feat(remaining_dist_eta): add check for velocity limit preventing unintended division by zero or negative time values / update readme

Signed-off-by: Ahmed Ebrahim <ahmed.ebrahim@leodrive.ai>

feat(remaining_dist_eta): add check for velocity limit preventing unintended division by zero or negative time values / update readme

Signed-off-by: Ahmed Ebrahim <ahmed.ebrahim@leodrive.ai>

Author: Ahmed Ebrahim

planning/autoware_remaining_distance_time_calculator/README.md

@@ -2,12 +2,12 @@
 
 ### Role
 
-This package aims to provide mission remaining distance and remaining time calculations
+This package aims to provide mission remaining distance and remaining time calculations.
 
 ### Activation and Timing
 
-- The calculations are activated once we have a route planned for a mission in Autoware
-- The calculations are triggered timely based on the `update_rate` parameter
+- The calculations are activated once we have a route planned for a mission in Autoware.
+- The calculations are triggered timely based on the `update_rate` parameter.
 
 ### Module Parameters
 
@@ -20,19 +20,20 @@ This package aims to provide mission remaining distance and remaining time calcu
 #### Remaining Distance Calculation
 
 - The remaining distance calculation is based on getting the remaining shortest path between the current vehicle pose and goal pose using `lanelet2` routing APIs.
-- The remaining distance is calculated by summing the 2D length of remaining shortest path, with exception to current lanelet and goal lanelet
-  - For the current lanelet, the distance is calculated from the current vehicle position to the end of that lanelet
+- The remaining distance is calculated by summing the 2D length of remaining shortest path, with exception to current lanelet and goal lanelet.
+  - For the current lanelet, the distance is calculated from the current vehicle position to the end of that lanelet.
   - For the goal lanelet, the distance is calculated from the start of the lanelet to the goal pose in this lanelet.
 - When there is only one lanelet remaining, the distance is calculated by getting the 2D distance between the current vehicle pose and goal pose.
-- Checks are added to handle cases when current lanelent, goal lanelet, or routing graph are not valid to prevent node process die
-  - In such cases when, last valid remaining distance and time are maintained
+- Checks are added to handle cases when current lanelent, goal lanelet, or routing graph are not valid to prevent node process die.
+  - In such cases when, last valid remaining distance and time are maintained.
 
 #### Remaining Time Calculation
 
 - The remaining time currently depends on a simple equation of motion by getting the maximum velocity limit.
-- The remaining distance is calculated by dividing remaining distance by the maximum velocity limit
+- The remaining distance is calculated by dividing the remaining distance by the maximum velocity limit.
+- A check is added to the remaining time calculation to make sure that maximum velocity limit is greater than zero. This prevents division by zero or getting negative time value.
 
 ### Future Work
 
-- Find a more efficient way for remaining distance calculation instead of regularly searching the graph for finding the remaining shortest path
-- Engage more sophisticated motion models for more accurate remaining time calculations
+- Find a more efficient way for remaining distance calculation instead of regularly searching the graph for finding the remaining shortest path.
+- Engage more sophisticated motion models for more accurate remaining time calculations.

planning/autoware_remaining_distance_time_calculator/src/remaining_distance_time_calculator_node.cpp

@@ -167,7 +167,9 @@ void RemainingDistanceTimeCalculatorNode::calculate_remaining_distance()
 
 void RemainingDistanceTimeCalculatorNode::calculate_remaining_time()
 {
-  remaining_time_ = remaining_distance_ / velocity_limit_;
+  if (velocity_limit_ > 0.0) {
+    remaining_time_ = remaining_distance_ / velocity_limit_;
+  }
 }
 
 void RemainingDistanceTimeCalculatorNode::publish_mission_remaining_distance_time()