is controlled by estimating the load torque of motor, thereby traction motor is not rotated after stop. In addition, coasting operation and brake test are performed from normal-opposite operation and start using a small-scale model comprising the inertial load equipment and the power converter. Further, traction motor is made to be equipped with a suspension torque. Pure electric braking that makes traction motor stop by an air brake at the time of stop is also implemented. Constant torque range and constant power range are expanded during braking so that braking force is secured with the electric brakes even in high speed region. Therefore, vehicle reduction effect can be expected by reducing parts related with an air brake which is not used frequently by using a pure electric brake in the M car in wide speed region. Further, maintenance of brake system can be reduced. Besides, ride comfort of passenger in the electric rail car, energy efficiency improvement, and noise reduction effect can be additionally expected. Further, an improved brake method that uses only an electric brake till motor stop is proposed by comparing those in the blending brake that uses an air brake while reducing brake torque at vehicle stop.

Development of an underactuated prosthetic hand with the step motor

We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device. The hybrid step motor is used as the actuator, which enables the finger to keep enough high contact torque on the grasped object with less energy consumption provided by the holding torque. The grasping force of the finger is estimated from the base joint torque, and the adoption of impedance control has provided compliance in the grasping. Also a parallel observer is used to switch over between the impedance control and the torque holding mode. The experimental results show the effectiveness of the design and control strategy.

Study on the Servo Drive of PM-LSM to Be Used in Parallel Synchronous Drive

Recently, linear motors can have high speed control, high acceleration-deceleration. So linear motors are widely used in industrial applications such as precision machine tools. In our laboratory focusing on transport system, we propose parallel synchronous drive of used the PM-LSM （permanent magnet linear synchronous motor）. It can pass luggage without having to stop the working. When you establish ＂parallel synchronous drive＂, a motor follows the other motor. In our laboratory, one of the motors is called ＂master motor＂ and the other motor called ＂slave motor＂. The master motor＇s speed and position pass slave motor then establish parallel synchronous drive. Therefore, slave motor requires high-responsive and precision that follows the master motor. This paper focuses on the control of the slave motor.

Researches On The Design And Application Of DSP Multi- motor Collaborative Control System

As an important branch in the field of servo control, multi-motor coordination motion control applications are increasingly widespread.For open CNC system requirement, taking DSP as master core, combing with specific integrated stepper motor driver chip LMDI8201T, this designed a serial communication-based new collaborative multi-motor control system, which has characters of highly integrated, good stability, real-time, convenient man-machine interface.The test results show that the system fully meet performance requirements and achieved the motion control functions.

Ignition-proof mechanism of ZM5 magnesium alloy added with rare earth

The ignition-proof mechanism of ZM5 magnesium alloy added with 0.1% （mass fraction） rare earth （RE） was investigated. The oxide scales and substrates were characterized by scanning electronic microscope （SEM）, X-ray diffraction （XRD）, energy dispersive spectrometer （EDS） and tensile test. And an oxidation model of ZM5 alloy with RE was established. The results show that the ignition temperature of ZM5 alloy is particularly elevated from 654 to 823 ℃, the microstructure is refined, and the tensile strength is slightly improved from 168.2 to 174.6 MPa by adding 0.1% RE. A double-layer oxidation film formed on the alloy surface under high temperature mainly consists of MgO, RE203 and A1203, which is 2.5-3.5 μm in thickness. It is found that the forming of protective oxidation film on the thermodynamics is attributed to RE elements congregating on the surface of molten Mg alloy.

Double-Fed Asynchronous Wind Power Generator by Fuzzy Logic

The objective of this study is the simulation of the fuzzy control of a double-fed induction wind generator （DFIG） and oriented stator flux using MATLAB/S[MULINK. The system consists of a horizontal wind turbine, coupled to a DFIG and driven by a feed consisting of two three＋phase PWM converters in double bridge in order to maximize the delivered power at different wind speeds. We used a traditional regulator and a fuzzy controller. A model of the wind speed and the wind turbine is presented followed by the modeling of double-fed asynchronous generator DFIG controlled by fuzzy logic is performed according to two scenarios： with and without MPPT.

Control Strategies for PM Synchronous Machine Controlled Rectifier Intended for Heavy-Duty Vehicle

In order to charge batteries and supply all the electrical devices like wheel-motors used in a heavy-duty hybrid electric vehicle, a solution consists in using an assembly permanent magnet generator driven by a diesel engine and a three-phase insulated gate bipolar transistor/diodes bridge controlled rectifier connected to the battery. In this work, hysteresis current control strategies combined with a judicious current sensing mode for the assembly permanent magnet synchronous machine-controlled rectifier are investigated. Main issues first concern the different kinds of transistors switching modes allowed by the proposed current sensing mode when the machine operates either as a generator or as a motor. Second, the modulated hysteresis method is presented, which merges the performances of robustness and dynamic of the classical hysteresis method and imposes the switching frequency alike pulsewidth modulation techniques. A test bench at reduced power permits to test the switching modes as well as classical and modulated hysteresis methods for both motor and generator operating modes and to validate the simulation predictions. The digital signal processor algorithm elaborated for the control strategy is flexible and adaptable to all kinds of transistor switchings and machine operating modes.

Study of the Adherence Mechanism Between the Metal and Inorganic Coating with Mill Addition of Li_2Ni_8O_(10) Nano Powder

The adherence strength between the metal and the inorganic coating can be greatly increased by mill addition of Li2Ni8O10. The interface structure between metal and the inorganic coating with excellent adherence has been studied by investigating the chemical composition and the microstrncture as well as elements valence bond on the interface with the help of scanning electron microscope （SEM）, electron microprobe, and Auger elctron spectroscope （AES）. The results show that there is a non-stoichiometrieal transitional layer on the interface between metal and the inorganic coating with excellent adherence, the adherence between metal and the non-stoichiometrical transitional layer is achieved by the metallic bond and the adherence between the non- stoichiometrical transitional layer and the inorganic coating is produced by ionic and covalent bond. The non-stoichiometrical transitional layer results in the strong adherence.

New, Simple Blade-Pitch Control Mechanism for Small-Size, Horizontal-Axis Wind Turbines

In the present research work, the pitch-control is carried out such that the rotor blades are rotated around their longitudinal axis while the rotor continues its normal rotation. It is really a challenge to produce a clever design to pitch the rotor blades by the optimal amount so as to maximize the power output at all wind speeds. The mechanism is implemented to a three-blade, horizontal-axis, home-scale wind turbine. The mechanism is powered by a suitable DC （direct-current） motor. The tests were carried out in the open section of a delivery wind tunnel. The air speed was measured by a suitable anemometer. The corresponding rotational speed （rpm） and output voltage at different wind speeds were measured and recorded for calibration of the control system. The mechanism proved to be successful in controlling the pitch angle over a wide range of wind speeds.

Control of Multiple PWM Servos by a Single Programmable Timer

An algorithm for control of several servo motors by a mi- crocontroller is presented. The limited ntanber of progranunable timers on the majority of micnocntrollers presents a problem for multiple generation of timing pulses. Two software approaches are discussed in the paper and experimental results given for operation of a set of small servos using a single timer.

Analysis and Control of a Three-Phase Switched Reluctance Wind Generator

This paper deals with various aspects of modeling, simulation, analysis, and control ofa SRG （switched reluctance generator） in different modes of operation. Excitation method of such a generator is shortly described. The output power of the SRG is controlled so that it can track the maximum output power of a wind turbine drive applications. Also, the output generator voltage is stabilized under either load or wind speed variations. Basic operational characteristics of a three-phase 6/4 SRG are developed through experimental observation. Meanwhile, the real-time operation was implemented in a DSP （digital signal processor） environment. The simulation of the complete system model has been obtained using the Matlab/Simulink software. A good agreement between experimental and simulation results has been observed which supports the validity of the proposed analysis.

Wind Generator Stabilization with Doubly-Fed Asynchronous Machine

This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)compensation from DASM can be regulated independently through secondary-excitation controlling.Simulation results by power system computer aided design(PSCAD)show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures.Comparison studies have also been performed between wind turbine pitch control and proposed method.

Fuzzy iterative learning control of electro-hydraulic servo system for SRM direct-drive volume control hydraulic press

A new kind of volume control hydraulic press that combines the advantages of both hydraulic and SRM(switched reluctance motor) driving technology is developed.Considering that the serious dead zone and time-variant nonlinearity exist in the volume control electro-hydraulic servo system,the ILC(iterative learning control) method is applied to tracking the displacement curve of the hydraulic press slider.In order to improve the convergence speed and precision of ILC,a fuzzy ILC algorithm that utilizes the fuzzy strategy to adaptively adjust the iterative learning gains is put forward.The simulation and experimental researches are carried out to investigate the convergence speed and precision of the fuzzy ILC for hydraulic press slider position tracking.The results show that the fuzzy ILC can raise the iterative learning speed enormously,and realize the tracking control of slider displacement curve with rapid response speed and high control precision.In experiment,the maximum tracking error 0.02 V is achieved through 12 iterations only.

A New Scheme to Direct Torque Control of Interior Permanent Magnet Synchronous Machine Drives for Constant Inverter Switching Frequency and Low Torque Ripple

DTC （direct torque control） can produce quick and robust response, but it has the problems of large torque ripples and inconstant inverter switching frequency. This paper introduces a modified direct torque control based on the SVM （space vector modulation） for IPMSM （interior permanent magnet synchronous motor） drive. Two PI （proportional-integral） controllers regulate the flux and torque, respectively, and the inverter is controlled by the SVM technique in the proposed DTC system. Simulation results show that the performance of the proposed DTC system has been improved with respect to the conventional DTC. The DTC system can effectively reduce the flux and torque ripples.