Recent Patents on Mechanical Engineering - Volume 14, Issue 3, 2021

Background: This work presents a review of international patents dealing with the measurement of the induced fatigue of electrical stimulators. Sometimes muscles cannot move or have limited movement because of an injury such as Spinal Cord Injury and are in need of therapy. A complement of such therapy is Electrical Stimulation. A device sends electrical pulses to the muscle in order to generate contractions. Such contractions also fatigue the muscle and can be detrimental if muscle fatigue is not considered as a measurable variable in such devices. The scientific community has made progress regarding this issue however, the literature lacks a review of international patents. Since patents are in the forefront of technological innovation, the current status of the international patents dealing with the measurement of induced muscle fatigue of these devices is addressed. Objective: Identify data related to international patents involving Electrostimulators and their use for reducing muscle fatigue. Methods: A search for international patents was conducted to evaluate Electrostimulators capable of measuring induced fatigue. Specialized databases for patents were consulted using the term “Electrostimulator” associated with “Muscle Fatigue”. Such databases are Patentscope (WIPO), USPTO, Google Patents and Espacenet. Results: A total of 245 international patents were found, of which 31 met the inclusion criteria. Out of the 31 patents, 15 were granted to a University, 13 to companies and 3 to individuals. Conclusion: Almost all the patents granted to a University have detailed information on how to reproduce them and can be used to develop new technology to address the issue with the induced muscle fatigue that electrical stimulation produces during therapy. Patents filed by companies have ambiguous details on how to reproduce them but some have information that in conjunction with the ones granted to universities, can be complemented. Patents in this area are scarce, which present an opportunity for organizations and individuals alike to further the knowledge in this area.

Background: Hydrostatic bearings possess the advantages of strong bearing capacity, good stability, small friction coefficient, and long life. The performance of liquid hydrostatic bearings directly affects the accuracy and efficiency of CNC machining equipment. The performance is conducive to the development of CNC machine tools towards high speed and heavy load, so it is necessary to sort out and summarize the existing research results. Objective: This study summarizes the current development status of hydrostatic bearings and explains the development trend of hydrostatic bearings. Methods: According to the recently published journal articles and patents, the recent experimental research on hydrostatic thrust bearings is summarized. This paper summarizes many factors that affect the performance of hydrostatic bearings, and discusses the effect of various factors on hydrostatic bearings. Finally, future research on hydrostatic bearings is also presented. Results: The study discusses experimental methods, simulation processes, and experimental results. Conclusion: Dynamic and static pressure effects can be produced by changing the structure of the oil cavity of the hydrostatic bearing. This effect can make up for the static pressure loss. By improving the theoretical formula and mathematical model and proposing a new simulation method, the accuracy of the hydrostatic bearing simulation can be obtained; the future development trends of the hydrostatic bearing have been proposed in this paper.

Background: The eccentric load has a great influence on the bearing capacity, which can easily lead to a decrease in bearing capacity or even the destruction of working conditions. Objective: The prospects for bearing eccentric load research are put forward, hoping to provide some help for the development and optimization of bearings. Methods: According to recently published patents and journal papers, the theoretical and experimental research on bearing eccentric load conditions are summarized, and research progress at home and abroad is discussed. This article summarizes the research status of bearing anti-eccentric load. Finally, the research direction of bearing eccentric load and anti-eccentric load is prospected. Results: The article discusses eccentric load-bearing theory method, simulation method, detection method, experimental method and anti-eccentric load method. Conclusion: Aiming at the research hotspot of eccentric load, this paper collects and analyzes the literature at home and abroad on theoretical analysis, experimental testing, anti-eccentric load and so on. After research, scholars at home and abroad have made good progress in the direction of the eccentric load, and put forward some methods and devices that have been applied in practical engineering. However, the detection of eccentric load and the anti-eccentric load cannot be synchronized, and the robustness of the design system is poor. Research on eccentric load at home and abroad is still in its infancy.

Background: In order to enable robots to complete complex tasks, robots are required to have higher intelligence and adaptability. RVSC (Robot Visual Servo Control) is an organic combination of machine vision and servo control and is a complex system with strong coupling and nonlinearity, which improves the performance of robots and provides feasible solutions for solving practical problems in many fields. Objective: To review the latest development of RVSC methods and provide references for researchers in related fields. Methods: RVSC related patents and literature were analyzed from the aspects of the algorithm, innovation and application. In addition, the typical RVSC methods are summarized. Results: This paper analyzes the advantages and disadvantages of various methods in many patents and literature. Moreover, the typical applications, potential problems and future development directions of this field is put forward. Conclusion: RVSC has better performance than traditional control methods. In addition, it can also be combined with some algorithms or knowledge to improve performance further. But, further improvements of RVSC are needed in the following areas: the convenience of operation, the optimization of trajectory planning, the combination of multiple sensors, etc. Furthermore, more patents of the RVSC also should be invented.

Background: With a growing demand for blueberries, the planting area of blueberries is also increasing. However, the main method of picking blueberries is the traditional manual picking, so the operation of picking is the most time-consuming and laborious in the chain of production. Objective: By analyzing and discussing the patents of equipment of blueberry picking, some valuable conclusions have been drawn to predict future research, and the development of equipment used in blueberry picking. Methods: This paper sketches out various current representative patents relevant to the equipment of blueberry picking. Results: Through summarizing a large number of patents about equipment of blueberry picking, the characters of those patents are analyzed and compared, and further development tendency of equipment of blueberry picking is discussed. Conclusion: The research on the multifunction, intelligence, versatility of blueberry picking machine is helpful in solving the problems of low efficiency, low quality and poor versatility.

Background: The motorized spindle preload technology is one of the motorized spindle key technologies, and adjusting the preload according to the working conditions can effectively improve the dynamic performance of the motorized spindle and enhance the machining accuracy. Objectives: Review the preload mechanism development, introduce various preload mechanisms, and show research status in recent years. Then to explore and predict the future development of preload technology through the analysis of the overall preload mechanism. Methods: Search for different kinds of patents and literature about spindle preload structure in recent years. Through structural research and comparison with the traditional preload mechanism, to review the structure principle of various preload mechanisms at the present stage, then shown the advantages and disadvantages of each structure. Result: According to the patents and research of the preload mechanism in recent years, classification introduced the piezoelectric ceramic preload device, electromagnetic preload device, and hydraulic preload device, and so on. Introduce their advantages and existing problems in detail, then comprehensively compare the advantages and disadvantages of various mechanisms in control and mechanism. Finally, discuss the prospects and development directions of preload technology. Conclusion: With the further development of technology, high-precision products have higher requirements for machine tools, such as low latency, low heat generation, high efficiency, and long life. People use electromagnetic force, air pressure, hydraulic pressure, and other methods, to control the magnitude of the preload, maintain the performance of the motorized spindle at a high level. Compared with the traditional quantitative preload, their applicable working conditions are more extensive and accuracy is higher. However, various new preload methods still have certain shortcomings and need further improvement.

Background: Electrochemical Machining (ECM) can machine most conductive materials and is not limited by physical properties of materials such as strength, hardness and toughness. However, the process of ECM is unstable as the structure of tool electrode, electrolyte composition and the machining device of ECM will affect machining accuracy and stability of shaped holes. Therefore, people pay more and more attention to the development trend of ECM of shaped holes. Objective: In order to increase machining accuracy and machining stability of ECM of shaped holes, ECM method has been constantly improved. Methods: This paper reviews various representative patents and papers on ECM of shaped holes at home and abroad. Results: By summarizing a large number of patents and papers about ECM of shaped holes, this paper analyzes the structure of tool electrode, electrolyte composition and the machining device of ECM, and the development trend of ECM of shaped holes is also discussed. Conclusion: The optimization of the technological equipment and process of ECM of shaped holes is beneficial to improve the machining accuracy and the machining stability of shaped holes. More interrelated patents on ECM of shaped holes will be invented later.

Background: Heat pump air conditioning technology has broad application prospects and high market value in the field of electric automobiles owing to its increasing performance and energy-saving properties. Pure electric vehicles require high-energy consumption at low temperatures, which seriously affects the popularity of electric vehicles with a heat pump air conditioning system. Objective: The aim of this research is to describe the recent developments in the study of the heat pump air conditioning system for electric vehicles. Methods: This paper summarizes the research work of scholars published worldwide based on the electric vehicle heat pump air conditioning system, premised on lately published patents and journal articles. Starting from the components of the air conditioning system, focusing on the research results and development trends that have been achieved in this field. Results: The new technology path and pattern of the electrical vehicle heat pump air conditioning system provide methods and suggestions for future growth, put forward by the current development situation. Conclusion: The latest progress of the electric vehicle heat pump air conditioning system has been summarized and prospected. There are still some problems and technical bottlenecks in heat pump air conditioning system. It is of great significance to improve the environmental adaptability of electric vehicles and optimize the reasonable heat pump air conditioning system for the endurance of electric vehicles.

Background: In the process of high-speed driving, the wheel hub is constantly subjected to the impact load from the ground. Therefore, it is important to estimate the fatigue life of the hub in the design and production process. Objective: This paper introduces a method to study the fatigue life of car hub based on the road load collected from the test site. Methods: Based on interval analysis, the distribution characteristics of the load spectrum are analyzed. The fatigue life estimation of one-dimensional and two- dimensional load spectra is compared by compiling load spectra. Results: According to the S-N curve cluster and the one-dimensional program load spectrum, the estimated range fatigue life of the hub is 397, 100km to 529,700km. For unsymmetrical cyclic loading, each level means and amplitude of load were obtained through the Goodman fatigue empirical formula, and then according to S-N curve clusters in the upper and lower curves and two-dimensional program load spectrum, estimate of the fatigue life of wheel hub of the interval was 329900km to 435200km, and then one-dimensional load spectrum fatigue life was reduced by 16.9% - 17.8%. Conclusion: This paper lays a foundation for the prediction of fatigue life and the bench test of fatigue durability of autoparts subjected to complex and variable random loads. At the same time, the research method can also be used to estimate the fatigue life of other bearing parts or high-speed moving parts and assemblies.

Background: With the continuous improvement of spindle speed, and the occurrence of problems, such as chattering, the hot bite of bearings or premature bearing failures during high-speed rotation are gradually exposed. Objective: The purpose of this paper is to explore the problem of premature failure of hydraulic dynamic- static bearing caused by temperature rise and vibration at high speed. Methods: The hydraulic dynamic-static spindles are taken as the research objects, and the spindles, static pressure bearings, and oil system are carried out based on theoretical analysis design. MATLAB is used to establish the mathematical model of hydraulic dynamic-static bearing, and thus the bearing gap and the diameter of small holes are determined. ANSYS is used to carry out static and thermodynamic simulation analysis of the main shaft and dynamic and static pressure bearings. In addition, the temperature rise, rotation accuracy, and overall vibration, amplitude fluctuation and vibration power of the spindle system are mainly tested, studied, and analyzed. Results: The highest temperature area of hydraulic dynamic-static bearings is mainly distributed around the oil cavity inside the bearing and the bearing end surface; the speed of the spindle system continues to increase, the rate of temperature rise accelerates, and the temperature stability range also rises. At the same time, the vibration frequency is also increasing, and the operation is unstable during the acceleration process. The rotation frequency of the spindle fluctuates greatly, but the vibration amplitude is within the accuracy range. Conclusion: The obtained parameters will provide references for hydraulic dynamic-static spindle design and reducing the design cycle.

Background: The parallel mechanism plays an important role in various fields. The multifunctional integrated innovation experiment platform can improve the utilization rate of the mechanism and be applied in many fields. Objective: The main objective of the study is to establish an integrated innovation experiment platform based on the 3-PRS parallel mechanism, which can be used in typical application and related technology development. Methods: The integrated innovation experiment platform is established and analyzed based on the 3-PRS parallel mechanism. According to the 3D model of the experiment platform, the kinematics and dynamics are analyzed. The force/position control strategy of the system is adopted. According to the function of the experiment platform, two kinds of application and the position and pose measurement technology are developed. The experiment platform is developed by the following methods: (1) The XY table is set up on the fixing platform of the 3-PRS parallel mechanism, so that the mechanism has five degrees of freedom, and the many kinds of workpiece can be easily processed. (2) By selecting the impedance parameter, the experiment platform can realize the compliant control of plantar flexion/dorsiflexion and varus/eversion simultaneously. (3) The binocular vision position and pose measurement method is used to obtain the marked images of the experiment platform through dual cameras, and the position and pose is obtained through image processing, 3D reconstruction and stereo matching, etc. (4) The position and pose detection based on deep learning is divided into two parts: one is to detect the slider height using the regression Convolutional Neural Network (CNN); the other is to compute the position and pose using the Back Propagation Neural Network (BPNN). Results: The experiment results show that the function of the 3-PRS parallel mechanism integrated innovation experiment platform can be effectively realized. The position and pose can be accurately measured in real time using the proposed two measurement methods. The impedance parameters are selected to achieve the rehabilitation training function of the 3-PRS ankle rehabilitation robot and the characters are processed to verify the function of the 3-PRS-XY series-parallel machine tool. Conclusion: The integrated innovation experiment platform based on the 3-PRS parallel mechanism can achieve the function of mechanical processing and rehabilitation training, and can also measure the state of motion in real time through machine vision and deep learning.

Background: For the cooling system of the traditional new-type engine and new-energy vehicle, the water pump is the core component. If the design of the water pump is not reasonable, the engine will be overcooled or overheated, which will affect the efficiency of the engine. Therefore, it is significant to propose a design method of electronic water pump for automobiles based on active regulation. Objective: In this study, an electric water pump was designed according to the following working condition: n = 4200r/min Q = 90L/min, and H #8805: 4.4m. The flow, head, and efficiency and power of this electric water pump will be discussed. And a brushless, direct current motor for this pump was designed and analyzed. Methods: The flow details of the pump, such as pressure distribution, velocity distribution, and turbulent kinetic energy distribution were obtained by Pumplinx. The head, efficiency, and power of the pump were established by the analysis of the flow field of the pump. Then, based on the working conditions of the pump mentioned above, a brushless direct current motor for the pump was designed by Maxwell and its performance was also analyzed. Results: The experimental results showed that the maximum efficiency of the motor reached 72%, the maximum efficiency point of the motor was near the rated speed, and the efficiency of the motor at rated power was 66.31%. Conclusion: The results showed that the complex condition of running water inside the pump can be exactly stimulated by the computational fluid dynamics technique, especially about the pump head and its efficiency, which provided the theoretical foundation for the later application research and development of automotive electronic water pump.

Background: Cold forging operation is done on small as well as large scale in manufacturing industries. These industries are facing problems such as higher rejection rate of the final product, low productivity, the high number of accidents during production, etc. Objective: The purpose of this research work is to develop a Voice-Assisted Forging System (VAFS) with a lower rejection rate, higher productivity, and lower number of accidents during production. Methods: Based on recently published journals and patents, traditional and automatic forging operations, Industry 4.0, and voice assisted systems are reviewed and VAFS is designed and developed. Then, the trial is taken on VAFS to investigate its performance. Finally, limitations and future research of the VAFS are proposed. Results: It is found that after implementation of the VAFS the average rejection count is reduced by 90.3 percentage, the operational productivity is increased by 71.2 percentage, and process accuracy is increased from 92.75 percentage to 99.30 percentage. Also, the number of accidents is reduced to zero. In comparison with the manual forging operation, the VAFS occupies less space, and it is easy to operate. Conclusion: This system will help the workers as well as the owner of industries to create a better man and machine relationship and to have a human-friendly working environment. VAFS reduces exhaustion and hassle of employees, components rejection, and energy consumptions in the production line.