GIANT MAGNETOSTRICTIVE ACTUATOR IN SERVO VALVE AND MICRO PIPE ROBOT

Performance of giant magnetostrictive material (GMM) is introduced. Principleof work, basic structure and key techniques of giant magnetostrictive actuator (GMA) are analyzed.Its dynamic models of magneto-mechanical coupling are established. The structure and principle ofthe pneumatic servo valve and the micro pipe robot with new homemade GMM are presented. Theexperiment is carried out under typical working conditions. The experiment results show that the GMMpneumatic servo valve has wide pressure control characteristics, good linearity, and fast responsespeed. The movement principles of the GMM robot system are reliably feasible and its maximal movingspeed is about 8 mm/s. It is preferable to the driving frequency of the robot within 100 approx 300Hz.

Fuzzy Theory Based Control Method for an In-pipe Robot to Move in Variable Resistance Environment

Most of the existing screw drive in-pipe robots cannot actively adjust the maximum traction capacity, which limits the adaptability to the wide range of variable environment resistance, especially in curved pipes. In order to solve this problem, a screw drive in-pipe robot based on adaptive linkage mechanism is proposed. The differential property of the adaptive linkage mechanism allows the robot to move without motion interference in the straight and varied curved pipes by adjusting inclining angles of rollers self-adaptively. The maximum traction capacity of the robot can be changed by actively adjusting the inclining angles of rollers. In order to improve the adaptability to the variable resistance, a torque control method based on the fuzzy controller is proposed. For the variable environment resistance, the proposed control method can not only ensure enough traction force, but also limit the output torque in a feasible region. In the simulations, the robot with the proposed control method is compared to the robot with fixed inclining angles of rollers. The results show that the combination of the torque control method and the proposed robot achieves the better adaptability to the variable resistance in the straight and curved pipes.

Dynamics analysis of drawing cables for pipe robot over long distance

Focusing on the speed control problem, this paper presents a study on the stick slip phenomena of cable driven by pipe robot and the critical conditions of stick slip. By dynamics simulation and field experiments, the theoretical analysis has been proved to be practical and valid. The result is of considerable theoretical value in the speed control for pipe robot on receiving and putting line.

BIMORPH PIEZOELECTRIC ACTUATOR FOR SMALL PIPE ROBOT

An experimental bimorph piezoelectric element (PZT) actuator for small piperobot is developed. The robot can move in φ20 mm pipe, and can carry a CCD camera for detectingcracks or fine holes on inner surface of pipe. The velocity of the robot can reach 17～22 mm/s forvertical pipe up/down, respectively. Moving principle and its performance characteristics arepresented.

A wheel-type in-pipe robot for grinding weld beads

To improve the safety and efficiency of polishing operations in circular boiler headers, a new type of wheel-drive polishing robot was developed in this study. The robot was designed to grind weld beads on the inner walls of pipes in diameter between 550 mm and 714 mm. The robot consists of a moving structure, a positioning structure, and a polishing structure. Charge coupled device （CCD） cameras and line lasers are used in the robot＇s vision system, thus the robot can be manually controlled to move, locate, and grind quickly and accurately. The experimental results showed that the robot performed well in practical applications.

Research on Oil/Gas In-pipe Inspection Robot

A new type of in-pipe mobile robot was designed and developed on the basis of w heel in-pipe robot and crawler in-pipe robot. The three sets of driving wheels circumferentially 120° apart in the cross section, both front and rear driving wheels are distributed on the same parallelogram mechanis m. The driving motor drives the three sets of driving wheels by worm couple, the regulating motor makes the three sets of driving wheels push against the pipe inwall with stable and adequate pressing force by the ball screw pair and p ressure sensor, so the in-pipe robot can provide adequate and stable traction force. The robot mechanism is simple and sm all in size and work reliably . It is particularly suitable to the pipe with diameter 400～650 mm.

MICRO-ROBOT FOR MEASUREMENT AND THREE-DIMENSION RECONSTRUCTION OF MICROPIPES

The presented system consists of field devices, a control system and a host computer system. The field devices, which are composed of an in-pipe micro-robot, a displacement sensor, a curvature sensor, and an inner surface measurement unit, can go into the pipe to get the data of displace- ment and axis curvature, and the shape data of the inner surface. With the conic-shape laser beam shot by the inner surface measurement unit, the intersectional curve between the laser beam and the inner-surface of the tested pipe can be calculated in the local coordination system （LCS） of the inner surface measurement unit. The relation between the LCS and the global coordination system （GCS） can be deduced, too. After the robot reaches the end of the pipe, all measured intersectional curves can be translated into the same coordination system to become a point cloud of the inner surface of the pipe according to the relations between LCS and GCS. Depending on this points cloud, the CAD model of the inner surface of the pipe can be reconstructed easily with reverse engineering tools, and the feature of flaw of the pipe can be obtained with flaw analysis tools.

Research on a New-style Pipeline Inspection Robot System

The pipe inspection robot system is developed for automatic inspection of gas pipeline with pipe diameter between 400 mm and 650 mm. It is composed of a pipe robot crawling mechanism controlled by remote network system, nondestructive examination sensor system, ground working station and so on. This paper presents the pipe inspection robot system design, the Key technique and the performance experiment of the robot. The main performance index of the pipe robot system prototype has reached domestic advanced level. The prototype has also the technical potential to be developed as a product used in industry for periodic check of main gas/oil pipe.

Pose Planning for the End-effector of Robot in the Welding of Intersecting Pipes

All-position robots are widely applied in the welding of complicated parts.Welding of intersecting pipes is one of the most typical tasks.The welding seam is a complicated saddle-like space curve,which puts a great challenge to the pose planning of end-effector.The special robots designed specifically for this kind of tasks are rare in China and lack sufficient theoretical research.In this paper,a systematic research on the pose planning for the end-effectors of robot in the welding of intersecting pipes is conducted. First,the intersecting curve of pipes is mathematically analyzed.The mathematical model of the most general intersecting curve of pipes is derived,and several special forms of this model in degraded situations are also discussed.A new pose planning approach of bisecting angle in main normal plane（BAMNP） for the welding-gun is proposed by using differential geometry and the comparison with the traditional bisecting angle in axial rotation plane（BAARP） method is also analytically conducted.The optimal pose of the welding-gun is to make the orientation posed at the center of the small space formed by the two cylinders and the intersecting curve to help the welding-pool run smoothly.The BAMNP method can make sure the pose vertical to the curve and center between the two cylinders at the same time,therefore its performance in welding-technique is superior to the BAARP method.By using the traditional BAARP method,the robot structure can become simpler and easier to be controlled,because one degree of freedom（DOF） of the robot can be reduced.For the special case of perpendicular intersecting,an index is constructed to evaluate the quality of welding technique in the process of welding.The effect of different combination of pipe size on this index is also discussed.On the basis of practical consideration,selection principle for BAARP and BAMNP is described.The simulations of those two methods for a serial joint-type robot are made in MATLAB,and the simulation results are consistent to the analysis.The mathematical model and the proposed new pose-planning method will lay a solid foundation for future researches on the control and design of all-position welding robots.

Mobile MicroRobotin Small Pipe Driven by ElectroMagnetic Force

It is required to develop micro machine for inspection and maintenance of defects inside small pipe with diameter smaller than one inch. Considering the advantages of electromagnetic actuators with simple mechanism, high response, convenience to control and fabricate, we tried to develop a new micro robot in small pipe based on interaction principle of electromagnetic attraction and spring force. This paper describes its structure and design. The dimension of the prototype is diameter of 15 mm, length of 30 mm and weight of 25 g. It can climb in small pipe of diameter of 20 mm with a speed of 6～8 mm/s in horizontal or in vertical situation.

Mathematical modeling and simulation application for a wheeled mobile robot applied on pipe welding

A geometric model was built to represent the position relation of a wheeled mobile robot relative to a pipe. The relationship between the deviation of falling off for the robot and the curvature of the pipe was formulated quantitatively. Based on the relationship, a mathematical model was derived and a fuzzy control algorithm for the robot was developed. Simulations were carried out to confirm the dynamic index and the validity of the mathematical model of the fuzzy control algorithm for seam tracking of pipe welding. Experiments for pipe welding with the mobile robot were also carried out to verify the algorithm, and the results showed that the seam has a good quality with a preferable appearance of weld.

A Pipeline Inspection Micro Robot Based on Screw Motion Wheels

The micro robot based on screw motion wheels, which features high payload/mass ratio, fast and continuous motion, adaptation to pipe diameter or roundness variations, is suitable for locomotion and inspection inside small diameter pipelines. The robot inspection system, Tubot I, developed at Shanghai University is composed of locomotion mechanism with an inner motor, a micro CCD camera and a monitor outside the pipeline. In the paper, the kinematics and statics analyses are presented for the screw locomotion system of Tubot I. The moving characteristics are obtained from experiments on the robot prototype.

NEW KIND OF WIRELESS MICRO ROBOT ACTUATED AND CONTROLLED THROUGH OUTSIDE MAGNETIC FIELD

A new method to drive and control micro in-pipe robot by means of magneticfield outside pipe is put forward, in which wireless micro robot can move forward driven by thevibration of its legs through converting magnetic energy into mechanical one under the action ofpiezomagnetism and magnetomechanical coupling of its micro GMA, when time varied oscillatingmagnetic field with different frequency applied outside pipe. Firstly its systematical structure andoperation principle are introduced, and energy converting process from outside magnetic one intomechanical one is analyzed through setting up the magnetic and mechanical dynamic model of GMA andestablishing dynamic model of two stage amplifier of mobile earner. Robot systematical experimentsshow the correctness of the theoretical analysis and its feasibility. As a result, drive and controlmethod without cable through outside magnetic field is realized.

ROBOT软件在斜拉输水管桥施工控制中的应用

采用ROBOT结构分析软件,全过程跟踪控制天津塘沽永定新河斜拉管桥施工过程中拉索的张拉顺序,并对其施工过程进行了仿真计算,得出了合理的施工步骤,从而保证了斜拉管桥有更高的安全度。

基于虚拟现实的立管横焊机器人辅助焊接工艺设计与实现

焊接工艺参数的选择对焊接质量有重要影响。针对立管J型铺设窄坡口横焊熔池下淌特性,提出基于横焊焊道厚度及热输入恒定策略的焊接工艺参数匹配算法。基于Unity3D开发平台和工艺参数匹配算法,通过C#开发了立管横焊CAPP模块,扩展了虚拟现实人机交互系统的功能模块;开展立管横焊计算机辅助焊接工艺实验,焊后焊缝成形良好,无焊接缺陷。实验结果表明:CAPP模块可有效获取匹配的焊接工艺参数,能缩短焊接工艺开发周期,降低工艺开发成本,有效提升系统的智能化水平。

管沟机器人自动化检测系统设计

随着铁路涵洞、公路排水渠和城市管网的快速发展,管沟维护任务的工作量逐年增加;为了确保工作人员的安全和提高管沟维护的效率,设计了一套管沟自动化检测系统;该系统由PC、控制手柄、管沟机器人和线缆车构成;管沟自动化检测系统以PC为核心,PC通过RS485与控制手柄、管沟机器人和线缆车进行通信;PC下发指令给机器人和线缆车,对管沟机器人和线缆车进行远程操控与传感器数据监测;PC通过同轴电缆接收管沟内部图像,实时对管沟进行监控;经实验测试,该管沟自动化检测系统能够正常运行在管沟环境中,机器人通信距离超过100 m,PC上位机实时显示1080P 30 Hz的管沟视频;该管沟自动化检测系统具有一定的应用价值,符合设计需求,具有一定的推广价值。

管桁架焊缝检测机器人夹紧机构瞬态振动特性分析与试验

为保证管桁架焊缝检测机器人夹紧瞬间的稳定性,对机器人夹紧瞬间的振动特性展开研究。根据夹紧机构零部件配合方式构建夹紧机构振动模型,对机器人夹紧瞬间进行仿真,分析夹紧瞬间夹紧机构的响应情况,研究夹紧机构对模型参数的敏感程度。对夹紧机构进行改进,提高弹簧刚度,增加动态吸收器,建立改进后的夹紧机构瞬态振动模型,并在MatLab中进行仿真分析。开展夹紧机构振动测试试验,测量原始与改进后机构的振动情况,对比弹簧支撑振动测试结果与仿真结果。结果表明:弹簧刚度对弹簧压缩量影响最大,弹簧阻尼对调整时间影响最大;机构改进后,调整时间缩短,弹簧压缩率显著降低,稳定性优于原始机构;试验结果与仿真结果的瞬态性能指标误差均小于5%,试验结果与仿真结果具有一致性。

全位置管道焊接机器人机头结构设计与运动仿真

从全位置管道焊接工艺对焊枪自由度的控制需求出发,设计了一种集焊枪摆动、升降、倾仰运动为一体的焊接机器人机头。机头组成包括摆动机构、升降机构和倾仰机构,其中倾仰机构控制焊枪角度,可为焊接工艺中使用电弧推力控制熔池成形提供机械结构基础。在Simcenter软件中对所设计的机头结构进行运动仿真。结果表明:在多轴插补联动下,该结构可以实现焊枪所需的自由度控制,机头结构设计良好。

机器人焊接技术在管道焊接中的应用现状

为介绍管道焊接中机器人焊接技术的应用情况,按照技术出现的顺序对油气管道焊接技术进行概括,分析了不同自动化焊接设备的工作原理,同时对工程中常用的设备进行了举例。文中介绍了管道铺设工程中相关的管道焊接检测技术以及管道接头腐蚀防护技术,最后介绍了焊接机器人的发展趋势,包括基于运动仿真的越障焊接、扩大应用场景与功能、引入新的传感器与原理。

示教工业机器人弯管卡线槽模具设计

示教工业机器人弯管卡线槽为直管+弯管形状,模具设计难点在于弯管段的脱模,塑件外壁的脱模简化为自动脱模和推杆推出方式,内壁的脱模设计了2个抽芯机构,分别是液压缸直管抽芯和液压缸弯管抽芯。在弯管抽芯机构中,先由液压缸活塞杆推动滑块直线移动,滑块再通过拉杆带动弯管圆弧滑块在摆杆和圆弧压条的共同导向下做旋转式抽芯,实现弯管内壁的旋转式抽芯脱模。