The old saying goes: If you want to do well, you must first sharpen your tools. Recently, in order to promote the next step of research and development, Amu Lab put in place a new set of "Wukong™"-optical motion capture system. We rebuilt the experimental site, installed and debugged the motion capture system, and shared this small process with everyone.
System installation process:
When there is no GPS signal indoors, the UAV wants to develop single-machine high-precision and difficult control algorithm development and multi-aircraft formation flight control development. It needs to know the altitude, position, attitude, jitter, delay, etc. in space. Indicators are measured to improve development efficiency.
1. Overview of optical motion capture system
Optical motion capture acquisition equipment is usually an optical camera, which is divided into two types: one is that no additional mark is added to the object, and the joint information extracted based on the two-dimensional image feature or the three-dimensional shape feature is used as the detection target. This type of system is collectively called unmarked point Type optical motion capture system; the other is to paste marked points on objects as target detection points. This type of system is called marking point optical motion capture.
The mark-point optical motion capture system is composed of an optical marker (Marker), a motion capture camera, a transmission device, and a data processing workstation. The optical motion capture system often referred to in the market usually refers to this kind of mark-point motion capture system. Paste the Marker points on the key parts of the moving object. Multiple motion capture cameras detect the Marker points in real time from different angles. The data is transmitted to the data processing workstation in real time. According to the image processing technology and triangulation principle, the spatial coordinates of the Marker points and the center of the object are accurately calculated Movement data. Different marking point lighting technologies are also divided into active and passive optical motion capture systems:
The Marker point of the active optical motion capture system is composed of active light-emitting LEDs, which are pasted on the main part of the object structure, and the installation is relatively simple. It uses high-bright LED to emit light, and the LED is controlled by the pulse signal to identify the time domain code. The recognition effect is better and the tracking accuracy is higher.
Passive optical motion capture system, also known as reflective optical motion capture system, its Marker point is usually a high-brightness reflective reflective ball, which is attached to the main part of the object structure, and the LED infrared light emitted by the motion capture camera is reflected by the reflective ball To the motion capture camera, perform Marker detection and spatial positioning.
2. System hardware and software architecture
Through the switch and router, the camera, the UAV onboard computer, and the main computer of the motion capture system are locally networked. On the one hand, the UAV can complete autonomous flight through its own sensors, and the motion capture system software can analyze various flight motion data.
On the other hand, the six-degree-of-freedom pose can be calculated by the host computer in real time and sent to the UAV through the router, and the motion capture system acts as a "GPS."
Third, the choice of indoor positioning
In previous articles, we have analyzed a variety of indoor positioning solutions, and also mentioned motion capture systems. Now our Amu laboratory has gathered the development experience of these several solutions, waiting for the birth of a magic machine.
4. Small test of motion capture system
A simple test of this system, the drone flies in the manual self-stabilization mode, and the motion capture system records the trajectory. Share with you the effect. We are also in the process of exploring and learning. For needs or cooperative development, please contact us for consultation.
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