2022, 11(6):1-4. DOI: 10.12146/j.issn.2095-3135.20220703001
Abstract:Mechanism and robotics play a significant role in the innovation and development of machines.With the development of human production and lifestyle, mechanism will meet the major needs and focus on the research and construction of the theoretical system of behavioral mechanism. Robotics will concentrate on the construction and development of Tri-Co Robots (Coexisting-Cooperative-Cognitive) theory, technology, and engineering application systems through multidisciplinary integration. The research and development of both mechanism and robotics will make great contributions to improve the design level of national high-end equipment, independence, and controllability of national technology.
2022, 11(6):5-22. DOI: 10.12146/j.issn.2095-3135.20220224002
Abstract:3D printing technology has been widely applied in aerospace, military, robotics and many other fields. However, some problems need to be solved, such as stacking error caused by the stair-stepping effect, anisotropy of printing parts caused by the 2.5D manufacturing principle, and time-consuming and energy consumption caused by printing and post-processing supporting structure. This paper studies the 3D printing method of rotary surface, carries out the innovative design research of multi-degree of freedom rotary 3D printing equipment, determines the printer’s structural parameters based on dimension design, and puts forward the path planning methods for curved layer printing. This paper verifies the correctness of type synthesis and dimension design of the 3D printing equipment through co-simulation and prototype experiments. Meanwhile, preliminary experimental research results show the feasibility of applying 3D printing equipment to curved layer printing from a qualitative point of view. Results of this study provide new ideas for innovative design methods of printing equipment, planning strategies for curved layer printing and related experimental research.
2022, 11(6):23-35. DOI: 10.12146/j.issn.2095-3135.20220510001
Abstract:The legged lander is the key equipment of deep space soft landing detection whose current version does not have the mobility capability making its one launching mission’s patrol range limited. In this work, a legged mobile lander is designed and studied. The complete kinematic model is established for a single leg of the legged mobile lander firstly. Then, the working mode of the legged mobile lander is introduced. To make the lander adapt to the complex terrain on the surface of planets, both periodic and free gait planning methods are proposed. The other problems like stability criteria, terrain evaluation as foothold, and foot trajectory planning are also investigated with consideration of the characteristics of the legged mobile lander. Finally, numerical simulation experiments demonstrate the feasibility and stability of the proposed motion planning method.
2022, 11(6):36-47. DOI: 10.12146/j.issn.2095-3135.20211229002
Abstract:Collaborative robots or Co-robots are widely used in automation industries and material handling. Co-robots are designed to work with human workers side by side. However, safety is a challenging major concern. Rigidity is required to carry a payload and achieve accuracy in motion, while flexibility is often required for safe human interaction. Robots with control over their stiffness could combine some of the advantages seen in compliant robots with the performance of traditional rigid robots. This paper introduces the related research on variable stiffness robots and several variable stiffness solutions based on mechanical structures. These methods are classified based on the working principles and compared quantitatively based on the criteria such as stiffness range, stiffness ratio, and response time. Pros and cons are also described for each method. Researchers in design innovation and simulation laboratory also present several example applications of these variable stiffness mechanisms to collaborative robotic arms and grippers.
2022, 11(6):48-56. DOI: 10.12146/j.issn.2095-3135.20220705001
Abstract:Personalized 3D printing titanium alloy cranial prosthesis can be designed and manufactured based on the patient’s CT data to perfectly match and effectively repair the cranial defect. However, previous studies paid little attention to the impact resistance of the cranial prosthesis. In this paper, a novel personalized 3D printing cranial prosthesis is developed based on the electron beam melting technology. The impact resistance of 3D printing titanium alloy personalized cranial prosthesis and digital 3D forming titanium mesh are measured via the falling ball impact device. Results show that the average maximum deformation of 3D printing titanium alloy personalized cranial prosthesis is 0.7 mm, which is much less than the 5.9 mm average maximum deformation of digital forming titanium mesh. In summary, 3D printing personalized cranial prosthesis has good impact resistance in repairing the cranial defect and protecting the intracranial brain tissue.
2022, 11(6):57-66. DOI: 10.12146/j.issn.2095-3135.20220701001
Abstract:Due to the ease of measurement, pulse wave has been widely used as a substitute of electrocardiogram to calculate heart rate and heart rate variability in the wearable medical field. However, its accuracy is controversial. To explore the impact of age on the accuracy of heart rate and heart rate variability estimation using pulse wave, 100 healthy people with a wide age distribution at 20～71 were recruited. The resting pulse wave and electrocardiogram were collected synchronously, the instantaneous heart rate and heart rate variability were calculated using the time interval sequence of adjacent peak points of the pulse wave, and were compared with those calculated from the adjacent R wave peak points of the electrocardiogram (gold standard), the error in estimating heart rate and heart rate variability using pulse wave was calculated. Results showed that the estimation error of heart rate was smaller in young people under 40 ages (with standard deviation of about 0.3 bpm), and slightly larger in middle-aged and elderly people over 40 years old (with standard deviation of about 0.7 bpm). The time domain heart rate variability parameters showed a similar pattern. This study suggests that the use of pulse wave peaks to calculate heart rate/heart rate variability in elderly people should be treated with caution even under resting conditions.
2022, 11(6):67-74. DOI: 10.12146/j.issn.2095-3135.20220527001
Abstract:Movable electrodes are important recording tools for in vivo electrophysiology in neuroscience. The traditional electrode holder supports the structure of the electrodes which can be mechanically moved. The entire electrode structure is manually assembled. During the chronic recordings, the electrode can be lowered towards deeper brain tissues so that more neurons can be recorded. However, the traditional electrode holder assembly requires multiple time-consuming steps with low-level component integration and multiple panel components are difficult to be aligned in parallel. Here, a novel eclectrode holder which consists of an intergrated design with fewer components and a stronger structues was designed. The new design reduces the differences between different electrodes and contributes to the standard experimental conditions. Simulation results show that the new electrode is resistant to deformation when the external force is applied. Compared with the traditional electrodes, the new electrode is lighter and helps reducing head loading pressure for experimental mice. Implantation of the electrode in the mouse brain demonstrates that it can obtain high-quality neural signals. Current reserach open new opportunities for improved experimental efficiency and the applications in various in vivo electrophysiology in small animals.
2022, 11(6):75-84. DOI: 10.12146/j.issn.2095-3135.20220225002
Abstract:Aiming at the technical problems of low surface precision and difficulty to control the microstructure and properties of titanium alloys formed by plasma arc 3D printing, the influence of process parameters on the size and shape parameters of the deposited metal was studied through the control variable method, and the most suitable deposition process parameters were obtained by optimization. The Ti-6Al-4V component can be divided into three regions, the top region is mainly composed of coarsen αGB and αM, and the middle layer region includes a small amount of lamellar structure (α colony) and αM, the size of which decreased significantly, and the bottom area was mainly composed of relatively uniform basket-like α＋β; The dimensional error of the titanium alloy components obtained by plasma arc 3D printing does not exceed 2%, and the tensile strength is 1 150 MPa. The forming accuracy and mechanical properties of the components meet the requirements for use.