Recent Patents on Mechanical Engineering - Volume 12, Issue 4, 2019

Background: Modular self-reconfigurable robot is a hot topic in current robotics research, the modular self-reconfigurable robot is composed of several modules with certain autonomous ability and perceptual ability. Through mutual docking and assembly, the overall configuration is changed to achieve different moves and operation functions. Compared with the traditional robot, it has strong adaptability to the environment and the ability to deal with changeable tasks. Objective: The recent modular self-reconfigurable robot is summarized, and its structure, characteristics and development are introduced. Methods: This paper summarizes the patents and research progress of modular self-reconfigurable robot, and introduces the current development of modular self-reconfigurable robot from the aspects of structure features, docking methods, driving types and applications. Results: This paper classifies the structural features, docking methods and driving types of various modular self-reconfigurable robots, summarizes the typical features, and discusses the current and future development of modular self-reconfigurable robots. Conclusion: Modular self-reconfigurable robot is a new subject in the field of robotics research in recent years. Through the docking among a large number of unit modules which changes the overall configuration, extends the motion form and realizes different motion gait, modular self-reconfigurable robot can replace traditional robot to complete the work in a complex environment, which is of great significance to the development of robot. Therefore, more modular self-reconfigurable robot patents should be invented.

Background: In order to increase the accuracy of radiotherapy and to improve the patient's comfort, diverse structures of radiotherapy bed have been designed and improved constantly. Objective: To provide an overview of recent patents about radiotherapy bed and to introduce their characteristics and development. Methods: In this study, various representative patents related to the radiotherapy bed were reviewed. Additionally, the structural characteristics and applications of the typical radiotherapy bed were introduced. Results: The characteristics of different radiotherapy beds were analyzed and concluded. Moreover, the main problems concerning their development were analyzed, and the current and future developments of patents on radiotherapy bed were also discussed. Conclusion: Radiotherapy bed is an important part of radiotherapy system, which also determines the therapeutic outcomes of radiotherapy. Further improvements are required in the aspects of accuracy, comfort, flexibility and result stability of the radiotherapy bed. More invention should be laid on more patents on radiotherapy beds.

Background: The fabrication of microstructures with high machining quality is always difficult when it is concerned with non-conductive hard and brittle materials such as glass and engineering ceramics. It is reported in related papers and patents that Electrochemical Discharge Machining (ECDM) process is a good choice for machining non-conductive, hard and brittle materials. However, the machining performance of ECDM process, especially in the aspect of geometric accuracy and surface quality, needs to be greatly improved. Objective: The purpose of this study was to improve the machining quality of conventional ECDM process by introducing ultrasonic vibration to ECDM process, develop an Ultrasonic Vibration Assisted Micro Electrochemical Discharge Machining (UAECDM) tool, and investigate the improvements of the machining performance by means of comparative experiments. Methods: Firstly, the machining principle of UAECDM was investigated, and the effects of ultrasonic vibration are discussed with the analysis of the micro process. Secondly, the hardware system, which consists of a machine tool body, XY and Z axes, an ultrasonic spindle system and motion control system, was established; and the software system was developed based on the analysis of the overall workflow of the machining process. Finally, comparative experiments, including ECDM drilling, UAECDM drilling, ECDM milling and UAECDM milling, were carried out to reveal the improvements of the machining quality. Results: In the UAECDM group, a micro-hole with the inlet diameter of 133.2μm as well as the 3 x 3 array of micro holes was fabricated on the glass workpiece with 300μm thickness, and a microgroove with the width of 119.2μm was successfully milled on the glass workpiece. It is shown in both microscopic photographs and optical measurements that the microstructures fabricated by UAECDM have better machining quality compared with similar microstructures fabricated by ECDM. Conclusion: Based on comparative experiments and discussions of the results, it has been proved that the machine tool can meet the requirement of the ultrasonic vibration-assisted micro electrochemical discharge machining and can improve the geometric accuracy and surface quality significantly.

Background: Several studies and patents have been carried out on the realization and optimization of structures and structural elements subjected to several-weights-critical-applications. Among the structures optimized in engineering, there are sandwich structures that are mainly used to react under these conditions. Objective: In this article, we have investigated the thermal bending response of simply supported Functionally Graded Sandwich Plate (FGSP). Methods: Using simple Hyperbolic Shear Deformation Theory (HSDT). A type of FGSP with both functionally graded materiel FGM face and ceramic hard core are considered. Based on the principle of virtual work, the governing equations are derived and then these equations are solved via Navier procedure. Analytical solutions are obtained to predict the deflection, axial and shear stress of FGSP. Results: To verify the efficiency of the present method a comparison with existing literature and patents results is employed. The influence of the plate aspect ratio, the relative thickness, the gradient index, the sandwich plate schemes, and the thermal loading conditions on the bending of FGSP are investigated. Conclusion: A good agreement is obtained between present results and the existing literature solutions. It can be concluded that the proposed theory is accurate and simple in solving the thermoelastic bending behavior of functionally graded sandwich plates. Various patents have been discussed.

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

Background: In Shell and Tube Heat Exchanger (STHX), heat is exchanged between hot water (coming from industrial outlet by forced convection) to the cold water. Instead of water, if Nano fluids are used into these tubes, then there is a possibility of improved heat transfer because of high thermal conductivity of the nanofluids. Objective: From many literature and patents, it was clear that the study of STHX using metal oxide nanoparticles is very scarce. Therefore, the objective of the present investigation is to check the thermal performance of STHX operated with zinc oxide nanofluid and compare with water as the base fluid. Methods: Heat transfer analysis of a shell and tube heat exchanger was carried out experimentally using Zinc oxide as a nanofluid. Mass flow rate on tube side was varied while on the shell side it was kept constant. Various heat transfer parameters like heat transfer coefficient, heat transfer rate effectiveness and LMTD (Log Mean Temperature Difference) were studied. The experimental readings were recorded after the steady-state is reached under forced flow conditions. Results: It was found that the effectiveness improves with increase in mass flow rate of nanofluids as compared to base fluid. Conclusion: From the obtained results, it was concluded that heat transfer enhancement and effectiveness improvement does occur with nano fluids but at the cost of pumping power.

Background: Vehicles generally travel on different road conditions, and withstand strong shock and vibration. In order to reduce or isolate the strong shock and vibration, it is necessary to propose and develop a high-performance vehicle suspension system. Objective: This study aims to report a pneumatic artificial muscle bionic kangaroo leg suspension to improve the comfort performance of vehicle suspension system. Methods: In summarizing the existing vehicle suspension systems and analyzing their advantages and disadvantages, this paper introduces a new patent of vehicle suspension system based on the excellent damping and buffering performance of kangaroo leg, A Pneumatic Artificial Muscle Bionic Kangaroo Leg Suspension. According to the biomimetic principle, the pneumatic artificial muscles bionic kangaroo leg suspension with equal bone ratio is constructed on the basis of the kangaroo leg crural index, and two working modes (passive and active modes) are designed for the suspension. Moreover, the working principle of the suspension system is introduced, and the rod system equations for the suspension structure are built up. The characteristic simulation model of this bionic suspension is established in Adams, and the vertical performance is analysed. Results: It is found that the largest deformation happens in the bionic heel spring and the largest angle change occurs in the bionic ankle joint under impulse road excitation, which is similar to the dynamic characteristics of kangaroo leg. Furthermore, the dynamic displacement and the acceleration of the vehicle body are both sharply reduced. Conclusion: The simulation results show that the comfort performance of this bionic suspension is excellent under the impulse road excitation, which indicates the bionic suspension structure is feasible and reasonable to be applied to vehicle suspensions.

Background: Hydraulic quadruped robot is a representative of the redundant transmission. This is a great challenge for multi-joints coordinated movement of the robot, because of the movement coupling with several freedom degrees among kinematic chains. Therefore, there is an urgent need to realize the decoupling among the joints of the hydraulic quadruped robot. Objective: The purpose of this study is to provide an overview of controller design from many studies and patents, and propose a novel controller to realize the decoupling control among joints of a hydraulic quadruped robot. Methods: For the coupling problems between the thigh and calf of a hydraulic quadruped robot, based on the Lagrangian method, dynamics model of the robot’s leg is established. The influence of driven system is considered. The model of the hydraulic servo driven system is built, so as to obtain the coupling relationship between thigh and calf of hydraulic quadruped robot. Based on the multivariable decoupling theory, a PID neural network decoupling controller is designed. Results: The researches on experiments are executed. The PID neural network decoupling control method is compared with the control that does not use any decoupling method. The decoupling effect of the proposed algorithm is verified on the thigh and the calf of the hydraulic quadruped robot. Conclusion: The designed PID neural network decoupling control method reduces the crosscoupling between thigh and calf of the hydraulic quadruped robot, and has obvious effect to improve the dynamic characteristics of single joint of robot's leg.

Background: One of the most common manufacturing equipment for polymer product is injection molding machine. In order to ensure the precise, stable and continuous operation of the injection molding machine, the maintenance of the lubrication system must be done well. The stability, reliability, rationality and low noise performance of the lubrication system of injection molding machine directly affect the quality of injection products, dimensional accuracy, molding cycle, working environment and maintenance. Objective: The purpose of this study is to introduce the methods of choice, maintenance of lubricating oil for injection molding machine from many literatures and patents in the recent years, such as lubricating oil device, lubricating composite and structure. Methods: An example of the 260M5 automatic injection molding machine is introduced for the inspection and maintenance of the lubrication system including lubricating oil and lubricating grease. Results: To ensure the lubrication of the injection molding machine, it needs to strictly observe the lubrication time and modulus of the injection molding machine. It needs to strictly control the temperature rise of the lubricating oil and select the correct lubricating oil and grease to ensure the lubrication quality. Conclusion: In the operation of the injection molding machine, it is necessary to check that the lubricating oil is sufficient and the lubricating points are working properly. It ensures sufficient lubrication of the injection molding machine and strictly observes the lubrication time and modulus of the injection molding machine. The stored lubricating oil should be sealed well to prevent air pollution.

Background: With the increasing mining depth, single rope winding hoist and multi-rope friction hoist may not be feasible in ultra-deep wells. For the single rope winding hoist, larger rope diameter and drum diameter are required, while a lot of inconveniences would arise in the manufacturing process. For the multi-rope friction hoist, the balance tail rope is necessary so that a fluctuation in stress greater than 11.5% of the wire rope breaking force increases. Objective: The purpose of this patent is to provide an overview of a tension balancing device using new bevel gear system in the multi-rope winding hoist. In the research, varying tension of the rope winded on each drum is conveniently and quickly adjusted in different working conditions. Methods: A bevel gear balancing device is designed in the multi-rope winding hoist. It mainly consists of big and small output bevel gear, shell, balance bevel gear, and support frame. Results: Unbalanced tension caused by different lengths of the ropes is compensated without any restrictions. The tension of all wire ropes is always in balance ensured by the balancing mechanism throughout the whole process of lifting and lowering containers. When the winding diameter of the drums is different, the tension of the hoisting-ropes will not be precisely adjusted. But it can be negligible. Conclusion: The bevel gear balancing device in the patent is installed on the main shaft of the multirope winding hoist. Through analysis, the device was observed to be simple and easy to operate. The tension of the hoisting-ropes can be accurately balanced.