AngulerJS set check box checked default with checklist-model

I've check boxes inside the ng-repeat loop and I'm using checklist-model to get the checked value. However I need to set those check boxes checked in by default. I've used ng-checked="true". however it shows check box is checked but value is empty when submit it.
code is:

<tr data-ng-repeat="line_items in orderItems">
<td align="center" data-ng-if="line_items.id">
    <div class="vd_checkbox checkbox-success">
          <input type="checkbox" id="checkbox-{{$index}}"
              checklist-model="comp.orderItemSelect"
              checklist-value="line_items.id"  ng-checked="true"/>
          <label for="checkbox-{{$index}}">&nbsp;</label>
     </div>
</td>
<tr>

ng-checked show check box is checked but checklist-model not get it as selected. How do I default checked checkbox with checklist-model ?