Acceleration

Acceleration code seems to work, at least according to my scoping of signals. Time to test it on the robot, this should make it never loose steps or overshoot.

Would be good to test it on the robot before merging to master, in case of issues

requested review from @pkorysko

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• 43584ef4 - Tweak timings and remove interrupts so the grabber works

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Problem: Slow speed is too slow! Should decouple fast and slow speeds.

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• d7bb0cc6 - Add note document (handwritten...) on stepper acceleration

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Seems like disabling interrupts was a bad idea: Servo works by pulse-width modulated pulses with 20ms cycle time, which are generated using timers. Disabling the interrupts disables the timers used to generate these pulses.

For now re-enabling interrupts ( 43584ef4 ) even if this results in some jitter.

In the future, it would be better to use hardware interrupt timers to generate these pulses...

Info on Arduino timers and interrupts:

• https://www.robotshop.com/community/forum/t/arduino-101-timers-and-interrupts/13072
• https://github.com/khoih-prog/TimerInterrupt#more-useful-information

Making the stepper-functions timer based instead of software sleep would enable:

• Simultaneous X-Y movement
• Network I/O during movement (network in main loop, movement with interrupts)
  • -> Possible to have a soft STOP command (that should also clear the command queue)
  • Output of what is current position during movement

mentioned in issue #9

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• 0fa5d0df - Setup for acceleration to slow-speed

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• c74f362c - Accelerate when moving slowly

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• 45242e10 - Now clearly works for even number of acceleration steps
• 8f72eccd - Acceleration for zeroseek

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OK, I implemented accleration to slow speed as well as fast, used in both STEPPER POS and STEPPER ZEROSEEK. Also fixed some small bugs in interval generation.

This means that we again have stepper_delay_slow in the config, and the acceleration will just truncate the program when it reaches this speed, then continue at this speed.

As mentioned in the previous comment I actually now see a possible way to implement a STOP command, and maybe even bring the jitter down - however if doing this it will be in a separate branch.

It's ready to be tested again!

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• 3f870b49 - Fixed default position of grabber to CLOSED

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mentioned in commit f935554b

merged