AP_UAVCAN: add option bit for disabling Node Unhealthy check

libraries/AP_UAVCAN/AP_UAVCAN.cpp

@@ -122,7 +122,7 @@ const AP_Param::GroupInfo AP_UAVCAN::var_info[] = {
     // @Param: OPTION
     // @DisplayName: UAVCAN options
     // @Description: Option flags
-    // @Bitmask: 0:ClearDNADatabase,1:IgnoreDNANodeConflicts,2:EnableCanfd
+    // @Bitmask: 0:ClearDNADatabase,1:IgnoreDNANodeConflicts,2:EnableCanfd,3:IgnoreDNANodeUnhealthy
     // @User: Advanced
     AP_GROUPINFO("OPTION", 5, AP_UAVCAN, _options, 0),
     

libraries/AP_UAVCAN/AP_UAVCAN.h

@@ -202,6 +202,7 @@ public:
         DNA_CLEAR_DATABASE        = (1U<<0),
         DNA_IGNORE_DUPLICATE_NODE = (1U<<1),
         CANFD_ENABLED             = (1U<<2),
+        DNA_IGNORE_UNHEALTHY_NODE = (1U<<3),
     };
 
     // check if a option is set

libraries/AP_UAVCAN/AP_UAVCAN_DNA_Server.cpp

@@ -475,8 +475,9 @@ void AP_UAVCAN_DNA_Server::handleNodeStatus(uint8_t node_id, const NodeStatusCb
     if (node_id > MAX_NODE_ID) {
         return;
     }
-    if (cb.msg->health != uavcan::protocol::NodeStatus::HEALTH_OK ||
-        cb.msg->mode != uavcan::protocol::NodeStatus::MODE_OPERATIONAL) {
+    if ((cb.msg->health != uavcan::protocol::NodeStatus::HEALTH_OK ||
+        cb.msg->mode != uavcan::protocol::NodeStatus::MODE_OPERATIONAL) &&
+        !_ap_uavcan->option_is_set(AP_UAVCAN::Options::DNA_IGNORE_UNHEALTHY_NODE)) {
         //if node is not healthy or operational, clear resp health mask, and set fault_node_id
         fault_node_id = node_id;
         server_state = NODE_STATUS_UNHEALTHY;
@@ -714,6 +715,10 @@ bool AP_UAVCAN_DNA_Server::prearm_check(char* fail_msg, uint8_t fail_msg_len) co
         return false;
     }
     case NODE_STATUS_UNHEALTHY: {
+        if (_ap_uavcan->option_is_set(AP_UAVCAN::Options::DNA_IGNORE_UNHEALTHY_NODE)) {
+            // ignore error
+            return true;
+        }
         snprintf(fail_msg, fail_msg_len, "Node %d unhealthy!", fault_node_id);
         return false;
     }