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[RPP] Remove dependency on collision checking to carrot location #2211

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Merged
merged 3 commits into from
Mar 3, 2021
Merged

[RPP] Remove dependency on collision checking to carrot location #2211

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f59d8d5
Remove dependency on collision checking to carrot location
SteveMacenski Feb 27, 2021
e911b73
Fix i removal
SteveMacenski Feb 27, 2021
8dbec95
changing API to be consistent with collision updates
SteveMacenski Mar 3, 2021
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3 changes: 1 addition & 2 deletions ...ller/include/nav2_regulated_pure_pursuit_controller/regulated_pure_pursuit_controller.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -174,8 +174,7 @@ class RegulatedPurePursuitController : public nav2_core::Controller
*/
bool isCollisionImminent(
const geometry_msgs::msg::PoseStamped &,
const geometry_msgs::msg::PoseStamped &,
const double &, const double &, const double &);
const double &, const double &);

/**
* @brief Whether point is in collision
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25 changes: 8 additions & 17 deletions nav2_regulated_pure_pursuit_controller/src/regulated_pure_pursuit_controller.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -270,7 +270,7 @@ geometry_msgs::msg::TwistStamped RegulatedPurePursuitController::computeVelocity
}

// Collision checking on this velocity heading
if (isCollisionImminent(pose, carrot_pose, curvature, linear_vel, angular_vel)) {
if (isCollisionImminent(pose, linear_vel, angular_vel)) {
throw std::runtime_error("RegulatedPurePursuitController detected collision ahead!");
}

Expand Down Expand Up @@ -333,16 +333,13 @@ geometry_msgs::msg::PoseStamped RegulatedPurePursuitController::getLookAheadPoin

bool RegulatedPurePursuitController::isCollisionImminent(
const geometry_msgs::msg::PoseStamped & robot_pose,
const geometry_msgs::msg::PoseStamped & carrot_pose,
const double & curvature, const double & linear_vel,
const double & angular_vel)
const double & linear_vel, const double & angular_vel)
{
// Note(stevemacenski): This may be a bit unusual, but the robot_pose is in
// odom frame and the carrot_pose is in robot base frame.

// check current point is OK
if (inCollision(robot_pose.pose.position.x, robot_pose.pose.position.y))
{
if (inCollision(robot_pose.pose.position.x, robot_pose.pose.position.y)) {
return true;
}

Expand All @@ -354,29 +351,23 @@ bool RegulatedPurePursuitController::isCollisionImminent(
pose_msg.header.frame_id = arc_pts_msg.header.frame_id;
pose_msg.header.stamp = arc_pts_msg.header.stamp;

// Using curvature (k = 1 / R) and carrot distance (chord on circle R), project the command
const double chord_len = hypot(carrot_pose.pose.position.x, carrot_pose.pose.position.y);

// Find the number of increments by finding the arc length of the chord on circle
const double r = fabs(1.0 / curvature);
const double alpha = 2.0 * asin(chord_len / (2 * r)); // central angle
const double arc_len = alpha * r;
const double delta_dist = costmap_->getResolution();
const unsigned int num_pts = static_cast<unsigned int>(ceil(arc_len / delta_dist));
const double projection_time = costmap_->getResolution() / linear_vel;

geometry_msgs::msg::Pose2D curr_pose;
curr_pose.x = robot_pose.pose.position.x;
curr_pose.y = robot_pose.pose.position.y;
curr_pose.theta = tf2::getYaw(robot_pose.pose.orientation);

for (unsigned int i = 1; i < num_pts; i++) {
int i = 1;
while (true) {
// only forward simulate within time requested
if (i * projection_time > max_allowed_time_to_collision_) {
break;
}

i++;

// apply velocity at curr_pose over distance delta_dist
// apply velocity at curr_pose over distance
curr_pose.x += projection_time * (linear_vel * cos(curr_pose.theta));
curr_pose.y += projection_time * (linear_vel * sin(curr_pose.theta));
curr_pose.theta += projection_time * angular_vel;
Expand Down