To fulfill the demands for higher quality,efficiency and flexibility in aviation industry,a multi-functional end effector is designed to automate the drilling and riveting processes in assembling carbon fiber reinforc...To fulfill the demands for higher quality,efficiency and flexibility in aviation industry,a multi-functional end effector is designed to automate the drilling and riveting processes in assembling carbon fiber reinforced polymer(CFRP)and aluminum components for a robotic aircraft assembly system.To meet the specific functional requirements for blind rivet installation on CFRP and aluminum materials,additional modules are incorporated on the end effector aside of the basic processing modules for drilling.And all of these processing modules allow for a onestep-drilling-countersinking process,hole inspection,automatic rivet feed,rivet geometry check,sealant application,rivet insertion and installation.Besides,to guarantee the better quality of the hole drilled and joints riveted,several online detection and adjustment measures are applied to this end effector,including the reference detection and perpendicular calibration,which could effectively ensure the positioning precision and perpendicular accuracy as demanded.Finally,the test result shows that this end effector is capable of producing each hole to a positioning precision within ±0.5 mm,aperpendicular accuracy within 0.3°,a diameter tolerance of H8,and a countersink depth tolerance of±0.01 mm.Moreover,it could drill and rivet up to three joints per minute,with acceptable shearing and tensile strength.展开更多
An improved hybrid position/force controller design of a flexible robot manipulator is presented using a sliding observer. The friction between the end effector and the environment is considered and compensated. For s...An improved hybrid position/force controller design of a flexible robot manipulator is presented using a sliding observer. The friction between the end effector and the environment is considered and compensated. For systematic reasons the controller is designed taking into consideration the rigid link subsystems and the flexible joints. The proposed control system satisfies the stability of the two subsystems and copes with the uncertainty of robot dynamics. A sliding observer is designed to estimate the time derivative of the torque applied as input to the rigid part of the robot. For the stability of the observer, it is assumed that the uncertainty of the observed system is bounded. A MRAC algorithm is used for the estimation of the friction forces at the contact point between the end effector and the environment. Finally simulation and experimental results are given, to demonstrate the effectiveness of the proposed controller.展开更多
To address the challenges of harsh harvesting environments,high labor intensity,and low picking efficiency in tomato harvesting,this study investigates the key technologies related to the end-effector design,detection...To address the challenges of harsh harvesting environments,high labor intensity,and low picking efficiency in tomato harvesting,this study investigates the key technologies related to the end-effector design,detection and recognition,and spatial localization of tomato-picking robots.A non-contact cavity-type end-effector is designed,which effectively prevents tomato damage caused by compression during picking while preserving the peduncle.Additionally,the motion of the robotic arm is simulated for performance analysis.Subsequently,tomato images are captured and annotated for training deep neural network models.Both the original YOLO v8n and the improved YOLO v8n models are used for tomato image detection,with a focus on the impact of varying light intensities and different tomato maturities on recognition and localization accuracy.Experimental results demonstrate that the robot’s vision system achieves optimal recognition and localization performance under light intensities ranging from 20000 to 30000 lx,with an accuracy of 91.5%,an average image detection speed of 15.1 ms per image,and an absolute localization error of 1.55 cm.Furthermore,the prototype tomato-picking robot’s end-effector successfully performed stable grasping of individual tomatoes without damaging the skin,achieving a picking success rate of 83.3%,with an average picking time of approximately 9.5 s per fruit.This study provides a technical support for the automated harvesting of tomato-picking robots.展开更多
Generalized robust systems-based theoretical kinematic inverse/regular wedge cam procedures which produce self-centering motion applicable to three-point clamping device design about cylindrical workpieces that vary w...Generalized robust systems-based theoretical kinematic inverse/regular wedge cam procedures which produce self-centering motion applicable to three-point clamping device design about cylindrical workpieces that vary within a prescribed size range are presented.Within such presentment,various parametric(trigonometric,combined loop closure with vector projection/resolution,transformation)and rectangular form(Taylor series approximation,trigonometric substitution&transformation(TS&T),nonlinear ODE)equation methods along with related statics and dynamics are explored.In connection,a simulated unified resultant amplitude method(URAM)is applied for generalization purposes.Moreover,the theoretical framework is validated within the context of a computer-generated model of a mechanism design which demon-strates self-centering over the prescribed design range with negligible to zero error.Furthermore,the static and dynamic analyses are verified through com-puter-aided engineering simulation in conjunction with equilibrium equations and a consideration of various calculus principles.Consequently,the self-centering theoretical formulation coupled with static and dynamic analyses provide for an accurate and generalized quantitative model couched within a holistic systems engineering framework which can be useful for providing state-of-the-art engineering and design optimization of various parameters for developing new and/or improved self-centering gripping devices of the inverse/regular wedge cam type.展开更多
基金supported by the National Natural Science Foundations of China(Nos.5157051626,51475225)
文摘To fulfill the demands for higher quality,efficiency and flexibility in aviation industry,a multi-functional end effector is designed to automate the drilling and riveting processes in assembling carbon fiber reinforced polymer(CFRP)and aluminum components for a robotic aircraft assembly system.To meet the specific functional requirements for blind rivet installation on CFRP and aluminum materials,additional modules are incorporated on the end effector aside of the basic processing modules for drilling.And all of these processing modules allow for a onestep-drilling-countersinking process,hole inspection,automatic rivet feed,rivet geometry check,sealant application,rivet insertion and installation.Besides,to guarantee the better quality of the hole drilled and joints riveted,several online detection and adjustment measures are applied to this end effector,including the reference detection and perpendicular calibration,which could effectively ensure the positioning precision and perpendicular accuracy as demanded.Finally,the test result shows that this end effector is capable of producing each hole to a positioning precision within ±0.5 mm,aperpendicular accuracy within 0.3°,a diameter tolerance of H8,and a countersink depth tolerance of±0.01 mm.Moreover,it could drill and rivet up to three joints per minute,with acceptable shearing and tensile strength.
文摘An improved hybrid position/force controller design of a flexible robot manipulator is presented using a sliding observer. The friction between the end effector and the environment is considered and compensated. For systematic reasons the controller is designed taking into consideration the rigid link subsystems and the flexible joints. The proposed control system satisfies the stability of the two subsystems and copes with the uncertainty of robot dynamics. A sliding observer is designed to estimate the time derivative of the torque applied as input to the rigid part of the robot. For the stability of the observer, it is assumed that the uncertainty of the observed system is bounded. A MRAC algorithm is used for the estimation of the friction forces at the contact point between the end effector and the environment. Finally simulation and experimental results are given, to demonstrate the effectiveness of the proposed controller.
基金supported by State Key Laboratory of Precision Blasting and Hubei Key Laboratory of Blasting Engineering,Jianghan University(Grant No.BL2021-16)the Natural Science Foundation of Hubei Province(Grant No.2025AFB176).
文摘To address the challenges of harsh harvesting environments,high labor intensity,and low picking efficiency in tomato harvesting,this study investigates the key technologies related to the end-effector design,detection and recognition,and spatial localization of tomato-picking robots.A non-contact cavity-type end-effector is designed,which effectively prevents tomato damage caused by compression during picking while preserving the peduncle.Additionally,the motion of the robotic arm is simulated for performance analysis.Subsequently,tomato images are captured and annotated for training deep neural network models.Both the original YOLO v8n and the improved YOLO v8n models are used for tomato image detection,with a focus on the impact of varying light intensities and different tomato maturities on recognition and localization accuracy.Experimental results demonstrate that the robot’s vision system achieves optimal recognition and localization performance under light intensities ranging from 20000 to 30000 lx,with an accuracy of 91.5%,an average image detection speed of 15.1 ms per image,and an absolute localization error of 1.55 cm.Furthermore,the prototype tomato-picking robot’s end-effector successfully performed stable grasping of individual tomatoes without damaging the skin,achieving a picking success rate of 83.3%,with an average picking time of approximately 9.5 s per fruit.This study provides a technical support for the automated harvesting of tomato-picking robots.
文摘Generalized robust systems-based theoretical kinematic inverse/regular wedge cam procedures which produce self-centering motion applicable to three-point clamping device design about cylindrical workpieces that vary within a prescribed size range are presented.Within such presentment,various parametric(trigonometric,combined loop closure with vector projection/resolution,transformation)and rectangular form(Taylor series approximation,trigonometric substitution&transformation(TS&T),nonlinear ODE)equation methods along with related statics and dynamics are explored.In connection,a simulated unified resultant amplitude method(URAM)is applied for generalization purposes.Moreover,the theoretical framework is validated within the context of a computer-generated model of a mechanism design which demon-strates self-centering over the prescribed design range with negligible to zero error.Furthermore,the static and dynamic analyses are verified through com-puter-aided engineering simulation in conjunction with equilibrium equations and a consideration of various calculus principles.Consequently,the self-centering theoretical formulation coupled with static and dynamic analyses provide for an accurate and generalized quantitative model couched within a holistic systems engineering framework which can be useful for providing state-of-the-art engineering and design optimization of various parameters for developing new and/or improved self-centering gripping devices of the inverse/regular wedge cam type.
