Valve-controlled asymmetric cylinder is widely used in servo loading system. As a kind of typical electro-hydraulic servo system (EHSS), it inherently has the characteristics such as high order nonlinear, strong coupling, and uncertain, therefore, conventional control strategy is difficult to satisfy the requirements of high-performance control. In this paper, a novel linear active disturbance rejection control (LADRC) method was proposed, in which the internal and external disturbances were actively estimated by the third-order linear extended state observer (LESO) in real-time, and rejected by the control law of proportional integral control (PID) with acceleration feed-forward. The stability of the proposed method was proved, and the influence rules of the LADRC parameters on the control performance were revealed by simulation. Finally, comparative experiments between LADRC and PID control were carried out, results showed that the disturbances can be effectively compensated and the control goals can be successfully achieved with the proposed method.

To enhance the comprehensive performance of solid oxide fuel cells (SOFCs) ferritic stainless steel (FSS) interconnectors, a novel approach involving composite electrodeposition and thermal conversion is proposed to prepare Ni-doped Co-Mn composite spinel protective coatings on FSS surfaces. The process involves the composite electrodeposition of a Ni-doped Co-Mn precursor coating, followed by thermal conversion to obtain the Co-Mn-Ni composite spinel coating. Crofer 22H was used as the substrate and orthogonal experiments were designed to investigate the influences of deposition solution pH, stirring rate, cathode current density, and the element content of Mn and Ni on the surface morphology and properties of the composite coatings, respectively. The characterization of the prepared coatings was conducted through macroscopic and microscopic morphology observations of the component surface, energy dispersive spectroscopy (EDS) analysis, and area specific resistance (ASR) testing, etc. Finally, the optimized composite electrodeposition parameters and the Mn-Ni content ratio in the solution were obtained. Experimental results indicated that the composite spinel coating prepared with the optimized process parameters exhibited excellent adhesion to the substrate, and the diffusion and migration of Cr element has been effectively inhibited. Compared with the substrate, the ASR of the coated components has also been decreased simultaneously, which provided an effective method for the surface modification of SOFC FSS interconnectors.

Electro‐codeposition was used to prepare the Co and Co‐Mn₃O₄ precursor coatings on ferritic stainless steel E‐brite. Plated samples were exposed at 800°C in air for different durations (i.e., 10 min and 4 h) for thermal conversion of the deposited layer to a spinel coating. The converted layer was characterized with scanning electron microscopy/energy‐dispersive spectroscopy (SEM/EDS) and X‐ray diffraction (XRD). The results showed that after 10 min heat treatment, the plated Co layer was not fully oxidized and converted into a double‐layer microstructure with an inner CoO layer and outer Co₃O₄ layer, while for the Co‐Mn₃O₄ layer, the Mn₃O₄ particles were not completely dissolved into the oxide layer. After 4 h of exposure, the surface layer was fully converted into the Co₃O₄ or (Co,Mn)₃O₄ spinel coating. Though the Mn content in (Co,Mn)₃O₄ was relatively low, the Mn‐doped spinel coating was advantageous over the pure cobalt spinel coating, as the thermally grown Cr₂O₃ scale at the coating/substrate interface was more compact and protective. Co diffusion from the deposited layer into the alloy substrate was observed for both coatings.