Aqua-Vision (An underwater panoramic camera with computer vision and analytics)

In the present social media-bound lifestyle, capturing memories and keeping them accessible is gaining a significant demand globally. For this purpose, a robust, portable camera system for recreational or commercial purposes can be of substantial advantage to society. Aqua-Vision intends to bring an affordable underwater camera system with various innovative features to the hands of consumers. The smart module consists of a waterproof gimbal camera that can be used underwater, providing a hassle-free and reliable user experience and offers rotary motion along two axes. The camera features various general modes like panorama, burst shot, and smart modes using inbuilt computer vision algorithms. The gimbal camera setup can be controlled and switched remotely between all possible modes using a mobile application. All the above features will allow the user to capture photos/videos in any possible setup and use the camera module for various applications. The advent of such innovative, convenient, and robust modules will help cater to the market demands effectively.

Positioning Performance of a Sub-Arc-Second Micro-Drive Rotary System

In the macro/micro dual-drive rotary system, the micro-drive system compensates for the position error of the macro-drive system. To realize the sub-arc-second (i.e., level of 1″–0.1″) positioning of the macro/micro dual-drive rotary system, it is necessary to study the positioning performance of the sub-arc-second micro-drive rotary system. In this paper, we designed a sub-arc-second micro-drive rotary system consisting of a PZT (piezoelectric actuator) and a micro rotary mechanism, and used simulation and experimental methods to study the positioning performance of the system. First, the micro-drive rotary system was developed to provide ultra-precise rotary motion. In this system, the PZT has ultrahigh resolution at a level of 0.1 nanometers in linear motion; a micro rotating mechanism was designed according to the composite motion principle of the flexible hinge, which could transform the linear motion of piezoelectric ceramics into rotating motion accurately. Second, the drive performance was analyzed based on the drive performance experiment. Third, kinematics, simulation, and experiments were carried out to analyze the transformation performance of the system. Finally, the positioning performance equation of the system was established based on the two performance equations, and the maximum rotary displacements and positioning error of the system were calculated. The study results showed that the system can provide precision motion at the sub-arc-second and good linearity of motion. This study has a certain reference value in ultra-precision positioning and micromachining for research on rotary motion systems at the sub-arc-second level.

Failures of Shafts

In addition to failures in shafts, this article discusses failures in connecting rods, which translate rotary motion to linear motion (and conversely), and in piston rods, which translate the action of fluid power to linear motion. It begins by discussing the origins of fracture. Next, the article describes the background information about the shaft used for examination. Then, it focuses on various failures in shafts, namely bending fatigue, torsional fatigue, axial fatigue, contact fatigue, wear, brittle fracture, and ductile fracture. Further, the article discusses the effects of distortion and corrosion on shafts. Finally, it discusses the types of stress raisers and the influence of changes in shaft diameter.

Posterior Temporary C1-2 Pedicle Screws Fixation for the Treatment of Unstable C1-2 Complex Fractures: Minimum of 2-Year Follow-Up

Study Design: Retrospective. Objectives: To present rarely reported complex fractures of the upper cervical spine (C1-C2) and discuss the clinical results of the posterior temporary C1-2 pedicle screws fixation for C1-C2 stabilization. Methods: A total of 19 patients were included in the study (18 males and 1 female). Their age ranged from 23 to 66 years (mean age of 39.6 years). The patients were diagnosed with complex fractures of the atlas and the axis of the upper cervical spine and underwent posterior temporary C1-2 pedicle screws fixation. The patients underwent a serial postoperative clinical examination at approximately 3, 6, 9 months, and annually thereafter. The neck disability index (NDI) and the range of neck rotary motion were used to evaluate the postoperative clinical efficacy of the patients. Results: The average operation time and blood loss were 110 ± 25 min and 50 ± 12 ml, respectively. The mean follow-up was 38 ± 11 months (range 22 to 60 months). The neck rotary motion before removal, immediately after removal, and the last follow-up were 68.7 ± 7.1°, 115.1 ± 11.7°, and 149.3 ± 8.9° ( P < 0.01). The NDI scores before and after the operation were 42.7 ± 4.3, 11.1 ± 4.0 ( P < 0.01), and the NDI score 2 days after the internal fixation was removed was 7.3 ± 2.9, which was better than immediately after the operation ( P < 0.01), and 2 years after the internal fixation was removed. The NDI score was 2.0 ± 0.8, which was significantly better than 2 days after the internal fixation was taken out ( P < 0.001). Conclusions: Posterior temporary screw fixation is a good alternative surgical treatment for unstable C1-C2 complex fractures.

Design and Error Compensation Performance of a Precision Micro-Drive Rotary System

In order to obtain motion with large travel and high precision, the micro-drive system is used to compensate for the motion error of the macro-drive system in the macro/micro dual-drive system. The research on the micro-drive rotary system lags behind the micro-drive linear system, so it is of great significance to study the designing and error compensation performance of a precision micro-drive rotary system. In this paper, a precision micro-drive rotary system is designed, the error compensation scheme of the system is proposed, and the system feasibility in design and error compensation is tested by FEM simulation analysis and performance experiments. Firstly, a precision micro-drive rotary system is designed to provide high-precision rotary motion, which consists of a micro rotary mechanism and PZT. In the system, the micro rotary mechanism is developed based on the compound motion principle of flexure hinge, which can accurately transform an input of linear motion into an output of rotary motion according to a certain relationship. Secondly, for finishing the error compensation scheme of the system, the maximum compensation modifier θ max ′ is proposed based on the analysis of error compensation equations of point-to-point motion and continuous motion. Finally, in order to facilitate the use of engineering, the driven voltage equation of error compensation is derived by the error compensation performance experiment. The simulation and experiment results indicate that both the design and error-compensation-range of the system satisfy the needs of practical application.

SYNTHESIS OF A LEVER-CAM MOTION TRANSDUCER FOR A ROTARY VANE PUMP

The article solves problem of synthesizing a lever-cam motion transducer that converts rotary motion of input shaft of a rotary pump into motion of its vanes required for volumetric pumping of gases and liquids. Analytical expressions for theoretical profile of cam of lever-cam transducer of the movement of rotary vane pump are obtained. The cam profile was built according to analytical expressions.

EXPERIMENTAL STUDIES OF BRUSHLESS MAGNETOELECTRIC MOTORS OF THE RETURN-ROTARY MOTION

The paper describes the structure and mathematical model of a specialized brushless magnetoelectric motor of return-rotary motion. The analysis of the parameters of the mathematical model is carried out and the methods of their experimental determination are described. Experimental frequency dependences of the rotor oscillations angle amplitude and the stator current effective value have been obtained. Based on the obtained parameters, the frequency characteristics of the motor were calculated and compared with the experimental dependences. Experimental oscillograms and calculated curves of stator voltages and currents are presented. References 7, figures 8.