Aiming at the workspace calculation problem of multi-joint serial manipulators,a surface enveloping and overlaying (SEO) method is presented to identify and visualize the manipulator workspace.The SEO method is compos...Aiming at the workspace calculation problem of multi-joint serial manipulators,a surface enveloping and overlaying (SEO) method is presented to identify and visualize the manipulator workspace.The SEO method is composed of two stages:the first stage is to choose reference points of the manipulator and calculate their boundary surfaces using the nth enveloping method;the second stage is to overlay these boundary surfaces to identify the final workspace.The SEO method is basically a combination of the analytic method and the numerical method.By delineating the graphic representation of the workspace step by step,the SEO method is easy to analyze the existence and the shape of voids and holes.The basic theory of the SEO method and formulas for workspace calculation are presented based on a 6R serial manipulator.By showing the workspace calculation results,the SEO method is proved working correctly.展开更多
A new scheme is proposed to model 3D angular motion of a revolving regular object with miniature, low-cost micro electro mechanical systems(MEMS) accelerometers(instead of gyroscope),which is employed in 3D mouse syst...A new scheme is proposed to model 3D angular motion of a revolving regular object with miniature, low-cost micro electro mechanical systems(MEMS) accelerometers(instead of gyroscope),which is employed in 3D mouse system.To sense 3D angular motion,the static property of MEMS accelerometer,sensitive to gravity acceleration,is exploited.With the three outputs of configured accelerometers,the proposed model is implemented to get the rotary motion of the rigid object.In order to validate the effectiveness of the proposed model,an input device is developed with the configuration of the scheme.Experimental results show that a simulated 3D cube can accurately track the rotation of the input device.The result indicates the feasibility and effectiveness of the proposed model in the 3D mouse system.展开更多
Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied ...Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied with the object pose space description method. The error mapping model between the connecting part of the front frame rack and its support base is modeled using the homogeneous transformation matrix(HTM) method. The probabilistic error is simulated using the Monte Carlo method. The measurement experiment was conducted by the laser tracker to verify the effectiveness of the approach, and the approach has been successfully applied to the production of transport jig.展开更多
Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome t...Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.展开更多
文摘Aiming at the workspace calculation problem of multi-joint serial manipulators,a surface enveloping and overlaying (SEO) method is presented to identify and visualize the manipulator workspace.The SEO method is composed of two stages:the first stage is to choose reference points of the manipulator and calculate their boundary surfaces using the nth enveloping method;the second stage is to overlay these boundary surfaces to identify the final workspace.The SEO method is basically a combination of the analytic method and the numerical method.By delineating the graphic representation of the workspace step by step,the SEO method is easy to analyze the existence and the shape of voids and holes.The basic theory of the SEO method and formulas for workspace calculation are presented based on a 6R serial manipulator.By showing the workspace calculation results,the SEO method is proved working correctly.
文摘A new scheme is proposed to model 3D angular motion of a revolving regular object with miniature, low-cost micro electro mechanical systems(MEMS) accelerometers(instead of gyroscope),which is employed in 3D mouse system.To sense 3D angular motion,the static property of MEMS accelerometer,sensitive to gravity acceleration,is exploited.With the three outputs of configured accelerometers,the proposed model is implemented to get the rotary motion of the rigid object.In order to validate the effectiveness of the proposed model,an input device is developed with the configuration of the scheme.Experimental results show that a simulated 3D cube can accurately track the rotation of the input device.The result indicates the feasibility and effectiveness of the proposed model in the 3D mouse system.
基金Supported by National Key Technology Research and Development Program of China(No.2012BAF01B07)
文摘Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied with the object pose space description method. The error mapping model between the connecting part of the front frame rack and its support base is modeled using the homogeneous transformation matrix(HTM) method. The probabilistic error is simulated using the Monte Carlo method. The measurement experiment was conducted by the laser tracker to verify the effectiveness of the approach, and the approach has been successfully applied to the production of transport jig.
基金State Administration of Science,Technology and Industry for the National Defense(No.JSJL2014206B001)。
文摘Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.
