Ivo/tilt control by izivkov · Pull Request #205 · ob-f/OpenBot

izivkov · 2021-07-09T01:21:13Z

Can now drive by just tilting the controller. See updated README file in the controller directory.
Selections on the controller for sound and image mirroring are automatically persisted on the bot app. so they are preserved across app restarts and switching controller device.
Added a kill switch to stop bot if does not receive drive commands within 1/2 second.
Updated the README file.

…o/tilt-control

thias15 · 2021-07-09T08:21:57Z

        );
  }

+  class KillSwitch {


Are you constantly sending some controls to make sure the bot does not get killed by mistake. For example if user drives at a constant speed, there may not be any new event for a while.

For the communication between robot and bot app, I have implemented a heartbeat (will make a PR soon). Basically every 250ms a heartbeat message will be sent from the phone to the bot. The bot will stop if there is some issue in the communication channel.

We send drive commands every 50 ms when the controller is active. The kill switch will trigger if it does not receive drive command in 500 ms.

When using sliders to drive, this is usually a non-issue, because the sliders revert back to zero. Using tilt control can leave the bot running after the controller has stopped sending commands. That is why I added this kill switch.

Ok sounds good. I have tested everything and it looks good. The one thing is that it is a bit difficult to find the zero point again to stop the car. I was wondering if it makes sense to add a brake button to the screen. Maybe even do throttle control on the screen and only use accelerometer for steering. What are your thoughts on this?

As for the kill switch, let's put in into a separate file since it is a class. Or is there a way to do this from the controller? I would prefer not to have this kill switch wrapper.

OK, I will remove the KillSwitch. It is a bit inefficient anyway. My original idea was to have this "Transmission" class wrapper, which can change the driving characteristics, and a killSwitch() being just one method. But I see your point, I will move it to another class and not use it. The only issue is a runaway bot. We send a stop command on disconnect, but if we change the controller type on the bot app, it will not get a disconnect event. Anyway, I will check this again.

For the zero point, I think I have a dead zone which will send 0,0 if the control is near zero. I will check if this is still there, and maybe widen the range. There is also an option to stop the robot if you place the controller flat on the table at any time, which should work now.

I will update the PR soon.

"I was wondering if it makes sense to add a brake button to the screen. Maybe even do throttle control on the screen and only use accelerometer for steering. What are your thoughts on this?"

Yes, I have seen this in other apps, like "Racing in a Car" app. If you think this is better, we can do this. Full "Zen" mode maybe a bit more difficult to drive.

I guess it's hard to know without trying. But I have also seen this in many car racing games. I guess it's easier to control only one axis via rotation.

I added accelerator and break pedals to the tilt screen. These are implemented in Accelerator.kt and Break.kt files. The icons are very basic, but if somebody can draw a better pedals, please go ahead and replace them.

In both if these files, there is a class called DrivingCharacteristics, which defines various parameters controlling responsiveness of the pedals. One can experiment with these to archive optimum driving experience.

Removed kill switch in the main app

thias15 · 2021-07-22T08:52:49Z

I like the pedal. I think it would be more intuitive if the car speed decreases when releasing the accelerator. When pressing the brake, the car should instantly go 0 and then start driving backwards. This is not like a real car, but common in car racing games on the phone.

thias15 · 2021-07-22T09:02:07Z

+  <img src="../../docs/images/orientation_axis.png" width="50%" />
+</p>
+
+Start with the controller in the up-right position in landscape mode. To move forward, increase the `roll` angle (rotate forward around the `Y` access). To turn left or right,


The documentation needs to be updated.

izivkov

I think it would be more intuitive if the car speed decreases when releasing the accelerator.

It is supposed to do this already. In the Accelerator class, decelerationTime controls how long it takes to decelerate after releasing the pedal, and minSpeed controls what is the final decelerated speed. Currently, decelerationTime is set to 5 seconds, maybe this is too long.
I will add ability to go backwards when pressing the break. I was thinking, we should start going backwords after some delay, say 2 seconds (I will add it as param to easily change it)
I will also update the documentation, just waited to finalise these.

izivkov · 2021-07-21T01:24:43Z

+            from = 1,
+            to = 10
+        ) val stepsToFullStop: Int = 3, // in haw many steps to get to min speed after releasing the accelerator
+    )


Can experiment with these parameters to taste. Same as in Break.kt file.

Looks good. Yes, the delay before going backwards makes sense.

- Brake pedal can put the robot in reverse - Updated the README file.

izivkov · 2021-07-26T22:00:05Z

The brake and accelerator pedals could be better looking. I spent quite a lot of time on these, originally rotating one pedal 90 degrees to use of the other pedal. This created some problem where the rotated pedal disappeared after a while. If somebody wants to make a better pedal icons, please go ahead.

…nificant change to the command. - Rename EventProcessor class to LocalEventBus for clarity.

thias15 · 2021-08-16T21:52:54Z

I'll just update the image with a compressed jpeg.

Ivo/tilt control

izivkov added 11 commits June 23, 2021 23:05

Controller settings are now persisted on the main app.

4abf4d6

Can drive by tilting phone.

9f55653

Fixes related to controller drive mode.

272e2e2

Updated the documentation.

c647205

Updated the documentation.

985a35c

Update image files for controller README.md.

d347481

Updated the documentation.

f5383d1

Updated the documentation.

05892ff

Merge branch 'master' of https://github.com/intel-isl/OpenBot into iv…

cb1f615

…o/tilt-control

Removed debug messages.

7be47b8

Fix style

079a7f0

thias15 reviewed Jul 9, 2021

View reviewed changes

Added accelerator and a break pedal to 'drive-by-tilt' screen.

c00fcfb

Removed kill switch in the main app

thias15 reviewed Jul 22, 2021

View reviewed changes

izivkov commented Jul 23, 2021

View reviewed changes

- Decelerate after releasing accelerator pedal

aec158b

- Brake pedal can put the robot in reverse - Updated the README file.

izivkov added 3 commits July 26, 2021 18:06

Update image files for controller README.md.

2ca877d

- Reduce number of drive commands sent to robot if there is not a sig…

fd27c52

…nificant change to the command. - Rename EventProcessor class to LocalEventBus for clarity.

Set minimum speed to zero after releasing accelerator.

51986f8

thias15 approved these changes Aug 16, 2021

View reviewed changes

thias15 added 3 commits August 16, 2021 23:56

compress large png image

b784798

refactor for clarity

d4c60c7

fix typos

913024e

thias15 merged commit 3e8f2bf into ob-f:master Aug 16, 2021

lacykaltgr pushed a commit to satinavrobotics/SatiBot that referenced this pull request Jun 1, 2025

Merge pull request ob-f#205 from izivkov/ivo/tilt-control

a6b28bf

Ivo/tilt control

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izivkov Jul 21, 2021 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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thias15 commented Jul 22, 2021

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izivkov commented Jul 26, 2021

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thias15 commented Aug 16, 2021

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izivkov commented Jul 9, 2021 •

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