Abstract: The present invention relates to the technical field of rockfall motion tests, and in particular to an indoor rockfall motion test device and a ramming structure, comprising a bearing component, comprising a support, a mounting crossbar arranged on the support, and a release assembly arranged on the mounting crossbar; and a throwing component, comprising a rockfall start section arranged on the support. In the present invention, the slope shape can be adjusted at will, different plates can be replaced for laying, and filling materials can be replaced, so as to simulate different throwing adjustments.

Abstract: The present invention discloses a method for measuring the distance between an excavator and a high-voltage transmission line, comprising obtaining camera parameters through the Zhang's Checkerboard calibration method; collecting images, inputting images fully entering the field of view of the camera into a model; obtaining the pixel coordinate of a target frame through the YOLOV5 algorithm; obtaining target world coordinate; analyzing lengths, widths, and heights of 3D models of excavators by using a clustering algorithm, and calculating the geometric mean of each cluster; and measuring the height of the transmission line by a millimeter wave radar, and estimating the height of an object from the steps above, thereby obtaining the distance between the excavator and the high-voltage transmission line.

Abstract: A circuit and a method for driving a SPIM are provide. The circuit comprises a driver and an alternating-current unit. The driver comprises a rectifying unit, a direct-current bus, a first inverter unit and a second inverter unit. The rectifying unit is connected to the direct-current bus, and the direct-current bus is respectively connected to the first inverter unit and the second inverter unit. The first inverter unit is connected to a first winding of the SPIM through a first switch, and the second inverter unit is connected to a second winding of the SPIM. The alternating-current unit comprises an input alternating-current power, a second switch and a capacitor. The input alternating-current power is connected to the first winding and the rectifying unit. The method can drive the SPIM in both variable frequency and industrial frequency, and hot switch from variable-frequency to industrial-frequency without interruption.

Abstract: A circuit and a method for driving a SPIM are provide. The circuit comprises a driver and an alternating-current unit. The driver comprises a rectifying unit, a direct-current bus, a first inverter unit and a second inverter unit. The rectifying unit is connected to the direct-current bus, and the direct-current bus is respectively connected to the first inverter unit and the second inverter unit. The first inverter unit is connected to a first winding of the SPIM through a first switch, and the second inverter unit is connected to a second winding of the SPIM. The alternating-current unit comprises an input alternating-current power, a second switch and a capacitor. The input alternating-current power is connected to the first winding and the rectifying unit. The method can drive the SPIM in both variable frequency and industrial frequency, and hot switch from variable-frequency to industrial-frequency without interruption.