Add RobotPoseEstimator (#571)

RobotPoseEstimator can pick the most likely pose for the robot given a number of possible poses, using a number of different strategies. Examples are still WIP.
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Jack
2022-12-30 00:40:13 -06:00
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12 changed files with 1805 additions and 4 deletions

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/*
* MIT License
*
* Copyright (c) 2022 PhotonVision
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package org.photonvision;
import edu.wpi.first.math.Pair;
import edu.wpi.first.math.geometry.Pose3d;
import edu.wpi.first.math.geometry.Rotation3d;
import edu.wpi.first.math.geometry.Transform3d;
import edu.wpi.first.math.geometry.Translation3d;
import edu.wpi.first.wpilibj.DriverStation;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import org.photonvision.targeting.PhotonTrackedTarget;
public class RobotPoseEstimator {
/**
*
*
* <ul>
* <li><strong>LOWEST_AMBIGUITY</strong>: Choose the Pose with the lowest ambiguity
* <li><strong>CLOSEST_TO_CAMERA_HEIGHT</strong>: Choose the Pose which is closest to the camera
* height
* <li><strong>CLOSEST_TO_REFERENCE_POSE</strong>: Choose the Pose which is closest to the pose
* from setReferencePose()
* <li><strong>CLOSEST_TO_LAST_POSE</strong>: Choose the Pose which is closest to the last pose
* calculated
* </ul>
*/
enum PoseStrategy {
LOWEST_AMBIGUITY,
CLOSEST_TO_CAMERA_HEIGHT,
CLOSEST_TO_REFERENCE_POSE,
CLOSEST_TO_LAST_POSE,
AVERAGE_BEST_TARGETS
}
private Map<Integer, Pose3d> aprilTags;
private PoseStrategy strategy;
private ArrayList<Pair<PhotonCamera, Transform3d>> cameras;
private Pose3d lastPose;
private Pose3d referencePose;
private HashSet<Integer> reportedErrors;
/**
* Create a new RobotPoseEstimator.
*
* <p>Example: {@code <code> <p> Map<Integer, Pose3d> map = new HashMap<>(); <p> map.put(1, new
* Pose3d(1.0, 2.0, 3.0, new Rotation3d())); // Tag ID 1 is at (1.0,2.0,3.0) </code> }
*
* @param aprilTags A Map linking AprilTag IDs to Pose3ds with respect to the FIRST field.
* @param strategy The strategy it should use to determine the best pose.
* @param cameras An ArrayList of Pairs of PhotonCameras and their respective Transform3ds from
* the center of the robot to the cameras.
*/
public RobotPoseEstimator(
Map<Integer, Pose3d> aprilTags,
PoseStrategy strategy,
ArrayList<Pair<PhotonCamera, Transform3d>> cameras) {
this.aprilTags = aprilTags;
this.strategy = strategy;
this.cameras = cameras;
lastPose = new Pose3d();
reportedErrors = new HashSet<>();
}
/**
* Update the estimated pose using the selected strategy.
*
* @return The updated estimated pose and the latency in milliseconds
*/
public Pair<Pose3d, Double> update() {
if (cameras.isEmpty()) {
DriverStation.reportError("[RobotPoseEstimator] Missing any camera!", false);
return Pair.of(lastPose, 0.);
}
Pair<Pose3d, Double> pair;
switch (strategy) {
case LOWEST_AMBIGUITY:
pair = lowestAmbiguityStrategy();
lastPose = pair.getFirst();
return pair;
case CLOSEST_TO_CAMERA_HEIGHT:
pair = closestToCameraHeightStrategy();
lastPose = pair.getFirst();
return pair;
case CLOSEST_TO_REFERENCE_POSE:
pair = closestToReferencePoseStrategy();
lastPose = pair.getFirst();
return pair;
case CLOSEST_TO_LAST_POSE:
referencePose = lastPose;
pair = closestToReferencePoseStrategy();
lastPose = pair.getFirst();
return pair;
case AVERAGE_BEST_TARGETS:
pair = averageBestTargetsStrategy();
lastPose = pair.getFirst();
return pair;
default:
DriverStation.reportError("[RobotPoseEstimator] Invalid pose strategy!", false);
return Pair.of(lastPose, 0.);
}
}
private Pair<Pose3d, Double> lowestAmbiguityStrategy() {
// Loop over each ambiguity of all the cameras
int lowestAI = -1;
int lowestAJ = -1;
double lowestAmbiguityScore = 10;
for (int i = 0; i < cameras.size(); i++) {
Pair<PhotonCamera, Transform3d> p = cameras.get(i);
List<PhotonTrackedTarget> targets = p.getFirst().getLatestResult().targets;
for (int j = 0; j < targets.size(); j++) {
if (targets.get(j).getPoseAmbiguity() < lowestAmbiguityScore) {
lowestAI = i;
lowestAJ = j;
lowestAmbiguityScore = targets.get(j).getPoseAmbiguity();
}
}
}
// No targets, return the last pose
if (lowestAI == -1 || lowestAJ == -1) {
return Pair.of(lastPose, 0.);
}
// Pick the lowest and do the heavy calculations
PhotonTrackedTarget bestTarget =
cameras.get(lowestAI).getFirst().getLatestResult().targets.get(lowestAJ);
// If the map doesn't contain the ID fail
if (!aprilTags.containsKey(bestTarget.getFiducialId())) {
if (!reportedErrors.contains(bestTarget.getFiducialId())) {
DriverStation.reportError(
"[RobotPoseEstimator] Tried to get pose of unknown April Tag: "
+ bestTarget.getFiducialId(),
false);
reportedErrors.add(bestTarget.getFiducialId());
}
return Pair.of(lastPose, 0.);
}
return Pair.of(
aprilTags
.get(bestTarget.getFiducialId())
.transformBy(bestTarget.getBestCameraToTarget().inverse())
.transformBy(cameras.get(lowestAI).getSecond().inverse()),
cameras.get(lowestAI).getFirst().getLatestResult().getLatencyMillis());
}
private Pair<Pose3d, Double> closestToCameraHeightStrategy() {
double smallestHeightDifference = 10e9;
double mili = 0;
Pose3d pose = lastPose;
for (int i = 0; i < cameras.size(); i++) {
Pair<PhotonCamera, Transform3d> p = cameras.get(i);
List<PhotonTrackedTarget> targets = p.getFirst().getLatestResult().targets;
for (int j = 0; j < targets.size(); j++) {
PhotonTrackedTarget target = targets.get(j);
// If the map doesn't contain the ID fail
if (!aprilTags.containsKey(target.getFiducialId())) {
if (!reportedErrors.contains(target.getFiducialId())) {
DriverStation.reportWarning(
"[RobotPoseEstimator] Tried to get pose of unknown April Tag: "
+ target.getFiducialId(),
false);
reportedErrors.add(target.getFiducialId());
}
continue;
}
Pose3d targetPose = aprilTags.get(target.getFiducialId());
double alternativeDifference =
Math.abs(
p.getSecond().getZ()
- targetPose.transformBy(target.getAlternateCameraToTarget().inverse()).getZ());
double bestDifference =
Math.abs(
p.getSecond().getZ()
- targetPose.transformBy(target.getBestCameraToTarget().inverse()).getZ());
if (alternativeDifference < smallestHeightDifference) {
smallestHeightDifference = alternativeDifference;
pose = targetPose.transformBy(target.getAlternateCameraToTarget().inverse());
mili = p.getFirst().getLatestResult().getLatencyMillis();
}
if (bestDifference < smallestHeightDifference) {
smallestHeightDifference = bestDifference;
pose = targetPose.transformBy(target.getBestCameraToTarget().inverse());
mili = p.getFirst().getLatestResult().getLatencyMillis();
}
}
}
return Pair.of(pose, mili);
}
private Pair<Pose3d, Double> closestToReferencePoseStrategy() {
if (referencePose == null) {
DriverStation.reportError(
"[RobotPoseEstimator] Tried to use reference pose strategy without setting the reference!",
false);
return Pair.of(lastPose, 0.);
}
double smallestDifference = 10e9;
double mili = 0;
Pose3d pose = lastPose;
for (int i = 0; i < cameras.size(); i++) {
Pair<PhotonCamera, Transform3d> p = cameras.get(i);
List<PhotonTrackedTarget> targets = p.getFirst().getLatestResult().targets;
for (int j = 0; j < targets.size(); j++) {
PhotonTrackedTarget target = targets.get(j);
// If the map doesn't contain the ID fail
if (!aprilTags.containsKey(target.getFiducialId())) {
if (!reportedErrors.contains(target.getFiducialId())) {
DriverStation.reportWarning(
"[RobotPoseEstimator] Tried to get pose of unknown April Tag: "
+ target.getFiducialId(),
false);
reportedErrors.add(target.getFiducialId());
}
continue;
}
Pose3d targetPose = aprilTags.get(target.getFiducialId());
double alternativeDifference =
Math.abs(
calculateDifference(
referencePose,
targetPose.transformBy(target.getAlternateCameraToTarget().inverse())));
double bestDifference =
Math.abs(
calculateDifference(
referencePose,
targetPose.transformBy(target.getBestCameraToTarget().inverse())));
if (alternativeDifference < smallestDifference) {
smallestDifference = alternativeDifference;
pose = targetPose.transformBy(target.getAlternateCameraToTarget().inverse());
mili = p.getFirst().getLatestResult().getLatencyMillis();
}
if (bestDifference < smallestDifference) {
smallestDifference = bestDifference;
pose = targetPose.transformBy(target.getBestCameraToTarget().inverse());
mili = p.getFirst().getLatestResult().getLatencyMillis();
}
}
}
return Pair.of(pose, mili);
}
/** Return the average of the best target poses using ambiguity as weight */
private Pair<Pose3d, Double> averageBestTargetsStrategy() {
// Pair of Double, Double = Ambiguity, Mili
List<Pair<Pose3d, Pair<Double, Double>>> tempPoses = new ArrayList<>();
double totalAmbiguity = 0;
for (int i = 0; i < cameras.size(); i++) {
Pair<PhotonCamera, Transform3d> p = cameras.get(i);
List<PhotonTrackedTarget> targets = p.getFirst().getLatestResult().targets;
for (int j = 0; j < targets.size(); j++) {
PhotonTrackedTarget target = targets.get(j);
// If the map doesn't contain the ID fail
if (!aprilTags.containsKey(target.getFiducialId())) {
if (!reportedErrors.contains(target.getFiducialId())) {
DriverStation.reportWarning(
"[RobotPoseEstimator] Tried to get pose of unknown April Tag: "
+ target.getFiducialId(),
false);
reportedErrors.add(target.getFiducialId());
}
continue;
}
Pose3d targetPose = aprilTags.get(target.getFiducialId());
try {
totalAmbiguity += 1. / target.getPoseAmbiguity();
} catch (ArithmeticException e) {
// A total ambiguity of zero exists, using that pose instead!",
return Pair.of(
targetPose.transformBy(target.getBestCameraToTarget().inverse()),
p.getFirst().getLatestResult().getLatencyMillis());
}
tempPoses.add(
Pair.of(
targetPose.transformBy(target.getBestCameraToTarget().inverse()),
Pair.of(
target.getPoseAmbiguity(), p.getFirst().getLatestResult().getLatencyMillis())));
}
}
Translation3d transform = new Translation3d();
Rotation3d rotation = new Rotation3d();
double latency = 0;
for (Pair<Pose3d, Pair<Double, Double>> pair : tempPoses) {
try {
double weight = (1. / pair.getSecond().getFirst()) / totalAmbiguity;
transform = transform.plus(pair.getFirst().getTranslation().times(weight));
rotation = rotation.plus(pair.getFirst().getRotation().times(weight));
latency += pair.getSecond().getSecond() * weight; // NOTE: Average latency may not work well
} catch (ArithmeticException e) {
DriverStation.reportWarning(
"[RobotPoseEstimator] A total ambiguity of zero exists, using that pose instead!",
false);
return Pair.of(pair.getFirst(), pair.getSecond().getSecond());
}
}
return Pair.of(new Pose3d(transform, rotation), latency);
}
/**
* Difference is defined as the vector magnitude between the two poses
*
* @return The absolute "difference" (>=0) between two Pose3ds.
*/
private double calculateDifference(Pose3d x, Pose3d y) {
return x.getTranslation().getDistance(y.getTranslation());
}
/** @param aprilTags the aprilTags to set */
public void setAprilTags(Map<Integer, Pose3d> aprilTags) {
this.aprilTags = aprilTags;
}
/** @return the aprilTags */
public Map<Integer, Pose3d> getAprilTags() {
return aprilTags;
}
/** @return the strategy */
public PoseStrategy getStrategy() {
return strategy;
}
/** @param strategy the strategy to set */
public void setStrategy(PoseStrategy strategy) {
this.strategy = strategy;
}
/** @return the referencePose */
public Pose3d getReferencePose() {
return referencePose;
}
/**
* Update the stored reference pose for use with CLOSEST_TO_REFERENCE_POSE
*
* @param referencePose the referencePose to set
*/
public void setReferencePose(Pose3d referencePose) {
this.referencePose = referencePose;
}
/**
* UPdate the stored last pose. Useful for setting the initial estimate with CLOSEST_TO_LAST_POSE
*
* @param lastPose the lastPose to set
*/
public void setLastPose(Pose3d lastPose) {
this.lastPose = lastPose;
}
}