ROS End-Effector Grasping Actions
TODO check explain better this page, put examples for create actions
In ROS End-Effector, an Action is a movement that the end effector can be commanded to do. In practice, an action is a container that include the position for all the involved joints. There are three main categories of Action:
Primitive Actions
Referred as ActionPrimitive in the code, this kind of actions is the one that is automatically detected thanks to the FindAction node (during the offline phase). Until now the following primitives have been defined:
Primitive |
Fingers |
Joints |
Description |
Constraints |
|---|---|---|---|---|
Trig |
1 |
1+ |
Move all finger joints toward their bound |
At least one joint that moves only one finger |
TipFlex |
1 |
1 |
Move the last joint of the finger toward its bound |
At least 2 joints that moves only one finger |
FingFlex |
1 |
1 |
Move the first joint of the finger toward its bound |
At least 2 joints that moves only one finger |
PinchTight |
2 |
1+ |
Collision between two fingertip links |
|
PinchWeak |
2 |
1+ |
Movement of two fingertips links towards each other but without collision |
|
MultiPinchTight_N |
N (\(\geq\) 3) |
1+ |
Collision between N (\(\geq\) 3) fingertip links |
|
SingleJointMultipleTips_N |
N (\(\geq\) 2) |
1 |
Move a joint that move more than one finger toward its bound |
A joint that move more than one finger (e.g. grasp for lot of hands |
Generic Actions
ActionGeneric are the customizable type. With ROSEE, you can add a custom action and then command the end-effector to do that action many time you want during the execution. Generic Action can be built in 2 different ways:
You can write by hand a yaml file (see files in config/generic
You can fill c++ structures with your code, and then emit the yaml file (or use directly the action as command)
There is also a third possibility: creating a ActionComposed object. This is a class that permit you to define an action as sum of other actions. For example, a grasp can be see as a sum of trig of each finger.
Timed Actions
ActionTimed are a special type of actions that permit you to execute more inner actions one after the other. As an example, this can be useful to perform a wide grasp. First we want the finger to spread, and then perform the clousure toward the palm. These type of action are creable in the code, using the class functions.