Interface Protocol

30 / 50
Copyright (c) 2009-2013 RoboPeak Team
Copyright (c) 2013-2019 Shanghai Slamtec Co., Ltd.
Figure 4-22 The Communication Status Sending Out the Dense Capsuled
Express Scan Request
Data Processing of the Express Scan Data (Capsuled Express Scans)
By compressing the redundant data, the data response packet used in express scan
mode makes it possible to send the 4khz sampling data via the original 115200bps
bandwidth communication link. For this reason, the host system needs extra data
recovery logic to get valid measurement data.
When working in express scan mode, the measurement sampling data is stored in
the cabin structural body with two sets as unit. It includes the distance
value(distance1/distance2) and the angular compensation (𝑑𝜃
1
、𝑑𝜃
2
). The distance
value is matched with the actual distance measured in this sampling, but the angular
compensation value is not the actual angle data between the measured object and
RPLIDAR required by the host system. The final angle data can be calculated out
with the start_angle_q6 in this request. The detailed calculation method is shown as
following:
A5
A5
…
…
…
S
=
0
°
A5
5A
54
00
00
40
8
5
82
05 …
S
=1
Start Express Scan Mode
𝜔

𝐶

𝐶

𝐶



𝐶

𝐶

𝐶

…
𝜔

𝐶

𝐶

𝐶

𝐶

…
𝜔

𝐶

𝐶

…
…
The First Data Response Packet
Cabin
𝑃

𝑃

𝑃

𝐶

:
(
𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒

,
𝑑
𝜃

)
𝐶



:
(
𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒



,
𝑑𝜃



)
…