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Spec 1.12: link_state, joint_state changes #1461
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Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Include joint_state.sdf from model_state.sdf and state.sdf for //world/joint states. Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Signed-off-by: Steve Peters <scpeters@openrobotics.org>
This deprecates the //joint_state/angle element in favor of a joint state specification that supports multi-axis joints by mirroring the //joint/axis and //joint/axis2 elements with * //joint_state/axis_state * //joint_state/axis2_state Each axis state can specify position, velocity, and acceleration, each with an optional @Degrees attribute. Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Deprecate the //link_state/velocity and //link_state/acceleration elements since the `pose` type is not well-suited to represent vector6 data. Add pairs of vector3 angular_* and linear_* elements for velocity and acceleration to replace the pose-typed elements. Signed-off-by: Steve Peters <scpeters@openrobotics.org>
also rephrase some element descriptions Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Also use a larger values in an angular_velocity. Signed-off-by: Steve Peters <scpeters@openrobotics.org>
update migration guide Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Migration.md
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### Deprecations | ||
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1. **joint_state.sdf**: | ||
+ `//joint_state/angle` is deprecated in favor of `//axis_state/position` |
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Just to make it clear that it's still within joint_state
.
+ `//joint_state/angle` is deprecated in favor of `//axis_state/position` | |
+ `//joint_state/angle` is deprecated in favor of `//joint_state/axis_state/position` |
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ok, will fix
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Migration.md
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+ `//link_state/wrench` is deprecated in favor of `//link_state/angular_wrench` | ||
and `//link_state/linear_wrench`. |
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I've commonly seen the term wrench refer to the 6D vector that represents torques and forces. If we split them into two 3D vectors, would it make sense to call them torque and force instead of angular_wrench and linear_wrench?
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yeah, that's a good point; I was trying to keep symmetry with angular_
and liner_
prefixes, but force
and torque
are better. I will update this
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I updated the pull request description with force
and torque
as well
sdf/1.12/joint_state.sdf
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<attribute name="degrees" type="bool" default="false" required="0"> | ||
<description> | ||
If true, the joint position is expressed in units of degrees [deg], |
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Can you specify that this would not apply to prismatic joints and the unit will be meters regardless of this attribute?
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sdf/1.12/joint_state.sdf
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<attribute name="degrees" type="bool" default="false" required="0"> | ||
<description> | ||
If true, the joint velocity is expressed in units of degrees per |
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Similar to the position, can you add a qualifier for prismatic joints?
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Contains the state of the first joint axis. | ||
</description> | ||
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<element name="position" type="double" default="0" required="0"> |
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Shouldn't position be a vector?
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this position
element is under //joint_state/axis_state
and represents the position of the first axis / degree of freedom. there is another position element under //joint_state/axis2_state
for the second axis. this mirrors the specification of the //joint/axis
and //joint/axis2
elements
Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Signed-off-by: Steve Peters <scpeters@openrobotics.org>
Signed-off-by: Steve Peters <scpeters@openrobotics.org>
🎉 New feature
Closes #1366, #83
Summary
This makes several changes to the specification for the
<state/>
element in SDFormat 1.12. It does not include DOM objects, which will be implemented in a future pull request. Note that part of the motivation for these changes is to allow specification of initial model state in gz-sim (see prototype in gazebosim/gz-sim#2359).Link state changes
vector3
datatypes to represent twist, spatial acceleration, and wrenches instead of apose
datatype, which distorts the angular values by interpreting them as Euler angles. This resolves link_state velocity, acceleration, and wrench data should not use pose type #1366. The new elements for velocity and acceleration have names starting withlinear_
orangular_
, while the replacement forwrench
isforce
andtorque
://link_state/linear_velocity
//link_state/angular_velocity
//link_state/linear_acceleration
//link_state/angular_acceleration
//link_state/force
//link_state/torque
vector6
type and renamevelocity
to twist,acceleration
tospatial_acceleration
. While this could allow for shorter XML files, it would require features to be added to gz-math to supportmath::Vector6
and has the potential for error in remembering which order to specify the angular and linear coefficients. Using a pair ofvector3
types is more verbose but more clear and is already supported by gz-math and libsdformat.Joint state changes
//joint_state/angle
and//joint_state/angle/@axis
to//joint_state/axis_state/position
and//joint_state/axis2_state/position
. This more closely matches the structure of//joint/axis
and//joint/axis2
, and the rename fromangle
toposition
was suggested in add joint velocity and joint acceleration to state structure #83 (comment).velocity
,acceleration
, andeffort
to//joint_state
. The addition ofvelocity
andacceleration
was requested by add joint velocity and joint acceleration to state structure #83, andeffort
is added to matchwrench
used in link states.Link and Joint states: add boolean
@degrees
attribute to some angular types@degrees
attribute to the following elements://link_state/angular_velocity
//link_state/angular_acceleration
//joint_state/axis_state/position
//joint_state/axis_state/velocity
//joint_state/axis_state/acceleration
//joint_state/axis2_state/position
//joint_state/axis2_state/velocity
//joint_state/axis2_state/acceleration
deg
instead ofrad
,deg/s
instead ofrad/s
, ordeg/s^2
instead ofrad/s^2
. The attribute is not added to joint effort and link wrench types.Allow specification of model state within a model
//world/state
element. To allow a model to specify a default initial configuration or initial velocity, the//model/model_state
element is added. If a world contains both a//world/state
and a model that specifies its own state, I think the world state should take precedence.<include>
d, the//model/include/model_state
and//world/include/model_state
elements are added as well.Test it
The
INTEGRATION_nested_model
test has been updated to use some of the new//link_state
elements, but there are not yet any tests using the new//joint_state
or//model/model_state
elements.Checklist
codecheck
passed (See contributing)Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining
Signed-off-by
messages.