How does Wren get off the ground?
October 16, 2019
October 16, 2019
By Marco Alberto
Just when you think you’ve figured it all out, trust the software to mess up! I’ve been working on the programming and electronics integration with the Wren, primarily using Mission Planner to set all the relevant parameters correctly and plan any autonomous missions as required.
The “brain” of the WREN is a Cube Autopilot (from Cubepilot) running Arduplane, which allows us to have Quad-plane support and features for the Wren. This gives us access to hundreds of different parameters, the ability to tune both quadcopter and regular plane flight, and accurately collect log data from each flight. This has allowed us to diagnose all issues with aircraft centre of gravity and controllability concerns in particular, during the development process.
In addition to these core features, we have begun experimenting with the use of UAVCAN for servo control, which worked wonderfully at the AUVSI SUAS competition in June 2019. Future versions of Wren will continue to use the UAVCAN architecture, while also including battery monitoring and ESC (electronic speed controller) control over the CAN lines as well.
Following some issues we had at the Land of Lakes challenge in 2017, the digital ESC protocol DShot was successfully implemented for use with the ESCs on Wren at the AUVSI SUAS competition. Using APD ESCs, DShot was found to be an extremely reliable and easy to implement protocol with Ardupilot. With no ESC calibrations required, like with a PWM ESC, setup time was reduced significantly with one less calibration process required.
Overall, we are extremely happy with the performance and future capabilities of the systems that were integrated onto WREN v1. As we move towards the end of the year, and progress towards competing in the AUVSI SUAS 2020 and Medical Rescue 2020, we will be testing these changes on WREN v1, streamlining the programming and parameter updating processes, as well as developing a lighter, faster WREN.
Please do not hesitate to contact us with any further questions about the WREN, its systems, or the team! We have some exciting things coming, so be sure to keep an eye on social media.