Ruoyu Tan, Jieji Zheng, Bin Yu, Baoyu Li, D. Fan, Xin Xie
Abstract. An electromagnetic brake is the key basic component to ensure the safety of robot joints. The conventional electromagnetic brake mostly uses a set of springs to provide braking force and solenoid power to provide a recovery force, which makes this kind of brake with large thickness and small braking torque that is not conducive to the application in light and small joint components. In many design processes, unclear understanding of the machine-electric-magnetic coupling characteristics leads to relatively simple theoretical models and inaccurate theoretical results, which do not provide more help for subsequent designs. In this paper, a hollow-ring type permanent magnetic power-loss protection brake, integrated inside a joint assembly, is designed. The brake uses rare earth Nd–Fe–B permanent magnets to provide braking suction instead of ordinary spring packs, and achieves motion guidance and braking torque transmission by means of leaf spring. Combined with the deformation model of the leaf spring and the magnetic circuit models of the brake under the power-on and power-off conditions, the overall coupling dynamics model of the brake is established. The theoretical results are compared through finite-element software, and a prototype is produced for experimental testing. Finally, the accuracy and validity of the theoretical model are verified, providing a theoretical and experimental basis for the design of this type of brake.
{"title":"Design and analysis of a hollow-ring permanent magnet brake for robot joints","authors":"Ruoyu Tan, Jieji Zheng, Bin Yu, Baoyu Li, D. Fan, Xin Xie","doi":"10.5194/ms-13-687-2022","DOIUrl":"https://doi.org/10.5194/ms-13-687-2022","url":null,"abstract":"Abstract. An electromagnetic brake is the key basic component to\u0000ensure the safety of robot joints. The conventional electromagnetic brake\u0000mostly uses a set of springs to provide braking force and solenoid power to provide a recovery force, which makes this kind of brake with large thickness\u0000and small braking torque that is not conducive to the application in light and\u0000small joint components. In many design processes, unclear understanding of\u0000the machine-electric-magnetic coupling characteristics leads to relatively\u0000simple theoretical models and inaccurate theoretical results, which do not\u0000provide more help for subsequent designs. In this paper, a hollow-ring type\u0000permanent magnetic power-loss protection brake, integrated inside a joint\u0000assembly, is designed. The brake uses rare earth Nd–Fe–B permanent magnets to\u0000provide braking suction instead of ordinary spring packs, and achieves\u0000motion guidance and braking torque transmission by means of leaf spring.\u0000Combined with the deformation model of the leaf spring and the magnetic\u0000circuit models of the brake under the power-on and power-off conditions,\u0000the overall coupling dynamics model of the brake is established. The\u0000theoretical results are compared through finite-element software, and a prototype is produced for experimental testing. Finally, the accuracy and\u0000validity of the theoretical model are verified, providing a theoretical and\u0000experimental basis for the design of this type of brake.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47585495","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. Active participation in training is very important for improving the rehabilitation effect for patients with upper limb dysfunction. However, traditional upper limb rehabilitation robots cannot drive the patients' arms by following their varying motion intents during active training. This control strategy can weaken the patients' active participation. This paper proposes a novel center-driven upper limb rehabilitation robot and an electromyogram (EMG)-based motion compensation control method for the upper limb rehabilitation robot in active training in order to improve the patients' active participation. In addition, the trajectory planning equations for the proposed robot manipulator are analyzed and built in order to provide the reference trajectory in active training. In the end, two experiments are carried out to verify the proposed control method. The EMG compensation experiments show that the maximum error between the theoretical and experimental motor rotating speeds is no more than 1.3 %. The active training control experiment results show that the proposed robot can implement the reference trajectory in real time. The control method can implement the positive relationship between the rotating speed and the intensity of EMG emerging during upper limb training. It shows that the proposed rehabilitation robot can provide auxiliary force according to the patients' motion intents. The proposed rehabilitation robot can guide the patients in implementing the reference task in active training.
{"title":"Electromyogram-based motion compensation control for the upper limb rehabilitation robot in active training","authors":"Qiaoling Meng, Yiming Yue, Sujiao Li, Hongliu Yu","doi":"10.5194/ms-13-675-2022","DOIUrl":"https://doi.org/10.5194/ms-13-675-2022","url":null,"abstract":"Abstract. Active participation in training is very important for improving the rehabilitation effect for patients with upper limb dysfunction. However,\u0000traditional upper limb rehabilitation robots cannot drive the patients' arms\u0000by following their varying motion intents during active training. This\u0000control strategy can weaken the patients' active participation. This paper\u0000proposes a novel center-driven upper limb rehabilitation robot and an\u0000electromyogram (EMG)-based motion compensation control method for the upper limb rehabilitation robot in active training in order to improve the patients'\u0000active participation. In addition, the trajectory planning equations for the\u0000proposed robot manipulator are analyzed and built in order to provide the reference trajectory in active training. In the end, two experiments are\u0000carried out to verify the proposed control method. The EMG compensation\u0000experiments show that the maximum error between the theoretical and\u0000experimental motor rotating speeds is no more than 1.3 %. The active training control experiment results show that the proposed robot can implement the reference trajectory in real time. The control method can implement the positive relationship between the rotating speed and the intensity of EMG emerging during upper limb training. It shows that the proposed rehabilitation robot can provide auxiliary force according to the patients' motion intents.\u0000The proposed rehabilitation robot can guide the patients in implementing the reference task in active training.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42974212","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 this paper, an innovative cylindrical deployable mechanism (DM) based on rigid origami is presented, which is used to design a parabolic cylindrical deployable antenna. The mechanism can be deployed from the cuboid folded configuration to the cylindrical unfolded configuration with only one actuator. First, an innovative deployable string is proposed based on different types of four-vertices origami unit cells and kirigami techniques. By considering the units as 6R single-loop mechanisms, the kinematics of the origami unit cells are analyzed. Through the connection of identical deployable strings, the cylindrical DM is constructed, and its mobility is analyzed utilizing the screw theory. Then the proposed DM is used to design a parabolic cylindrical deployable antenna. A number of pillars are installed on the panels of the DM, and their lengths are determined to fit the required parabolic cylindrical surface. To verify the feasibility of the design, a scaled prototype of the deployable antenna is constructed.
{"title":"Design of an origami-based cylindrical deployable mechanism","authors":"Long Huang, Peng Zeng, Lairong Yin, Juan Huang","doi":"10.5194/ms-13-659-2022","DOIUrl":"https://doi.org/10.5194/ms-13-659-2022","url":null,"abstract":"Abstract. In this paper, an innovative cylindrical deployable\u0000mechanism (DM) based on rigid origami is presented, which is used to design\u0000a parabolic cylindrical deployable antenna. The mechanism can be deployed\u0000from the cuboid folded configuration to the cylindrical unfolded\u0000configuration with only one actuator. First, an innovative deployable string\u0000is proposed based on different types of four-vertices origami unit cells and\u0000kirigami techniques. By considering the units as 6R single-loop\u0000mechanisms, the kinematics of the origami unit cells are analyzed. Through\u0000the connection of identical deployable strings, the cylindrical DM is\u0000constructed, and its mobility is analyzed utilizing the screw theory. Then\u0000the proposed DM is used to design a parabolic cylindrical deployable\u0000antenna. A number of pillars are installed on the panels of the DM, and\u0000their lengths are determined to fit the required parabolic cylindrical\u0000surface. To verify the feasibility of the design, a scaled prototype of the\u0000deployable antenna is constructed.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46942301","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}
Longjun Wang, Zhiyong Yang, Xiangdong Chen, R. Zhang, Yu Zhou
Abstract. When autonomous vehicles pass through uneven roads, especially the consecutive speed control humps (SCHs) on expressways, the speed of them will have a significant influence on the safety and comfort of driving. How to automatically select the most appropriate speed has become a practical research subject. This paper studies the nonlinear vibration process of the suspension system when the autonomous vehicle passes through the SCHs on a highway. Firstly, the paper establishes a four-degree-of-freedom (4-DOF) nonlinear half-vehicle model and a stimulation function of trapezoidal SCHs and then uses the Runge–Kutta method to numerically solve the differential equations of motion of the suspension system. In the next part, the paper chooses the genetic algorithm to build a multi-objective optimization problem model, which selects the vertical displacement of the vehicle body, the suspension's dynamic deflection and the dynamic load of the tire as optimization objectives and combines the method of the unified objective function to find the optimal passing speed. Finally, the paper designs and carries out the solution process of the multi-objective optimization problem for the vehicle under three scenarios, conventional passive suspension, semi-active suspension, active suspension, and compares the optimized state with the pre-optimized state to prove the effectiveness of the optimization model.
{"title":"Research on adaptive speed control method of an autonomous vehicle passing a speed bump on the highway based on a genetic algorithm","authors":"Longjun Wang, Zhiyong Yang, Xiangdong Chen, R. Zhang, Yu Zhou","doi":"10.5194/ms-13-647-2022","DOIUrl":"https://doi.org/10.5194/ms-13-647-2022","url":null,"abstract":"Abstract. When autonomous vehicles pass through uneven roads, especially the consecutive speed control humps (SCHs) on expressways, the\u0000speed of them will have a significant influence on the safety and comfort of\u0000driving. How to automatically select the most appropriate speed has become a\u0000practical research subject. This paper studies the nonlinear vibration\u0000process of the suspension system when the autonomous vehicle passes through\u0000the SCHs on a highway. Firstly, the paper establishes a\u0000four-degree-of-freedom (4-DOF) nonlinear half-vehicle model and a\u0000stimulation function of trapezoidal SCHs and then uses the Runge–Kutta method to numerically solve the differential equations of motion of the suspension system. In the next part, the paper chooses the genetic algorithm to build a\u0000multi-objective optimization problem model, which selects the vertical\u0000displacement of the vehicle body, the suspension's dynamic deflection and the dynamic load of the tire as optimization objectives and combines the method\u0000of the unified objective function to find the optimal passing speed. Finally, the paper designs and carries out the solution process of the\u0000multi-objective optimization problem for the vehicle under three scenarios, conventional passive suspension, semi-active suspension, active suspension,\u0000and compares the optimized state with the pre-optimized state to prove the\u0000effectiveness of the optimization model.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43565141","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}
Haiqiang Zhang, J. Tang, Changtao Yan, G. Cui, Minghui Zhang, Yan’an Yao
Abstract. There are considerably rigorous requirements for accuracy and stability of the mechanism to accomplish large-scale and complex surface machining tasks in the aerospace field. In order to improve the stiffness performance of the parallel mechanism, this paper proposes a novel three degrees of freedom (DOF) redundantly actuated 2RPU-2SPR (where R, P, U and S stand for revolute, prismatic, universal and spherical joints, respectively) parallel mechanism. Firstly, the kinematics position inverse solution is derived and a dimensionless generalized Jacobian matrix is established through the driving Jacobian matrix and constraint Jacobian matrix. Secondly, the stiffness model of the parallel mechanism is deduced and the accuracy of the stiffness model is verified through finite-element analysis. Using eigenscrew decomposition to illustrate the physical interpretation of the stiffness matrix, the stiffness matrix is equivalent to six simple screw springs. Finally, the simulation experiment results demonstrate that redundantly actuated parallel mechanism has better stiffness performance compared to the traditional 2RPU-SPR parallel mechanism.
{"title":"Stiffness analysis of a 3-DOF parallel mechanism for engineering special machining","authors":"Haiqiang Zhang, J. Tang, Changtao Yan, G. Cui, Minghui Zhang, Yan’an Yao","doi":"10.5194/ms-13-635-2022","DOIUrl":"https://doi.org/10.5194/ms-13-635-2022","url":null,"abstract":"Abstract. There are considerably rigorous requirements for accuracy\u0000and stability of the mechanism to accomplish large-scale and complex surface\u0000machining tasks in the aerospace field. In order to improve the stiffness\u0000performance of the parallel mechanism, this paper proposes a novel three\u0000degrees of freedom (DOF) redundantly actuated 2RPU-2SPR (where R, P, U and\u0000S stand for revolute, prismatic, universal and spherical joints,\u0000respectively) parallel mechanism. Firstly, the kinematics position inverse\u0000solution is derived and a dimensionless generalized Jacobian matrix is\u0000established through the driving Jacobian matrix and constraint Jacobian\u0000matrix. Secondly, the stiffness model of the parallel mechanism is deduced and\u0000the accuracy of the stiffness model is verified through finite-element analysis. Using eigenscrew decomposition to illustrate the physical interpretation of the\u0000stiffness matrix, the stiffness matrix is equivalent to six simple screw\u0000springs. Finally, the simulation experiment results demonstrate that\u0000redundantly actuated parallel mechanism has better stiffness performance\u0000compared to the traditional 2RPU-SPR parallel mechanism.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43281656","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. Higher cutting force and its temperature with faster tool wear are the causes of higher production costs and lower machining efficiency. In this paper, with the help of electrical discharge machining (EDM) and laser technology, texture holes are implemented on the rake face and the principal flank face of the tool. The cutting force, friction characteristics of rake face and surface roughness of rake face are compared with the micro-textured cutting tool and the processing technology system of non-textured inner cooling hole. The results show that the coolant can be effectively sent to the interface surfaces due to the internal cooling texture cutter.
{"title":"Short communication: Experiment study on micro-textured tool with internal cooling","authors":"Gang Yang, Wei Feng","doi":"10.5194/ms-13-619-2022","DOIUrl":"https://doi.org/10.5194/ms-13-619-2022","url":null,"abstract":"Abstract. Higher cutting force and its temperature with faster tool\u0000wear are the causes of higher production costs and lower machining\u0000efficiency. In this paper, with the help of electrical discharge machining (EDM) and laser technology, texture holes are implemented on the rake face and the principal flank face\u0000of the tool. The cutting force, friction characteristics of rake face and\u0000surface roughness of rake face are compared with the micro-textured\u0000cutting tool and the processing technology system of non-textured inner\u0000cooling hole. The results show that the coolant can be effectively sent to\u0000the interface surfaces due to the internal cooling texture cutter.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42453529","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. China is one of the first countries that produced textiles in the world. It has designed and developed a variety of equipment to facilitate textile work, for instance, reeling wheels for fiber processing, treadle spinning wheels for spinning, and looms for weaving cloth. These textile mechanisms can be found in the literature, and there are physical objects left as well. However, due to unclear descriptions of the transmission modes in the records and illustrations, as well as the long history and vast area of their use, a variety of designs with different structures may have been produced. Based on the generalized kinematic chain concept, this paper briefly describes the historical development of textile mechanisms in ancient China and analyzes the structures of mechanisms, such as reeling wheels, treadle spinning wheels, and looms. Finally, it explores the degree of freedom of the mechanisms to find feasible designs in line with functional requirements.
{"title":"Structural analysis of ancient Chinese textile mechanisms","authors":"Shi-wu Li, Kan Shi, M. Wang, Yan-an Yao","doi":"10.5194/ms-13-625-2022","DOIUrl":"https://doi.org/10.5194/ms-13-625-2022","url":null,"abstract":"Abstract. China is one of the first countries that produced textiles in the\u0000world. It has designed and developed a variety of equipment to facilitate\u0000textile work, for instance, reeling wheels for fiber processing, treadle spinning wheels for spinning, and looms for weaving cloth. These\u0000textile mechanisms can be found in the literature, and there are physical\u0000objects left as well. However, due to unclear descriptions of the\u0000transmission modes in the records and illustrations, as well as the long\u0000history and vast area of their use, a variety of designs with different\u0000structures may have been produced. Based on the generalized kinematic chain\u0000concept, this paper briefly describes the historical development of textile\u0000mechanisms in ancient China and analyzes the structures of mechanisms, such as\u0000reeling wheels, treadle spinning wheels, and looms. Finally, it explores the\u0000degree of freedom of the mechanisms to find feasible designs in line with\u0000functional requirements.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42877305","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}
Tao Zhang, Taimu Jin, Ziwei Zhou, Zaigang Chen, Kaiyun Wang
Abstract. As a vital means of transportation to alleviate urban traffic congestion, the metro vehicle has been developing rapidly in China during recent years. For the violent vibration and shock under the frequent switches between traction and braking conditions, higher requirements are put forward in the drive system. The dynamic performance of the traction motor and gearbox, which are the key elements in the drive system of the metro vehicle, is worthy of attention. Based on the classical vehicle–track coupled dynamics and the gear dynamics theory, a vertical–longitudinal dynamics model for a metro vehicle with frame-hung motors and gearboxes is developed in this paper. This model enables the consideration of some complicated excitations, such as external excitations (the track vertical irregularity) and internal excitations (the mesh stiffness and the dynamic transmission error). The established dynamics model is then validated by comparing the simulated results with the field test results in both time domain and time–frequency domain under traction conditions. Consequently, the established dynamics model is demonstrated to be capable of revealing the dynamic performance of the metro vehicle effectively, especially for the traction and transmission system in the entire vehicle vibration environment of a metro. In turn, the results indicate that the gear transmission has a great and lasting effect on the force state of the traction motors and gearboxes compared to its effect on the axle load transfer.
{"title":"Dynamic modeling of a metro vehicle considering the motor–gearbox transmission system under traction conditions","authors":"Tao Zhang, Taimu Jin, Ziwei Zhou, Zaigang Chen, Kaiyun Wang","doi":"10.5194/ms-13-603-2022","DOIUrl":"https://doi.org/10.5194/ms-13-603-2022","url":null,"abstract":"Abstract. As a vital means of transportation to alleviate urban\u0000traffic congestion, the metro vehicle has been developing rapidly in China during recent\u0000years. For the violent vibration and shock under the frequent\u0000switches between traction and braking conditions, higher requirements are\u0000put forward in the drive system. The dynamic performance of the traction\u0000motor and gearbox, which are the key elements in the drive system of the\u0000metro vehicle, is worthy of attention. Based on the classical vehicle–track coupled dynamics and the gear dynamics theory, a vertical–longitudinal dynamics model for a metro vehicle with frame-hung motors and gearboxes is developed in this paper. This model enables the consideration of some complicated excitations, such as external excitations (the track vertical irregularity) and internal excitations (the mesh stiffness and the dynamic transmission error). The established dynamics model is then validated by comparing the simulated results with the field test results in both time domain and time–frequency domain under traction conditions. Consequently, the established dynamics model is demonstrated to be capable of revealing the dynamic performance of the metro vehicle effectively, especially for the traction and transmission system in the entire vehicle vibration environment of a metro. In turn, the results indicate that the gear transmission has a great and lasting effect on the force state of the traction motors and gearboxes compared to its effect on the axle load transfer.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45306417","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}
Lingtao Yu, Yongqiang Xia, Pengcheng Wang, Lining Sun
Abstract. Laparoscopic arm and instrument arm control tasks are usually accomplished by an operative doctor. Because of intensive workload and long operative time, this method not only causes the operation not to be flow, but also increases operation risk. In this paper, we propose a method for automatic adjustment of laparoscopic pose based on vision and deep reinforcement learning. Firstly, based on the Deep Q Network framework, the raw laparoscopic image is taken as the only input to estimate the Q values corresponding to joint actions. Then, the surgical instrument pose information used to formulate reward functions is obtained through object-tracking and image-processing technology. Finally, a deep neural network adopted in the Q-value estimation consists of convolutional neural networks for feature extraction and fully connected layers for policy learning. The proposed method is validated in simulation. In different test scenarios, the laparoscopic arm can be well automatically adjusted so that surgical instruments with different postures are in the proper position of the field of view. Simulation results demonstrate the effectiveness of the method in learning the highly non-linear mapping between laparoscopic images and the optimal action policy of a laparoscopic arm.
{"title":"Automatic adjustment of laparoscopic pose using deep reinforcement learning","authors":"Lingtao Yu, Yongqiang Xia, Pengcheng Wang, Lining Sun","doi":"10.5194/ms-13-593-2022","DOIUrl":"https://doi.org/10.5194/ms-13-593-2022","url":null,"abstract":"Abstract. Laparoscopic arm and instrument arm control tasks are usually accomplished by an operative doctor. Because of intensive workload and long operative time, this method not only causes the operation not to be flow,\u0000but also increases operation risk. In this paper, we propose a method for\u0000automatic adjustment of laparoscopic pose based on vision and deep\u0000reinforcement learning. Firstly, based on the Deep Q Network framework, the raw laparoscopic image is taken as the only input to estimate the Q values\u0000corresponding to joint actions. Then, the surgical instrument pose\u0000information used to formulate reward functions is obtained through object-tracking and image-processing technology. Finally, a deep neural network\u0000adopted in the Q-value estimation consists of convolutional neural networks\u0000for feature extraction and fully connected layers for policy learning. The\u0000proposed method is validated in simulation. In different test scenarios, the\u0000laparoscopic arm can be well automatically adjusted so that surgical\u0000instruments with different postures are in the proper position of the field\u0000of view. Simulation results demonstrate the effectiveness of the method in learning the highly non-linear mapping between laparoscopic images and the optimal action policy of a laparoscopic arm.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44665907","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 roundness error is the main geometric characteristic parameter of shaft and hole parts. Evaluation accuracy is an important indicator of the quality inspection technology. Existing roundness error evaluation methods are insufficient in terms of the calculation amount, convergence speed, and calculation accuracy. This study proposes a novel roundness error evaluation method based on improved bee colony algorithm to evaluate the roundness error of shaft and hole parts. Population initialization and search mechanism were considered for the optimal design to improve the convergence precision of the algorithm. The population was initialized in the local search domain defined by the contour data. The roughness error was obtained by the convergence solution of the circle center calculated iteratively by the step-decreasing method. The roundness error was also evaluated by taking the same set of image domain data as an example to verify the feasibility of the proposed method. The algorithm exhibited higher accuracy than that traditional methods and thus can be widely used to evaluate the roundness error of shaft and hole parts.
{"title":"Roundness error evaluation in image domain based on an improved bee colony algorithm","authors":"Benchi Jiang, X. Du, Shilei Bian, Lulu Wu","doi":"10.5194/ms-13-577-2022","DOIUrl":"https://doi.org/10.5194/ms-13-577-2022","url":null,"abstract":"Abstract. The roundness error is the main geometric characteristic parameter of shaft and hole parts. Evaluation accuracy is an important indicator of the quality inspection technology. Existing roundness error evaluation methods are insufficient in terms of the calculation amount, convergence speed, and calculation accuracy. This study proposes a novel roundness error evaluation method based on improved bee colony algorithm to evaluate the roundness error of shaft and hole parts. Population initialization and search mechanism were considered for the optimal design to improve the convergence precision of the algorithm. The population was initialized in the local search domain defined by the contour data. The roughness error was obtained by the convergence solution of the circle center calculated iteratively by the step-decreasing method. The roundness error was also evaluated by taking the same set of image domain data as an example to verify the feasibility of the proposed method. The algorithm exhibited higher accuracy than that traditional methods and thus can be widely used to evaluate the roundness error of shaft and hole parts.\u0000","PeriodicalId":18413,"journal":{"name":"Mechanical Sciences","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2022-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49601915","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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