Recent Patents on Mechanical Engineering - Volume 11, Issue 1, 2018

Background: Hand is one of the most important and common parts of the body. Hand dysfunction caused by hemiplegia and hand injury is difficult to restore, which leads to high disability rates. The patients' daily life and work ability are seriously affected. With the aging of the society, the number of stroke patients with hemiplegia is gradually increasing. The research and application of the robot with the combination of robot and assistive rehabilitation therapy have come into being. Hand function rehabilitation robot has more practical value. It can simulate the human hand's movements to realize the rehabilitation training of human hands. Objective: To give a general summary of recent hand function rehabilitation robot, and a presentation of their respective characteristics including drive type and rehabilitation training mode. Methods: This paper summarizes various patents and research developments about hand function rehabilitation robot. From the aspects of structural characteristics, drive type and rehabilitation training mode and applications situation, the advantages and disadvantages of the typical hand function rehabilitation robots are represented. Results: Current and future development trends on the structural characteristics, drive type and rehabilitation training mode and applications situation of hand function rehabilitation robots are discussed to improve the humanization, marketization, modularization and intelligence of the hand function rehabilitation robot. Conclusion: Considerable attention has been paid onto the hand function rehabilitation robot. Hand function rehabilitation robot can effectively improve the hand function of patients' and the elderly's the actual quality of life and family well-being. Further improvements are needed in the aspects of hand biomechanics, neurophysiology, rehabilitation training mode, actuators and sensors, physical manmachine interaction and ergonomics of the hand function rehabilitation robot. More patents on hand function rehabilitation robot should be invented.

Background: Hydraulic quadruped robots play an important role in many different fields, such as field investigation, seismic site search, mine transportation and planetary exploration. Gait planning is the core of the motion control of quadruped robots, which affects the obstacle surmounting ability and movement speed of the quadruped robot. The reasonable gait control method is very important to the stability of quadruped robots. Objective: To provide an overview of recent gait control strategies of the hydraulic quadruped robot and introduce their respective characteristics. Methods: This paper reviews various representative patents and papers related to hydraulic quadruped robot, especially focusing on the gait planning and the motion control algorithm of the hydraulic quadruped robot. Results: Current and future developments of the gait planning and control strategies of hydraulic quadruped robots are finally provided and discussed. Conclusion: Hydraulic quadruped robot has important practical significance. Further improvements are needed in the methods of gait planning. It is effective and reasonable to combine three kinds of motion control strategies for hydraulic quadruped robot, so that the quadruped robots are more intelligent and autonomous.

Background: Due to the shortage of energy resources, the problem of energy consumption has attracted much more attention. How to reduce the energy consumption or obtain the regenerative energy becomes one of the hot topics. To solve this problem, the vibration energy recovery device has an increasing development. The working principle of the vibration energy recovery device can be divided into three types: piezoelectric effect, electrostatic effect and electromagnetic effect. The vibration energy recovery device of the piezoelectric effect is widely used. It mainly uses piezoelectric materials to convert vibration energy into electrical energy. When external vibrations apply stress to the piezoelectric material, the positive and negative charge centers inside the piezoelectric material are moved relatively to produce an electrode. Therefore, the voltage is generated on both sides of the piezoelectric material. Objective: In order to know the latest development of the vibration energy recovery device and reduce the energy consumption. Methods: Firstly, the structure and working principle of the vibration energy recovery device has been discussed. Secondly, the paper reviews recent patents of the piezoelectric vibration energy recovery device. Meanwhile, the advantages and disadvantages have been clearly discussed through the analysis of the structure and working principle of these patents. Results: Compared with the traditional devices and structures, the new ones have and can convert vibration energy of multiple directions into electric energy. Moreover, the expenses of the vibration energy recovery device will be reduced by designing the new devices. Conclusion: The patents of the vibration energy recovery device utilizing piezoelectric effect have solved several problems. However, these devices still need more improvements to increase the application prospects.

Background: With the mining depth and width increasing, coal auger mining is prone to collapse accident in the poor existing conditions, which reduces the security and reliability of mining workface and wastes the large amounts of coal resources due to the remaining coal pillars. Objective: To eliminate the prearranged pillars, control the subsidence and collapse and promote the widespread use of coal auger mining method in thin or extremely thin coal seam. Methods: According to the mining geological condition and the mining technology of five-bits coal auger, the whole technology of pneumatic conveying and filling included the technology of gangue pneumatic conveying from surface to underground, the technology of coal and gangue separation during drivaging, and the technology of gangue filling in coal auger mining, was proposed. Results: The filling system for coal auger mining with little space occupation, high production efficiency and simple equipment structure has been developed. The system of pneumatic conveying and filling for coal auger mining was constructed and the pneumatic conveying system and the pneumatic filling system were designed, which could make up the disadvantages of large volume and heavy equipments which limited the traditional filling system to apply in coal auger mining goaf. Conclusion: This system provided design guidance for the pneumatic conveying and filling system for coal auger mining and had strong practical significance to improve the green mining technological system of thin coal seam. In this article, various patents have been discussed.

Background: With the elderly population increasing at a phenomenal rate in the world, the disabled elderly care has become a hot issue concerned with society and government. The latest survey showed that the elder, who wish to grow old in their own house, is more than 85%. It is a pending problem that how to meet the elder's need and relieve the burden of society and their children. The nursing service market could reach 3.3 trillion yuan in 2020, and then the technology industry of elderly nursing will grow into a new increasing point for the national economy. Therefore, the informatization and robotization of elderly nursing will become the necessary development trend in the future. Objective: To provide an overview of the existing nursing robots and introduce their classification, characteristics and development. Methods: This paper reviews various productions and patents related to the nursing robot. The structural characteristics, differentiations and applications of the typical nursing robot are also introduced. Results: The three types of the nursing robot are compared and analyzed, and the typical characteristics are concluded. The main problems in its development are analyzed, the development trend is foreseen, and the current and future research of the productions and patents on the nursing robot are discussed. Conclusion: Nursing robots are divided into an independent nursing robot, rehabilitation nursing robot bed and multifunctional mobile nursing robot. The nursing robot has important practical significance for promoting social nursing services, and it plays an important role in improving nursing quality of patients and the elderly and reducing the pressure of nursing staff. Further improvements are needed in the aspects of reliability, comfortable capability, humanization, intelligence and security of the nursing robot. More patents on nursing robot should be invented.

Background: Friction brake is the most important safety device of mechanical systems. In order to avoid accidents caused by braking failure, it is highly important to forecast the remaining useful life of brakes accurately. Objective: The purpose of this study is to provide an overview about life prediction methods of brake friction pair based on physical models and statistical analysis. Methods: In this paper, the widely used life prediction methods of brake friction pair based on physical model and statistical analysis are summarized. To be specific, the fatigue life of brake disc/drum and the wear life of brake pad are analyzed in depth based on their physical models. Meanwhile, three life prediction methods based on statistical analysis which are linear regression, grey prediction and neural network, are discussed. Results: Life predictions based on the physical model often ignore random, mutation and nonlinear factors in building failure model, while life predictions based on statistical analysis don't need to explore the detailed failure mechanism. Curve fitting, grey prediction and neural network are mainly used in life prediction based on the statistical analysis. Conclusion: Data mining technology such as neural network plays a more important role as a result of its comprehensive consideration of braking conditions and braking frequency, and studies on real-time monitoring system for life predictions have practical significance for forecasting the catastrophic failure timely.

Background: The shock absorber is an important component of vehicle suspension that attenuates the vehicle vibration. It is used widely in vehicle engineering. Its running state directly affects the performance of the vehicle suspension. The test platform for developing shock absorber is the key equipment in this literature, furthermore, the controller design is the key part of the test platform. Objective: The purpose of this study is to provide an overview of controller design and realization of test platform from many literatures and patents, and propose a novel controller development method for ensuring precision and rapidity of shock absorber test platform. Methods: The power mechanism mathematical model of the hydraulic test platform is established to analyze the bandwidth of the test system, and the three-state feedback and feed-forward compound control strategy is proposed to increase the system bandwidth. The embedded controller with high speed digital signal processing chip as the core processor is developed to realize the real-time control of hydraulic shaking system. The embedded controller shares data with the monitoring computer through the Ethernet. The control strategy of the hydraulic system developed from the high-level language named Matlab/Simulink can generate C code executed on embedded controller. Results: The improved hydraulic shaking platform control method is fully evaluated by simulation and experiments. The results show that the proposed compound control strategy greatly extends the system bandwidth, and the reliability and effectiveness of the developed embedded controller is verified. Conclusion: The improved hydraulic shaking platform control algorithm has improved the precision and speed of the test platform of shock absorber. But because the executing efficient of the C code generated by Matlab/Simulink is lower than the control strategy programmed by direct C language, the stronger computing power chip must be selected as the core processor and the control strategy will be coded by low-level programming language in the future.

Background: The dimple distribution has a significant effect on the property of mechanical seal with dimples, as investigated in recent patents and studies. Specifically, dimples with various distributions while with the same size were considered in the previous researches, overlooking that different positions on the seal face have different working conditions. In other words, different positions on the seal face should have different dimple parameters. Objective: Thus, the performance of mechanical seal with varying dimple depth along the radial face was studied in this paper. Methods: Based on the Computational Fluid Dynamics (CFD) method, the three-dimensional flow field between seal faces with varying dimple depth along the radial direction was numerically solved using Fluent software. The pressure distribution, opening force and leakage rate under various shaft speeds were also obtained. Results: The results show a close relationship between the distribution of dimple depth along the radial face and sealing performance. Comparing the seal faces with uniform dimple depth, it showed a better sealing performance when the dimple depth decreased or decreased first, then increased, and at last, decreased along the leaking direction under the given conditions. Specifically, the opening force increased when the dimple with smaller depth was located in the high pressure region, while the leakage rate decreased, when the dimple with smaller depth concentrated in the low pressure region. Conclusion: It has proved that the seal face with varying dimple parameters should be taken into account in the design of mechanical seal with dimples.