A self-adaptive alignment strategy for large components based on dynamic compliance center

PurposeAiming at the problems of geometric precision misalignment and unconsidered physical constraints between large components during the measurement-assisted assembly, a self-adaptive alignment strategy based on the dynamic compliance center (DCC) is proposed in this paper, using force information to guide alignment compliantly.Design/methodology/approachFirst, the self-adaptive alignment process of large components is described, and its geometrical and mechanical characteristics are analyzed based on six-dimensional force/torque (F/T). The setting method of DCC is studied and the areas of DCC are given. Second, the self-adaptive alignment platform of large components driven by the measured six-dimensional F/T is constructed. Based on this platform, the key supporting technologies, including principle of self-adaptive alignment, coordinate transfer, calculation of six-dimensional F/T and alignment process control, are illustrated.FindingsUsing the presented strategy, the position and orientation of large component is adjusted adaptively responding to measured six-dimensional F/T and the changes of contact states are consistent with the strategy. Through the setting of DCC, alignment process runs smoothly without jamming.Practical implicationsThis strategy is applied to the alignment experiment of large components muff coupling. The experimental results show that the proposed alignment strategy is correct and effective and meets the real-time requirement.Originality/valueThis paper proposed a novel way to apply force information in large component self-adaptive alignment, and the setting method of DCC was presented to make the alignment process more feasible.

REKONSTRUKSI BATAS BIDANG TANAH MENGGUNAKAN JARINGAN REFERENSI SATELIT PERTANAHAN

ORS is a GNSS station operating continuously for 24 hours. It is also used as a reference for determining a, both asa real time and as post-processing. Cors in BPN RI is known as Jaringan Referensi Satelit Pertanahan (JRSP). BPN RI has notyet optimized the use JRSP to reconstruct parcel boundaries. The research is aimed at examine the JRSP in reconstructingparcel boundaries. The analysis on lateral displacement tolerance and the difference on the area of parcles was based ontechnical guidance of PMNA/KBPN No. 3 of 1997 and the t test using the level of significance of ( )=5%. The resultswere:1)The reconstruction of parcels using JSRP can be done by firstly implementing the coordinate transfer and the mostaccurate Helmert coordinate transfer method using a posteriori variance of ( ) = 1.143020313; 2) The lateral transformationand the difference on parcel areas using JRSP suited the tolerance and the result of the t test did not show anysignificance level of ( ) = 5% .Keywords: reconstruction, parcel boundaries, JRSPAbstrak: CORS merupakan stasiun GNSS yang beroperasi secara kontinyu selama 24 jam sebagai acuan penentuan posisi, baiksecara real time maupun post-processing. CORS di BPN RI dikenal sebagai Jaringan Referensi Satelit Pertanahan (JRSP). BPN RIbelum mengoptimalkan pelaksanaan rekonstruksi batas bidang tanah menggunakan JRSP. Tujuan dalam penelitian ini adalahuntuk menguji JRSP dalam pelaksanaan rekonstruksi batas bidang tanah. Analisis terhadap toleransi pergeseran lateral danperbedaan luas bidang tanah hasil rekonstruksi batas bidang tanah menggunakan JRSP berdasarkan Juknis PMNA/KBPN No 3tahun 1997 dan uji t dengan taraf signifikansi ( )=5%. Hasil penelitian ini adalah : 1)Rekonstruksi batas bidang tanah tanahmenggunakan JRSP dapat di laksanakan dengan terlebih dahulu melaksanakan transformasi koordinat dan metode transformasikoordinat yang paling teliti adalah metode Helmert dengan varian posteriori ( ) = 1.143020313; 2)Pergeseran lateral danperbedaan luas bidang tanah hasil rekonstruksi batas bidang tanah menggunakan JRSP memenuhi syarat toleransi dan dari uji tdengan taraf signifikansi ( ) = 5% tidak terdapat perbedaan yang signifikan.Kata Kunci: Rekonstruksi, Batas Bidang Tanah , JRSP

A Method of Robust Control for Nonlinear Inverted Pendulum System

In this paper, the controller of inverted pendulum with parametric uncertainty and nonlinearity was proposed. The controller was composed of two terms. Control law of linear part of the system was obtained by Coordinate Transfer and Backstepping algorithm. To the nonlinear part and uncertainty of the system which are usually not accords with the form of Backstepping algorithm, a BP neural network was applied to the design of the controller. Method submitted in this paper was less restrictive to the form of the nonlinear system, and has a wider universality. At the end of the paper, simulations proved the effectiveness of the proposed method.

Interactive Use of Cerebral Angiography and Magnetoencephalography in Arteriovenous Malformations: Technical Note

OBJECTIVE: To minimize the risks associated with treating cortical cerebral arteriovenous malformations (AVMs), we developed a technique combining functional imaging and cerebral angiography. The functional loci obtained by performing magnetoencephalography (MEG) are projected onto stereoscopic pairs of a stereotactically derived digital subtraction angiogram. The result is a simultaneous three-dimensional perspective of the angioarchitecture of an AVM and its relationship to the sensorimotor cortex. METHODS: Eight patients underwent multimodality brain imaging, including magnetic resonance imaging, functional mapping via MEG, and stereotactic angiography using a modified Compass fiducial system (Compass International, Rochester, MN). The coordinates derived by performing MEG were superimposed onto stereotactic, stereoscopic, angiographic pairs using custom-made distortion correction and coordinate transfer software. RESULTS: The magnetoencephalographic angiogram allowed simultaneous viewing of the angioarchitecture of the AVM nidus, the feeding vessels, and the draining veins and their relationship to the normal cerebral vasculature and functional cortex. This imaging technique was particularly valuable in identifying en passant vessels that supplied functional cortex and was used during the treatment of these lesions. CONCLUSION: The techniques of MEG and cerebral angiography were combined to provide simultaneous viewing of both modalities in a three-dimensional perspective. This technique can aid in risk stratification in the management of patients with cerebral AVMs. In addition, this technique can facilitate the selective targeting of vessels, thus potentially reducing the risks associated with embolization of these formidable lesions.