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- Zhang, Yang-Fei, et al.
(författare)
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Study on the Viscoelastic Properties of the Epoxy Surface by means of Nano-Dynamic Mechanical Analysis
- 2008
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Ingår i: Journal of Polymer Science Part B. - : Wiley periodicals, Inc.. - 0887-6266 .- 1099-0488. ; 46:3, s. 281-288
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Tidskriftsartikel (refereegranskat)abstract
- The viscoelastic properties of the epoxy surface have been investigated by nano-dynamic mechanical analysis (nano-DMA). Both a Berkovich tip and a conospherical tip were used under the condition of different forces (i.e. different penetration depths) in the frequency range of 10–200 Hz. Loss tangent and storage modulus are characteristics that describe the viscoelastic properties. The effect of force frequency, penetration depth and tip shape on the viscoelastic properties is studied and discussed according to the features of microstructures and mobility of molecular chains. The experimental results show important variations when the penetration depth is shallow (<30 nm). As the depth becomes deeper, the results tend to be stable and become almost constant over 120nm. The two kinds of indenter tip can cause a slight difference of the storage modulus. A “master curve” of the storage modulus as a function of force frequency is established.
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| 2. |
- Xu, Yuan, et al.
(författare)
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Indoor Vision/INS Integrated Mobile Robot Navigation Using Multimodel-Based Multifrequency Kalman Filter
- 2021
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Ingår i: Mathematical problems in engineering (Print). - : Hindawi Limited. - 1024-123X .- 1563-5147. ; 2021
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Tidskriftsartikel (refereegranskat)abstract
- In order to further improve positioning accuracy, this paper proposes an indoor vision/INS integrated mobile robot navigation method using multimodel-based multifrequency Kalman filter. Firstly, to overcome the insufficient accuracy of visual data when a robot turns, a novel multimodel integrated scheme has been investigated for the mobile robots with Mecanum wheels which can make fixed point angled turns. Secondly, a multifrequency Kalman filter has been used to fuse the position information from both the inertial navigation system and the visual navigation system, which overcomes the problem that the filtering period of the integrated navigation system is too long. The proposed multimodel multifrequency Kalman filter gives the root mean square error (RMSE) of 0.0184 m in the direction of east and 0.0977 m in north, respectively. The RMSE of visual navigation system is 0.8925 m in the direction of east and 0.9539 m in north, respectively. Experimental results show that the proposed method is effective. © 2021 Yuan Xu et al.
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