This paper proposes a variable stiffness joint based on a symmetrical crank slider mechanism (SCM-VSJ). Firstly, the mechanical design and the working principle of the variable stiffness joint is described, and its stiffness regulation characteristics are studied. Secondly, the dynamical model of variable stiffness joint including joint motor, harmonic reducer and stiffness adjustment motor is established, in addition, the transmission mechanism of the crank slider mechanism and the elastic deformation of the spring bar are considered in the dynamic modeling. Finally, in order to control the dynamic stiffness of the variable stiffness joint in real time, a kind of improved PID (proportional-integral-derivative) control algorithm based on feed-forward and feedback closed-loop is proposed on the basis of the existing dynamical model, and the simulation analysis of real-time tracking control of dynamic stiffness for sinusoidal wave expected stiffness signal and random expected stiffness signal is carried out respectively. The research shows that the real-time stiffness control of SCM-VSJ can be realized effectively, and during the stiffness adjustment process, the output torque of the stiffness adjustment motor will be affected by the elastic deformation of the spring bar.

The main distribution frame (MDF) is an important component between the user and the operator that supplies a telecommunication service and is the only layer in the seven-layer communication architecture that is not fully automated. In this paper, a cross-connect method for simulating the rapier picking of a rapier loom (shuttleless loom) is proposed to imitate the shedding and the picking action to achieve quick switching. Using the designed “shedding device” and “picking device”, a model prototype of the automatic optical distribution frame (AODF) was constructed and tested for verification.

Outdoor communication wiring is mainly used to provide a physical connection between telecommunication services. With many fibers to the X networks having been built to provide high-level reliability services and to reduce operational costs, the operator has a strong demand for an automatic optical distribution frame. Based on the mathematics of knots to study the relationship of the fiber-optic connections on the main distribution frame, we proposed the ``HIGHER ALWAYS ON TOP”method for fiber-optic switching. Two prototypes of a 1-D array of input lines and a 1-D array of output lines use a line match line and a line match circle to demonstrate these concepts. We proposed the method of constructing non-coplanar lines in a 1-D array of input lines and a 2-D array of output lines, as well as a 2-D array of input lines and a 2-D array of output lines, for scalability. We imitated the opening of a shuttle in the textile field and proposed a high-speed cross-connect method and a simulation experiment to show its feasibility.

Cross‐connection is the only point in the communications field that has not been automated. With the many fibre networks that have been built, there is strong demand from operators for an automatic optical distribution frame (AODF) to reduce operational costs and provide high‐level services. From the twisting relationships between the fibre patch cords on the main distribution frame (MDF), the relationship between the input lines and output lines on the MDF is reversed to be perpendicular to each other, and one‐dimensional arrays of input lines and output lines (1D to 1D) are formed to construct the model. According to the model, the AODF prototype of the 1D to 1D form was fabricated with the smallest Lucent connector connector and verified through several cross‐connect experiments. The prototype designed has a simple structure, a three‐degrees‐of‐freedom Cartesian coordinate robot can meet switch requirements, and there is non‐winding between the fibres after multiple cross‐connects. Compared to the single‐layer and double‐layer form tests, the switch process requires multiple hand‐over operations, and handovers take a long time in the switch process. Further research is needed to optimise the handover method and greatly improves the switching speed.