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The working mechanism of suggested tunable bandstop filtered with asymmetrical multiple‐mode resonator equipped with tree‐shape branches is described in this letter. Because of the established degree of freedom, the suggested bandstop filters’ (BSFs) centre frequencies may be modified based on the design approach. Meanwhile, the suggested BSFs have small dimensions and abrupt roll‐off skirts for transition bands. A technology demonstration filter with six stopbands placed at 1.91/2.38/3.54/5.19/5.79/6.85 GHz was constructed to verify the design and analyses. It is found that the measurement of a filter is consistent with the comparison of simulation data, which indicates that the proposed structure is an optional approach for BSF design. The filter proposed can be applied in the field of communication, information and coal mine automation.

Purpose – This paper aims to present a new intelligent wall-climbing welding robot system for large-scale steel structure manufacture, which is composed of robot body, control system and welding system. Design/methodology/approach – The authors design the robot system according to application requirements, validate the design through simulation and experiments and use the robot in actual production. Findings – Experimental results show that the robot system satisfies the demands of automatic welding of large-scale ferromagnetic structure, which contributes much to on-site manufacturing of such structures. Practical implications – The robot can work with better quality and efficiency compared with manual welding and other semi-automatic welding devices, which can much improve large-scale steel structure manufacturing. Originality/value – The robot system is a novel solution for large-scale steel structures welding. There are three major advantages: the robot body with reliable adsorption ability, large payload capability and good mobility which meet the requirements of welding; the control system with good welding seam tracking accuracy and intelligent automatic welding ability; and friendly human – computer interface which makes the robot easy to use.

In this paper, a design method of multiband bandstop filters with symmetric split structure multimode resonators is proposed. Because of the established degree of freedom, the suggested bandstop filters' center frequencies may be modified based on the design approach. Meanwhile, the suggested BSFs have small dimensions and abrupt roll-off skirts for transition bands. A technology demonstration filter with six stopbands placed at 1.91/2.37/3.43/4.35/5.16/6.81 GHz was constructed to verify the design and analyses. It is found that the measurement of filter is consistent with the comparison of simulation data, which indicates that the proposed structure is an optional approach for BSF design. The filter proposed can be applied in the field of communication, information and coal mine automation.