Development Of Hand-held Three-axis Stabilization Gimbal With Visual Tracking Function

Stabilization Gimbal is mostly used for aerial photography of drone.In addition to aerial photography,in many scenes of daily life,people also have high demand for stable,clear,smooth and high-quality video shot by themselves.Without auxiliary equipment,human motion shakes the camera and seriously affects the quality of the recorded video.In order to meet the needs of filming fixed target,in the Stabilization Gimbal Control System,we join the visual tracking technology to achieve the function that track an object and shoot it,which make the video shooting more diversified,higher degree of freedom.This article developed a hand-held Three-Axis Stabilization Gimbal Control System for mobile phones combined with visual tracking.The main research work is as follows:(1)We analyze the structure of hand-held Three-Axis Stabilization Gimbal,describe its main work process.Meanwhile we analyze its principle of self-balance and various factors that affect self-balance,and design self-balance control algorithm based on these.(2)According to the performance index of hand-held Three-Axis Stabilization Gimbal control system and the data characteristics of six-axis attitude device including accelerometer and gyroscope,we analyzes several filtering algorithms and selects the appropriate attitude calculation algorithm.(3)According to the gesture solution part of the attitude information,design Stabilization Gimbal self-balance control algorithm.Three-phase Brushless DC Motor(BLDC)is used in the Stabilization Gimbal control system.In the attitude control strategy,we use Sensored Magnetic Field Orientation Control(FOC)as the motor driving method based on a magnetically-sensing and non-contact absolute position encoder.Combining the motor driving algorithm with attitude information,we control the gimbal precisely.This control method is adaptable to load changes and has good robustness.(4)In the visual tracking part,based on the research of visual tracking theory,we design visual tracking algorithm and apply it to consumer-grade mobile devices,such as mobile phones.At the same time,taking the center of the camera lens as a reference,the position information of the tracked target is integrated with the Stabilization Gimbal control algorithm to keep the target near the center of the lens.(5)Design hardware and software systems.In order to simplify the hardware circuit,improve the production yield and reduce the cost of the Stabilization Gimbal,this paper adopts an improved method to remove the current loop based on the FOC.The control unit adopts the STM32f1 series of processing chips.In the visual tracking,relying on mobile phones and other mobile devices powerful processing capabilities,the location of the target being tracked is sent to the Gimbal control system via Bluetooth.Finally,on the basis of the above research,a hand-held Three-axis Stabilization Gimbal experiment machine with tracking function for mobile phones is prepared and field tested.The test results show that the hand-held Three-axis Stabilization Gimbal is stable and has good anti-jamming effect.It also has strong adaptability to load fluctuation and external interference,which can well meet the needs of various shooting scenes.