Piezoelectric film-actuated motion platform with high resolution

A piezoelectric film-actuated motion platform with high resolution, which can run in two directions within a horizontal plane, is presented. On the basis of the analysis of the working principle of a stick-slip mechanism, a mathematical model describing its dynamic behavior is set up and simulated. Experiments of the motion performance and carrying ability on the prototype are conducted. Results show that this type of platform has advantages including a simple structure, small volume, light weight, stable step length, and large traveling range. When the driving voltage is less than 30 V, step error is less than 0.5 ?m. The carrying ability of the platform is terrific and about 7–8 times its weight.     

Parameter prediction in laser bending of aluminum alloy sheet

Based on the basic platform of BP neural networks, a BP network model is established to predict the bending angle in the laser bending process of an aluminum alloy sheet (1–2 mm in thickness) and to optimize laser bending parameters for bending control. The sample experimental data is used to train the BP network. The nonlinear regularities of sample data are fitted through the trained BP network; the predicted results include laser bending angles and parameters. Experimental results indicate that the prediction allowance is controlled less than 5%–8% and can provide a theoretical and experimental basis for industry purpose. __________ Translated from Optics and Precision Engineering, 2007, 15(6): 915–921 [译自: 光学精密工程     

Investigation on a cylindrical ultrasonic micromotor

The relationship between the arrangement of ceramics and the force coefficient shows that the maximum excitation efficiency will be obtained when the ceramics are placed at the trough of the first bending mode of the stator. Therefore, a cylindrical ultrasonic micromotor with a novel stator is proposed. The prototype motor is 5 mm in diameter, 30 mm in length and 4.2 g in weight. The micromotor operates with the first bending mode at 53 kHz. Its maximum speed is 350 r/min when the drive voltage is 200 V and the stall torque reaches 2.5 mN · m. As this motor is suitable for miniaturization because of its simple structure, another cylindrical ultrasonic micromotor is developed. Piezoelectric ceramic tube is used as its stator. This micromtor is 2 mm in diameter, 7 mm in length and 0.258 g in weight. Its speed reaches 813 r/min when the drive voltage is 60 V at 75 kHz. The operation mechanism, structure and design method of these two motors are introduced. __________ Translated from Proceedings of the CSEE, 2006, 26(12): 128–133 [译自: 中国电机工程学报]     

Correlation analysis of couple optical paths for microstereovision with stereo light microscope

A micro stereovision system with a stereo light microscope (SLM) has been applied in micromanipulation systems. There is a coupling connection between two optical paths of a stereo light microscope. The coupling intension corresponds with two factors: the structure of an SLM and the position of an object point in the view of an SLM. In this paper, a correlation function is proposed to describe the coupling intension between the couple optical paths of an SLM. The quantified results are applied to the error analysis of the imaging model. Experiments show that the correlation of the optical paths of a common main objective of stereo light microscope (CMO-SLM) is little more than that of a G-SLM, and the error must be considered when a pinhole imaging model is used to analyze its correlation. __________ Translated from Journal of Beijing University of Technology, 2006, 32(8): 724–729 [译自: 北京工业大学学报]     

Novel drive mechanism for in-tube micro robots

The volume of an in-tube micro robot is small and its interior space is very limited. However, conventional transmission methods are unfit to drive in-tube micro robots. A novel micro drive mechanism called the micro-elastic-meshing-wheel is presented in this paper. It can be used for transmitting power and locomotion between two shafts, which are upright and cross in a micro space. The mechanical model of the novel drive mechanism is built, and the maximal transmission force is deduced. Then, sufficient experiments are carried out to test maximal transmission force produced by the novel drive mechanism. The calculation and experiment results show that the novel drive mechanism can transmit sufficient power to in-tube micro robots. __________ Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(7): 45–49 [译自: 华南理工大学学报 (自然科学版)]     

Mobile platform for hydraulic turbine blade repair robot

The wall-climbing mobile platform (MP) of a robot for repairing a hydraulic turbine blade onsite is developed. The MP is equipped with ferromagnetic adhesive devices and can work on a spatial curved surface. The contradiction between mobility and load-bearing ability is analyzed, and the problem of self-adaptation to the curved face is solved using differential-driven wheeled locomotion with ferromagnetic adhesive devices. The platform adheres to the blade surface through the force provided by the ferromagnetic devices, and a certain gap exists between the magnetic devices and the blade’s surface. A mechanism of three revolution degrees of freedom, which connects the magnetic devices with the platform’s chassis, is developed to make the platform self-adapt to the complex curved surface of the turbine blade. A proof-of-principle prototype has been manufactured, and experiments prove the success of the MP. The payload of the zero-turn-radius MP with excellent maneuverability exceeds 80 kg. The platform can automatically adapt to complex spatial surfaces, which satisfy the requirements of a hydraulic turbine blade in-situ repair robot. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(11): 156–161 [译自:机械工程学报]     

Analysis of actuating mechanics characteristics for a flexible miniature robot system

Based on the inchworm movement, a miniature endoscope inspection robot system with a flexible structure is designed. The system is actuated by a pneumatic rubber actuator with three degrees of freedom, and it holds its position by air chambers. The actuating mechanics characteristics of the robot are analyzed. An electro-pneumatic pressure system is designed to control the motion of the robot. Results of the calculation and experiments are consistent, and the robot system can move smoothly in a soft tube. __________ Translated from Chinese Journal of Scientific Instrument, 2007, 28(1): 7–11 [译自: 仪器仪表学报]     

Friction and Wear Properties of Electrodeposited Nickel–Titania Nanocomposite Coatings

The Einstein–Debye relationship gives the time, λ _EB, for Brownian motion to remove the alignment of polar molecules resulting from an imposed electrical field after the field is removed. Measurements of the dielectric relaxation time and the shear-dependent viscosity in low-molecular-weight liquids, however, show that the theoretical Einstein–Debye rotational relaxation time is much better correlated with the characteristic time in the Carreau law for low-molecular-weight liquids than with the dielectric relaxation time. In fact, the dielectric relaxation time of bis(phenoxyphenoxy)benzene is better approximated by the ratio of viscosity to limiting-high-rate shear modulus. Flow curves for the low molecular weight, monodisperse liquids, di(2-ethylhexyl)phthalate and squalane, can be well-represented by the Carreau law with the Einstein–Debye time as the characteristic time. Doing so yields the standard form for time–temperature–pressure superposition.     

Novel precision piezoelectric step rotary actuator

A novel piezoelectric (PZT) precision step rotary actuator was developed on the basis of PZT technology. It adopts the principle of bionics and works with an inside anchoring/loosening of the stator and a distortion structure of the uniformly distributed thin flexible hinge to solve problems such as ineffective anchoring/loosening, low step rotary frequency, small travel, poor resolution, low speed and unsteady output. The developed actuator is characterized by high frequency (30 Hz), high speed (380 μrad/s), large travel (>270°), high resolution (1 μrad/step), and work stability. It greatly improves the ability to drive the existing PZT step rotary actuator. The new actuator can be applied in the field of micromanipulation and precision engineering, including precision driving and positioning and optics engineering. __________ Translated From Journal of Jilin University (Engineering and Technology Edition), 2006, 36(5): 673–677 [译自: 吉林大学学报 (工学版)]     

Dynamical research on spherical micro actuator with piezoelectric ceramic stacks drivers

This paper develops a 30 mm × 30 mm × 50 mm spherical micro actuator driven by piezoelectric ceramic stacks (PZT), and analyzes its dynamic performances. First, the space coordinate relationship of the spherical micro actuator and a dynamic model are set up. Second, The Runge-Kutta arithmetic is used to calculate the dynamical parameters of the micro actuator; the SIMULINK module of MATLAB is used to build the dynamical simulating model and then simulate it. Third, an experimental sample of the spherical micro actuator is developed, a micromanipulator is integrated with a micro-gripper based on the sample spherical micro actuator, and the experimental research on the micro assembly is conducted between a micro shaft of Φ180 μm and a micro spindle sleeve of Φ200 μm. Finally, the characteristics of the spherical micro actuator influenced by the mass of the metal sphere of the micro actuator, driving signal frequency, friction coefficient of the contact surface between the metal sphere and the friction block of the micro driving unit are analyzed. The experimental results indicate that the rotation resolution of the micro actuator reaches 0.000 1°, the rotation positioning precision reaches 0.000 5°, and the maximum working frequency is about 1200 Hz. The experimental results validate the back rotation vibration model of the spherical micro actuator. The micromanipulator integrated by the spherical micro actuator can meet the requirements of precise micro operation and assembly for micro electro mechanical systems (MEMS) or other microelements in micro degree fields. __________ Translated from Optics and Precision Engineering, 2007, 15(2): 248–253 [译自: 光学精密工程]     

Modular structure of a self-reconfigurable robot

This paper proposes a novel, hermaphroditic, and lattice self-reconfigurable modular robot. Each module is composed of a center body—a cubic part and six sides that can rotate independently. There are two holes and two extensible pegs on each side. The rotary motion of each side and the extensible motion of the pegs are generated by a motor connected to a reducer, using a cone-shaped gear, belt, clutch, etc. The structure of the module is compact, and has space to extend further. __________ Translated from Journal of Shanghai Jiaotong University, 2005, 39(6): 877–879 [译自: 上海交通大学学报]     

A new controlling system for the solar tower telescope of IZMIRAN: II. A solar image motion compensator

A solar image motion compensator for the solar tower telescope is described. Two mutually perpendicular CCD linear arrays are used as photodetectors. An algorithm for forecasting the system behavior is used for generation of correction signals. Analyzing the solar image motion data obtained using the compensator and without it has shown that, thanks to its use, the total image motion value decreases to 0.5″–0.6″ in a frequency band of 0–100 Hz, being close to the amplitude of noncorrelated image motion component. The compensator operates equally effectively in both the pointing and scanning modes.     

Leakage location system for oil pipeline on basis of stress wave detection

An online monitoring system was developed for rapidly determining the exact location of the holing position in an oil pipeline by monitoring and analyzing the characteristics of the strain wave caused by the hole. The system has a master-slaver computer structure based on a remote wireless network. The master system takes charge of managing and controlling the whole system, identifying the holing stress wave, and calculating the holing position. The slaver system is responsible for sampling the strain wave signal from the pipeline. The characteristics of the strain wave signal are extracted by a Hilbert-Huang transform based on a signal processing approach. The exact holing position can be obtained by a time delay locating method with stress wave characteristics. The experimental results of the in-service pipeline show that the average locating error of the system is less than 10 m, the accuracy ratio for the holing alarm is more than 90%, and the time that the system takes to respond to the leakage is less than 10 s. __________ Translated from Chinese Journal of Scientific Instrument, 2007, 28(6): 1012–1017 [译自: 仪器仪表学报]     

Impact drive rotary precision actuator with piezoelectric bimorphs

An impact drive rotary precision actuator with end-loaded piezoelectric cantilever bimorphs is proposed. According to finite element analysis and experiments of the dynamic characteristics of end-loaded piezoelectric cantilever bimorphs, a specific fixed-frequency and adjustable-amplitude is confirmed to control the actuator. The results show that an actuator excited by fixed-frequency and the adjustable-amplitude ramp voltage waveform works with a large travel range (180°), high resolution (1 μrad), speed (0.2 rad/min) and heavy-load ability (0.02 Nm). With advantages of high-precision positioning ability, simple structure and only one percent the cost of traditional impact drive mechanisms, the actuator is expected to be widely used in precision industries. __________ Translated from Optics and Precision Engineering, 2005, 13(3): 298–304 [译自: 光学精密工程]     

An autonomous miniature wheeled robot based on visual feedback control

Using two micro-motors, a novel omni-direction miniature wheeled robot is designed on the basis of the bi-corner driving principle. The robot takes advantage of the Bluetooth technology to wirelessly transmit data at a short distance. Its position and omni-direction motion are precise. A Charge Coupled Device (CCD) camera is used for measuring and for visual navigation. A control system is developed. The precision of the position is 0.5 mm, the resolution is about 0.05 mm, and the maximum velocity is about 52 mm/s. The visual navigation and control system allow the robot to navigate and track the target and to accomplish autonomous locomotion. Translated from Journal of Harbin Institute of Technology, 2006, 38(3): 348–349 [译自: 哈尔滨工业大学学报]     

Interfacial heat transfer coefficient between metal and die during high pressure die casting process of aluminum alloy

The present work focused on the determination of the interfacial heat transfer coefficient (IHTC) between metal and die during the high pressure die casting (HPDC) process. Experiments were carried out on an aluminum alloy, ADC12Z, using “step shape” casting—so-called because of its shape. The IHTC was successfully determined by solving one of the inverse heat problems using the nonlinear estimation method first used by Beck. The calculation results indicated that the IHTC immediately increased after liquid metal was brought into the cavity by the plunger and decreased as the solidification process of the liquid metal proceeded. The liquid metal eventually solidified completely, a condition when the IHTC tended to be stable. Casting thickness played an important role in affecting the IHTC between the metal and die not only in terms of its value but also in terms of its change tendency. Also, under the test conditions, different change tendencies of the metal solid fraction were found between castings with different thicknesses and the die. __________ Translated from Acta Metallurgica Sinica, 2007, 43(1): 103–106 [ 译自: 金属学报]     

Design and analysis of millimeters-scale omnidirectional mobile microrobot for microfactories

An omnidirectional mobile microrobot with a 9 mm × 8 mm × 8 mm size is introduced. The microrobot is driven by three electromagnetic micromotors with 2 mm diameter, two of which are for linear movement and the third one for steering. Dynamics is analyzed to present the relationship between the micromotor torque and the dual-wheel structure size as well as the frictions. Experiment results show that the microrobot payload ability can satisfy the requirements of conveying tasks in microfactories. __________ Translated from Robot, 2007, 29(5): 423–427 [译自: 机器人]     

A novel soft-switching twin arc pulse MAG welding inverter

The high-speed double wire pulse metal-gas arc (MAG) welding process possesses advantages of automation and high efficiency and quality. Thus, it attracts much more attention nowadays. To meet the requirements of the double wire pulse MAG welding process, a novel double wire pulse MAG welding inverter integrated with technologies, such as soft-switching, double closed loop control, and synchronic control, is produced. A complete performance test was done for the pulsed MAG welding power supply by using a computer testing platform. The results of the experiment indicate that the novel welding inverter has an excellent performance both in the dynamic and the static characteristics. Also, the synchronic control between the master inverter and the slave inverter is reliable. Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(7): 31–34, 59 [译自: 华南理工大学学报 (自然科学版)]     

The prediction technology study of fatigue life for key parts of a tracked vehicle''s suspension system

In allusion to fatigue life of a tracked vehicle torsion bar, a virtual prototype model of the tracked vehicle suspension system including a flexible torsion bar was built based on dynamic simulation software—ADAMS. Node force and stress results of the torsion bar from last step simulation were acquired; taking into account the material characteristics and influential factors, fatigue life of the flexible body of the torsion bar was predicted. Engineering results can be acquired through the contrast of the result of virtual test and statistical fatigue. __________ Translated from Journal of Academy of Armored Force Engineering, 2006, 20(1): 44–47 [译自: 装甲兵工程学院学报]