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It fails to return to its initial position.

asked 2019-03-31 21:22:54 -0600

jdj gravatar image

I try to get the robot back to its initial position.

First, I used the 2D Pose Estimate in rviz to find the initial position and move the robot to Goal Position.

The robot tries to return to its initial position after it has arrived at the goal position properly However, the position of robot in rviz is different from the position of robot in reality while rotating, so it can not return.

When the robot moves in one direction, it arrives well, but I wonder why the round trip does not work properly.

I need your help. Thank you.

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You should add more information to your question: What robot are you using? What commands are you running? What are the initial and goal positions? What error is being displayed? Why are you using the 2D Pose Estimate?

fvd gravatar image fvd  ( 2019-04-01 00:11:28 -0600 )edit

I want to navigate using a mobile robot with four wheels. After moving from the initial position to the goal position, we try to return to the initial position but can not return to the initial position.

The actual rotation speed of the robot is different from the rotation state of the robot on the rviz, and I think that the odometry of the mobile robot with four wheels is mistakenly written.

I want to know how to create an odometry for a mobile robot with four wheels.

jdj gravatar image jdj  ( 2019-04-01 01:40:21 -0600 )edit

"rotation speed" of the motors or the movement speed of the whole robot? What kind of wheels are you using? Holonomic wheels can have a lot of slip and may not work as you expect without feedback from a localization mechanism.

fvd gravatar image fvd  ( 2019-04-01 01:52:56 -0600 )edit

I want to know the moving speed of the robot, the dynamixel motor for the motor, and the wheel for the 3D printer.

jdj gravatar image jdj  ( 2019-04-01 01:56:07 -0600 )edit

So you are using a Dynamixel motor with 3D printed wheels? What happens exactly when you move the robot? Does it slip? How far is it off the target? In which direction? How far do you move it? Please add more details.

fvd gravatar image fvd  ( 2019-04-01 02:04:07 -0600 )edit

I put a track on both wheels to prevent slipping, and I want to go straight about 10m and then come back again.

jdj gravatar image jdj  ( 2019-04-01 02:09:15 -0600 )edit

A track? Like rubber? Rails? How far away is the robot from where it is supposed to be after the two moves? Please respond to all of the questions.

fvd gravatar image fvd  ( 2019-04-01 06:13:40 -0600 )edit

The material of the track is rubber. I try to make a round trip to just 10 meters away.

jdj gravatar image jdj  ( 2019-04-02 01:54:18 -0600 )edit

1 Answer

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answered 2019-04-01 00:19:42 -0600

fvd gravatar image

updated 2019-04-01 00:20:19 -0600

I assume you are requesting a 7-DOF robot (like a KUKA iiwa) to move to a cartesian Pose. Because it has a redundant degree of freedom, the redundant "elbow" angle is changed after the two moves.

The easiest way to return to a set configuration is to record the position in joint angles, not in cartesian space. It is convenient to set up a named pose via the MoveIt setup assistant. You can then select the named poses in Rviz as a planning target.

To find the joint angles of your phsyical robot in a certain position, you can also run rostopic echo /joint_states and copy the results.

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Asked: 2019-03-31 21:22:54 -0600

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Last updated: Apr 01 '19