Periodic Motion Planning and Control for Double Rotary Pendulum via Virtual Holonomic Constraints

Periodic motion planning for an under-actuated system is rather difficult due to differential dynamic constraints imposed by passive dynamics, and it becomes more difficult for a system with higher underactuation degree, that is with a higher difference between the number of degrees of freedom and the number of independent control inputs. However, from another point of view, these constraints also mean some relation between state variables and could be used in the motion planning.We consider a double rotary pendulum, which has an underactuation degree 2. A novel periodic motion planning is presented based on an optimization search. A necessary condition for existence of the whole periodic trajectory is given because of the higher underactuation degree of the system. Moreover this condition is given to make virtual holonomic constraint(VHC) based control design feasible. Therefore, an initial guess for the optimization of planning a feasible periodic motion is based on this necessary condition. Then, VHCs are used for the system transformation and transverse linearization is used to design a static state feedback controller with periodic matrix function gain. The controller gain is found through another optimization procedure. The effectiveness of initial guess and performance of the closed-loop system are illustrated through numerical simulations.

Cable Harness Assembly Planning in Virtual Environment

Based on the analysis of characteristic of cable harness planning in virtual environment,a discrete control node modeling (DCNM) method of cable harness in virtual environment and the cable harness assembly routing technique based on it are proposed. DCNM converts a cable harness into continuous flexed line segments connected by a series of section center points,and the design can realize cable harness planning through controlling those control nodes. This method of cable harness routing in the virtual environment breaks the status that virtual assembly process planning is just suitable for the rigid components at present,and impulse the virtual assembly process planning to be more practical. Relation algorithms have been verified in a self-developed system named virtual cable harness assembly planning (VCHAP) system,and this VCHAP system has been applied in assembly process planning of aerospace-related products.

基于Virtual-Hub多企业协作生产计划系统仿真研究

提出一种基于Virtual-Hub的多企业协作生产计划系统,并设计开发了支持多企业生产信息共享的Virtual-Hub,采用消息机制快速处理协作企业间的信息传递,屏蔽分布式企业异构系统之间信息共享的复杂性.基于成组技术的先粗后精订单分解方法,提高外部订单分解的效率.以某订单为例,着重就订单分解、企业生产进度更新和子任务实时监控等进行仿真,论证了所提系统和方法的有效性.

Motion Planning for Industrial Robots Based on Task Process Decomposition

The existing research of the industrial robotic motion planning mainly focuses on the trajectory planning and the path planning, which aim at obtaining a minimum-time trajectory and finding an obstacle-free path respectively. In the trajectory planning, the jerks of robotic joints are usually not considered, so the smoothness of the robotic motion cannot be ensured. In the path planning, the complex spatial curves generally cannot be tracked easily, and it needs the fussy teach-and-playback operation. In this paper, based on the different constraint characteristic of the variable motion phases in the practical robotic task, the complicated task is decomposed into two kinds of sub processes, which are the free motion process and the constrained motion process. In the free motion process, the kinematic models of quasi trapezoidal waveform and quasi triangular waveform are proposed with the dynamic limits of maximum velocities, accelerations and jerks of robotic joints, so the minimum-time trajectory can be obtained with the motion smoothness. In the constrained motion process, the mathematical presentation of the task paths is extracted from the CAD models of the workpieces, so the complex spatial curves can be tracked autonomously without much teaching operation. In addition to the theoretical research, a robotic virtual prototyping system is also developed for the industrial arc welding production. The proposed research ensures the robotic motion smoothness, enhances the ability for tracking the complex spatial curves, and improves the quality and efficiency of the robotic motion planning.

Virtual Facilit Layout Design Using Virtual Reality Techniques

Manufacturing facility layout design has long been recognized as one of the most critical and difficult design tasks in manufacturing industries. Traditional layout methods can not fully solve this complex spatial layout problem. Virtual reality (VR) is a new form of human\|computer interaction, which has the potential to support a range of engineering applications. This paper discusses the reasons why manufacturing facility layout design is considered to be an appropriate new area of VR utilization. A VR\|based layout design framework is proposed. The virtual environment construction issues are discussed. An example of the immersive VR application of facility layout is examined.

Research on Biologically Inspired Hexapod Robot's Gait and Path Planning

Realistically there are many robot joints in the biologically inspired hexapod robot, so they will generate many complexities in the calculations of the gait and the path planning and the control variables. The software Solidworks and MSC. ADAMS are adopted to simulate and analyze the prototype model of the robot. By the simulations used in our design, the applicability of the tripod gait is validated, and the scheme which uses cubic spline curve as the endpoint of foot＇s path is feasible. The principles, methods, and processes of the simulation of hexapod robot are illustrated. A methodology is proposed to get the robot inverse solution in ADAMS, and to simplify the theoretical calculation, and further more to improve the efficiency of the design.

Gait planning and intelligent control for a quadruped robot

We present a method for designing free gaits for a structurally symmetrical quadruped robot capable of performing statically stable, omnidirectional walking on irregular terrain. The robot＇s virtual model is constructed and a control algorithm is proposed by applying virtual components at some strategic locations. The deliberative-based controller can generate flexible sequences of leg transferences while maintaining walking speed, and choose optimum foothold for moving leg based on integration data of exteroceptive terrain profile. Simulation results are presented to show the gait＇s efficiency and system＇s stability in adapting to an uncertain terrain.

基于虚拟仿真技术的会展策划与管理专业人才培养方案优化研究

紧盯国家战略、数字经济发展和产业转型升级需求,融合新的《职业教育专业目录》规定,服务新时代复合型技术技能人才培养,服务“双师型”教师队伍建设,将科技引领、虚实结合融入会展专业人才培养,推进会展专业教师、教材、教法改革。将虚拟仿真技术融入课程资源和活页式教材编写,提升教师的数字素养,结合数字会展资源和虚拟仿真技术开展混合式教学,重构实训实践教学内容,开展新技术赋能下的职业教育教学改革。

基于虚拟空间三维体素—语义地图的机械臂任务规划

任务规划算法是机械臂在未知环境下具备抓取能力的基础,为此提出一种基于三维体素—语义地图的机械臂虚拟空间任务规划方法。在获取完整点云场景的基础上,利用基于掩码区域的卷积神经网络实现目标检测与实例分割,构建由三维点云、语义信息、三维计算机辅助设计模型组成的体素-语义混合地图;优化A*算法完成机械臂末端执行器最优路径规划,利用贝塞尔曲线完成轨迹优化;探究抓取不同几何体时的机械臂末端位姿,分解抓取、放置等复杂任务,形成基于语义驱动的空间任务规划。在虚拟空间通过仿真试验,表明了所提算法的有效性和快速性,同时该算法可支撑机械臂执行各种复杂的抓取任务,并提升机械臂的智能水平。

面向智能航行避碰决策与规划的虚拟仿真测试技术研究

研究了面向智能航行避碰决策与规划的虚拟仿真测试技术。介绍了智能航行在货运船舶中的应用需求,分析了当下避碰决策策略、路径规划算法以及避碰决策与规划测试技术的研究现状。面向货运船舶智能航行避碰决策与规划能力,基于避碰规则中的会遇态势划分,结合四元船舶领域和贝塞尔曲线插值理论,提出了一种智能航行避碰决策与规划算法。构建了一种基于虚拟仿真环境的避碰决策与规划算法仿真测试方法,通过AIS(automatic identification system)模拟器模拟目标船的状态数据,结合船载综合导航系统(integrated navigation system,INS)实现了避碰决策与规划算法的测试。通过复杂水域仿真测试验证了所提算法的有效性和可行性,为货运船舶智能航行功能的开发与实践提供了参考。

改进人工势场算法的路径规划

人工势场法是一种适用于局部路径规划的算法,针对人工势场法存在的目标不可达、局部极小值等固有缺陷,提出了一种改进后的人工势场法。首先针对目标不可达问题,将引力影响因子添加到斥力场的生成中,改进斥力场函数,从而避免引力与斥力合力为零的情况。针对局部极小值问题,通过设立虚拟目标点来引入额外外力,打破机器人的平衡问题。通过与其他算法的对比实验,仿真结果显示,改进人工势场法规划的路径长度和消耗时间都更短,稳定性更强。

Application of Virtual Reality Technology in Aerospace

As a new support platform of information technology for social development, virtual reality technology(VRT) has been widely used in many fields. Here, the concept and important features of VRT are summarized first. Then, the analysis requirement for VRT in design, display, operation and maintenance training, and state monitoring for aerospace products is elaborated. This is followed with a review of foreign and domestic policy planning of VRT, and their application in aerospace. Last, future development of VRT is discussed.

基于虚拟现实的火星车路径规划方法

火星表面巡视探测具有环境复杂、资源受限等特点,火星车自主避障路径规划是在火星车运动能力约束下,综合安全性和效率,规划能够安全抵达目标位置的最优路径,对开展火星探测具有重要意义。针对火星车路径规划问题,提出一种基于虚拟现实技术的火星车路径规划方法。首先,在分析火星数字高程模型(DEM)数据、坡度处数据、粗糙度数据和阶梯地形数据的基础上,建立火星环境危险度地图;其次,设计集成危险度函数的改进A*算法,在虚拟现实开发引擎Unity3D中开发火星车路径规划系统;最后,对路径规划算法进行仿真验证。实验结果表明,与传统A*算法相比,改进A*算法的危险度显著降低,有效提高了火星车行驶的安全性,验证了虚拟现实技术在火星车路径规划的可行性。

基于人工磁场的防疫机器人路径规划

针对传统人工势场法在防疫机器人路径规划过程中容易陷入局部极小值和目标不可达的问题,提出一种基于人工磁场的路径规划算法。首先,对障碍物周围建立人工磁场,引入洛伦兹力,洛伦兹力与引力保持垂直,避免机器人陷入局部极小值点;其次,在洛伦兹力函数中引入机器人与目标点的距离影响因子,解决目标不可达问题;再次,通过建立目标点与障碍物之间的虚拟直线优化洛伦兹力的方向,避免迂回路径,减少路径规划的步数。最后,在MATLAB环境下对传统人工势场法和人工磁场法进行了仿真实验,实验结果表明,人工磁场法可以克服局部极小值和目标不可达问题,规划的路径对障碍物进行了避障,避免了徘徊振荡的情况出现,提高了路径规划的质量。

Effective Virtual Reality Based Building Navigation Using Dynamic Loading and Path Optimization

Although computer capabilities have been improved significantly, a large-scale virtual reality （VR） system demands much more in terms of memory and computation than the current computer systems can offer. This paper discusses two important issues related to VR performance and applications in building navigation. These are dynamic loading of models based on cell segmentation for the optimal VR operation, and the route optimization based on path planning for easy navigation. The VR model of engineering and information technology complex （EITC） building at the University of Manitoba is built as an example to show the feasibility of the proposed methods. The reality, enhanced by three-dimensional （3D） real-time interactivity and visualization, leads navigators into a state of the virtual building immersion.

煤矿井下掘进机器人路径规划方法研究

针对煤矿非全断面巷道条件下掘进机器人移机难度大、效率低下等问题,分析了煤矿井下非结构化环境特征及掘进机器人运动特性,提出了基于深度强化学习的掘进机器人机身路径规划方法。利用深度相机将巷道环境实时重建,在虚拟环境中建立掘进机器人与巷道环境的碰撞检测模型,并使用层次包围盒法进行虚拟环境碰撞检测,形成巷道边界受限下的避障策略。考虑到掘进机器人形体大小且路径规划过程目标单一,在传统SAC算法的基础上引入后见经验回放技术,提出HER-SAC算法,该算法通过环境初始目标得到的轨迹扩展目标子集,以增加训练样本、提高训练速度。在此基础上,基于奖惩机制建立智能体,根据掘进机器人运动特性定义其状态空间与动作空间,在同一场景下分别使用3种算法对智能体进行训练,综合平均奖励值、最高奖励值、达到最高奖励值的步数以及鲁棒性4项性能指标进行对比分析。为进一步验证所提方法的可靠性,采用虚实结合的方式,通过调整目标位置设置2种实验场景进行掘进机器人的路径规划,并将传统SAC算法和HER-SAC算法的路径结果进行对比。结果表明:相较于PPO算法和SAC算法,HER-SAC算法收敛速度更快、综合性能达到最优;在2种实验场景下,HER-SAC算法相比传统SAC算法规划出的路径更加平滑、路径长度更短、路径终点与目标位置的误差在3.53 cm以内,能够有效地完成移机路径规划任务。该方法为煤矿掘进机器人的自主移机控制奠定了理论基础,为煤矿掘进设备自动化提供了新方法。

面向电量-调频-容量市场的数据中心园区算力及电力资源规划

数据中心广泛建设是智能时代的发展趋势。如何在保证数据中心服务质量的前提下,考虑数据中心负荷转移特性,并对其进行合理规划,对降低数据中心规划总成本及提升新型电力系统灵活性均有显著意义。为此,提出一种考虑多元电力市场引导下的数据中心园区算力及电力资源优化规划方法。首先,通过多面体定界收缩法建立虚拟发电机和虚拟储能模型,描述数据中心园区的聚合可调特性。然后,根据不同电力市场的结算规则,研究了数据中心园区参与电量-调频-容量市场的方式和经济收益。在此基础上,以综合成本最小化为目标,优化数据中心园区发电机、储能的建设容量以及服务器的建设数量。最后,以阿里巴巴公开运行数据为例,证明考虑多元电力市场能够大大降低数据中心规划成本,激励数据中心园区投资建设更多灵活性资源,为电网提供有效的调频服务和容量支撑。

虚实坐标智能匹配与自适应三维轨迹规划

针对数字孪生增材修复任务中,物件仿真与真实坐标对应困难、三维轨迹误差较大的问题,提出虚实坐标智能匹配与自适应三维轨迹规划方法。采用图像分割方法获取实际场景下物件的分割图像,通过最小外接矩形预估物件真实坐标,仿真端据此执行旋转与平移操作,调整仿真物件的模型位置,实现坐标智能匹配;为最小化虚实坐标误差,设计基于Attention的多尺度残差UNet图像分割模型,利用多尺度残差模块获取物件多尺度特征,通过Attention策略增强网络对位置信息的描述。三维轨迹规划部分,设计融合特征高度的自适应分层算法,减少分层高度偏移,缩减阶梯误差;根据分层结果进行轮廓提取、填充,生成三维轨迹。结果表明,坐标匹配误差小于1mm,三维修复轨迹规划质量较高。

虚拟荔枝果园建模与采摘行为仿真研究

随着5G技术的发展和应用,基于数字孪生技术的虚拟果园成为智慧果园管理的新模式。为此,基于物联网数据信息采集,提出了一种虚拟荔枝果园模型构建及采摘行为仿真平台构建方法。首先,分析了荔枝果园的组成要素,并使用3dmax、SolidWorks等工具进行了单元模型构建,运用面向对象技术搭建了荔枝果园虚拟场景平台。基于虚拟仿真软件Unity3D,综合三维建模软件与脚本代码,搭建了采摘机器人采摘试验平台,实现了采摘机器人路径规划仿真,并研发了虚拟荔枝果园三维全景虚拟漫游系统。通过虚拟实验平台设置不同的采摘场景,仿真分析获取优化的采摘决策,可预测采摘机器人的真实作业性能,降低采收作业成本。