Html 控制器中的Angularjs$范围。如何取得身份证？

请帮我拿控制器。rails应用程序页面已选择：系统组和系统。系统有设备，系统组有系统。当我选择一组系统时，我希望看到属于该组的所有系统的设备。目前，仅在选择his系统的情况下显示设备

 $scope.loadEquipments = (complex_id, object) ->
  if object == 'group'
    $scope.systems = SystemResource.where
      ppr_group_system_id: complex_id
    # load equipment of system
    $scope.equipments = EquipmentResource.where
      ppr_system_id: $scope.systems

  else if object == 'system'
    # load equipment of system
    $scope.equipments = EquipmentResource.where
      ppr_system_id: complex_id
  else
    $scope.equipments      = []
    $scope.equipment_works = []

如何获取$scope.systems的ID？或者怎么做

其中方法设备工厂：

where: (params, successHandler) ->
  @service.query
    ppr_equipment: params
    ((equipments) -> successHandler?(equipments))
    @errorHandler

视图：

系统
选择系统

组的视图相同

  <div class='form-group'>
    <label class='control-label' for='issue_service_id'>System</label>
    <select required class='form-control' id='current_system' data-ng-model='current_system'
            data-ng-options='system.id as system.title for system in systems'
            data-ng-change="loadEquipments(current_system, 'system')">
      <option value=''>Select system</option>
    </select>
  </div>