N. She, Tao Gong, Bingsan Chen, Minrui Lu, Y. Xu, Xiao-dong Peng
Abstract. Additive manufacturing has attracted increasing attention in recent years due to its flexibility and near-net shaping advantages. Although recent advancements in metal additive manufacturing accuracy have met the post-processing requirement for dimensional tolerance, the finishing post-processing of functional surfaces must be further investigated in conjunction with material characteristics. This research aims to investigate the use of a flexible process in the polishing of additive molding samples. As an example, the surface of a 316L stainless steel sample formed by powder bed laser melting was polished using magnetorheological polishing technology. Magnetic field simulation was used to create a longitudinally staggered magnetorheological polishing tool. Surface roughness and residual stress were studied with process parameters such as abrasive content, magnetic particle content, machining gap, and spindle speed. Results show that the polishing effect is better at 4 % and 40 % abrasive and magnetic particles, respectively. The surface roughness Ra is 99 nm when the working gap is 0.6 mm, the surface roughness Ra value is the lowest when the spindle speed is 600 r min−1. The surface roughness was reduced to 61.43 nm after polishing the sample under improved processing conditions (4 % abrasive, 40 % magnetic, 0.6 mm working clearance, 600 r min−1 spindle speed). A nano-scale smooth surface can be obtained by powder bed laser melting and magnetorheological polishing of 316L stainless steel.
摘要近年来，增材制造因其灵活性和近净成型优势而受到越来越多的关注。虽然最近金属增材制造精度的进步已经满足了尺寸公差的后处理要求，但功能表面的精加工后处理必须结合材料特性进一步研究。本研究旨在探讨在增材成型样品抛光中使用柔性工艺。以粉末床激光熔化成型的316L不锈钢样品为例，采用磁流变抛光技术对其表面进行抛光。采用磁场模拟的方法制备了一种纵向交错磁流变抛光工具。研究了磨料含量、磁粉含量、加工间隙、主轴转速等工艺参数对表面粗糙度和残余应力的影响。结果表明，磨料和磁性颗粒含量分别为4%和40%时，抛光效果较好。当工作间隙为0.6 mm时，表面粗糙度Ra值为99 nm，当主轴转速为600 r min−1时，表面粗糙度Ra值最低。在改进的加工条件下(磨料含量为4%，磁性含量为40%，工作间隙为0.6 mm，主轴转速为600 r min−1)，表面粗糙度降至61.43 nm。对316L不锈钢进行粉末床激光熔化和磁流变抛光，可以获得纳米级的光滑表面。
{"title":"Surface quality improvement for 316L additive manufactured prototype based on magnetorheological polishing","authors":"N. She, Tao Gong, Bingsan Chen, Minrui Lu, Y. Xu, Xiao-dong Peng","doi":"10.5194/ms-14-179-2023","DOIUrl":"https://doi.org/10.5194/ms-14-179-2023","url":null,"abstract":"Abstract. Additive manufacturing has attracted increasing attention in recent years due to its flexibility and near-net shaping advantages.\u0000Although recent advancements in metal additive manufacturing accuracy have\u0000met the post-processing requirement for dimensional tolerance, the finishing post-processing of functional surfaces must be further investigated in conjunction with material characteristics. This research aims to investigate the use of a flexible process in the polishing of additive molding samples. As an example, the surface of a 316L stainless steel sample formed by powder\u0000bed laser melting was polished using magnetorheological polishing\u0000technology. Magnetic field simulation was used to create a longitudinally\u0000staggered magnetorheological polishing tool. Surface roughness and residual\u0000stress were studied with process parameters such as abrasive content,\u0000magnetic particle content, machining gap, and spindle speed. Results show\u0000that the polishing effect is better at 4 % and 40 % abrasive and\u0000magnetic particles, respectively. The surface roughness Ra is 99 nm when the working gap is 0.6 mm, the surface roughness Ra value is the lowest when the spindle speed is 600 r min−1. The surface roughness was reduced to 61.43 nm\u0000after polishing the sample under improved processing conditions (4 %\u0000abrasive, 40 % magnetic, 0.6 mm working clearance, 600 r min−1 spindle speed). A nano-scale smooth surface can be obtained by powder bed laser melting and magnetorheological polishing of 316L stainless steel.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48992591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Shape memory alloy (SMA) is a kind of active deformation material with a self-sensing and driving ability. It is very similar to the performance of human muscles, and through temperature changes to produce phase changes to output force and displacement, it has the ability to restore the initial shape and size. The combination of SMA and wearable robotic technology has the advantages of being light weight, energy-saving, and having great human–exoskeleton interaction. However, the existing flexible exoskeletons driven by SMA are only designed with bionic primary muscles, ignoring the role of antagonistic muscles. This study presents a novel soft bionic elbow exoskeleton based on SMA spring actuators (Sobee-SMA). The exoskeleton adopts a bionic design, combining active deformation material SMA and a high-elastic-material rubber band to simulate the contraction and relaxation of elbow skeletal muscles. Through a pulse width modulation (PWM) experiment, the driving voltage is selected as 12 V, the PWM duty cycle is 90 % during heating, and the PWM duty cycle is 18 % during heat preservation. In a relaxed state of healthy subjects, the range of motion of the elbow is about 0–80∘, and the maximum temperature is about 60–70 ∘C. During the circular movement of the elbow, the maximum temperature can be maintained within the SMA operating temperature without a high temperature. In conclusion, the exoskeleton provides elbow-assisted motion and ensures the safety of the heating process.
{"title":"Design of a soft bionic elbow exoskeleton based on shape memory alloy spring actuators","authors":"Qiaolian Xie, Qiaoling Meng, Wenwei Yu, R.-Q. Xu, Zhiyu Wu, Xiaoming Wang, Hongliu Yu","doi":"10.5194/ms-14-159-2023","DOIUrl":"https://doi.org/10.5194/ms-14-159-2023","url":null,"abstract":"Abstract. Shape memory alloy (SMA) is a kind of active deformation\u0000material with a self-sensing and driving ability. It is very similar to the\u0000performance of human muscles, and through temperature changes to produce phase\u0000changes to output force and displacement, it has the ability to restore the\u0000initial shape and size. The combination of SMA and wearable robotic\u0000technology has the advantages of being light weight, energy-saving, and having great\u0000human–exoskeleton interaction. However, the existing flexible exoskeletons\u0000driven by SMA are only designed with bionic primary muscles, ignoring the\u0000role of antagonistic muscles. This study presents a novel soft bionic elbow\u0000exoskeleton based on SMA spring actuators (Sobee-SMA). The exoskeleton\u0000adopts a bionic design, combining active deformation material SMA and a high-elastic-material rubber band to simulate the contraction and relaxation of elbow skeletal muscles. Through a pulse width modulation (PWM) experiment, the driving voltage\u0000is selected as 12 V, the PWM duty cycle is 90 % during heating, and the\u0000PWM duty cycle is 18 % during heat preservation. In a relaxed state of\u0000healthy subjects, the range of motion of the elbow is about 0–80∘, and the maximum temperature is about 60–70 ∘C. During the\u0000circular movement of the elbow, the maximum temperature can be maintained\u0000within the SMA operating temperature without a high temperature. In\u0000conclusion, the exoskeleton provides elbow-assisted motion and ensures the\u0000safety of the heating process.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43429160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Jia, Jiankang Yang, Xiaojiao Gu, Ziliang Liu, Xiaoying Ma
Abstract. In this article, the composite synchronization of three inductor motors with a circular distribution by a fuzzy PID (proportional–integral–derivative) method in a vibration system is investigated. The composite synchronization motion is comprised of self-synchronization and controlled synchronization motions. In the self-synchronization section, the electromechanical coupling dynamical model of the vibration system is established by introducing an inductor motor model into the dynamic model. The responses of the vibrating system are calculated, and the synchronous condition and stability criterion are both derived. With the controlled synchronization section, a master–slave controlling strategy and fuzzy PID method are applied on the controlling model. The stability of the control system is proved by the Lyapunov stability theory. A series of simulations are employed to demonstrate the practicability of the designed method. Finally, some experiments are conducted to verify the effectiveness of the proposed control method in practical application. The proposed control method exhibits a superior ability to satisfy the control of multiple motors, to be accurate in targeting the rotational speed arrival, and to be strongly robust against uncertainties and disturbances. The composite synchronization theory introduces a novel concept to design and develop types of vibration equipment.
{"title":"Composite synchronization of three inductor motors with a circular distribution by a fuzzy proportional–integral–derivative method in a vibration system","authors":"Lei Jia, Jiankang Yang, Xiaojiao Gu, Ziliang Liu, Xiaoying Ma","doi":"10.5194/ms-14-143-2023","DOIUrl":"https://doi.org/10.5194/ms-14-143-2023","url":null,"abstract":"Abstract. In this article, the composite synchronization of three inductor motors with a circular distribution by a fuzzy PID (proportional–integral–derivative) method in a vibration system is investigated. The composite synchronization motion is comprised of self-synchronization and controlled synchronization motions. In the self-synchronization section, the electromechanical coupling dynamical model of the vibration system is established by introducing an inductor motor model into the dynamic model. The responses of the vibrating system are calculated, and the synchronous condition and stability criterion are both derived. With the controlled synchronization section, a\u0000master–slave controlling strategy and fuzzy PID method are applied on the\u0000controlling model. The stability of the control system is proved by the\u0000Lyapunov stability theory. A series of simulations are employed to demonstrate the practicability of the designed method. Finally, some experiments are conducted to verify the effectiveness of the proposed control method in practical application. The proposed control method exhibits a superior ability to satisfy the control of multiple motors, to be accurate in targeting the rotational speed arrival, and to be strongly robust against uncertainties and disturbances. The composite synchronization theory introduces a novel concept to design and develop types of vibration equipment.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45707602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. In the present study, Fourier theory is applied to establish the expression of rigid-body poses of a spherical four-bar crank slider rigid-body guidance mechanism. According to an analysis of the harmonic components of the trajectory curve and rigid-body rotation angle, it has a certain relationship with the geometric parameters of the mechanism. On this basis, the rigid-body poses are normalized by preprocessing. Then, the rotation angle of the curve around the y axis and z axis is determined, respectively. The theoretical formulas used for calculating the real sizes and the installation position parameters of the desired spherical four-bar crank slider rigid-body guidance mechanism are established. Besides this, a genetic optimization algorithm and theoretical formulas are applied to solve the dimensional synthesis of motion generation for the spherical four-bar crank slider mechanism. The effectiveness of the proposed method is illustrated by an example. The maximum Euclidean distance error of the rigid-body position of the results with the highest similarity is 0.0086, and the average Euclidean distance error is 0.0044. The maximum error of the rigid-body orientation is 0.0179, and the average error is 0.0065.
{"title":"Dimensional synthesis of a spherical linkage crank slider mechanism for motion generation using an optimization algorithm","authors":"Wei Zhang, Z. Liu, Wenrui Liu, Jianwei Sun, He Lu","doi":"10.5194/ms-14-125-2023","DOIUrl":"https://doi.org/10.5194/ms-14-125-2023","url":null,"abstract":"Abstract. In the present study, Fourier theory is applied to establish the expression of rigid-body poses of a spherical four-bar crank slider rigid-body guidance mechanism. According to an analysis of the harmonic components of the trajectory curve and rigid-body rotation angle, it has a certain relationship with the geometric parameters of the mechanism. On this basis, the rigid-body poses are normalized by preprocessing. Then, the rotation angle of the curve around the y axis and z axis is determined, respectively. The theoretical formulas used for calculating the real sizes\u0000and the installation position parameters of the desired spherical four-bar\u0000crank slider rigid-body guidance mechanism are established. Besides this, a\u0000genetic optimization algorithm and theoretical formulas are applied to solve the dimensional synthesis of motion generation for the spherical four-bar crank slider mechanism. The effectiveness of the proposed method is\u0000illustrated by an example. The maximum Euclidean distance error of the rigid-body position of the results with the highest similarity is 0.0086, and the\u0000average Euclidean distance error is 0.0044. The maximum error of the rigid-body orientation is 0.0179, and the average error is 0.0065.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48423682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. It is a conundrum to use robots to complete the intelligent operation of leather and clothing fabrics; this is mainly reflected in the design of an end effector that can realize this function. We have determined the design requirements and objectives of the end effector by observing the action of manually grabbing and spreading leather, and put forward an end effector composed of a reconfigurable multi-link mechanism and roller-type fingertip, which can be used to grab and spread flaky deformable object manipulation. At the same time, the reconfigurable multi-link mechanism and roller-type fingertip are introduced and analyzed in detail. By setting up the prototype of the end effector and completing the grabbing experiment of three kinds of soft pieces, we verified and tested the rationality of the prototype design. The result shows that the grabbing success rate will be affected by many factors, and further exploration is needed to further improve the performance of the end effector.
{"title":"A versatile end effector for grabbing and spreading of flaky deformable object manipulation","authors":"Yuan Huan, Gongchang Ren, Xiangyu Su, W. Tian","doi":"10.5194/ms-14-111-2023","DOIUrl":"https://doi.org/10.5194/ms-14-111-2023","url":null,"abstract":"Abstract. It is a conundrum to use robots to complete the intelligent operation of leather and clothing fabrics; this is mainly reflected in the design of an end effector that can realize this function. We have determined the design requirements and objectives of the end effector by observing the action of manually grabbing and spreading leather, and put forward an end effector composed of a reconfigurable multi-link mechanism and roller-type fingertip, which can be used to grab and spread flaky deformable object manipulation. At the same time, the reconfigurable multi-link mechanism and roller-type fingertip are introduced and analyzed in detail. By setting up the prototype of the end effector and completing the grabbing experiment of three kinds of soft pieces, we verified and tested the rationality of the prototype design. The result shows that the grabbing success rate will be affected by many factors, and further exploration is needed to further improve the performance of the end effector.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46898183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. The design of new lightweight and dexterous configurations is a major research focus for continuum robotics. This work proposes a cruciform continuum robot. Its unique feature is that it is formed by multiple cruciform-arranged elastic sheets with a single dimension of motion connected in series, and thus it has low-coupling motion characteristics. In addition, the cruciform continuum robot has the advantages of lighter weight (65 g), better dexterity, and higher motion accuracy. In this paper, the forward and inverse kinematics models of the cruciform continuum robot are established by geometric methods based on the assumption of constant curvature, and its workspace is analysed. It is experimentally verified that the tip position errors are less than 1 mm, and the cable length errors are less than 0.4 mm. Further, the cruciform continuum robot is successfully used for the nucleic acid detection simulation experiment, which confirms its good dexterity and man–machine safety. The main contribution of this paper is to provide a new configuration for the lightweight and dexterous continuum robots, and to further provide a reference method for improving their modelling accuracy from the perspective of structure.
{"title":"Design and kinematics of a lightweight cruciform continuum robot","authors":"Pan Zhou, Jiantao Yao, Hongyu Zhang, Xuanhao Zhang, Shuaiqi Kong, Kunming Zhu","doi":"10.5194/ms-14-99-2023","DOIUrl":"https://doi.org/10.5194/ms-14-99-2023","url":null,"abstract":"Abstract. The design of new lightweight and dexterous configurations is a major\u0000research focus for continuum robotics. This work proposes a cruciform\u0000continuum robot. Its unique feature is that it is formed by multiple\u0000cruciform-arranged elastic sheets with a single dimension of motion\u0000connected in series, and thus it has low-coupling motion characteristics. In\u0000addition, the cruciform continuum robot has the advantages of lighter weight\u0000(65 g), better dexterity, and higher motion accuracy. In this paper, the\u0000forward and inverse kinematics models of the cruciform continuum robot are\u0000established by geometric methods based on the assumption of constant\u0000curvature, and its workspace is analysed. It is experimentally verified that\u0000the tip position errors are less than 1 mm, and the cable length errors are\u0000less than 0.4 mm. Further, the cruciform continuum robot is successfully\u0000used for the nucleic acid detection simulation experiment, which confirms\u0000its good dexterity and man–machine safety. The main contribution of this\u0000paper is to provide a new configuration for the lightweight and dexterous\u0000continuum robots, and to further provide a reference method for improving their\u0000modelling accuracy from the perspective of structure.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43015942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Path planning is a key technique used in the operation of bending robots. In this paper, an obstacle-avoidance path-planning method of a 5 degrees of freedom (5 DOF) bending robot based on improved artificial potential field is proposed. Firstly, a connecting-rod coordinate system of the 5 DOF Cartesian bending robot is established to determine an equation of motion trajectory of the bending robot. Secondly, in view of the problem of the local minimum in the artificial potential field (APF) method and the failure of path planning, an improved APF path-planning method based on a rapidly exploring random tree (RRT) algorithm is proposed, which reduces the length of the path and enhances path smoothness. Finally, through simulation and obstacle-avoidance experiments on the path of a mechanical arm, effective path planning based on the improved APF method is verified. The experimental results show that the proposed path-planning method can plan an optimal path and meet the technical requirements of bending robot operations.
{"title":"Obstacle-avoidance path planning based on the improved artificial potential field for a 5 degrees of freedom bending robot","authors":"Q. Jiang, Kai Cai, Fengyu Xu","doi":"10.5194/ms-14-87-2023","DOIUrl":"https://doi.org/10.5194/ms-14-87-2023","url":null,"abstract":"Abstract. Path planning is a key technique used in the operation of\u0000bending robots. In this paper, an obstacle-avoidance path-planning method of\u0000a 5 degrees of freedom (5 DOF) bending robot based on improved artificial\u0000potential field is proposed. Firstly, a connecting-rod coordinate system of\u0000the 5 DOF Cartesian bending robot is established to determine an equation of\u0000motion trajectory of the bending robot. Secondly, in view of the problem\u0000of the local minimum in the artificial potential field (APF) method and\u0000the failure of path planning, an improved APF path-planning method based on a\u0000rapidly exploring random tree (RRT) algorithm is proposed, which reduces the length of\u0000the path and enhances path smoothness. Finally, through simulation and\u0000obstacle-avoidance experiments on the path of a mechanical arm, effective\u0000path planning based on the improved APF method is verified. The experimental\u0000results show that the proposed path-planning method can plan an optimal path\u0000and meet the technical requirements of bending robot operations.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44155382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiabao Pan, Jin Ye, Hejin Ai, Jiamei Wang, You Wan
Abstract. Optimizing the structure of the suction port is the key to effectively improving the performance of the sweeping vehicle. The CFD (computational fluid dynamics) method and gas–solid two-phase flow model are used to analyse the influence rule of the structural parameters and the height above ground on the cleaning effect, which is verified by real vehicle tests. The data set was established by an orthogonal test method, and a BP (backpropagation) neural network was used to fit the structural parameters and evaluation indexes. The fitting errors were all within 5 %, indicating that the fitting results of this method were good. According to the fitting relation of the BP neural network output, the whale algorithm should be further used to solve the optimal structural parameters. The results show that the optimal parameter combination is β=63∘, d=168 mm and h=12 mm. The energy consumption of the optimized model is reduced, and the internal airflow loss is reduced. The particle residence time becomes shorter, and the particle can flow out from the outlet faster, thus improving the dust absorption effect. The research can provide a theoretical reference for performance optimization and parameter matching of sweepers.
{"title":"Parameter optimization of a pure electric sweeper dust port by a backpropagation neural network combined with a whale algorithm","authors":"Jiabao Pan, Jin Ye, Hejin Ai, Jiamei Wang, You Wan","doi":"10.5194/ms-14-47-2023","DOIUrl":"https://doi.org/10.5194/ms-14-47-2023","url":null,"abstract":"Abstract. Optimizing the structure of the suction port is the key to effectively improving the performance of the sweeping vehicle. The CFD (computational fluid dynamics) method and gas–solid two-phase flow model are used to analyse the influence rule of the structural parameters and the height above ground on the cleaning effect, which is verified by real vehicle tests. The data set was established by an orthogonal test method, and a\u0000BP (backpropagation) neural network was used to fit the structural\u0000parameters and evaluation indexes. The fitting errors were all within 5 %,\u0000indicating that the fitting results of this method were good. According to\u0000the fitting relation of the BP neural network output, the whale algorithm should\u0000be further used to solve the optimal structural parameters. The results show\u0000that the optimal parameter combination is β=63∘, d=168 mm and h=12 mm. The energy consumption of the optimized model is reduced,\u0000and the internal airflow loss is reduced. The particle residence time\u0000becomes shorter, and the particle can flow out from the outlet faster, thus\u0000improving the dust absorption effect. The research can provide a theoretical\u0000reference for performance optimization and parameter matching of sweepers.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45803062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Harvesting energy from human body motion to supply electricity for wearable devices is focused on in this paper. Based on the fact that the frequency of human body motion is lower and the motions of different human body parts are variable, a piezoelectric energy harvester subjected to two different transversal reciprocating excitations is studied in this paper. Each excitation is treated as a transverse rheonomic constraint. The dynamics equation of the beam is established using the Hamiltonian principle. Expressing the transverse rheonomic constraint as a periodic function, closed-form solutions of the dynamics equation are obtained. And the characteristics of energy harvesters are investigated based on the closed-form solutions. The results show that the difference between the two excitations will certainly cause the energy harvester to generate more output power at lower frequencies of excitations, and the larger the difference, the more the output power will be generated. This unusual characteristic at the lower frequency enables the proposed harvester to be quite suitable to harvest energy from the motions of the human body.
{"title":"A piezoelectric energy harvester for human body motion subjected to two different transversal reciprocating excitations","authors":"W.M. Ding, J. Xie","doi":"10.5194/ms-14-77-2023","DOIUrl":"https://doi.org/10.5194/ms-14-77-2023","url":null,"abstract":"Abstract. Harvesting energy from human body motion to supply\u0000electricity for wearable devices is focused on in this paper. Based on the\u0000fact that the frequency of human body motion is lower and the motions of\u0000different human body parts are variable, a piezoelectric energy harvester\u0000subjected to two different transversal reciprocating excitations is studied\u0000in this paper. Each excitation is treated as a transverse rheonomic\u0000constraint. The dynamics equation of the beam is established using the\u0000Hamiltonian principle. Expressing the transverse rheonomic constraint as a\u0000periodic function, closed-form solutions of the dynamics equation are\u0000obtained. And the characteristics of energy harvesters are investigated\u0000based on the closed-form solutions. The results show that the difference\u0000between the two excitations will certainly cause the energy harvester to\u0000generate more output power at lower frequencies of excitations, and the\u0000larger the difference, the more the output power will be generated. This\u0000unusual characteristic at the lower frequency enables the proposed harvester\u0000to be quite suitable to harvest energy from the motions of the human body.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49029561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Due to the inherent dynamic coupling between mechanical components such as the steering system and suspension system, the vertical external input will affect the lateral movement of the chassis, which makes it difficult to track the ideal trajectory when complex excitation conditions exist. To solve the abovementioned problems, the X-by-wire chassis is taken as the research object in this work, and the coupling dynamic model is established. Then, based on proving the reversibility of the coupling dynamic model, a pseudo-linear composite system is proposed to decouple the lateral and vertical signals of the chassis system. Next, the decoupling active disturbance rejection (DADR) trajectory-tracking control strategy is proposed. And a multi-objective optimization method of the bandwidth parameters of the DADR trajectory-tracking controller is proposed according to its convergence conditions. Experiments show that the proposed control strategy can effectively suppress the vehicle roll and yaw motion caused by the lateral–vertical dynamic coupling in the process of trajectory tracking to realize the accurate tracking of the ideal trajectory.
{"title":"Decoupling active disturbance rejection trajectory-tracking control strategy for X-by-wire chassis system","authors":"Haixiao Wu, Yong Zhang, Fengkui Zhao, Pengchang Jiang","doi":"10.5194/ms-14-61-2023","DOIUrl":"https://doi.org/10.5194/ms-14-61-2023","url":null,"abstract":"Abstract. Due to the inherent dynamic coupling between mechanical components such as the steering system and suspension system, the vertical external input will affect the lateral movement of the chassis, which makes it difficult to track the ideal trajectory when complex excitation conditions exist. To solve the abovementioned problems, the X-by-wire chassis is taken as the research object in this work, and the coupling dynamic model is established. Then, based on proving the reversibility of the coupling dynamic model, a pseudo-linear composite system is proposed to decouple the lateral and vertical signals of the chassis system. Next, the decoupling active disturbance rejection (DADR) trajectory-tracking control strategy is proposed. And a multi-objective optimization method of the bandwidth parameters of the DADR trajectory-tracking controller is proposed according to its convergence conditions. Experiments show that the proposed control strategy can effectively suppress the vehicle roll and yaw motion caused by the lateral–vertical dynamic coupling in the process of trajectory tracking to realize the accurate tracking of the ideal trajectory.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47033852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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