Where effort joint values come from
Dear all,
When I subscribe to the topic /joint_states I get the name of the joints, the angular positions of these joints and the current effort values. I assume that the effort values are in M.m, but my question is, where these effort values come from? The effort values should depend on the force and torque values of the parent and the child link of a joint. Torque and forces are denoted by 3D vectors (x,y,z), in N.m as well. So how can I get these effort values if I have the 3D force and torque vectors of the parent and child links?
Thank you!!!
It doesn't matter for the more fundamental question, but can you please give a bit of context? Are you referring to a specific
/joint_states
topic (ie: published by a specific driver)?Yes exactly. For example: rostopic echo /joint_states or for any specific group like rostopic echo /left_arm/joint_states.
Thank you
left_arm
? Are you using a baxter?Please provide a bit more context.
No, I am using a Kinova Jaco arm attached to a Kinova Movo base
I also want to know this question! I use UR5, which has no torque sensor on each joint/link. So the values are from motor currents or a computed torques?
ok, I got the result of UR5.
/joint_states/effort
is motor current, see this issue.About the unit of
effort
, you could see this link. Theeffort
isNm
for revolute.@Yummy_Ou: all messages are documented. For
JointState
: sensor_msgs/JointState:which all makes sense, as those are the appropriate (derived) SI units, which adheres to REP 103.