fix(avoidance): prevent sudden steering at avoidance maneuver

planning/behavior_path_planner/config/avoidance/avoidance.param.yaml

@@ -190,7 +190,8 @@
           max_deviation_from_lane: 0.5                  # [m]
         # avoidance distance parameters
         longitudinal:
-          prepare_time: 2.0                             # [s]
+          min_prepare_time: 1.0                         # [s]
+          max_prepare_time: 2.0                         # [s]
           min_prepare_distance: 1.0                     # [m]
           min_slow_down_speed: 1.38                     # [m/s]
           buf_slow_down_speed: 0.56                     # [m/s]

planning/behavior_path_planner/include/behavior_path_planner/utils/avoidance/avoidance_module_data.hpp

@@ -211,7 +211,8 @@ struct AvoidanceParameters
   double stop_buffer{0.0};
 
   // start avoidance after this time to avoid sudden path change
-  double prepare_time{0.0};
+  double min_prepare_time{0.0};
+  double max_prepare_time{0.0};
 
   // Even if the vehicle speed is zero, avoidance will start after a distance of this much.
   double min_prepare_distance{0.0};

planning/behavior_path_planner/include/behavior_path_planner/utils/avoidance/helper.hpp

@@ -91,10 +91,16 @@ class AvoidanceHelper
     return std::max(getEgoSpeed(), values.at(idx));
   }
 
+  double getMinimumPrepareDistance() const
+  {
+    const auto & p = parameters_;
+    return std::max(getEgoSpeed() * p->min_prepare_time, p->min_prepare_distance);
+  }
+
   double getNominalPrepareDistance() const
   {
     const auto & p = parameters_;
-    return std::max(getEgoSpeed() * p->prepare_time, p->min_prepare_distance);
+    return std::max(getEgoSpeed() * p->max_prepare_time, p->min_prepare_distance);
   }
 
   double getNominalAvoidanceDistance(const double shift_length) const

planning/behavior_path_planner/src/scene_module/avoidance/avoidance_module.cpp

@@ -437,10 +437,27 @@ bool AvoidanceModule::canYieldManeuver(const AvoidancePlanningData & data) const
 {
   // transit yield maneuver only when the avoidance maneuver is not initiated.
   if (helper_.isShifted()) {
+    RCLCPP_DEBUG(getLogger(), "avoidance maneuver already initiated.");
     return false;
   }
 
+  // prevent sudden steering.
+  const auto registered_lines = path_shifter_.getShiftLines();
+  if (!registered_lines.empty()) {
+    const size_t idx = planner_data_->findEgoIndex(path_shifter_.getReferencePath().points);
+    const auto to_shift_start_point = calcSignedArcLength(
+      path_shifter_.getReferencePath().points, idx, registered_lines.front().start_idx);
+    if (to_shift_start_point < helper_.getMinimumPrepareDistance()) {
+      RCLCPP_DEBUG(
+        getLogger(),
+        "Distance to shift start point is less than minimum prepare distance. The distance is not "
+        "enough.");
+      return false;
+    }
+  }
+
   if (!data.stop_target_object) {
+    RCLCPP_DEBUG(getLogger(), "can pass by the object safely without avoidance maneuver.");
     return true;
   }
 
@@ -1652,6 +1669,10 @@ void AvoidanceModule::applySmallShiftFilter(
       continue;
     }
 
+    if (s.start_longitudinal < helper_.getMinimumPrepareDistance()) {
+      continue;
+    }
+
     shift_lines.push_back(s);
   }
 }
@@ -2405,9 +2426,8 @@ AvoidLineArray AvoidanceModule::findNewShiftLine(
   for (size_t i = 0; i < shift_lines.size(); ++i) {
     const auto & candidate = shift_lines.at(i);
 
-    // new shift points must exist in front of Ego
-    // this value should be larger than -eps consider path shifter calculation error.
-    if (candidate.start_idx < avoid_data_.ego_closest_path_index) {
+    // prevent sudden steering.
+    if (candidate.start_longitudinal < helper_.getMinimumPrepareDistance()) {
       break;
     }
 

planning/behavior_path_planner/src/scene_module/avoidance/manager.cpp

@@ -221,7 +221,8 @@ AvoidanceModuleManager::AvoidanceModuleManager(
   // avoidance maneuver (longitudinal)
   {
     std::string ns = "avoidance.avoidance.longitudinal.";
-    p.prepare_time = getOrDeclareParameter<double>(*node, ns + "prepare_time");
+    p.min_prepare_time = getOrDeclareParameter<double>(*node, ns + "min_prepare_time");
+    p.max_prepare_time = getOrDeclareParameter<double>(*node, ns + "max_prepare_time");
     p.min_prepare_distance = getOrDeclareParameter<double>(*node, ns + "min_prepare_distance");
     p.min_slow_down_speed = getOrDeclareParameter<double>(*node, ns + "min_slow_down_speed");
     p.buf_slow_down_speed = getOrDeclareParameter<double>(*node, ns + "buf_slow_down_speed");
@@ -390,7 +391,8 @@ void AvoidanceModuleManager::updateModuleParams(const std::vector<rclcpp::Parame
 
   {
     const std::string ns = "avoidance.avoidance.longitudinal.";
-    updateParam<double>(parameters, ns + "prepare_time", p->prepare_time);
+    updateParam<double>(parameters, ns + "min_prepare_time", p->min_prepare_time);
+    updateParam<double>(parameters, ns + "max_prepare_time", p->max_prepare_time);
     updateParam<double>(parameters, ns + "min_slow_down_speed", p->min_slow_down_speed);
     updateParam<double>(parameters, ns + "buf_slow_down_speed", p->buf_slow_down_speed);
   }