Joints widget: avoid flickering of the nullspace slider

Show a (disabled) dummy slider if there is no nullspace. This avoids flickering between zero and one slider, which is the most common case. Also provide some tooltips to explain the usage.
rickstaa · Dec 8, 2021 · 4592f89 · 4592f89
1 parent 8dc3701
commit 4592f89
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Showing 2 changed files with 35 additions and 2 deletions.
diff --git a/...ros/visualization/motion_planning_rviz_plugin/src/motion_planning_frame_joints_widget.cpp b/...ros/visualization/motion_planning_rviz_plugin/src/motion_planning_frame_joints_widget.cpp
@@ -335,6 +335,9 @@ void MotionPlanningFrameJointsWidget::updateNullspaceSliders()
   if (i == 0)
     nullspace_.resize(0, 0);
 
+  // show/hide dummy slider
+  ui_->dummy_ns_slider_->setVisible(i == 0);
+
   // hide remaining sliders
   for (; i < ns_sliders_.size(); ++i)
     ns_sliders_[i]->hide();

diff --git a/...ualization/motion_planning_rviz_plugin/src/ui/motion_planning_rviz_plugin_frame_joints.ui b/...ualization/motion_planning_rviz_plugin/src/ui/motion_planning_rviz_plugin_frame_joints.ui
@@ -43,14 +43,44 @@
       </widget>
      </item>
      <item>
-      <widget class="QLabel" name="label">
+      <widget class="QLabel" name="nullspace_label">
+       <property name="toolTip">
+        <string>The sliders below allow for jogging the nullspace of the current configuration,
+i.e. trigger joint motions that don't affect the end-effector pose.
+
+Typically, redundant arms (with 7+ joints) offer such a nullspace.
+However, also singular configurations provide a nullspace.
+
+Each basis vector of the (linear) nullspace is represented by a separate slider.</string>
+       </property>
        <property name="text">
         <string>Nullspace exploration:</string>
        </property>
       </widget>
      </item>
      <item>
-      <layout class="QVBoxLayout" name="nullspace_layout_"/>
+      <layout class="QVBoxLayout" name="nullspace_layout_">
+       <item>
+        <widget class="QSlider" name="dummy_ns_slider_">
+         <property name="enabled">
+          <bool>false</bool>
+         </property>
+         <property name="toolTip">
+          <string>The slider will become active if the current robot configuration has a nullspace.
+That's typically the case for redundant robots, i.e. 7+ joints, or singular configurations.</string>
+         </property>
+         <property name="minimum">
+          <number>-1</number>
+         </property>
+         <property name="maximum">
+          <number>1</number>
+         </property>
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+        </widget>
+       </item>
+      </layout>
      </item>
     </layout>
    </item>