Tool frame calibration has been widely used in robot-assisted printing, welding, and grinding, but it is not suitable for ultrasonic testing because the robot is submerged in water. The purpose of this paper is to present a tool frame calibration method, which is suitable for improving the precision of ultrasonic testing. In uniform mediums, sound travels along a straight line like ray. A reflector is fixed in water to reflect ultrasound, which makes it possible to measure distances between incidence points on a reflector and tool center point (TCP) on an ultrasound transducer. In addition, the positions and poses of the end flange are recorded through a robot controller. Finally, an optimization method is applied to calculate the position and pose errors of the tool frame relative to the end flange according to such records. The presented method was implemented in an ultrasonic testing system. We selected 100 incidence points on the reflector to calculate the assembly errors of the transducer. The pulse amplitude rose obviously after calibration, which verifies that this is an effective method. Considering that ultrasonic transducers can be used as a measuring tool, this paper proposes a tool frame calibration method for ultrasonic testing robots without introducing other measuring devices, which draws the conclusion that tool frame can be calibrated through ultrasound.

Diverse model factories have been established in universities and enterprises to support practical education across various fields. Increasingly stringent health and safety regulations have made practical equipment more complex and costlier. With the advancement of digital infrastructure, virtual reality (VR) technology has been widely adopted in education to simulate real-world environments. This study explores the application of VR technology in enhancing manufacturing process education. To achieve this, an interaction methodology based on the OPC UA standard is proposed to enable data exchange between virtual and physical environments. Additionally, a detailed workflow of the practice course, conducted in a physical model factory at North China University of Technology, is presented. This approach is particularly noteworthy because it allows students to validate simulated results using a physical system, rather than relying solely on virtual scenes to mimic real-world settings. Students were divided into two groups: a practice group using the proposed digital method, and a control group without digital tools. The number of mistakes from the practice group was 37% less than that of the control group. Statistical analysis of students’ grades and questionnaire responses concludes that the proposed methodology is valuable to improve students’ engagement and practical skills. The presented course is replicable for other training institutions.

With wide application of new materials, structures, and technologies in modern industry, testing objects were no longer limited to conventional materials and common shapes. Demands of testing new materials and complex shapes bring challenges to researchers in non-destructive testing area. Combining robots, which have been widely used in industry, with the non-destructive testing technology can replace manual operation and improve testing precision. Additionally, the robot-assisted systems can enhance efficiency and safety of the testing process. The researchers have carried out numerous designs and implementations to combine robots with non-destructive testing devices. This article presents four non-destructive testing systems with robot, including single-arm robot holding a transducer, single-arm robot holding a tested part, and twin-arm robot holding two transducers. In conclusion, application scopes are analyzed to help users select appropriate systems according to sizes, materials and defect types.

Before a manipulator begins operation, its initial position needs to be confirmed. The manipulator will work more accurately after eliminating offsets in the initial position. Though some measuring devices have been widely used to calibrate the initial position, they are generally used to measure absolute position and featured with high cost and complex operation. Considering that ultrasonic testing system has measurement capability, we proposed a calibration method based on ultrasonic theory. This method employs relative position to calibrate the initial position of the manipulator, which can avoid complex process in measuring absolute position. According to reflection characteristics existing in ultrasonic theory, we find that the initial position of the manipulator can be calculated according to the relative position and posture between an ultrasonic transducer and a reflective surface. Firstly, D-H parameters are introduced to build kinematic model. Then, the model is rewritten according to Taylor series. The first order of Taylor series is retained to estimate relative relationship between joint angle and spatial position of the end-effector. The positioning error in X, Y and Z direction is increased by 85.8%, 69.2% and 81.4% respectively, demonstrating that this method can calibrate initial position effectively.

In recently years, diverse education platforms have been progressively established across various disciplines to support engineering practice. In addition, the teaching method to improve students’ practical ability is equally important. This paper presents a novel education platform from NCUT (North China University of Technology) and introduces corresponding teaching methods based on the platform to promote the practical ability in engineering students. Taking the manufacturing process of a rotary part as an example, this paper explains the virtual reality integrated method, which is an innovative approach to enhance students’ engagement during the practice sessions. Students are divided into several groups and collaborate to complete the practice. The study concludes that the virtual environment simulated by CAD (computer-aided design) software, serve as an excellent complement to the real-world equipment, enabling students to complete operations repeatedly without the constraints of time and space. The proposed virtual reality integrated education platform and corresponding teaching method significantly enhance students' engagement and practical skills.