#robotics Logs

Aug 11 2014

00:06 MrCurious is
00:07 Oracle989 Damn. There was a flight test of Fenrir for the university aerial robotics club today that I couldn't make it to. The aircraft performed a rapid, unplanned, high-energy landing operation.
00:08 MrCurious is that of the same flavor as a high speed automotive design upgrade?
00:08 Oracle989 MrCurious: Energy dissipation was provided via lithobraking/lithobreaking
00:08 rue_shop2 Oracle989, :( maybe next time?
00:08 MrCurious so there was fire?
00:09 Oracle989 rue_shop2: We've got 6 weeks to get the system in top operational status for a competition in Australia.
00:09 rue_shop2 the lithium broke in the process of the high energy landing?
00:09 rue_shop2 ah
00:09 MrCurious is the design easy to replicate? or was it a undocumented one off?
00:09 Oracle989 This is our first hull loss accident in 4 or 5 years.
00:10 rue_shop2 good for the upgrade
00:10 Oracle989 MrCurious: It's all designed to be built off a laser cutter, we've got the files.
00:10 MrCurious ok,so not a huge setback
00:10 Oracle989 Which is a HUGE improvement over the last aircraft, which we made 3 of.
00:10 rue_shop2 I just finished the frame for the heater for my vacuum former :)
00:10 Oracle989 Well it's still a huge effort to get the thing rebuilt, re-evaluated, and retuned in 6 weeks.
00:11 Oracle989 I don't think there was a fire.
00:11 rue_shop2 so there were several! how many compeditors planes did you destroy?
00:12 MrCurious next time... have a self destruct that trigger a relay to short the lipo's
00:12 MrCurious all starships come with self destruct....
00:13 MrCurious would a landing net have minimized damage
00:13 Oracle989 We'll need a new fuselage and wings cut and coated, new nosecone and engine fairings laid up, new flight computer ordered and built, very possibly some extensive autopilot repairs, new camera gimbal, new lens mount for the camera, new 2.4GHz radio system, and everything else from the wreck needs to be extensively evaluated.
00:13 Oracle989 MrCurious: Considering it landed in an inverted dive into a cow field, no.
00:14 Oracle989 We also have no idea why it crashed yet. The left wing was slid out with its antirotation pins and lock tabs broken off, but that could have happened on impact.
00:20 Oracle989 Unfortunately, we didn't have our operator video recording set up yet. I'd kind of like to see the reactions when the thing went down. Rocketry had an issue with a motor experiencing a fast-moving flame front earlier this year, they had the whole thing on video, complete with the designer of the motor mount saying "That is...not ideal." as the thing erupted in fire.
10:23 cambazz if we are designing a tracked bot, and if we put one motor on the back driving left track and one motor on the front driving right track that are the implication of this design?
10:23 cambazz as to compared to both motors on the pack
10:23 cambazz back
10:23 cambazz they are still driving tracks so it should not be a problem right?
10:26 robotust1a cambazz: I think it should be ok
10:28 Hyratel cambazz, if you have simple one drive cog one idler wheel, it'll be ok
10:28 Hyratel but if you add bogie wheels it'll need to be properly tensioned and that's more difficult with them assymetrical
10:29 cambazz what is a cog one idler?
10:29 cambazz i take it in the case of a small robot it should not be a problem right?
10:33 cambazz oh also another question: i am now using encoded motors. before i had just done simple pwm control. what are some algorithms to use when you have encoders. i thought to write a function motorControl(int goEncoderCount, int pwm)
10:33 cambazz so it will go encoder count times, at pwm speed
10:35 cambazz or a function motorControl(int desiredEncoderCounterSpeed) and it will regulate pwm to catch desired counter speed
10:38 Hyratel cambazz, one drive cog and one idler wheel
10:39 Hyratel cambazz, youll want some kind of control loop to keep your motor speeds from oscillating
10:39 Hyratel PWM only sets the torque power % of the motor
10:40 Hyratel you'll need something like PID or one of its relatives to control the PWM RPM relationship