Search found 23 matches

by doctorlu
Mon Jul 03, 2017 3:13 am
Forum: Bitcraze
Topic: vl53l0x question
Replies: 5
Views: 3381

Re: vl53l0x question

Dear all, I still have this question about Z-ranger. The laser sensor vl53l0x, is not always accessable using I2C. Sometimes, when the test board is powered up, the laser starts to work normally after quite a long time ( a few seconds from my observation ). We have ten such PCBs, all of which have s...
by doctorlu
Thu Apr 27, 2017 1:50 pm
Forum: Bitcraze
Topic: How to place the LPS anchors?
Replies: 9
Views: 4962

Re: How to place the LPS anchors?

Oh that is not what I mean. I want to ask if there is any algorithm that uses ranged distances to ''directly'' calculate the exact position, rather than using kalman filtering to ''estimate'' the position. As I recall, ROS may have provided such algorithm or implemented by you guys, I am not sure of...
by doctorlu
Thu Apr 27, 2017 5:36 am
Forum: Bitcraze
Topic: How to place the LPS anchors?
Replies: 9
Views: 4962

Re: How to place the LPS anchors?

Thanks Arnaud, and sorry for my so many questions...
Is there existing algorithm to calculate the position coordinates, based on the ranged distances? I do not find such stuff in CF firmware.
by doctorlu
Wed Apr 26, 2017 8:40 am
Forum: Bitcraze
Topic: How to place the LPS anchors?
Replies: 9
Views: 4962

Re: How to place the LPS anchors?

OK. I get that. Glad to hear you are working on the mocap thing. It is amazing! So from what you have just said, I think the distances got from LPS TWR could only be used to feed kalman estimation, am I right? If I do not want to use kalman estimation, I then have no way to obtain the position of cr...
by doctorlu
Wed Apr 26, 2017 7:33 am
Forum: Bitcraze
Topic: How to place the LPS anchors?
Replies: 9
Views: 4962

Re: How to place the LPS anchors?

Thanks for the clarification. I understand it now. Another question: what is the diffference between stateEstimatorHasDistanceMeasurement and stateEstimatorHasPositionMeasurement in kalman estimation? As I recall, the distance is used to calculate position. The distanceMeasurement_t and positionMeas...
by doctorlu
Tue Apr 25, 2017 7:10 am
Forum: Bitcraze
Topic: How to place the LPS anchors?
Replies: 9
Views: 4962

How to place the LPS anchors?

Dear all, I saw CF with locodeck could communicate with 6 anchors (as shown in the code). Could anyone tell me how to place these anchors? IMHO, only 3 anchors could position the CF, why do we need 6 anchors? How can we get the coordinates using 6 distances values? If we really need more than 3 anch...
by doctorlu
Wed Apr 19, 2017 5:22 am
Forum: Bitcraze
Topic: What are these configurations for in LPS firmware?
Replies: 3
Views: 2728

Re: What are these configurations for in LPS firmware?

Thanks. I get it. So my question is why you change the channel from 5 to 2?
by doctorlu
Mon Apr 17, 2017 3:59 am
Forum: Bitcraze
Topic: What are these configurations for in LPS firmware?
Replies: 3
Views: 2728

What are these configurations for in LPS firmware?

Dear all, I have a question in terms of the LPS configuration. I see the current code has configured this mode, in UWB.c dwNewConfiguration(dwm); dwSetDefaults(dwm); dwEnableMode(dwm, MODE_SHORTDATA_FAST_ACCURACY); dwSetChannel(dwm, CHANNEL_2); dwSetPreambleCode(dwm, PREAMBLE_CODE_64MHZ_9); I just g...
by doctorlu
Tue Mar 14, 2017 6:12 am
Forum: Bitcraze
Topic: vl53l0x question
Replies: 5
Views: 3381

Re: vl53l0x question

Oh yes, so this is not only from my observation.
Have you guys decided to find out why it happens?
by doctorlu
Fri Mar 10, 2017 6:58 am
Forum: Bitcraze
Topic: vl53l0x question
Replies: 5
Views: 3381

vl53l0x question

Dear all, I have a question about this laser ranging module. I use the code provided in the deck driver and give it a try. However, the ranging distance could only attain 1.2m or so, but I recall that this module could achieve as maximum as 2m ranging distance. May I ask if any specific regs of this...