ROV attitude control method based on error quaternion feedback

Abstract

The invention discloses an ROV attitude control method based on error quaternion feedback. An inertial coordinate system and an ROV motion coordinate system are established; a three-freedom-degree rotating attitude of an ROV is modeled; an attitude sensor detects the ROV and outputs an attitude quaternion, the current quaternion of the ROV is compared with a target quaternion, and an error quaternion is solved; the error quaternion is input into a PID controller, needed torque on three axes in the ROV motion coordinate system is calculated, a processor controls the voltage of a propeller motor according to the needed torque, corresponding push force is generated, the ROV attitude adjustment is finished, the ROV is made to rotate by 360 degrees without the dead angle, the attitude is stable, and operation under the complex work environment is achieved.

Description

technical field [0001] The invention relates to an ROV attitude control method, in particular to an ROV attitude control method based on error quaternion feedback. Background technique [0002] Unmanned remotely operated submersibles (Remote OperatedVegicle) can be used for various purposes such as operations and observations. Depending on the specific use, its technical implementation schemes are also different. The traditional ROV's motion is mostly linear motion of front and rear, left and right, up and down, and rotational motion of the Z axis. However, in some more complex operating environments, such as attaching to the bottom of the ship, walls, pipes, etc. with continuous and large attachment surfaces, ROVs are required to be able to complete 360° rotation in the X, Y, and Z directions without dead angles. And achieve posture stability. Correspondingly, ROV control cannot use the commonly used Euler angle control method for attitude control, because the Euler angle...

AI Technical Summary

Problems solved by technology

Among them, the Euler angle is easy to understand, the image is intuitive, and only three values ​​are needed, but the rotation order of the three values ​​​​will lead to different results, and must be rotated in a fixed order, and it will cause the gimbal lock phenomenon; Quaternary The numerical method can avoid the gimbal lock phenomenon. Only a four-dimensional quaternion can perform rotation around any vector passing through the origin, and can provide a smooth difference, but its understanding is relatively difficult and unintuitive. Compared with Euler angle Relatively complicated; the rotation axis of the rotation matrix method can be any vector, but the matrix method requires 16 elements, which is not only difficult to understand, but also greatly increases the amount of calculation

[0004] Chinese patent 201410422945.2 discloses a pose control method for underwater robots, which mainly obtains the Euler angles through the attitude quaternion and inputs the error of the expected value into the PID controller for calculation, but still cannot realize 360° no dead angle rotation motion control

Images