Robot Movement is Jerky

Authors: Justin Hwang

Date: 7/14/23

Status

• N/A

Symptoms

• Robot movement is jerky
• LEDs flicker on and off
• If battery indicator in DriverStation flashes red and dips to low voltage (less than 8.0), you are overdrawing your battery. See Solutions 1-3.
• If the battery indicator in DriverStation is NOT dipping, you may have packet loss. See Frequent Packet Loss Spikes

Battery overdraw can be obvious, like the end of Trial 51, or more subtle like Trial 41. The sound is the clearest indicator.

Solutions

Solution 1: Replace Battery

• The robot sputters during its movement because the battery is being over-drawn. Replacing the battery often fixes this issue.

Solution 2: Check your current limits

• The battery may also be getting overdrawn because the subsystems do not have proper current limits.
• If the jerkiness tends to happen when a particular subsystem is in use, check those current limits first.
• See "Resources: 2023 MBR" for a past example

Solution 3: Check for faulty connections

• If power connections are not secure, they may prevent the flow of electricity.
• See "Resources: 2023 CVR" for a past example

Resources

2023 CVR

We replaced our main breaker right before practice day and were unable to move without jittering. In the pit, we found that the main breaker was not connected properly. Fixing that connection resolved the jerkiness issues we were seeing.

2023 MBR

In 2023, we replaced our Mk4i L1 modules for L2 modules between CVR and MBR. On the MBR practice day, we couldn't get through a full match without the robot jittering. At the end of practice day, we realized we had our DriveBase motors limited to 80 amps, which is very high. After limiting the current to 50 amps per motor, we ran smoothly during quals.