Trajectory compensation for multi-robot coordinated lifting system considering elastic catenary of the rope

The multi-robot coordinated lifting system is an unconstrained system with a rigid and flexible coupling.The deformation of the flexible rope causes errors in the movement trajectory of the lifting system.Based on the kinematic and dynamic analysis of the lifting system,the elastic catenary mod-el considering the elasticity and mass of the flexible rope is established,and the effect of the deform-ation of the flexible rope on the position and posture of the suspended object is analyzed.According to the deformation of flexible rope,a real-time trajectory compensation method is proposed based on the compensation principle of position and posture.Under the lifting task of the low-speed move-ment,this is compared with that of the system which neglects the deformation of the flexible rope.The trajectoy of the lifting system considering the deformation of flexible rope.The results show that the mass and elasticity of the flexible rope can not be neglected.Meanwhile,the proposed trajectory compensation method can improve the movement accuracy of the lifting system,which verifies the ef-fectiveness of this compensation method.The research results provide the basis for trajectory plan-ning and coordinated control of the lifting system。

TightRope钢板与锁骨钩钢板内固定术治疗RockwoodⅢ型肩锁关节脱位疗效比较

目的比较Tight Rope钢板与锁骨钩钢板内固定术治疗RockwoodⅢ型肩锁关节脱位的临床效果。方法选择2014年6月至2018年3月于新乡医学院第三附属医院采用Tight Rope钢板内固定治疗的20例RockwoodⅢ型肩锁关节脱位患者为观察组,另选择2007年5月至2012年3月采用锁骨钩钢板内固定治疗的23例RockwoodⅢ型肩锁关节脱位患者为对照组;对2组患者手术时间、术中失血量、术后住院时间、术后并发症进行比较;术前及术后6个月,采用视觉模拟评分法(VAS)评估2组患者肩关节疼痛情况,采用Constant评分系统和自我评分系统(SSV)评估患者肩关节功能;术后12个月,采用Karlsson标准评估2组患者临床疗效。结果2组患者手术时间比较差异无统计学意义(P>0.05);与对照组比较,观察组患者术中出血量少,术后住院时间短(P<0.05)。2组患者术前VAS评分、Constant评分及SSV评分比较差异均无统计学意义(P>0.05);2组患者术后6个月VAS评分显著低于术前,Constant评分和SSV评分显著高于术前(P<0.05);术后6个月,观察组患者VAS评分显著低于对照组,Constant评分和SSV评分显著高于对照组(P<0.05)。术后12个月,观察组和对照组患者治疗效果优良率分别为95.00%(19/20)、69.57%(16/23),观察组患者治疗效果优良率明显高于对照组(χ^2=4.570,P<0.05)。观察组和对照组患者术后并发症发生率分别为5.00%(1/20)、39.13%(9/23),观察组患者并发症发生率低于对照组(χ^2=6.982,P<0.05)。结论与锁骨钩钢板内固定比较,Tight Rope钢板内固定治疗RockwooddⅢ型肩锁关节脱位可以减少术中出血量,更有利于术后肩关节功能恢复,降低并发症发生率。

ISAR MOTION COMPENSATION USING ROPE

Motion compensation is a key step for inverse synthetic aperture radar (ISAR) imaging. Many algorithms have been proposed. The rank one phase estimation (ROPE) algorithm is a good estimator for phase error widely used in SAR. The ROPE algorithm is used in ISAR phase compensation and the concrete implementation steps are presented. Subsequently, the performance of ROPE is analyzed. For ISAR data that fit the ROPE algorithm model, an excellent compensation effect can be obtained with high computation efficiency. Finally, ISAR real data are processed with ROPE and its imaging result is compared with that obtained by the modified Doppler centroid tracking (MDCT) method, which is a robust and good estimator in ISAR phase compensation.

解剖型锁定钢板联合TightRope内固定治疗锁骨远端骨折的效果

目的:探讨解剖型锁定钢板联合Tight Rope内固定治疗锁骨远端骨折的效果。方法:回顾分析常熟市第二人民医院创伤骨科2015年4月—2021年6月收治的93例锁骨远端骨折患者,按其治疗方式分对照组(n=46)和观察组(n=47)。对照组接受锁骨钩钢板内固定治疗,观察组接受解剖型锁定钢板联合Tight Rope内固定治疗。比较两组患者围手术期指标、肩关节功能、骨形成蛋白-2(BMP-2)、凝血指标、并发症发生率。结果:两组术中出血量比较,差异无统计学意义(P>0.05);观察组手术时间长于对照组,但骨折愈合时间、术后住院时间均短于对照组,差异均有统计学意义(P<0.05)。术后1、3个月,观察组肌力、肩关节活动度、日常活动、疼痛评分均高于对照组,差异均有统计学意义(P<0.05)。术后1周,观察组BMP-2、凝血酶原时间(PT)均高于对照组,纤维蛋白原(FIB)、D-二聚体(D-D)均低于对照组,差异均有统计学意义(P<0.05)。观察组并发症发生率(4.26%)低于对照组(21.74%),差异有统计学意义(P<0.05)。结论:相比于锁骨钩钢板内固定术,解剖型锁定钢板联合Tight Rope内固定术治疗锁骨远端骨折的效果更理想,在患者术后肩关节功能恢复、骨折愈合、并发症控制等方面均有明确优势。

FEASIBILITY AND EXPERIMENT ANALYSIS OF FOUR-ROPES FRICTION HOIST WITHOUT ROPE GROOVES CUTTING

Based on theoretical analysis and experiment, when the difference between the ropes length is ensured, the radius difference between the rope grooves and the difference of the rope strain of a double rope friction hoist will decrease with the increasing of hoisting times. Then the rope grooves cutting are not needed. If the connection form of the ropes or the structure of the frictional wheel of a four ropes friction hoist are changed into as a double ropes hoists, the hoist rope grooves will not need to be cut as well, and the working time will be saved and the service life of the rope lining will be lengthened also.

对ROPES分析阶段的研究

利用ROPES分析阶段中需求分析、系统分析和对象分析技术,多方面分析了不同嵌入式系统的特点,从而可以确定合适的解决方案.

ROPE与PGA在ISAR运动补偿中的对比研究

ISAR运动补偿通常分为两步:距离对准和相位补偿。在现有的相位补偿方法中,相位梯度自聚焦(PGA)算法是较好的一种。本文在把秩一相位估计(ROPE)算法用于ISAR相位补偿后,针对ROPE与PGA两者在ISAR相位补偿中的性能作了详细地分析比较。最后用ISAR外场实测数据比较了它们的成像结果。

CONDITION MONITORING AND FAULT DIAGNOSIS FOR TENSION UNBALANCE OF ROPES IN MULTI-ROPE FRICTION WINDER

This paper analyzes the reasons of the tension unbalance of the ropes in multi-rope fric-tion winder, introduces the method of an on-line monitoring rope tensions with a testing device de-veloped by authors, and proposes the criteria of the fault diagnosis and the method of adjustment for the tension unbalance of the ropes, which is important to the theoretical study on the tension unbalance of the ropes and the maintenance of multi-rope winder.

关节镜下Tight Rope悬吊钢板治疗Neer Ⅱ型锁骨远端骨折

目的探讨关节镜下Tight Rope悬吊钢板固定术治疗NeerⅡ型锁骨远端骨折的临床疗效。方法分析24例NeerⅡ型锁骨骨折经关节镜下Tight Rope悬吊钢板固定术后的临床结果,其中男13例,女11例;年龄32~65岁,平均(52.7±10.3)岁。通过美国肩与肘协会评分系统(American shoulder and elbow surgeons evaluation form,ASES)对患者在末次随访时的肩关节功能进行评价。结果 24例患者均获得随访,随访时间11~32个月,平均(20.0±5.7)个月。所有患者骨折均愈合,愈合时间为(3.4±0.7)个月。术中发现有2例合并肩胛盂缘上唇自前向后的撕脱(superior labrum from anterior to posterior,SLAP)损伤,有1例合并Bankart损伤,在骨折固定前分别给予修复。患者术后ASES肩关节功能评分77~100分,平均(90.6±6.9)分。结论关节镜下Tight Rope悬吊钢板治疗NeerⅡ型锁骨远端骨折具有损伤小、临床疗效确切、对肩关节活动影响小、不需要二次手术取出内固定物并可同时微创处理关节内合并损伤等优点,可以作为锁骨远端骨折治疗的一个选择。

对ROPES设计阶段的研究

ROPES设计阶段的目标是在分析阶段的结果中添加了一些元素,在根据某些判定准则进行优化的基础上,从而确定一份特定的解决方案。架构设计能够给出可部署软件系统的大尺度软件分解;机制是对协作的具体化,将对象中这些机制结合在一起的过程就形成了机制设计;详细设计定义类的结构并对各个类的内部进行组织。

Dynamic design of a nonlinear energy sink with NiTiNOL-steel wire ropes based on nonlinear output frequency response functions

A novel vibration isolation device called the nonlinear energy sink(NES)with NiTiNOL-steel wire ropes(NiTi-ST)is applied to a whole-spacecraft system.The NiTi-ST is used to describe the damping of the NES,which is coupled with the modified Bouc-Wen model of hysteresis.The NES with NiTi-ST vibration reduction principle uses the irreversibility of targeted energy transfer(TET)to concentrate the energy locally on the nonlinear oscillator,and then dissipates it through damping in the NES with NiTi-ST.The generalized vibration transmissibility,obtained by the root mean square treatment of the harmonic response of the nonlinear output frequency response functions(NOFRFs),is first used as the evaluation index to analyze the whole-spacecraft system in the future.An optimization analysis of the impact of system responses is performed using different parameters of NES with NiTi-ST based on the transmissibility of NOFRFs.Finally,the effects of vibration suppression by varying the parameters of NiTi-ST are analyzed from the perspective of energy absorption.The results indicate that NES with NiTi-ST can reduce excessive vibration of the whole-spacecraft system,without changing its natural frequency.Moreover,the NES with NiTi-ST can be directly used in practical engineering applications.

Distribution of wire deformation within strands of wire ropes

Using ANSYS software, we developed a modeling program for several kinds of wire ropes with metal cores and built a geometric model for the 6×19 IWS wire rope. Through proper grid partitioning, a finite element model for calculating the deforma-tion of wire rope was obtained. Completely constraining one end of the wire rope and applying an axial force to the other end, we established the boundary conditions for solving the model. In addition, we numerically simulated the stress and deformation of the wire, obtaining the deformation distribution of each wire within the wire rope under different laying directions. At the end, a tensile test of the 6×19 IWS wire rope was carried out and the results of simulation and experiment compared.

Theoretical coupling longitudinal-transverse model and experimental verification of transverse vibration of rope for multi-rope friction hoisting system

Using the mass of time-varying length balance rope focused on the hoisting conveyance, the coupling longi- tudinal-transverse model of mine friction hoist was established by using of the Hamilton＇s principle. The modified Galerkin＇s method was used to discretize partial differential Eqs. The mine hoisting system was used to the example to analysis the relation between the load, velocity and transverse vibration of rope. The in situ tests were illustrated to evaluate the proposed mathematical model. The results showed that the modeling method can well represent the transverse vibration of rope.

Dynamic behavior of bridge-erecting machine subjected to moving mass suspended by wire ropes

The dynamic behavior of a bridge-erecting machine, carrying a moving mass suspended by a wire rope, is investigated. The bridge-erecting machine is modelled by a simply supported uniform beam, and a massless equivalent ＂spring-damper＂ system with an effective spring constant and an effective damping coefficient is used to model the moving mass suspended by the wire rope. The suddenly applied load is represented by a unitary Dirac Delta function. With the expansion method, a simple closed-form solution for the equation of motion with the replaced spring-damper-mass system is formulated. The characters of the rope are included in the derivation of the differential equation of motion for the system. The numerical examples show that the effects of the damping coefficient and the spring constant of the rope on the deflection have significant variations with the loading frequency. The effects of the damping coefficient and the spring constant under different beam lengths are also examined. The obtained results validate the presented approach, and provide significant references in the design process of bridgeerecting machines.

Effect of Tension on Friction Coefficient Between Lining and Wire Rope with Low Speed Sliding

In order to obtain the exact friction coefficient between lining and wire rope, the tension of wire rope is studied as a factor which affects this coefficient. A mechanical model of a wire rope subjected to axial load was established to determine the torque of the wire rope. The contact motion between lining and wire rope was regarded as a screw rotation and the axial force of the lining resulting from the torque of the wire rope was analyzed. Theoretical formulas relating tension of the wire rope and the friction coefficient was obtained. Experiments between lining and wire rope with low sliding speed were carried out with friction tester made by us. Experimental results show that increment of the friction coefficient is proportional to that of the tension of the wire rope with a low sliding speed. The experimental results agree with the theoretical calculation; the errors are less than 6%, which oroves the validity of the theoretical model.

Numerical investigation of the seismic response of a UHV composite bypass switch retrofitted with wire rope isolators

An ultra-high voltage(UHV)composite bypass switch(BPS)faces increasing seismic challenges when UHV projects extend to high seismic intensity areas.The UHV composite BPS still generates excessive stress at the bottom section although hollow composite insulators with high flexural strength are adopted.Since the standard retrofitting strategy by using stiffer supports cannot reduce stress responses,wire rope isolation is introduced.The optimal design of isolation considers both stress and displacement responses since the slenderness and composite material of insulators contribute to significant displacement.The results show that properly designed isolation can significantly reduce stress without excessive displacement responses.A larger radius configuration helps to improve the applicability of small stiffness isolators under high winds.When the isolation still cannot satisfy the requirement,smaller stiffness isolators with a larger radius,or isolators with increased loops and smaller radius,can be introduced to gain better energy dissipation capacity and effectiveness in response mitigation.Accordingly,a three-step design procedure is proposed to increase the damping force but fix the rotational stiffness of isolation.Hence,the application of wire rope isolation can be extended to UHV composite BPS with a low natural frequency,but conductors with enough redundancy should be used.

The finite element modeling of spiral ropes

Accurate understanding the behavior of spiral rope is complicated due to their complex geometry and complex contact conditions between the wires.This study proposed the finite element models of spiral ropes subjected to tensile loads.The parametric equations developed in this paper were implemented for geometric modeling of ropes.The 3D geometric models with different twisting manner,equal diameters of wires were generated in details by using Pro/ENGINEER software.The results of the present finite element analysis were on an acceptable level of accuracy as compared with those of theoretical and experimental data.Further development is ongoing to analysis the equivalent stresses induced by twisting manner of cables.The twisting manner of wires was important to spiral ropes in the three wire layers and the outer twisting manner of wires should be contrary to that of the second layer,no matter what is the first twisting manner of wires.

Key technique of a detection sensor for coal mine wire ropes

Wire ropes,employed extensively in coal mine hoists and transportation systems are subject to damage due to wear,corrosion and fatigue.The extent of damage and the carrying capacity of ropes are closely related to the sense of safety by staff and equipments.Magnetic flux leakage detection method(MFL),as an effective method,is these days widely used in detection of broken strands of wire ropes.In order to improve the accuracy of detection of flaws in wire ropes by magnetic flux leakage(MFL),the effect of the distance between a sensor and the surface of a wire rope(i.e.,lift-off) on detection by magnetic flux leakage was in-vestigated.An analysis of the main principles for the choice of lift-off is described by us and a new method that improves the structure of the detector is proposed from the point of view of the design of a magnetic circuit,to restrain the impact of fluctuations of sensor lift-off.The effect of this kind of method is validated by simulation and computation.The results show that the detection sensitivity is markedly increased by this method.Furthermore,the signal-to-noise ratio(SNR) can be increased by over 28%.This method will lend itself to offer reliable scientific information to optimize the structure of excitation devices and improve the accuracy of MFL detection.

Analysis and control of vibration of ropes in a high-rise elevator under earthquake excitation

In this research, the vibration of elevator ropes, including the main rope and compensation rope are investigated simultaneously in a high-rise elevator system under earthquake excitation. Moreover, the paper presents a new control method to restrain the sway of both ropes. This study considers varying rope lengths during elevator operation which cause other system parameters such as natural frequency, and damping ratio to be time-variant variables. The dynamics of the ropes are analyzed by solving the governing non-stationary, nonlinear equation numerically. In order to mitigate the vibration of ropes in several motion conditions, particularly upwards movement, downward movement, stopped at the lowest position, and stopped at the highest position, an active equipment is installed at the compensation sheave. The stability of the system using the controller is analyzed at four states: without disturbance and static car, without disturbance and mobile car, including disturbance and static car, and including disturbance and mobile car. The efficiency of the controller used for dampening the vibration of elevator ropes is validated by numerical simulation results.

A discrete model of a rope with bending stiffness or viscous damping

A discrete model of a rope is developed and used to simulate the plane motion of the rope fixed at one end.Actually,two systems are presented,whose members are rigid but non-ideal joints involve elasticity or dissipation.The dissipation is reflected simply by viscous damping model, whereas the bending stiffness conception is based on the classical curvature-bending moment relationship for beams and simple geometrical formulas.Equations of motion are derived and their complexity is discussed from the computational point of view.Since modified extended backward differentiation formulas（MEBDF）of Cash are implemented to solve the resulting initial value problems,the technique scheme is outlined.Numerical experiments are performed and influences of the elasticity and damping on behaviour of the model are analyzed.Basic energy principles are used to verify the obtained results.