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Using SetForce and GetJoint() Function

I'm trying to use the SetForce() function on my sdf model using a plugin, on a particular joint using the following commands:

std::string joint1 = this->model->GetName() + "::" + "rearleftwheel_joint";

physics::JointPtr rearleftwheel_joint=this->model->GetJoint(joint1);

rearleftwheel_joint->SetForce(0,20.0);

While running this plugin on my sdf model, I keep getting this error:

gzserver: /usr/include/boost/smartptr/sharedptr.hpp:648: typename boost::detail::spmemberaccess::type boost::sharedptr::operator->() const [with T = gazebo::physics::Joint; typename boost::detail::spmember_access::type = gazebo::physics::Joint*]: Assertion `px != 0' failed.

I couldn't find much documentation for this error online; could someone please help me with this?

Running gazebo 7.14 and ubuntu 16.04

Plugin code:

Asked by rmv24 on 2019-04-14 22:51:04 UTC

Comments

@kumpakri could you have a look at this? Turns out I was running the wrong plugin when I said it worked

Asked by rmv24 on 2019-04-14 22:52:51 UTC

C:\fakepath\throttle_plugin2.cc - plugin code

Asked by rmv24 on 2019-04-15 09:23:12 UTC

Can you update this question with your SDF model? That might help with diagnosing the problem.

Asked by josephcoombe on 2019-04-15 14:18:55 UTC

@josephcoombe, I'm using the Polaris Ranger XP900 file from the model database: https://bitbucket.org/osrf/gazebo_models/src/e6d645674e8a99cb7955ce3b9a1fbe26c58c41f2/polaris_ranger_xp900/?at=default

Asked by rmv24 on 2019-04-15 18:29:12 UTC

Your plugin has this line std::string joint = this->model->GetName()+ "polaris_ranger_xp900" + "rear_left_wheel_joint" ; The "polaris_ranger_xp900" substring is what cases the plugin not to find the joint (There for Assertion px != 0 failed.) The name of the model is already provided by the this->model->GetName() and you need to devide the model name and the joint name with :: sign. Just as in you question description.

Asked by kumpakri on 2019-04-17 03:12:29 UTC

@kumpakri, I'd already tried doing what you have suggested, but the same error showed up.

Asked by rmv24 on 2019-04-17 09:20:31 UTC

Answers