Determination of the dynamic characteristics of locomotive drive systems under re-adhesion conditions using wheel slip controller

To investigate the re-adhesion and dynamic characteristics of the locomotive drive system with wheel slip controller,a co-simulation model of the train system was established by SIMPACK and MATLAB/SIMULINK.The uniform running and starting conditions were considered,and the influence of structural stiffness of the drive system and the wheel slip controller on the re-adhesion and acceleration performance of the locomotive was investigated.The simulation results demonstrated that the stick-slip vibration is more likely to occur in locomotives with smaller structural stiffnesses during adhesion reduction and recovery processes.There are many frequency components in the vibration acceleration spectrum of the drive system,because the longitudinal and rotational vibrations of the wheelset are coupled by the wheel‒rail tangential force when stick-slip vibration occurs.In general,increasing the structural stiffness of the drive system and reducing the input energy in time are effective measures to suppress stick-slip vibration.It should also be noted that inappropriate matching of the wheel slip controller and drive system parameters may lead to electro-mechanical coupling vibration of the drive system,resulting in traction force fluctuation and poor acceleration performance.

足式机器人SLIP模型向上跳跃台阶的运动控制

由于存在地势起伏,台阶对足式机器人运动稳定性会带来较大挑战.弹簧负载倒立摆模型(SLIP)作为研究足式机器人的优良模板,能否完成向上跳跃台阶的动作与其腿部摆角,起跳位置和跳跃高度都有密切的关系.由于调整模型腿部摆角规律容易引发运动失效,故本文在算法中引入虚拟弹簧腿,根据虚拟弹簧腿的运行规律确定合理起跳位置,根据起跳位置来控制系统跳跃高度进而完成跳跃台阶的动作.最后利用仿真软件进行多组仿真,结果表明本文算法对起跳区间划分合理,对起跳高度控制精准,能够实现SLIP模型跳跃台阶前后的稳定运动.

Research on control technology of elderly-assistant & walking-assistant robot based on tactile-slip sensation

In this paper,according to the old people's physical characteristics and their technical requirements for comfort and mastery when operating the robot,a control approach driven by tactile and slip senses is investigated to control the elderly-assistant & walking-assistant robot. First,on the basis of the proposed driving control system program of tactile and slip,a detection system of tactile and slip senses are designed. Based on the tactile and slip feature representation and extraction,an improved classification and recognition method is proposed which combines K-nearest neighbor (KNN) algorithm and K-means algorithm. And then,a robot control system based on TMS320F2812 is designed in this paper,including its hardware and software design. Then,a moving control method including the fuzzy adaptive control algorithm is presented for the walking-assistant robot to realize some different moving properties. At last,by the experimental verification in the walking-assistant robot,the research results show that the tactile and slip senses detection and recognition method is effective,and the whole control system has good feasibility and adaptability.

Neural Network-Based Adaptive Motion Control for a Mobile Robot with Unknown Longitudinal Slipping

When the mobile robot performs certain motion tasks in complex environment, wheel slipping inevitably occurs due to the wet or icy road and other reasons, thus directly influences the motion control accuracy. To address unknown wheel longitudinal slipping problem for mobile robot, a RBF neural network approach based on whole model approximation is presented. The real-time data acquisition of inertial measure unit(IMU), encoders and other sensors is employed to get the mobile robot’s position and orientation in the movement, which is applied to compensate the unknown bounds of the longitudinal slipping using the adaptive technique. Both the simulation and experimental results prove that the control scheme possesses good practical performance and realize the motion control with unknown longitudinal slipping.

Longitudinal and lateral slip control of autonomous wheeled mobile robot for trajectory tracking

研究目的:轮式机器人广泛应用于自主移动机器人研究。已有文献大多数将机器人抽象成具备非完整约束的机械模型,这一假设条件仅在机器人低速运动时成立。本文考虑四轮机器人,同时考虑其纵向和侧向滑动控制,与实际情况更贴近。创新要点:针对轮式移动机器人模型,同时考虑纵向和侧向滑动分量。研究方法:设计纵向滑行控制策略(图1)。改变自然频率(图4)、阻尼和质量(图5)、轮子半径(图6)分别测试控制器响应,最终获取最优控制参数(表2)。重要结论:仿真结果验证所提控制策略的有效性。通过测试选择合适参数使控制器实现快速平滑响应。所设计的控制器对轮子滑动扰动不作限制性假设,即可实现误差指数收敛。

Slip Suppression of Electric Vehicles Using Sliding Mode Control Method

This paper presents a slip suppression controller using sliding mode control method for electric vehicles which aims to improve the control performance and the energy conservation by controlling the slip ratio of wheel. In this method, a robust sliding mode controller against the model uncertainties is designed to obtain the maximum driving force by suppressing the slip ratio. The numerical simulations for one wheel model under variations in mass of vehicle and road condition are performed and demonstrated to show the effectiveness of the proposed method.

An ARX-Based PID-Sliding Mode Control on Velocity Tracking Control of a Stick-Slip Pi-ezoelectric-Driven Actuator

Piezoelectric-driven stick slip actuators have been drawn more and more attention in the nano- positioning application due to the high accuracy and theoretical unlimited displacement. However, the hysteresis of piezoelectric actuator (PEA) and the nonlinear friction force between the end- effector and the stage make control of piezoelectric-driven stick slip actuator challenge. This paper presents the development of an autoregressive exogenous (ARX)-based proportional-integral-derive (PID)-sliding mode control (SMC) for the velocity tracking control of the piezoelectric-driven stick slip actuator. Stability is guaranteed by rigorously choosing the appropriate PID parameters and the zero steady state error is achieved. To verify the effectiveness of the proposed method, experiments were carried out on a commercially-available piezoelectric-driven stick slip actuator. The tracking errors were compared with the traditional PID controller, illustrating that in spite of existing of modeling error, the ARX-based PID-SMC is able to better improve the velocity tracking performance of piezoelectric-driven stick slip actuator, compared with the traditional PID controller.

Re-adhesion control strategy based on the optimal slip velocity seeking method

In the railway industry, re-adhesion control plays an important role in attenuating the slip occurrence due to the low adhesion condition in the wheel-rail inter- action. Braking and traction forces depend on the normal force and adhesion coefficient at the wheel-rail contact area. Due to the restrictions on controlling normal force, the only way to increase the tractive or braking effect is to maximize the adhesion coefficient. Through efficient uti- lization of adhesion, it is also possible to avoid wheel-rail wear and minimize the energy consumption. The adhesion between wheel and rail is a highly nonlinear function of many parameters like environmental conditions, railway vehicle speed and slip velocity. To estimate these unknown parameters accurately is a very hard and competitive challenge. The robust adaptive control strategy presented in this paper is not only able to suppress the wheel slip in time, but also maximize the adhesion utilization perfor- mance after re-adhesion process even if the wheel-rail contact mechanism exhibits significant adhesion uncer- tainties and/or nonlinearities. Using an optimal slip velocity seeking algorithm, the proposed strategy provides a satisfactory slip velocity tracking ability, which was demonstrated able to realize the desired slip velocity without experiencing any instability problem. The control torque of the traction motor was regulated continuously to drive the railway vehicle in the neighborhood of the opti- mal adhesion point and guarantee the best traction capacity after re-adhesion process by making the railway vehicle operate away from the unstable region. The results obtained from the adaptive approach based on the second- order sliding mode observer have been confirmed through theoretical analysis and numerical simulation conducted in MATLAB and Simulink with a full traction model under various wheel-rail conditions.

Observer-based State Feedback Control to Suppress Stick-slip Vibrations in Oil Well Drill-string

In drilling field, stick-slip vibrations of the drill-string are the main reason for the failure of the drilling system. To suppress the undesired stick-slip vibrations, an observer-based state feedback control method is proposed. The drilling system is described by a lumped parameter model including a Karnopp friction torque model. A state observer is designed to estimate the bit velocity in bottom hole and a state feedback controller is proposed to control the top drive velocity. By simulation, the performance of the control algorithm is demonstrated. Based on the control algorithm, a stick-slip vibration control system is developed. Test results show that the control system can effectively eliminate stick-slip vibrations of the drill-string and can be applied to the drilling field.

塔里木盆地超深层走滑断控油气藏研究进展与趋势

在塔里木盆地开辟了超深层走滑断控油气藏勘探开发领域,但断控油气藏极为复杂,难以效益开发,亟需加强油气藏基础地质研究。走滑断控油气藏具有非均质性强、储集层与流体分布复杂、油气产量变化大及采收率低的共性,不同地区走滑断控油气藏的断裂、储集层、成藏与流体存在较大的差异,面临一系列勘探开发难题。建立了差异成因的走滑断裂破碎带及其控储模型,揭示了沿走滑断裂带“相-断-溶”三元复合控储、连片差异规模发育的成储机制;构建了“源-断-储-盖”四元耦合成藏、“小藏大田”的走滑断控油藏模型,揭示了超深层走滑断控油藏的形成与保存机理。突破了克拉通盆地弱走滑断裂难以形成走滑断控大规模储集层与大油气田的理论认识局限,明确了克拉通盆地走滑断裂系统大规模发育的成因机制、走滑断裂破碎带差异成储成藏机理与油气富集规律。

汽车电子机械制动系统的ABS自抗扰控制

为解决传统车辆液压制动系统响应滞后、ABS存在滑移率非线性等问题,设计了一种“行星齿轮减速机构+滚珠丝杠+活塞”的电子机械制动执行器方案,提出一种基于滑移率的ABS自抗扰控制策略,使电子机械制动系统能够快速、准确地调节各个车轮的制动力,有效满足ABS的要求。运用Matlab/Simulink验证执行器的响应性能,分别在2种路面工况下进行ABS制动过程的仿真。研究结果表明:自抗扰控制对于系统内外部扰动具有较强的鲁棒性,能保证车辆的前、后轮滑移率更快稳定在目标滑移率处,有效减少了车辆的制动时间与制动距离。

新疆克拉玛依乌尔禾张扭性走滑断裂特征及其控藏作用研究

乌尔禾沥青矿断裂带位于准噶尔盆地西北缘乌夏断裂带乌尔禾鼻隆之上,是一个小型左旋走滑断裂带。断裂带形成后未发生强烈改造,断裂带内发育沥青矿脉,露头地质条件好,且有三维地震覆盖,是研究走滑断裂特征和控藏作用的天然实验室。本文采用无人机三维立体建模技术,结合野外剖面实测,对乌尔禾沥青矿走滑断裂带野外剖面露头进行定量分析和解剖。结果表明,沥青矿断裂带共发育17条断层,主断层西北侧断层呈雁列状分布,东南侧断层呈马尾状,断裂带纵向呈负花状。研究表明,断层形成于燕山期左旋剪切应力场,受拉张应力影响,整体处于张扭环境,形成张扭性走滑断裂带。断层发育空腔和诱导裂缝,尤其主动盘裂缝更为发育,空腔的开度与油气侵染宽度呈正相关。结合塔里木盆地张扭性走滑断裂与油气藏关系分析,本文认为张扭性走滑断裂是良好的垂向油气运移通道,主动盘具有侧向输导作用,被动盘具有封堵作用,走滑断裂主动盘一侧圈闭是良好的油气聚集区域。

轮毂式电动汽车电子差速复合控制方法

为实现轮毂式电动汽车在弯道的稳定转向,解决传统控制方法对汽车行驶速度的局限性,提出一种高-低速复合电子差速控制方法。当汽车处于低速行驶状态时,根据Ackermann转向模型获取驱动轮期望转速,提出一种模糊PID控制方法,实现轮速的稳定跟踪;当汽车处于高速行驶状态时,以驱动轮的相对滑移率作为反馈控制量,提出一种基于模糊逼近的滑移率优化控制方法,无需建立精确的系统状态空间模型,同时根据LQR理论保证了汽车驱动轮相对滑移率最小。Matlab/Carsim联合仿真证明,所提出的高-低速复合控制方法能够使汽车在不同行驶速度下实现稳定转向。

深部矿井软底回采巷道底鼓机理及防治研究

针对山阳煤矿软底回采巷道严重底鼓的难题,采用理论分析、数值模拟和现场应用的方法,基于塑性理论建立了巷道底板岩体滑移线底鼓力学模型。研究表明,巷道底板破坏岩体主要分为3个区,分别为主动极限区、过渡区和被动极限区,推导了巷道底板岩体的最大破坏深度,提出了锚索+卸压槽联合控制底鼓的方法。采用数值模拟的方法验证了联合控制方案的可行性,现场应用效果表明该方法能够有效控制软底巷道底鼓,为相似地质条件底鼓问题的研究提供了一定的帮助。

塔里木盆地顺北1号断裂带奥陶系碳酸盐岩储层结构表征及三维地质建模

综合利用地震、测井、岩心以及动态生产资料,对塔里木盆地顺北1号断裂带断控型碳酸盐岩储集体的内部结构进行了层级划分;基于层级划分,通过地震资料属性提取与转换、深度学习、基于目标示性点过程模拟以及离散裂缝网络模拟(DFN)等方法建立了三维地质模型,并以模型进行油气储量和油藏数值模拟,将拟合结果与实际生产数据进行对比。研究结果表明:(1)顺北1号断裂带奥陶系断控型储层按层级由大到小分为走滑断裂影响带、断控体、类洞穴、类洞穴内簇充填和裂缝带共5个层级。(2)走滑断裂影响带受应力差异影响具有分段性,可细分为挤压段、拉分段和平移段;断控体在拉分段发育断裂交会型、单支走滑型,在平移段发育双断裂交错型和两断裂交会型,在挤压段发育双断裂扭曲型和双断裂交会型,共有6种平面组合样式;类洞穴在地震剖面上呈串珠状反射特征;类洞穴内部分为栅体与栅间(基岩),其中栅体又可进一步分为簇(角砾带)、簇间(裂缝带),整体表现为栅状结构,簇的物性更好;裂缝带为类洞穴的主要储集空间,在簇内部比簇间更发育,在一间房组比鹰山组更发育,一间房组和鹰山组均以发育高角度裂缝为主,在两者连接处则以发育水平缝为主。(3)地质模型预测的油气储量与地质分析储量误差为1.75%,模型模拟的生产井地层压力及累产液结果与生产动态吻合度较高,拟合误差小于10%。

双层滑带滑坡土环剪试验与稳定性分析

以云南省文山至麻栗坡高速公路K39段复合型双层滑带滑坡为例,采用室内环剪试验探明该滑坡深层、浅层滑带各自的残余强度,分析不同含水率、法向应力和剪切速率对滑带土残余强度的影响;采用FLAC3D软件进行数值模拟,基于滑坡应力-应变历史对滑坡稳定性进行评价。结果表明:滑带土在低含水率情况下力学强度较高,饱和状态抗剪强度参数表现出明显的衰减趋势;在地下水位保持高位时,深层滑带更易发生渐进式蠕动滑移。模拟结果显示:滑坡的深层滑带应力集中现象较为显著,浅层滑坡危险性较小,滑坡在暴雨工况下整体稳定性明显降低,存在一定风险,可通过设置排水洞等降水措施进行治理。

车轮打滑对2万吨重载列车纵向冲动影响分析

针对低黏着接触条件下车轮滑行所引起的列车纵向冲动问题,文章建立了“1+1”编组2万吨重载列车-轨道垂纵耦合动力学模型,对比分析电制动工况下不同轮轨接触状态对2万吨列车纵向冲动的影响,分别计算了车轮发生滑行位置和电制动力载荷大小对纵向冲动的影响规律。结果表明,在电制动运行工况下,当列车施加100%电制动力时,列车在湿润、油污和冰雪接触条件下均检测到了车轮滑行,在25%~75%电制动工况下列车仅在冰雪接触条件下检测到了车轮滑行;车轮滑行导致了车钩力的波动,特别是中部机车发生车轮滑行时会引起其前、中、后部车钩力较大幅度波动,并增大中部机车前部车辆压钩力,严重影响列车的平稳运行;随着制动力的降低,低黏着接触状态下的车轮滑行对最大车钩力的影响明显减小。

基于变量马达控制的喷雾机驱动防滑系统设计与试验

高地隙自走式喷雾机因其作业环境复杂易产生车轮滑转,影响静液压驱动系统流量及压力稳定性,严重时导致整机失去通过性能,故须进行防滑控制,保证其具备驱动稳定性和脱困能力。本文提出一种高地隙自走式喷雾机静液压驱动系统防滑控制方法,采用双线性模型定义滑转率与附着系数之间的关系,设计了滑模控制器,并通过田间非道路试验验证了驱动防滑系统的控制性能。试验结果表明,该系统可将喷雾机滑转率控制在0.15以内。在起步加速与匀速工况下,喷雾机滑转率均值为0.020和0.019;在越沟工况下,可2 s内实现整机快速脱困。以上结果验证了所设计的喷雾机滑模驱动防滑系统具有良好的防滑性能,能够保证喷雾机在典型工况下平稳行驶,有效减少了地面不利条件对整机行驶稳定性的影响。

露天地下楔形转接过渡诱导冒落控制边坡岩移危害技术研究

露天地下楔形转接过渡模式的安全管控是利用崩落法开采挂帮矿形成的塌陷坑阻止边坡岩移威胁露天采场,但地采扰动下的高陡边坡破坏过程不易控制,因而制约了楔形转接过渡模式在大型深凹露天矿山中的应用。针对上述问题,结合极限平衡分析方法,揭示出崩落法开采扰动下的高陡边坡渐进破坏规律,提出了边坡滑移体体积计算方法,以及通过调控回采顺序控制边坡滑移进程以实现塌陷坑完全承接边坡滑移体的边坡岩移危害控制技术。研究表明:边坡岩体不会随挂帮矿向下开采而发生持续破坏,只有当挂帮矿开采至关键分段时,边坡岩体受力状态超过极限平衡状态才发生滑移破坏,可通过滞后回采关键分段上盘三角矿延缓边坡滑移,以及通过滞后回采关键分段下盘矿体和采用下向阶梯状回采工作面增大塌陷坑容积,最终实现塌陷坑有序承接边坡滑移体。研究成果完善了大型深凹露天矿楔形转接过渡的安全管控方法,提高了楔形转接过渡模式的适用性。

温州瓯江北口大桥施工期索夹抗滑移控制

温州瓯江北口大桥为主跨2×800 m的三塔四跨双层钢桁梁悬索桥,主跨钢桁梁采用1000 t缆载吊机大节段吊装,施工期索夹受力大、索夹螺杆紧固力损失大,索夹滑移风险高。为给施工期索夹滑移风险评估和抗滑移控制措施提供依据,在《公路悬索桥设计规范》(JTG/T D65-05—2015)索夹抗滑移系数计算公式的基础上,考虑索夹上临时荷载、主缆轴力增加引起的主缆直径变小和主缆丝股重新排列、螺杆时变效应造成的索夹螺杆紧固力损失,提出适用于大跨悬索桥施工期的索夹抗滑移系数计算方法,分析主要参数对施工期索夹抗滑移系数的影响,并评估该桥施工期索夹抗滑移风险,提出索夹抗滑移控制措施。结果表明:钢桁梁吊装过程中,索夹倾角变化大,应采用当前施工阶段索夹倾角计算施工期索夹抗滑移系数,主缆轴力增加引起主缆直径变小是造成索夹滑移的主要原因之一;该桥除主跨跨中钢桁梁节段对应索夹抗滑移系数满足规范要求外,其余索夹抗滑移系数均不满足规范要求。根据索夹滑移风险评估结果,采取紧固索夹螺杆的抗滑移控制措施,并明确了该桥索夹螺杆紧固次数和时机。该桥采取索夹抗滑移控制措施后,施工过程中索夹均未出现滑移现象。