Fuzzy PD Control of Networked Control Systems Based on CMAC Neural Network

The network and plant can be regarded as a controlled time-varying system because of the random induced delay in the networked control systems. The cerebellar model articulation controller (CMAC) neural network and a PD controller are combined to achieve the forward feedback control. The PD controller parameters are adjusted adaptively by fuzzy reasoning mechanism, which can optimize the control effect by reducing the uncertainty caused by the network-induced delay. Finally, the simulations show that the control method proposed can improve the performance effectively

Clinical report of the key techniques used in the external-route microsurgery for rhegmatogenous retinal detachment

AIM: To conclude the clinical situation of the key techniques used in the external-route microsurgery for rhegmatogenous retinal detachment. <p>METHODS: A total of 152 patients with rhegmatogenous retinal detachment who underwent drainage of sub-retinal fluids, cryotherapy, localization of the retinal break, silicone scleral buckling by surgical microscope.<p>RESULTS: Retinal reattachment were achieved in 89.5% of patients after the primary surgery and the final reattachment rate was 96.7%, and 89.8% of the eyes achieved the corrected visual acuity high above 0.05, 35.2% above 0.3 at 1mo postoperatively. In 83.6% of eyes had a succeed drainage of sub-retinal fluids by the first acupuncture, and 13.1% of eyes achieved it by the second try after silicone buckling and circling; in 82.9% of cases, the retinal tear localization directly under microscope was accurate, in 90.0% of eyes were achieved it after check and adjustment by the end of operation; in 6.6% of cases,the scleral buckling had to be adjusted to more correct position in the first operation, and 10.6% of eyes had to be adjusted in the next operation; in 95.4% of eyes, the posterior edge of silicone buckling were within 20mm behind corneal limbus, 4.6% of eyes were behind 20mm.<p>CONCLUSION: The external-route microsurgery can bring us expected clinical results for rhegmatogenous retinal detachment. Its key microsurgical techniques are applied in convenient, reliable, and can be adjusted timely when some deviations occurred. The observable retina under microscope range from ora serrata to 20mm behind corneal limbus, and even to 20-24mm in some high myopia eye with large axial length

Back-stepping variable structure controller design for off-road intelligent vehicle

In this paper, off-road path recognition and navigation control method are studied to realize intelligent vehicle autonomous driving in unstructured environment. Firstly, the traversable path is achieved by vision and laser sensors. The vehicle steering and driving coupled dynamic model is established. Secondly, a coordinated controller for steering and driving is proposed via the back-stepping variable structure control method, which can be used to deal with the unmatched uncertainties of the control system model. To reduce the chattering phenomenon caused by variable structure, the boundary layer approach is introduced. The results of simulation and off-road experiment show the effectiveness and robustness of the proposed controller

Synergistic effect of scaffold composition and dynamic culturing environment in multi-layered systems for bone tissue engineering

Bone extracellular matrix (ECM) is composed of mineralized collagen fibrils which support biological apatite nucleation that participates in bone outstanding properties. Understanding and mimicking bone morphological and physiological parameters at a biological scale is a major challenge in tissue engineering scaffolding. Using emergent (nano)technologies scaffold designing may be critically improved, enabling highly functional tissue substitutes for bone applications. This study aims to develop novel biodegradable composite scaffolds of tricalcium phosphate (TCPs) and electrospun nanofibers of poly(e-caprolactone) (PCL), combining TCPs osteoconductivity with PCL biocompatibility and elasticity, mimicking bone structure and composition. We hypothesized that scaffolds with such structure/composition would stimulate the proliferation and differentiation of bone marrow stromal cells (BMSCs) towards the osteogenic phenotype. Composite scaffolds, developed by electrospining using consecutive stacked layers of PCL and TCPs, were characterized by FTIR spectroscopy, X-Ray diffraction and scanning electronic microscopy. Cellular behavior was assessed in goat BMSCs seeded onto composite scaffolds and cultured in static or dynamic conditions, using basal or osteogenic media during 7, 14 or 21 days. Cellular proliferation was quantified and osteogenic differentiation confirmed by alkaline phosphatase activity, alizarin red staining and immunocytochemistry for osteocalcin and collagen I. Results suggest that PCL-TCP scaffolds provide a 3D support for gBMSCs proliferation and osteogenic differentiation with production of ECM. TCPs positively stimulate the osteogenic process, especially under dynamic conditions, where PCL-TCP scaffolds are sufficient to promote osteogenic differentiation even in basal medium conditions. The enhancement of the osteogenic potential in dynamic conditions evidences the synergistic effect of scaffold composition and dynamic stimulation in gBMSCs osteogenic differentiation.Fundação para a Ciência e a Tecnologia (FCT)European NoE EXPERTISSUES (NMP3-CT- 2004-500283