Potential Problems and Solutions on Improving Robot Intakes

[AlvinZou]

After my team completed building the robot and moved on to the testing phase, we encountered the issue that the robot could only intake a small number of cubes (barely four). After putting in some thought and researching online, I found some potential problems that our robot might have, and some potential solutions to these problems.

I believe that many teams also have similar issues, so I decided to post some information that I have gathered. Hopefully, you find this to be just as useful as I do! (Excuse my grammar)

Potential problems that your robot’s intake system might have:

1. Angle of the ramp is too large. (extreme case is perpendicular to the ground)
2. Cubes are twisting when they are being intaked.
3. Intake arms are bending/twisting.
4. Intake arms are not in sync with each other when moving up/down.
5. Intake rollers flip out when it is intaking cubes.
6. Intake rollers do not have enough compression/torque to intake many cubes.
   7.Note: too much compression can cause motors to burn out quickly.
7. Intake rollers get in the way when trying to stack cubes.

Potential methods for improving the intake ramp & arms:

1. Decrease the angle of the ramp.
2. Place lexan/aluminum plates/zip-ties/rubber bands on your ramp.
3. Place rail guards on the sides of the ramp.
4. Box each individual intake arm and brace the two intake arms together.
5. Place “locks” on the chassis of the robot so that when the arms are down they are locked in position and can not move. (helps intake compression)
6. Adjust the angle of the arms so that the intake rollers are more parallel to the ramp. (So that the intakes will be exerting more force up the ramp instead of into the ramp.)

Potential methods for improving the intake rollers:

1. Adjust the distance between the intake rollers. (Smaller distance = increased compression)
2. Adjust the size of the sprocket. (smaller sprocket = more torque and less speed)
3. Adjust the flap size on the intake rollers. (Medium and small flaps seem to work better than the long ones, since they are shorter, which means they are more stiff and can provide better compression. However, testing is needed to figure out the best combination of flaps to use on your robot)
4. Make sure that there is the same number of flaps on both intake rollers and they are aligned perfectly.
5. Make sure that the ramp is centered so that the intake rollers are the same distance to the ramp.
6. Make sure that the flaps on the intake rollers are not hitting anything. (Ex: the ramp, c-channels, screws)
7. Avoid cantilevering your intake rollers (only supporting the axles on one side of the sprocket). One way to solve this is to add an additional c-channel on the other side of the sprocket and connecting it to the top c-channel with standoffs. Some teams chose not to use an axel at all, using screws instead.

8. Adjusting the speed of the intake rollers through changing the cartridge of the motor or implementing a gear reduction. (changes the torque)
9. Adjusting the number of rubber bands used.
10. For flip-out intake rollers, using a lock can greatly increase the compression.

Other methods of improvement through control & coding (test to see if helpful):

1. Adjust the velocity of the motors through code.
   2.Note: for experienced coders, using a PID loop can improve the accuracy of the code and the smoothness of certain robot functions. (Ex: as the ramp gets closer to being vertical, the motor reduces its velocity)
2. Lift the arms a bit when stacking so that the intake rollers do not interfere with the cubes.
3. Reverse the intake rollers at a low velocity when moving away from the stack.
4. Create “macro controls”-- an output sequence from a single input-- so that the robot is easier to control and less prone to human error. (Ex: when button A is pressed the robot will push the ramp forward to the vertical position, then retract the ramp, then move away while the intake rollers spin in reverse at a low velocity for two seconds.)

This is everything that I could think of and find. If you have anything else to add, please share your ideas!

Here are some helpful links (I summarized a lot of the information in this post, but more information can be found below):

__Intake information

__Macros for v5 - #6 by Doctortictac

__Intakes not working

Long v. short flaps

What is the difference between long and short intake flaps? Is there one that’s better? I’ve seen both used (not on the same bot) but don’t know if one works better or not.

Need help with Intakes *Urgent*

Our team has a competition this Saturday and we have ran into some issues. When our robot intakes cubes they tend to hop around and bounce out. We have done the following changes to try to fix the issue: adjust compression, change intake flap size and number, change angle of the intake relative to the tray, adjust spacing, added guard rail, and messed around with rubber bands. At this point i am kinda lost. I would really appreciate if someone could help explain how to fix this issue. (Pictures …

[Railgunawesome]

@AlvinZou

Intake arms are bending/twisting.

I would say that bending and twisting of the arms is necessary is you’re doing a hard mount, as it would allow you to intake cubes at an angle. Just make sure they don’t twist out too much.

@AlvinZou

take rollers get in the way when trying to stack cubes.

For this problem, you could simply make a macro for the outtaking to place down a stack. If you do it right, stack placing becomes a brainless procedure.

[SaltyCB]

@AlvinZou

Lift the arms a bit when stacking so that the intake rollers do not interfere with the cubes.

our tray is abl;e to push the intake rollers out when stacking so we dont have this issue.

@AlvinZou

Make sure that there is the same number of flaps on both intake rollers and they are aligned perfectly.

how much difference does that make?
i thought you could just have the flaps where ever

[AlvinZou]

If the flaps on both rollers aren’t aligned, when they are taking in a cube the flaps might hit on the cube at different times, so it might become harder to intake more cubes.