A vision-guided approach method for cascaded manipulators driven by an online CAD model

Abstract

The invention discloses a vision-guided approach method for a cascaded manipulator driven by an online CAD model. In the pose estimation stage, the present invention obtains the estimated pose by matching the pre-calculated pose hierarchy tree, and then automatically plans the trajectory according to the estimated pose and the target pose, and generates several path template images online in the program, The robotic arm is guided to approach the part along a preset path, and finally the precise alignment is accomplished using an image-based visual servoing method in the precise guidance stage. The invention has high guiding precision and controllable trajectory, avoids the disadvantage of using a single method, and can meet the requirements of practical industrial applications.

Description

technical field [0001] The invention relates to the technical fields of computer vision and industrial automation, in particular to an online CAD model-driven cascade manipulator vision-guided approach method. Background technique [0002] The precise guidance of the robotic arm has always been an important part of industrial automation, but at present, the robots on many industrial assembly lines can only complete repetitive and monotonous actions. It is not enough. When the position and orientation of the part relative to the end effector of the manipulator is uncertain, the manipulator cannot complete some precise work. Therefore, it is particularly important to study a reliable approach method for the precise guidance of the manipulator. [0003] At present, the methods for recognizing the pose of parts and guiding the approach of the manipulator are mainly divided into two categories: one is to calculate the error between the current image (or position) and the target i...

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Problems solved by technology

[0002] The precise guidance of the robotic arm has always been an important part of industrial automation, but at present, the robots on many industrial assembly lines can only complete repetitive and monotonous actions. It is not enough to do enough. When the position and orientation of the part relative to the end effector of the manipulator is uncertain, the manipulator cannot complete some precise work. Therefore, it is particularly important to study a reliable approach method for the precise guidance of the manipulator.

[0003] At present, the methods for recognizing the pose of parts and guiding the approach of the manipulator are mainly divided into two categories: one is to calculate the error between the current image (or position) and the target image (or position) through the method of visual servoing. The error signal is used as feedback to control the movement of the manipulator. The advantage of this method is that the control precision is high. The disadvantage is that the part may be out of the camera's field of view and lose image features during the movement, so that the manipulator cannot converge to the desired target state; The second is to calculate the relative pose directly through the current image and the target image, and then control the robotic arm to complete the approach. The advantage of this method is that it can calculate the pose of the part only by relying on the image of the starting position, and hand over the path planning part to the robot. The arm controller is completed, the disadvantage is that the difference between the two images cannot be too large, the path cannot be planned, and its control method is open-loop control, which cannot guarantee the final accuracy

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