Search found 17 matches

by malintha
Tue Aug 21, 2018 12:51 pm
Forum: Developer Discussions
Topic: Publishing PWM values for motors
Replies: 14
Views: 2428

Re: Publishing PWM values for motors

1). For that PWM enabled implementation, I entirely relied on VICON data to calculate the attitude, velocity etc. So I only had to send data packets with PWM values to the drone. 2). There are some changes I did on the cf_ros to send the PWM packets out. Feel free to try this out. This might not be ...
by malintha
Sat Aug 18, 2018 4:33 am
Forum: Developer Discussions
Topic: Publishing PWM values for motors
Replies: 14
Views: 2428

Re: Publishing PWM values for motors

Hi natolambert, The approach you have followed to send the PWM values sounds correct to me. Make sure that you are not held up by unnecessary tasks by commenting them out in the stabilizer.c. And also make sure that the stabilizer.c runs at 1000Hz (RATE_MAIN_LOOP RATE_1000_HZ). However, did you take...
by malintha
Wed Jul 04, 2018 10:19 pm
Forum: Developer Discussions
Topic: Unable to stabilize Crazyflie in air.
Replies: 1
Views: 417

Re: Unable to stabilize Crazyflie in air.

I think it is possible to drift the drone as it is not perfectly balanced (worn rotors, unbalanced frame, motor frictions etc.). One way to stop the drift is providing it some external feedback about its position in the world frame using some position feedback system. An optic flow sensor would even...
by malintha
Mon Jun 25, 2018 1:32 am
Forum: Developer Discussions
Topic: Decentralised Inter-communicating Swarm
Replies: 4
Views: 830

Re: Decentralised Inter-communicating Swarm

You can also checkout crazyswarm project[1] from Wolfgang et al. It is not exactly decentralized though, you can study the project as a reference. This tutorial [3] also has a lot of information on crazyflie_ros and crazyswarm projects. You can send the external position to the drone via /external_p...
by malintha
Fri Jun 22, 2018 5:10 am
Forum: Developer Discussions
Topic: Publishing PWM values for motors
Replies: 14
Views: 2428

Re: Publishing PWM values for motors

Hi All, I have implemented the code for the geometric controller (Lee's controller) onboard and was able to get the attitude controlling part working successfully. So when the drone is on, it was able to stabilize and float around. However, the issue was getting the position controlling part tuned. ...
by malintha
Mon Jun 04, 2018 4:21 pm
Forum: Developer Discussions
Topic: Integrate Magnetometer with Kalman Estimator
Replies: 3
Views: 626

Re: Integrate Magnetometer with Kalman Estimator

Hi thasu, As far as I understand, currently the magnetometer doesn't play a part in the estimation [1]. If you want to simply find the yaw value, you can use the value from the state variable. It seems to be pretty good. (It doesn't have the sense of north, that'll produce the yaw relative to the in...
by malintha
Fri Jun 01, 2018 5:33 am
Forum: Developer discussions
Topic: Attitude values slowly converging to zero in EKF
Replies: 2
Views: 696

Re: Attitude values slowly converging to zero in EKF

I think I figured it out. When I switch quadIsFlying=true, attitude values become stable. Apparently, we assume the drone's initial position is flat (R=I) and hence reverse the attitude to 0 with at a given rate when the accelerometer and gyroscope values are idle. Hence the attitude values should b...
by malintha
Thu May 31, 2018 10:31 pm
Forum: Developer discussions
Topic: Attitude values slowly converging to zero in EKF
Replies: 2
Views: 696

Attitude values slowly converging to zero in EKF

Hi All, I am required to calculate the instantaneous linear velocity, acceleration and attitude for the controller I'm working on. I'm using the EKF implemented by Hamer and I noticed that the attitude values are slowly converging to zero when even the drone is idle at a given pose. But when I use t...
by malintha
Wed May 02, 2018 6:36 pm
Forum: Developer Discussions
Topic: Publishing PWM values for motors
Replies: 14
Views: 2428

Re: Publishing PWM values for motors

Thanks a lot, tobias and whoenig! I did a latency test by simultaneously measuring the same movement using IMU and VICON/ROS and it turned out that the mean latency was 24.75ms with a SD of 4ms, out of 50 readings (IMU readings had to be leveraged with VICON by a small offset). I think its believabl...
by malintha
Mon Apr 30, 2018 4:46 pm
Forum: Developer Discussions
Topic: CPU halted - Only one blue light is on
Replies: 3
Views: 674

Re: CPU halted - Only one blue light is on

Nice! It worked! Thanks a lot Tobias! For anybody who is looking for a solution for a similar issue with STM32, you can first flash the stm32 bootloader[1] as in [2]. Then flash the cf-fw [3] using CLOAD=1 option. [1] https://github.com/bitcraze/crazyflie2-stm-bootloader [2] https://wiki.bitcraze.io...