Abstract
The three-dimensional (3D) geometric evaluation of large thermal forging parts online is critical to quality control and energy conservation. However, this online 3D measurement task is extremely challenging for commercially available 3D sensors because of the enormous amount of heat radiation and complexity of the online environment. To this end, an automatic and accurate 3D shape measurement system integrated with a fringe projection-based 3D scanner and an industrial robot is presented. To resist thermal radiation, a double filter set and an intelligent temperature control loop are employed in the system. In addition, a time-division-multiplexing trigger is implemented in the system to accelerate pattern projection and capture, and an improved multi-frequency phase-shifting method is proposed to reduce the number of patterns required for 3D reconstruction. Thus, the 3D measurement efficiency is drastically improved and the exposure to the thermal environment is reduced. To perform data alignment in a complex online environment, a view integration method is used in the system to align non-overlapping 3D data from different views based on the repeatability of the robot motion. Meanwhile, a robust 3D registration algorithm is used to align 3D data accurately in the presence of irrelevant background data. These components and algorithms were evaluated by experiments. The system was deployed in a forging factory on a production line and performed a stable online 3D quality inspection for thermal axles.
Highlights
As robot technology develops, robots replace labor in more and more fields [1]
In an automated forging factory, the first products of a new mold must be inspected to determine if the mold is suitable for mass production
Until the inspection is finished and a report is made, the line must keep the power on standby to avoid out-of-tolerance mass production
Summary
Robots replace labor in more and more fields [1]. An ever-growing number of forging tasks are performed automatically by robots. To obtain more accurate data, Liu et al adopted a high lumen projector [6,7] and line laser array [8] in a system for the triangulation-based measurement of large hot cylindrical forgings. In 2015, Zhao et al [11] used a blue sinusoidal structured light sensor to measure high-temperature objects in 3D, and obtained the dense point cloud data of a small forging part from a fixed view In their system, optical and digital filters were applied to prevent the influence of visible radiation. Irrelevant background data are inevitable in online environments; for example, it may come from the transferring line or the gripper, which support the parts being inspected To this end, an automatic and accurate 3D shape measurement system with heat and radiation resistance is presented. The system was deployed in a forging factory on a production line and was shown to perform stable online 3D quality inspection for thermal axles
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
