Recent Patents on Mechanical Engineering - Volume 14, Issue 2, 2021

Background: In recent times, large diameter plastic pipes have been widely used in many functions because of their unique advantages. These applications include water supply, drainage, heating network, industrial transportation, gas delivery, agricultural irrigation, etc. Therefore, manufacturing large diameter plastic pipes economically and efficiently has now become an important research area. Objective: This paper reviews patents of plastic pipe manufacturing or forming to provide insights and references to researchers in the domain of larger diameter plastic pipe production. Methods: This paper reviews the Spouted-accumulated Forming, a production method that combines the advantages of traditional extrusion, calendaring, and additive manufacturing. It is a novel process to manufacture large diameter plastic pipes. Results: The experiment result shows that Spouted-accumulated Forming can be used to manufacture large diameter plastic pipes efficiently with lower costs. This paper argues that this novel method will serve as a promising technology to manufacture larger diameter pipes in the future. Conclusion: Since traditional manufacturing processes cannot fulfil the requirement of large diameter of plastic pipes, it is necessary to develop novel processes such as Spouted-Accumulated Forming (SAF, based on additive manufacturing).

Background: With the rapid growth of the elderly population, the phenomenon of shoulder subluxation caused by stroke is increasing. For young people, frozen shoulders caused by works and shoulder fractures caused by accidents are also increasing. With the development and popularization of rehabilitation medicine, more and more people realize that rehabilitation and treatment are equally important. Therefore, more and more shoulder rehabilitation devices are designed. Objective: To provide an overview of the end traction shoulder rehabilitation device and introduce their classification, characteristics and development. Methods: This paper reviewed various productions and patents related to the end traction shoulder rehabilitation device. The structural characteristics, differentiations, applications of the end traction rehabilitation device are also introduced. Results: By analyzing the physiological structure and movement characteristics of the shoulder, the rehabilitation mechanism is understood. According to the usage and training track of the end traction shoulder rehabilitation device, it is classified and compared, and the typical characteristics are concluded. The main problems in its development are analyzed and studied. The current and future research of the productions and patents on it are discussed. Conclusion: As a single joint rehabilitation device, the rehabilitation goal of the end traction shoulder rehabilitation device is clearer. Through analysis of existing patents, it is found that the safety, the rehabilitation effect and the rehabilitation program of device need to be further improved. In the future, in order to better serve patients, technologies such as human-machine interaction and rehabilitation process monitoring are also essential.

Background: The non-conductive materials are widely applied in electronics, optics, instrumentation, aerospace, national defense and civil industry because of their strong wear resistance, high hardness and good insulation performance. However, it is difficult for traditional machine methods to process the non-conductive materials. Electrical Discharge Machining (EDM), as a nontraditional advanced processing technology, is an alternative method for machining the non-conductive materials. Therefore, the development trend of EDM of non-conductive materials has been paid more and more attention. Objective: To meet the growing processing requirement of processing efficiency and processing quality of EDM of non-conductive materials, the processing devices and processing methods of EDM of nonconductive materials, such as high-voltage spark machining, auxiliary electrode spark machining and electrolysis spark discharge machining are being improved continuously. Methods: This paper retraces various current representative patents relative to high-voltage spark machining, auxiliary electrode spark machining and electrolysis spark discharge machining of nonconductive materials. Results: Through investigating a large number of patents on EDM of non-conductive materials, the main current existing problems, such as low processing efficiency and poor processing quality, are summarized and analyzed. Moreover, the development tendency of EDM of non-conductive materials in the future is also discussed. Conclusion: The optimization of processing devices and processing methods of EDM of nonconductive materials are conducive to improve processing efficiency and processing quality. More correlative patents will be invented in the future.

Background: Space docking technology and space docking mechanism are indispensable parts of modern complex spacecraft and important means to expand satellite functions in the future. However, there is still some technology to be broken through in the research of their buffer and locking, so that the docking mechanism can be better used in the future. Objective: Through the introduction and discussion of the characteristics of space docking mechanism patents in recent years, some valuable conclusions are summarized, and the future research and development of space docking mechanisms are anticipated. Methods: This paper studied the patents of various docking mechanisms, and summarized the patents and research progress of the docking mechanism in space. Results: With the development of the space industry, docking mechanism has become more and more important. So the docking mechanisms are needed to achieve the replenishment for long-term spacecraft in orbit, personnel exchange, spacecraft maintenance, and so on. Conclusion: By elaborating on the structural characteristics of the docking mechanism, the importance of the docking mechanism is consulted for investigation. Through the comparison of these patents, it is concluded that weak impact docking mechanism and electromagnetic docking mechanism are the main development trends of docking institutions in the future.

Background: In this paper, we present a completely new type of propulsion system where thrust force is created by the helicoidal shape of the hull rather than screw propellers. The method and device have been recently patented. The inspiration comes from nature, the world of bacteria, where some organisms have been using the drilling motion or rotating flagella to move in fluid media for several million years. The hull of device consists of three parts – bow and stern (which create the propulsion force) and the middle part which can serve as a cargo compartment containing all control mechanisms and communications. The Cardan-joint mechanism that allows changing the direction of the vehicle is actuated by bending drives. A bending drive velocity control algorithm is proposed for the automatic control of vehicle movement direction. Objective: Development of a new propulsion system for underwater vehicles. Methods: The watercraft dynamics were simulated using multibody simulation software MSC Adams. For accurate interaction with medium, polynomial metamodels were created on the basis of computer experiments with CFD software. Computational Fluid Dynamics software was used for flow interaction with the prototype geometry, implementing the same idea that is used in wind tunnel experiments. Results and Conclusion: The results are compared with measurements of the physical prototype, built at the Institute of Mechanics and Mechanical Engineering of Riga Technical University. These results showed good validation with mathematical simulation and confirmed the effectiveness and future potential of the proposed principle.

Background: As the realization of the flexibility of the wheel handling manipulator, the key technical problem that needs to be overcome is the design of a flexible end effector. Objective: The purpose of this study is to design a flexible manipulator end effector to complete the handling of wheels of different sizes on the flexible production line of wheels. Methods: According to the size range and mass range of the wheel to be grasped, the preliminary design plan of the cylinder drive and the gripping wheel hub is determined. Afterwards, the end effector is subjected to a force analysis. The safety, stability and rationality of the design structure is tested through simulation. Results: The simulation results indicate that the strength of the key parts of the end effector fully meets the design requirements. Strength check provides a basis for institutional optimization. Conclusion: This paper completes the design of the end effector of the flexible manipulator. The size diversity of the wheel requires the end effector to have better flexibility. For further development, the structure of the clamping device and the force control device should be further studied. In this article, patents have been discussed.

Background: The electromagnetic aircraft launch system helps the carrier aircraft accelerate take-off on a short distance on the flight deck. Linear motors are required to have high efficiency and thrust / volume ratio, as the actuator of the EMALS. In addition, linear motors were required to have the fluctuation of the thrust is as small as possible to prevent impact and overstress on the airborne equipment. The thrust performance and thrust fluctuation suppression of linear motors are the current research hotspots in the field of EMALS. Objective: This paper proposes a multi-segment LPMSM to improve the efficiency of the system. Methods: We design a decentralized primary structure based on the Autonomous Decentralized System (ADS) concept. Only the coils near the moving secondary are motivated during the launch process. The others could be released from being driven after the secondary slide over; this control will save energy. Results: A multi-segment linear motor is proposed to improve the efficiency of the EMALS. This motor consists of two sections - the one with iron core for the low speed process and the one without iron core for the high speed process. Conclusion: The normal direction component of the air gap magnetic flux density is much larger than that of the longitudinal component, and their values are 80-90% and 10-20%, respectively. For the normal direction component, it is mainly affected by the third, seventh, and ninth harmonics. The accelerating and energy test results show that, in the accelerating process, the efficiency of the linear motor can be more than 90%, and the acceleration is stable.

Background: Problems, such as severe hardening and poor processing quality, are present in the cutting process of difficult-to-machine materials. Objective: The aim of this study was to investigate and optimize the machining parameters of 630 stainless steel by using an independently designed 28-KHz double-excitation elliptical vibration cutting process. Methods: Using the AdvantEdge platform and response surface method, the effects of the cutting speed v, feed rate f, and cutting depth ap on the cutting forces Fx and Fy in the feed and depth directions, respectively, and cutting temperature T were analyzed. Then, regression prediction models with three response variables for each of the three independent variables were established, and the best cutting parameter combination was optimized. Finally, the results were obtained and validated through physical experiment methods. Results: Results show that the error of the experimental results relative to the predicted ones under the optimized cutting parameter combination is less than 9%. Conclusion: Based on the response surface method, the optimal cutting parameters are obtained, and the cutting force and cutting temperature are at a lower level. The findings indicate the feasibility of the optimized machining parameters and provide a reference for the selection of cutting parameters and the publishing of patents, and when ultrasonic vibration is used, for cutting difficult-to-machine materials.

Background: The spiral drum is the working mechanism of the coal shearer, whether the design of spiral drum is reasonable or not, will directly affect the cutting performance, which has an important impact on the reliability, productivity and working stability of coal shearer. Objective: In order to improve the working performance of the spiral drum, a program for the structural design and load calculation of the spiral drum was developed. According to the parameters of MG400 / 951-WD shearer, two types of spiral drums were designed. Methods: The distribution of cutting resistance moment and cutting power of two types of spiral drum were obtained. The stress of the key parts and the acceleration of spiral drum centroid were obtained by the dynamic simulation. Results: According to the analysis of the cutting performance of the spiral drum combined with the results of the dynamic analysis of the shearer, the appropriate spiral drum was selected to match with the MG400/951-WD shearer. Conclusion: The accuracy of the analysis method was verified by tracking the production process of the finalized shearer. The results provide a certain reference for the comprehensive evaluation of the cutting performance of spiral drum.

Background: The safety of vehicles has been valued throughout the world, whether it is now or in the future, the automobile safety issue is the hotspot and focus of the research by experts and scholars both at home and abroad. The continuous increase of car ownership not only brings convenience to people's lives, but it also poses a threat to people's lives and security of the property. Objective: Vehicle active safety system is the hotspot of current research and development as it plays an important role in automobile safety. Through the analysis of patents and references, we aim to understand the development of an active steering system. In order to improve the development efficiency of the active steering system, the paper proposes a feedback control method of the front-wheel angle. Methods: Based on yaw velocity and center of a mass side angle, the Active Front Steering (AFS) model is established respectively by fuzzy control and sliding mode control under the establishment of seven degrees of freedom vehicle dynamics model and the Dugoff tire model. Results: The simulation results show that both the control algorithm of sliding mode control and fuzzy control can improve the handling stability of vehicle steering on high adhesion coefficient road surface. On the low adhesion coefficient road, the control effect of slide mode control is more ideal while fuzzy control caused larger oversteer. Conclusion: The simulation results show that the control effect of sliding mode is superior to fuzzy control.

Background: Assistive exoskeleton robot is required to improve the control of exoskeleton joints. The robust response of all joint controls is planned to improve the performance of joint tracking control. Recent patents of an assistive exoskeleton robot concern to explore the system design and integration have been used. Objective: To design and improve the control performance to gain more stability locomotion of exoskeleton device by using the Sliding Mode Control (SMC) technique, and to explore the recent patents of assistive exoskeleton robots and methods. Methods: The recent patents of assistive exoskeleton robots were investigated in this research. The trajectory generation of the gait cycle was approximated using a polynomial equation of the ninth order in the curve fitting of the Human Clinical Gait Cycle (CGC) of lower limb joints. The position and velocity control along the gait cycle were controlled using SMC methods. The robust design of controller performance of position and velocity control for each joint was established via design simulation in three cases. Results: The output tracking performance of hip, knee, and ankle joint’s position and velocity shows the controller performance. Three cases of control design study are validated by simulation methods. Conclusion: The SMC controller significantly improves the motion control of the exoskeleton robot, even with disturbance affecting the system. Thus, it is robust to external forces with humans in the loop system. The steepest command trajectory will cause a lower output tracking response and vice versa.

Background: Friction stir welding is an advanced process that could be used to join dissimilar materials and alloys. However, there are some areas that require some further analysis. This involves the impact of the material positioning on various dissimilar joints. Objective: The purpose of this paper is to investigate the influence of material positioning on the microstructure and the mechanical properties of AA8011/AA6082 and AA6082/AA8011 dissimilar joints. Methods: The materials used in this study were the 6mm thick AA8011 and AA6082-T6 plates. The welding conditions include a tool rotational speed of 1100 rpm, and a traverse speed of 60 mm/min. Microstructural analysis, Vickers hardness and tensile tests were conducted in order to be able to draw a comparison between the respective joints. Results: The joints (AA8011/AA6082 and AA6082/AA8011) both experienced dynamic recrystallization. The positioning of the stronger strength alloy on the advancing side resulted in finer microstructural grains compared to when the lower strength alloy was positioned on the advancing side. The maximum stir zone hardness of 75 HV was obtained on the AA8011/AA6082 dissimilar joint, while the AA6082/AA8011 had a minimum hardness of 68 HV. Both hardness values were lower than the AA6082 hardness but greater than that of the AA8011. The positioning of AA6082 on the advancing side resulted in higher ultimate tensile strength than when AA8011 was on the advancing side. The AA6082/AA8011 joint was found to be more ductile in comparison to the AA8011/AA6082 joint. The fracture surface morphology of the post tensile specimens also revealed a ductile failure morphology. Conclusion: Placing the stronger strength alloy on the advancing side resulted in valid overall results of the tests conducted.