Abstract: A method for detecting a surface welding quality of friction stir welding includes: acquiring a continuous surface depth image of a welding seam; intercepting a surface depth image segment of the welding seam with a proper step size, and dividing the intercepted surface depth image segments of the welding seam into a front reference region, a thinned region and a rear reference region; judging whether flatness of the front reference region is less than a threshold, and if yes, taking a height of the front reference region at this point as a latest reference height; if no, judging whether the flatness of the rear reference region is less than the threshold, and if yes, taking a height of the rear reference region at this point as the latest reference height; if no, taking the reference height of previous depth image segment as the latest reference height; and calculating a difference.

Abstract: A method for detecting a surface welding quality of friction stir welding includes: acquiring a continuous surface depth image of a welding seam; intercepting a surface depth image segment of the welding seam with a proper step size, and dividing the intercepted surface depth image segments of the welding seam into a front reference region, a thinned region and a rear reference region; judging whether flatness of the front reference region is less than a threshold, and if yes, taking a height of the front reference region at this point as a latest reference height; if no, judging whether the flatness of the rear reference region is less than the threshold, and if yes, taking a height of the rear reference region at this point as the latest reference height; if no, taking the reference height of previous depth image segment as the latest reference height; and calculating a difference.

Abstract: A method and device for controlling a two-wire discharge circuit of a battery, introducing a whole-bus voltage outer loop and an inductive current average value or inductive current actual value closed loop as a main control loop of the two-wire discharge circuit of the battery so as to guarantee a stable voltage of the whole bus. On the basis of the main control loop, duty ratios of switch transistors in respective discharge branches are adjusted to control the respective discharge branches to independently charge and discharge corresponding half-buses so as to balance the bus voltage. The method and the device avoid accessing a central wire of the battery and any additional circuits, and satisfy a technical specification of a three-wire access of the battery, thereby improving a circuit performance of the two-wire discharge circuit of the battery.

Abstract: A method and device for controlling a two-wire discharge circuit of a battery, introducing a whole-bus voltage outer loop and an inductive current average value or inductive current actual value closed loop as a main control loop of the two-wire discharge circuit of the battery so as to guarantee a stable voltage of the whole bus. On the basis of the main control loop, duty ratios of switch transistors in respective discharge branches are adjusted to control the respective discharge branches to independently charge and discharge corresponding half-buses so as to balance the bus voltage. The method and the device avoid accessing a central wire of the battery and any additional circuits, and satisfy a technical specification of a three-wire access of the battery, thereby improving a circuit performance of the two-wire discharge circuit of the battery.

Abstract: A repetitive controller, a control method thereof and a feedback control system are disclosed. The repetitive controller includes an internal model section, a periodic delay module and a compensation module. An input quantity is input into the repetitive controller via an input terminal of the internal model section; the internal model section, the periodic delay module and the compensation module are connected in series. The repetitive controller further includes a particular frequency selection and passing module, connected in series with the internal model section, the periodic delay module and the compensation module or configured on a forward path of the internal model section. In the repetitive controller of the disclosure, a particular frequency selection and passing module is incorporated such that only the harmonic at the selected frequency are filtered out, thereby realizing the function of removing the harmonic at the particular frequency.

Abstract: A repetitive controller, a control method thereof and a feedback control system are disclosed. The repetitive controller includes an internal model section, a periodic delay module and a compensation module. An input quantity is input into the repetitive controller via an input terminal of the internal model section; the internal model section, the periodic delay module and the compensation module are connected in series. The repetitive controller further includes a particular frequency selection and passing module, connected in series with the internal model section, the periodic delay module and the compensation module or configured on a forward path of the internal model section. In the repetitive controller of the disclosure, a particular frequency selection and passing module is incorporated such that only the harmonic at the selected frequency are filtered out, thereby realizing the function of removing the harmonic at the particular frequency.