Designing Endgame Mechanisms
Endgame is the last 20 to 30 seconds of a match. Most FRC games award significant points for tasks completed during this window (climbing, parking, balancing, or some other action). The mechanical challenge is that you're designing a mechanism that sits idle for 85% of the match and then has to work perfectly under time pressure with no second chance.
Is endgame worth it?
This is a strategy question that should be answered before any design work begins. Not every endgame task is worth building a mechanism for.
How many points is the endgame worth?
Compare it to one or two additional scoring cycles. If a climb is worth 12 points and a scoring cycle is worth 6, the climb replaces two cycles. Is that worth the weight, design time, and risk?
How consistent can we make it?
A climb that works 95% of the time is worth a lot. A climb that works 60% of the time is worth less than the scoring cycles you're giving up to attempt it.
Does everyone else do it?
If every competitive robot at your event can climb, not climbing puts you at a disadvantage in alliance selection. Even if the points are marginal, the strategic value of being a reliable climber matters.
How much weight and space does it cost?
A dedicated climber that weighs 15 lbs and takes up a quarter of your frame is a big investment. A hook that bolts to your existing elevator and adds 2 lbs is almost free.
Can we test it enough before competition?
A mechanism that's finished in week 5 and tested twice is going to fail when it matters. If the endgame mechanism can't be finished early enough to test extensively, it might not be worth building.
In most recent FRC games, climbing has been worth enough points and common enough in the competitive meta that we treat it as a requirement, not an option. The question is usually not "should we climb" but "how do we climb with the least cost to the rest of the robot."
Design priorities
Endgame mechanisms have a different set of priorities than scoring mechanisms. Scoring mechanisms need to be fast, precise, and handle game pieces well. Endgame mechanisms need to be reliable, simple, and fast to execute under pressure.
Reliability over performance
A climb that works every time in 8 seconds is better than a climb that sometimes works in 4 seconds. You get one attempt. The driver is stressed, there's defense happening, and the clock is running. Design for consistency.
Simplicity over elegance
The endgame mechanism should have as few moving parts and as few dependencies on other mechanisms as possible. If climbing requires stowing the intake, retracting the elevator, extending the climber, aligning precisely, and then actuating the winch in a specific sequence, you've created too many failure points. The best climbers are one button: press and it climbs.
Driver-proof engagement
The hook, latch, or contact point that engages the climbing structure needs generous tolerances. If the driver has to line up within 1/4" to engage, it will fail at competition. Design the engagement geometry with funneling, chamfers, or wide capture zones so it works even when alignment is off by an inch or more.
Independent from scoring
Ideally the endgame mechanism can execute without requiring other mechanisms to be in a specific state. If the intake needs to be retracted before the climber can extend, add a software interlock but don't make it a physical interference. The fewer things that have to happen in sequence, the fewer things that can go wrong.
Time budgeting
Endgame has a hard time limit. You need to account for every second.
Transit
Driving from the last scoring position to the climbing structure
2 to 5 seconds
Alignment
Lining up with the climbing structure
1 to 3 seconds (less if the hook has generous capture)
Engagement
Hook or mechanism contacts the climbing structure
1 to 3 seconds
Climb
Winching up or pulling the robot off the ground
3 to 8 seconds
Settling
Waiting for the robot to stop swinging so the position is scored
1 to 3 seconds
Add these up for your specific design. If the total is 15 seconds, you need to start with at least 15 seconds remaining, plus a buffer for things not going perfectly. Most teams target starting the climb sequence with 15 to 20 seconds left.
Practice the full endgame sequence with the driver, including driving from a realistic field position, not just climbing from directly underneath the structure. Transit and alignment eat more time than teams expect.
Integration with the rest of the robot
The endgame mechanism lives alongside everything else, so it needs to be designed with the whole robot in mind.
Decide early how much weight you're allocating to endgame. A typical climber is 5 to 15 lbs depending on complexity. If you're already tight on weight, look for dual-purpose mechanisms (use the elevator or arm you already have) rather than a dedicated climber.
CAD the climber in its stowed position alongside every other mechanism in various positions. Check for interference with the intake deployed, the elevator extended, and the arm at different angles. The climber stowed inside the frame for 2 minutes and 10 seconds cannot interfere with anything that's moving during that time.
When the robot is hanging, the forces go through the climber, through its mounting points, and into the frame. The mounting points should connect directly to the frame rails or to reinforced structure, not to thin unsupported plates.
Think about where the load goes. If the hook is at the top of a telescoping arm and the winch is at the base, the entire robot weight pulls down on the base mount. That mount needs to be bolted through the frame rail with multiple bolts, not attached to a single plate with two screws.
The climber's motor, sensor, and any solenoid wires need to route from the bellypan to wherever the mechanism lives. Plan the wire path early so you're not threading wires through a fully assembled robot at midnight before bag day (or, these days, before your first event).
If the climber extends or telescopes, the wires to any sensors on the extending portion need a service loop and strain relief (see the Strain Relief page).
Fail-safe design
Endgame is the highest-stakes part of the match. The mechanism should fail safely.
Ratchet on winch
If the motor loses power or code crashes, the rope can't unspool and the robot can't fall
WCP ratchet plates, or a ratchet mechanism on the spool shaft
Brake mode on motors
Mechanism holds position when the motor isn't being driven
Set all climber motors to brake mode in software
Mechanical lock
Motors disable when the match timer hits zero. The robot needs to stay climbed after the match ends with no motor power.
Ratchet, worm gear reduction (naturally non-backdrivable), or a physical latch that engages when the robot reaches the climbed position
Engagement verification
Prevents the winch from reeling in before the hook has actually caught
A limit switch or beam break on the hook that confirms contact before the climb sequence proceeds
Testing protocol
The climber should be one of the most tested mechanisms on the robot, despite running for the shortest time during a match.
Test the full sequence 50+ times before competition. This includes driving to the climbing structure, aligning, engaging, climbing, and settling. Not just the climb in isolation.
Test under match conditions. Have other robots nearby. Have the driver stressed. The first time you test under pressure should not be at a real event.
Test failure modes. What happens if the hook doesn't engage? What if the driver is misaligned? What if the robot gets bumped during the climb? Know the answers before competition.
Time every attempt. Log the time from "driver presses climb" to "robot fully climbed and settled." If the average is 12 seconds and the worst case was 18, plan to start with at least 20 seconds remaining.
Past endgame lessons
2026 Rebuilt (cage climb)
The cage structure requires robots to grab onto and lift themselves off the ground. Telescoping hook and winch is the most common approach. The cage geometry is fixed and relatively forgiving for hook engagement compared to swinging chains. Teams that prioritized a fast, reliable single-button climb have the highest success rates.
2024 Crescendo (chain climb)
Robots climbed a chain suspended from a stage structure. The chain swung freely, which made engagement harder than a fixed bar. Teams that designed hooks with wide capture zones and self-centering geometry had much higher success rates. Several teams lost critical matches because the chain swung away from the hook during engagement.
2023 Charged Up (charge station balance)
The endgame was balancing on a teeter-totter platform rather than climbing. This required precise drivetrain control rather than a dedicated mechanism. Teams that invested in auto-balance code (using the gyro to detect tilt and adjust motor power) had the most consistent endgames. Some teams added physical brakes or high-friction pads to prevent sliding.
2020/2021 Infinite Recharge (bar climb)
Robots climbed metal bars at different heights, with bonus points for higher bars and traversing between them. The Climber in a Box kit was developed from designs used in this game. Teams that could traverse had a significant scoring advantage, but the mechanism complexity was much higher. Most teams targeted the simpler low or mid bar for reliability.
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