I moved your question to the lidar you use. Because the better navigator is only the mapping not the lidar.

I don’t see an option for doing that in the skill. Not sure how something like that can be done. Hmmm

Hi there - we have moved the question from where DJ moved it into its own thread to isolate it.

When using a 360-degree LiDAR, the optimal placement is at the center of rotation of the robot. While it may seem practical to move the LiDAR to the front of the robot, this decision introduces several serious problems that degrade the accuracy and reliability of SLAM (Simultaneous Localization and Mapping) and obstacle detection. Below are the key reasons why this is impractical and unreliable.

1. Distorted SLAM Data Due to Sensor Offset

SLAM algorithms, including Hector SLAM, typically assume the LiDAR is at the robot’s center of rotation. If the LiDAR is moved forward, the robot's turning motion causes an arc-shaped distortion in scan data, leading to map inconsistencies.

Example:

• If a center-mounted LiDAR rotates with the robot, all scanned points remain consistent.
• If a front-mounted LiDAR rotates, it moves in an arc, meaning objects appear to shift in unexpected ways, breaking scan-matching algorithms.

Result: The robot may misinterpret the environment, causing localization drift, incorrect obstacle positioning, or total SLAM failure.

2. Parallax Errors Cause Mapping Inconsistencies

When the LiDAR is off-center, measurements are taken from a moving, offset perspective rather than the actual center of the robot. This means objects close to the robot appear to shift significantly as the robot turns.

Example:

• If an obstacle is 1 meter in front of a center-mounted LiDAR, it stays directly in front.
• If an obstacle is 1 meter in front of a front-mounted LiDAR, and the robot rotates 90, the LiDAR moves sideways, making the object appear to shift unexpectedly.

Result: SLAM struggles to align scans properly, causing misaligned walls, floating obstacles, and poor map consistency.

3. Obstructed Field of View

A 360 LiDAR is designed to have an unobstructed panoramic view. Placing it at the front of the robot blocks part of the scanning area, reducing its effectiveness.

Example:

• A center-mounted LiDAR sees everything equally in all directions.
• A front-mounted LiDAR has blocked areas behind the robot, making navigation decisions harder.

Result: The robot has blind spots, leading to missed obstacles and less efficient navigation.

4. Increased Motion Blur at High Speeds

When moving forward at higher speeds, a front-mounted LiDAR experiences more movement per scan compared to a center-mounted LiDAR, which remains more stable.

Example:

• A center-mounted LiDAR rotates smoothly as the robot turns.
• A front-mounted LiDAR swings in an arc, meaning scans don’t align perfectly frame-to-frame.

Result: Data becomes blurry and less accurate, making it difficult for the SLAM algorithm to track features reliably.

Why 360 LiDARs Are Always Mounted in the Center

Every commercial and research-based robot using a 360-degree LiDAR mounts it at or near the center because:

1. Minimized Scan Distortion The LiDAR remains in one place relative to the robot’s motion.
2. Accurate SLAM Performance Scan matching algorithms work as expected without unpredictable shifts.
3. Full 360 Coverage No blind spots or missing data.
4. Better Obstacle Avoidance The LiDAR sees obstacles consistently from a stable perspective.

Alternative Solution

If you want front-mounted obstacle detection, a better option is to use a 2D forward-facing LiDAR or depth camera, which is designed for that purpose rather than misusing a 360 LiDAR.

Keep the LiDAR at the Center

While moving a 360 LiDAR to the front may seem appealing, it creates serious problems that impact SLAM, navigation accuracy, and obstacle avoidance. To ensure reliable mapping and navigation, always keep the LiDAR at the center of the robot’s rotation.

ah, okay - that makes sense. I figured it would be a weird thing to do. I'm not sure how the math would compensate for the distances - but technically, it should "Sort of" be possible - just not very accurate.

How come u wanna move it?

Can you create a configuration similar to that of turtle bots or delivery robots? Where is the lidar in the center? By having a thin cutout for the laser all the way around?

Using standoffs to raise the top shelf on all 4 sides of the roomba.