All-attitude three-frame four-axis inertial platform servo ring control method

Abstract

The invention relates to an all-attitude three-frame four-axis inertial platform servo ring control method. The method includes the steps of: (1) closing the stability loop of a four-axis inertial platform system; (2) bringing a controller into a servo work mode, when the outer ring axis angle reaches a limited range, letting the controller enter a current position locking mode, otherwise, maintaining the servo work mode; (3) under the current position locking mode, when the outer ring axis angle and the inner ring axis angle reach turnover conditions, bringing the controller into a 90-degree turnover mode; otherwise, when the outer ring axis angle reaches the limited range, maintaining the current position locking mode, when the outer ring axis angle does not reach the limited range, switching the controller to the servo work mode; and (4) under the 90-degree turnover mode, turning the servo ring over from the current servo axis angle position forward or backward by 90 degrees by the controller, and switching the controller to the servo work mode. The method provided by the invention overcomes the disadvantages of the prior art, and endows the four-axis inertial platform with all-attitude working ability.

Description

technical field [0001] The invention relates to a control method for a follower ring of a full-attitude three-frame four-axis inertial platform system. Background technique [0002] According to the frame structure, the platform inertial guidance system can be divided into two-frame three-axis inertial platform (referred to as three-axis inertial platform) and three-frame four-axis inertial platform (referred to as four-axis inertial platform). After the inner ring shaft of the three-axis inertial platform rotates ±90°, the platform axis will be parallel to the outer ring axis, and one degree of freedom will be lost, resulting in abnormal operation of the three-axis inertial platform. This phenomenon is the "frame" of the three-axis inertial platform. Lock-in phenomenon". In order to avoid this phenomenon, it is necessary to set a limit angle (generally ±45°) in the rotation direction of the inner ring shaft of the three-axis inertial platform, that is, when using a three-a...

AI Technical Summary

Problems solved by technology

However, when the axis angle of the outer ring is around ±90°, the follow-up working mode will enter an unstable state and lose its normal function, resulting in abnormal operation of the platform system. This phenomenon is called the "90° outer ring problem" of the four-axis inertial platform

In response to this problem, the control of the follow-up ring has added a zero-lock mode. The function of the zero-lock mode is to lock the follow-up ring at a position where the angle of the follow-up axis is 0°, and reduce the four-axis inertial platform to a three-axis inertial platform. The outer ring can work at ±90°, but at this time the angle in the rotation direction of the inner ring shaft cannot exceed ±45°, and when switching from the follow-up mode to the zero-lock mode, the angle of the follow-up axis must be between ±45°, otherwise , the angle of the inner ring shaft will reach the limit angle position, the inner ring shaft will lose its degree of freedom, and the platform system will work abnormally

[0004] To sum up, the existing four-axis inertial platform has a dead zone no matter whether it is working in the follow-up mode or the zero-lock mode, and it cannot realize the true full-position work.

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