Author: Zhu Jincan
Source: clever101's column
Slam is a multi-science technology integrating hardware and software, involving many technical terms, concepts, mathematical formulas, and so on. Below I will combine online information and personal understanding to introduce.
What is cloud platform
The gimbal is a supporting device for installing and fixing mobile phones, cameras, and video cameras. It is divided into two types: fixed and electric gimbals. The cloud platform can be rotated arbitrarily, which is convenient for users to use.
How to understand the cloud platform? First of all, it is a device carrier, on which some electronic devices can be built, and secondly, it can be rotated and controlled remotely.
What is IMU
The inertial measurement unit (English: Inertial measurement unit, IMU for short) is a device that measures the three-axis attitude angle (or angular rate) and acceleration of an object. In general, an IMU includes three single-axis accelerometers and three single-axis gyroscopes. The accelerometer detects the acceleration signal of the object in the three-axis independent of the carrier coordinate system, and the gyroscope detects the angular velocity of the carrier relative to the navigation coordinate system. Signal, measure the angular velocity and acceleration of the object in three-dimensional space, and use this to calculate the attitude of the object. It has very important application value in navigation.
Simply put, you can understand the IMU as a sensor, and the data it collects is the angular velocity and acceleration of the object in three-dimensional space.
What is robustness
Robustness in English is robustness, which actually means robustness or stability. Personally, I think the translation is better for stability, but everyone calls it that, and it may be a transliteration. Robustness is generally used to describe the stability of something, that is to say, when encountering some kind of disturbance, the nature of this thing can be relatively stable. For example, such as the mean and median in statistics, the mean is easily affected by extreme values. If there are large or small values in the data, the mean will be larger or smaller. The median is much more stable, even if there are large or small values in the data, the median will not change much. Therefore, the median statistic is robust.
This can be regarded as a typical case of a few translators in China. It really should be translated as stability. The robustness of a certain characteristic of things means that this property has a strong ability to resist abnormal data interference of original statistical data.
What is hardware time synchronization
When performing slam with a robot, a single sensor often cannot achieve strong robustness. In many cases, the fusion of multiple sensors is required, such as lidar + camera + IMU + GPS + wheel speedometer + millimeter wave radar, etc. The fusion of sensors involves a problem of time synchronization. Specifically, for example, the data generated by the lidar at 17:01:59 must be fused with the data generated by the IMU at 17:01:59. Both lidar and IMU have data recording time, which one shall prevail? This is the problem of time synchronization. There is a solution on the Internet: time alignment or time synchronization when multi-source sensor fusion