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jimazeyu / franka_grasp_baseline

Table top manipulation calibration between the robot arm, the fixed cameras and the camera in hand.
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How to obtain the transformation matrix of the gripper relative to the Franka base coordinate system #2

Open upc-ghy opened 5 months ago

upc-ghy commented 5 months ago

Sorry to bother you, may I ask how to obtain the transformation matrix of the gripper relative to the Franka base coordinate system. I have used Realsense and Franka robots for hand eye calibration to obtain the transformation matrix from the camera to the end axis of the robotic arm. How to obtain the coordinate system from the end axis to the Franka base, and how to obtain the Franka gripper relative to the base coordinate system?

jimazeyu commented 5 months ago

Cam to gripper is from the calibration result. Gripper to base is directly from the robot directly, something like franke.get_pose(). Combing the two transformation then you can know cam to base.

upc-ghy commented 5 months ago

@jimazeyu Thank you very much for your reply and time! I know that the result of camera hand eye calibration is the transformation of the camera coordinate system relative to the end axis Link8 of the Franka robotic arm. If I obtain the transformation from the end axis to base (Link0) using the method you mentioned franka. get_pose(), based on these two, I can obtain the coordinates of the point cloud in the base coordinate system. But in real grasping, it is hoped that the Franka robot's gripper moves to a certain position, and the gripper is connected to the end axis. Is the coordinate system of these two the same? I don't quite understand. How do we obtain the transformation of the gripper relative to the base?

What do the positions, offsets, and rotations set on the desk interface in the picture represent? Which coordinate system is the translation and rotation in which coordinate system image

Does the panda. movetto_jointposition (sol [0])in your code control whether the end axis or the gripper reaches a certain position image

jimazeyu commented 5 months ago

I don't understand what you mean. Since you have gotten the coordinates of the point cloud in the base coordinate system, then you knw everything. I've never used GUI before. If you mean you want to control the gripper to a certain pose, it's another problem, i used a IK lib to solve that. I generated the joint pose and visualize it in a virtual env, if it's right, i just send it to the arm.

upc-ghy commented 5 months ago

Thank you for your reply！ @jimazeyu I just don't quite understand whether to control the end arm of Franka to a certain position or to control the gripper to a certain position. Generally speaking, it should be to obtain the gripper's grasping position, convert it to the end arm position, and then control the end arm of Franka to move to this position.

jimazeyu commented 5 months ago

“Generally speaking, it should be to obtain the gripper's grasping position, convert it to the end arm position, and then control the end arm of Franka to move to this position.” That's what i've down in this repo.