Robot Workspace Reconstructing Solving Method Based on Image Engine
Research and application of spatial multi-joint robot become hot point in recent years. In this paper, a practical arc welding robot produced by ABB is selected as research subject, separate essential structural parameters of it, establish coordinate frame of link as well as D-H parameter list, analyze its forward kinematics and get position vector of the end-effector. Then, visual model is created to checkout rationality of the forward kinematics analysis. Finally, workspace reconstruction based on DirectX is raised. When researchers compare robot workspace simulation based on Monte Carlo method with our new method, the latter has the feature of modelling and digitization, which lays a foundation of designing arc welding robot efficiently and steadily.
Conceptual design and workspace analysis of reconfigurable fixturing robots for sheet metal assembly
Purpose – Reconfigurability of the assembly fixtures, which enables a set of sheet metal automotive parts to be produced on a single production line, is becoming crucial to maintaining competitiveness in the rapidly changing market. One of the key issues in reconfigurable fixture design is to identify the fixture configuration and make sure there is enough workspace for a family of parts. The purpose of this paper is to address this issue, through the design and analysis of two novel reconfigurable fixturing robots.Design/methodology/approach – Following an introduction, the application of the reconfigurable fixturing robot addressed in this paper is described; it is characterized by using parallel manipulator as programmable fixture elements. Kinematic design and reconfigurable design of the fixturing robot is presented based on screw theory and modularized design, respectively.Findings – The proposed reconfigurable fixturing robots can transform their configurations with 4 DoF (degrees‐of‐freedom), and ...
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.