fix(planning_validator): cherry-pick numerically safe calculation of max lateral acceleration

Signed-off-by: kaigohirao <kaigo.hirao@proxima-ai-tech.com>

Author: kaigohirao

planning/planning_validator/include/planning_validator/utils.hpp

@@ -36,8 +36,10 @@ std::pair<double, size_t> getAbsMaxValAndIdx(const std::vector<double> & v);
 
 Trajectory resampleTrajectory(const Trajectory & trajectory, const double min_interval);
 
-void calcCurvature(const Trajectory & trajectory, std::vector<double> & curvatures);
-
+void calcCurvature(
+  const Trajectory & trajectory, std::vector<double> & curvatures,
+  const double curvature_distance = 1.0);
+  
 void calcSteeringAngles(
   const Trajectory & trajectory, const double wheelbase, std::vector<double> & steering_array);
 

planning/planning_validator/src/planning_validator.cpp

@@ -247,7 +247,6 @@ void PlanningValidator::validate(const Trajectory & trajectory)
 
   s.is_valid_finite_value = checkValidFiniteValue(trajectory);
   s.is_valid_interval = checkValidInterval(trajectory);
-  s.is_valid_lateral_acc = checkValidLateralAcceleration(trajectory);
   s.is_valid_longitudinal_max_acc = checkValidMaxLongitudinalAcceleration(trajectory);
   s.is_valid_longitudinal_min_acc = checkValidMinLongitudinalAcceleration(trajectory);
   s.is_valid_velocity_deviation = checkValidVelocityDeviation(trajectory);
@@ -260,6 +259,7 @@ void PlanningValidator::validate(const Trajectory & trajectory)
 
   s.is_valid_relative_angle = checkValidRelativeAngle(resampled);
   s.is_valid_curvature = checkValidCurvature(resampled);
+  s.is_valid_lateral_acc = checkValidLateralAcceleration(resampled);
   s.is_valid_steering = checkValidSteering(resampled);
   s.is_valid_steering_rate = checkValidSteeringRate(resampled);
 

planning/planning_validator/src/utils.cpp

@@ -89,26 +89,67 @@ Trajectory resampleTrajectory(const Trajectory & trajectory, const double min_in
   return resampled;
 }
 
-void calcCurvature(const Trajectory & trajectory, std::vector<double> & curvature_arr)
+void calcCurvature(
+  const Trajectory & trajectory, std::vector<double> & curvature_arr,
+  const double curvature_distance)
 {
   if (trajectory.points.size() < 3) {
     curvature_arr = std::vector<double>(trajectory.points.size(), 0.0);
     return;
   }
 
-  curvature_arr.push_back(0.0);
+  // calc arc length array: arc_length(3) - arc_length(0) is distance from point(3) to point(0)
+  std::vector<double> arc_length(trajectory.points.size(), 0.0);
+  for (size_t i = 1; i < trajectory.points.size(); ++i) {
+    arc_length.at(i) =
+      arc_length.at(i - 1) + calcDistance2d(trajectory.points.at(i - 1), trajectory.points.at(i));
+  }
+
+  // initialize with 0 curvature
+  curvature_arr = std::vector<double>(trajectory.points.size(), 0.0);
+
+  size_t first_distant_index = 0;
+  size_t last_distant_index = trajectory.points.size() - 1;
   for (size_t i = 1; i < trajectory.points.size() - 1; ++i) {
-    const auto p1 = getPoint(trajectory.points.at(i - 1));
+    // find the previous point
+    size_t prev_idx = 0;
+    for (size_t j = i - 1; j > 0; --j) {
+      if (arc_length.at(i) - arc_length.at(j) > curvature_distance) {
+        if (first_distant_index == 0) {
+          first_distant_index = i;  // save first index that meets distance requirement
+        }
+        prev_idx = j;
+        break;
+      }
+    }
+
+    // find the next point
+    size_t next_idx = trajectory.points.size() - 1;
+    for (size_t j = i + 1; j < trajectory.points.size(); ++j) {
+      if (arc_length.at(j) - arc_length.at(i) > curvature_distance) {
+        last_distant_index = i;  // save last index that meets distance requirement
+        next_idx = j;
+        break;
+      }
+    }
+
+    const auto p1 = getPoint(trajectory.points.at(prev_idx));
     const auto p2 = getPoint(trajectory.points.at(i));
-    const auto p3 = getPoint(trajectory.points.at(i + 1));
+    const auto p3 = getPoint(trajectory.points.at(next_idx));
     try {
-      curvature_arr.push_back(tier4_autoware_utils::calcCurvature(p1, p2, p3));
+      curvature_arr.at(i) = tier4_autoware_utils::calcCurvature(p1, p2, p3);
     } catch (...) {
-      // maybe distance is too close
-      curvature_arr.push_back(0.0);
+      curvature_arr.at(i) = 0.0;  // maybe distance is too close
     }
   }
-  curvature_arr.push_back(0.0);
+
+  // use previous or last curvature where the distance is not enough
+  for (size_t i = first_distant_index; i > 0; --i) {
+    curvature_arr.at(i - 1) = curvature_arr.at(i);
+  }
+  for (size_t i = last_distant_index; i < curvature_arr.size() - 1; ++i) {
+    curvature_arr.at(i + 1) = curvature_arr.at(i);
+  }
 }
 
 std::pair<double, size_t> calcMaxCurvature(const Trajectory & trajectory)