https://code.cor-lab.de/https://code.cor-lab.de/favicon.ico?14019720732014-01-06T09:56:42ZOpen Source Collaboration PlatformRobot Control Interface - Bug #1713: RCI is getting messed up with Torques, JointTorques and TorqueSensinghttps://code.cor-lab.de/issues/1713?journal_id=48632014-01-06T09:56:42ZAnonymous
<ul><li><strong>Category</strong> set to <i>Modeling</i></li><li><strong>Status</strong> changed from <i>New</i> to <i>Feedback</i></li><li><strong>Target version</strong> set to <i>rci0.5</i></li></ul><p>Christian Emmerich wrote:</p>
<blockquote>
<p>In my opinion, RCI is a little messed up with the different torque dtos and the sensing interface. There is a JointTorque type (joint space), a Torque (cartesian space) type and a TorqueSensing interface which doesn't sense Torques (as the name might suggest) but JointTorques.</p>
</blockquote>
<p>You are right. This confusion came up as <code>Toqques</code> was introduced way after <code>JointTorques</code>, when the TorquesSensing interface was already created for JointTorques. Do you have a suggestion/preference on how to clean up this mess?</p>
<blockquote>
<p>An interface for sensing Torques (the cartesian ones) is missing at all.</p>
</blockquote>
<p>Indeed. Can you file an (short!) issue for this?</p>
<blockquote>
<p>By the way, is it necessary at all to have two different/parallel torque types? Is there any conceptual difference between them? Maybe one is a specification/derivate of the other one...?</p>
</blockquote>
<p>This was subject to extensive discussion already and in my opinion these are indeed different concepts (but I am open for other opinions), as reflected in the API documentation of these concepts. <code>JointTorques</code> are as the name suggests torques in / around / about mechanical joints. <code>Torques</code>, however, are the three torque components in cartesian space around x, y and z. They share the same representation (units), but the latter one is for example restricted to 3 components.</p>
<p>This doesn't mean of course, that it can't be (technically) derived from each other.</p> Robot Control Interface - Bug #1713: RCI is getting messed up with Torques, JointTorques and TorqueSensinghttps://code.cor-lab.de/issues/1713?journal_id=48702014-01-06T19:33:52ZC. Emmerichcemmeric@cor-lab.de
<ul></ul><p>Arne Nordmann wrote:</p>
<blockquote>
<p>Do you have a suggestion/preference on how to clean up this mess?</p>
</blockquote>
Hmm, I think you have to options here:
<ol>
<li>You stick with the current difference between torques and joint torques. Then obviously the current <code>TorqueSensing</code> needs to be renamed to <code>JointTorqueSensing</code> and a new <code>TorqueSensing</code> interface needs to be created</li>
<li>You kill one of the types and dont care about conceptual differences. Then only one type and one sensing interface is needed (which should be named corresponding to each other).</li>
</ol>
<p>I would prefer number 1. In my opinion (and the more I think about the wrench type and cartesian torques) there is a conceptual difference between a (multi-dim) joint torque and a 3-dim cartesian torque. But then, the latter one actually is the torque part of a wrench and you can re-use it for rethinking that type (<a href="https://code.cor-lab.de/issues/1715" class="issue tracker-2 status-3 priority-5 priority-high3 closed" title="Provide better interface for creation of wrench (Resolved)">#1715</a>, <a href="https://code.cor-lab.de/issues/1043" class="issue tracker-1 status-4 priority-5 priority-high3" title="Modelisation of Wrench seems wrong (Feedback)">#1043</a>) ;-)</p>