基于三坐标测量仪的Stewart平台标定技术

针对空间对接半物理仿真系统中Stewart平台的运动精度问题,提出一种基于三坐标测量仪的低成本标定方法.利用通用的三坐标测量仪获取运动平台的位姿信息,构造一个统一度量的残差方程,辨识出运动平台的几何参数并进行误差补偿.此方法的特点是能够保证所有几何参数的可辨识性,不再需要设计和加工专门用于标定的各种辅助机构和冗余传感器,具有较强的通用性和可操作性.本文阐述了该标定方法的标定过程,对残差方程的构造方式进行了讨论,仿真表明标定后平台的运动精度能够达到测量噪声的量级.最后将此方法用于某实际运动平台的标定,经过误差补偿后其精度提高了5倍以上.     

基于机器视觉的机油冷却管圆度检测与分拣研究

针对机油冷却管生产过程中,管口的圆度误差主要是人工测量导致的,且检测效率低,无法实时检测的问题,基于视觉检测提出一种机油冷却管口圆度检测与分拣方法。构建机器人SR7CL的运动学模型,利用ADAMS和MATLAB对其运动学和动力学进行仿真,验证模型的正确性,以保证抓取的准确性。以机油冷却管为抓取对象,通过自适应阈值分割,突出管口特征;利用Canny算法提取出边缘信息,通过最小二乘法检测圆度误差,并根据圆度误差对冷却管进行分拣。结果表明：所提方法提高了检测的质量和效率,解决了实时性的问题。     

基于Pro/Ewildfire2.0的路面切缝机虚拟样机与运动仿真

介绍了在路面切缝机设计的过程中应用Pro/E wildfire2.0进行零件三维建模、虚拟装配和运动学仿真的一般过程和基本方法.     

Time-optimal trajectories of a rod in the plane subject to velocity constraints

We consider the problem of moving a line segment (a “rod” or “ladder”) in the plane between two given placements when subject to the constraint that no point on the line segment may exceed a given velocity bound. Specifically, we consider those trajectories which minimize the total time between given initial and goal placements, and provide a complete characterization of all solution, together with explicit constructions for each of the various cases encountered. This research was supported by the National Science Foundation under Grant CCR-9207422, and by a grant from the James H. Zumberge Research Innovation Fund. This problem was initially posed in an open problem session of the Second DIMACS Workshop in Computational Geometry, held at Princeton University in October, 1989. A preliminary version of this paper was presented at the 9th Annual ACM Symposium on Computational Geometry [8].     

An equilateral tetrahedral mechanism

Input-output kinematics of a novel, exoskeletal manipulator mechanism has been analysed. The abstract model is two equilateral tetrahedral wire frames which move relatively so that their edges remain in intersecting, parallel or coincident pairs. A mechanical, rigid body model was constructed and a computer animation was performed.     

载体位姿不受控的空间机械臂非完整特性研究

载体位姿不受控的空间机械臂系统,其载体和机械臂之间存在角动量守恒方程约束。由于该约束是非完整约束,所以普通的固定基座机器人运动学理论不能直接用来解决这类空间机械臂系统的运动学问题,基于这类非完整性约束,推出载体位姿不受控空间机械臂的运动学方程,在速度层次上分析这类载体位姿不受控的空间机械臂的运动学问题,并进行由于非完整特性引起载体位姿干扰与奇异问题的仿真研究。     

一种三平移一转动多维激振台关节的分析

为解决基于并联机构中运动副存在间隙而使得激振台在高频激振的情况下运动无法传递的问题,提出了运用柔性万向节代替普通万向节的并联机构激振台。在ADMAS中建立柔性关节激振平台的虚拟样机模型,通过仿真验证并联机构柔性激振台的可行性。并对普通万向节测试其运动输出。     

Forming of cross-profile holes by adding rotations around coplanar axes

This paper presents two methods of forming profile holes, previously drilled in rotational and casing blanks. The methods can be implemented on lathes, milling, drilling and centering machines, etc. Kinematic synthesis of the methods is shown based on the kinematics of a body rotating around coplanar axes. The rational field of application of the methods has been found. Principal diagrams of the devices and tools enabling implementation of the method are shown.     

轴类件柔性辊轧的运动分析

根据几何学原理,推导出轴类件辊轧变形时各变形阶段轧轮的几何参数、运动参数与工件的运动和材料变形之间的关系,分析结果对工艺参数的选择和有限元模拟分析提供了理论基础。     

Comparison of joint angle,velocity and acceleration estimators for hydraulically actuated manipulators to a novel dynamical approach

Excavators are used for a wide range of applications like earthworks and material handling. Assistance systems are becoming more common to support the operator. For monitoring and control based assistance functions the angular position, velocity and acceleration of the joints from the working implement are required. Commercial systems often use inertial measurement units, consisting of triaxial accelerometers and gyroscopes, to accomplish an estimation of those states. A novel joint angle, velocity and acceleration estimation for hydraulic manipulators is proposed and compared to state of the art methods. A decentralized kinematic filter using no information about the underlying system and a centralized kinematic filter taking the system kinematics into account are implemented as state of the art approaches. Both filters only use inertial measurement units to obtain information about the current state of the system. The novel centralized dynamic filter uses the same information as the centralized kinematic filter and extends it by a dynamic model containing additional information about the angular acceleration due to pressure readings of the hydraulic cylinders. Kalman filtering is used to combine the derived system and measurement models with the sensor information. The methods are evaluated on a material handling excavator for single and coupled movements of the working implement. The novel centralized dynamic filter enables improvements for the angular acceleration estimation compared to the decentralized and centralized kinematic filter. Less noise of the acceleration estimation and a better tracking of the actual acceleration are shown.