Backlash · FRC Charged Up Robot CAD

Design a full Charged Up robot that could score cones and cubes across all three node levels, pick up from multiple field locations, and stay realistic enough to be manufactured with FRC Team 4079's fabrication resources.

Charged Up required robots to move cones and cubes from loading areas to scoring grids. Each alliance grid included multiple node locations across low, mid, and high scoring levels, which made vertical reach and game piece control major design priorities.

For Backlash, this meant the robot needed to:

• Score cones and cubes on low, mid, and high nodes
• Handle both cone and cube geometry with the same manipulator
• Pick up from the ground, single substation, and double substation
• Fit into a realistic starting configuration
• Balance scoring reach, mechanism complexity, and manufacturability
• Preserve enough drivetrain stability for fast cycling and Charge Station interaction

Before settling on the final Backlash architecture, I explored linear, angled elevator concepts as the initial robot direction. These layouts had strong competitive potential, and a similar style of concept was used successfully by FRC 4414 during Charged Up.

The main issue I ran into was packaging. To reach the high nodes while staying inside the frame perimeter, the elevator concepts needed 3 or even 4 stages. That added a lot of complexity for a project I was trying to keep realistic for my skill level and my old team's fabrication capabilities at the time.

Even though the elevator concepts were not carried forward, they were still valuable as reach and packaging studies. They helped me understand the Charged Up node geometry, substation pickup positions, extension requirements, and the tradeoffs between elevator and arm-based scoring systems before committing to the final 2 DoF arm and wrist robot.

The final Backlash design used a 2 DoF arm and wrist system instead of an elevator. The main arm was driven through chain and gearbox reduction, with a 7/8" round-tube dead-axle arm pivot as the shoulder joint. A powered chain-driven wrist controlled the end effector angle so the robot could position game pieces for ground pickup, substation pickup, and scoring on different Charged Up node levels.

The end effector was inspired by FRC 111 WildStang's Charged Up manipulator concept and went through multiple iterations. The v1 intake used 2 rollers to pick up cones, but it only worked well when cones were upright. It could also intake cubes using the bottom roller, but it could not reliably pick up tipped cones, which was a major limitation for real match play. I also explored making the intake wider to make pickup easier for the driver, but that created more packaging concerns around the wrist, arm, and frame perimeter.

The v2 intake simplified the mechanism by using the same 2 polybelt rollers to pick up both cubes and cones in any orientation. This made the manipulator much more versatile because it could handle cubes, upright cones, and tipped cones without needing separate geometry for each pickup case.

The end effector went through a major redesign from v1 to v2.

The v1 intake used 2 rollers to pick up cones, but it only worked well when cones were upright. It could not reliably intake cones that were knocked over, which was a major limitation for Charged Up because cones often ended up tipped on the floor during a match. The bottom roller was also used for cube intaking, so the design could handle both game pieces, but not with the same level of flexibility I wanted.

During v1, I also explored making the intake wider to make game piece pickup easier. A wider intake would give the driver more room for error, but it also created more packaging concerns around the wrist, arm, and robot frame.

The v2 intake simplified the concept by using the same 2 polybelt rollers to pick up both cubes and cones in any orientation. This made the manipulator more versatile because it could handle cubes, upright cones, and tipped cones without needing separate geometry for each pickup case.