3results about How to "Improve precision control" patented technology

This invention discloses a control method and system for indirectly obtaining commutation signals based on BLDC terminal voltage, belonging to the field of brushless DC motor positionless control. The method includes: sampling the voltage of the floating phase at the current commutation point after a set electrical angle; sampling the voltage of the floating phase at the next detected zero-crossing point after the current commutation point; calculating the actual zero-crossing time using the linear relationship between the back electromotive force of the first and second sampling points; obtaining the lag compensation time from the zero-crossing point to the commutation point by combining the difference between the actual and detected zero-crossing times and the commutation reference time delay; sampling the same floating phase at an electrical angle interval of α after the current commutation point and at an electrical angle interval of (60°-α) after the turn-off point, summing the two samples, and determining whether the commutation is leading or lagging based on the result; and using a PI regulator to correct the lag compensation time in a closed loop. This invention is simple, practical, and can accurately obtain the commutation signal.

The utility model discloses an embodiment relates to a kind of lifting movement mechanism of three comprehensive test box, box fixed bracket is set below the lifting movement mechanism of three comprehensive test box;Test box body is fixed above box fixed bracket;The whole of fixed test box body and box fixed bracket is placed in screw fixed frame;Horizontal moving platform is fixedly connected at the bottom of screw fixed frame;Driving device is fixed in box fixed bracket;Turbine screw lifting machine assembly is set in screw fixed frame;Driving device drives turbine screw lifting machine assembly synchronous lifting operation to lift box, its advantage is that: stable structure, stable operation, little by environmental factor, support greater load, lifting height is higher, with certain self-locking capacity, and precision control is high, structure is simple, solve in prior art, the technical problem of unstable operation, volume and load restriction, maintenance complex, potential leakage risk of traditional hydraulic scissor brace.

This utility model discloses an installation and alignment device for T-bolts on large equipment foundations, belonging to the field of concrete foundation technology, and mainly used for the installation of large equipment foundations. The technical problem to be solved by this utility model is to provide an installation and alignment device for T-bolts on large equipment foundations, including a vertically arranged support column to enclose and form a T-bolt sleeve installation cavity. A T-bolt sleeve is provided inside the installation cavity. The support column includes a pre-embedded section and an extension section. The pre-embedded section is located within the secondary poured concrete, and a tie beam is provided between two adjacent pre-embedded sections at intervals along its length. One side of the T-bolt sleeve is fixedly connected to the tie beam. The extension section is located above the secondary poured concrete, and a alignment frame beam for hanging alignment lines is provided between two adjacent extension sections. This device can both fix the installation position of the T-bolt sleeve and be used as an alignment frame for aligning the T-bolt sleeve, improving installation accuracy and reducing material consumption.