[ros-users] values are zero in joint.h

[Andreas Vogt]

Hi,

The values,

  /// The joint position in radians or meters (read-only variable)
  double position_; 
  /// The joint velocity in randians/sec or meters/sec (read-only variable)
  double velocity_;
  /// The measured joint effort in Nm or N (read-only variable)
  double measured_effort_;

are zero all the time but the joint is turning. Where is the problem?

I am using this in the xml:

<transmission name="joint_p-a1_trans" type="SimpleTransmission">
                <actuator name="joint_p-a1_motor" />
                <joint name="joint_p-a1" />
                <mechanicalReduction>1</mechanicalReduction>
                <motorTorqueConstant>1</motorTorqueConstant>
    </transmission>

in the yaml:

  my_controller_ns:
    type: MyControllerPlugin
    wheel1: joint_c-w1


in the code:


  wheel1_state = robot->getJointState(wheel1);
  if (! wheel1_state )
  {
    ROS_ERROR("MyController could not find joint named '%s'",
               wheel1.c_str());
    return false;
  }
...
...
ROS_ERROR(  wheel1_state>commanded_effort etc...

-- 

 Andreas Vogt 
 Logistics and Production Robotics

 DFKI Bremen
 Robotics Innovation Center
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