Multiple imu time synchronization method, device and terminal

Abstract

The embodiment of the present invention discloses a multiple IMU time synchronization method, device, and terminal. The method includes: performing external parameter calibration on multiple IMUs based on the camera to obtain external parameters between each IMU and the angle obtained by each IMU After the data is converted to the same coordinate system, calculate the angle change value of each IMU at the pre-selected attitude angle; take the time stamp of the IMU with the largest sampling frequency as the reference, and according to the current IMU and the respective starting time of the reference IMU. The initial time difference is roughly synchronized with the time stamp, and then the current IMU is shifted for the first preset number of time stamps according to the first preset value range corresponding to the initial time difference, so as to calculate the optimal time difference corresponding to the first precision . Compared with the prior art, the technical solution of the present invention can solve the problem of hardware cost, and the time synchronization has also been greatly improved.

Description

technical field [0001] The invention relates to the technical field of multi-sensor fusion for navigation, in particular to a method, device and terminal for time synchronization of multiple IMUs. Background technique [0002] With the continuous decline in the cost of inertial measurement units (hereinafter referred to as IMUs) and the emergence of integrated inertial sensors, more and more platforms such as robots are equipped with multiple IMUs. Typically, what these platforms have in common is that the primary IMU is used for positioning and alignment (i.e. mounted close to the center of gravity and aligned with the platform's major axis), with the secondary IMU mounted less obstructed. For most platforms, these two locations are very different. In order to fuse data from multiple IMUs, they need to be aligned with their timestamps. [0003] However, there are two main types of time stamp alignment or synchronization of the current common multiple IMUs: [0004] One is...

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Problems solved by technology

Although this type of method has high precision, its cost is also high, and it is not suitable for most users or enterprises, etc.

[0005] The second is to use the method of software synchronization, mainly based on the different time stamp information of the two IMUs, and use the thread lock method to align the data of the two sets of IMUs. Although this method is more convenient, it cannot meet the high-precision requirements. For some requirements Not suitable for high-precision occasions

In addition, there are other time synchronization methods combining software and hardware. For example, the patent publication No. CN109729277A "multi-sensor acquisition time stamp synchronization device" mainly realizes time stamp synchronization through serial port transmission when solving the problem of time synchronization Moreover, each sensor can obtain time stamp information, and this point is not applicable to scenes where the camera itself does not have a time stamp, and has relatively large limitations; Time Synchronization Method for Sensor Networks" It mainly uses the clock face time when the sensor node to be synchronized and the neighbor node exchange data packets to send / receive the clock face time, fit the linear regression formula between the clock face time of each neighbor node and its own clock face time, and continuously iteratively update itself Clock face time parameters to achieve time synchronization between sensor nodes

Since this method requires communication between sensors, this is not applicable to IMUs that do not have mutual communication capabilities and work independently of each other, that is, they also have certain limitations, etc.

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