Difference between revisions of "Intakes"
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=== Effective Intake Area === | === Effective Intake Area === | ||
| − | The effective intake area is the size of the area in front of the robot where reliable intaking can happen. The larger the effective intake area, the more easily game pieces can be acquired and scored. For a tank drive robot, measuring the width of the intake (parallel to the front bumper) is more important than measuring its length (perpendicular to the front bumper). For a swerve drive, the critical measurement is the total ground area under the intake where reliable intaking happens. | + | The effective intake area is the size of the area in front of the robot where reliable intaking can happen. The larger the effective intake area, the more easily game pieces can be acquired and scored. For a tank drive robot, measuring the width of the intake (parallel to the front bumper) is more important than measuring its length (perpendicular to the front bumper). For a swerve drive, the critical measurement is the total ground area under the intake where reliable intaking happens. A large intake is only valuable if the intake works reliably across the entire area. If a robot has a full width intake that jams when intaking at the sides, then a narrow intake would be more valuable. |
=== Speed === | === Speed === | ||
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r = The intake's radius in inches | r = The intake's radius in inches | ||
| − | "Reasonable" values of rotational velocity can range from ~700 RPM (4" diameter roller used in a two-roller design on a slow robot) | + | "Reasonable" values of rotational velocity can range from ~700 RPM (4" diameter roller used in a two-roller design on a slow robot) to ~12,000 RPM (1" diameter roller in a single-roller design on a fast robot). Once a value has been arrived at mathematically, it should be tested as much as possible. Each game piece and robot will behave differently, and will require tweaking and adjustment. Due to this, be careful to select motors and gearing capable of spinning faster than the calculated value. |
=== Deployment === | === Deployment === | ||
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This deployment typically happens with a linear slide, pivot, or [[Four_Bars|four bar]]. Intake deployment is an ideal use for [[pneumatics]] as most intakes have only two positions, stowed and deployed. Deploying an intake with a motor is useful in some cases where pneumatics aren't present on the robot (such as the [[2021 Robot (Oreo)]]), or when the intake's exact position needs to be controlled (such as the [[2019 Robot (Flip)]]). | This deployment typically happens with a linear slide, pivot, or [[Four_Bars|four bar]]. Intake deployment is an ideal use for [[pneumatics]] as most intakes have only two positions, stowed and deployed. Deploying an intake with a motor is useful in some cases where pneumatics aren't present on the robot (such as the [[2021 Robot (Oreo)]]), or when the intake's exact position needs to be controlled (such as the [[2019 Robot (Flip)]]). | ||
| + | |||
| + | Choosing a deployment method is almost entirely based on the geometry of the robot, and what fits in the available space. | ||
| + | |||
| + | === Compression and Compliance === | ||
| + | In most cases in order to grip a game piece, an intake needs to provide a compression force on it. In order to provide a compression force, either the intake or the game piece needs to be able to move or flex; this movement is called compliance. If a game piece is soft (such as the balls used in [[Balls#Boulder_(2016)|2016]], [[Balls#Cargo_(2019)|2019]], or [[Balls#Power Cell_(2020)|2020]]), the intake can be rigid because compliance comes from the game piece (although different amounts of compliance can still help - testing is required). If a game piece is hard (such as the boxes used in [[Boxes#Tote_(2015)|2015]] or [[Boxes#Power_Cube_(2018)|2018)]], an effective intake will always have compliance because the game piece is unable to flex out of the way. An intake that is more rigid will grip the game piece harder, but will require more torque from the motor to do so. A more flexible intake will grip the game piece less forcefully, but will put less torque on the motor and may be able to acquire a game piece in a more difficult position or orientation. | ||
| + | |||
| + | The range of motion of an intake and the force required to move it are both variables that should be tested in the prototyping stages of a design. If possible, they should be adjustable on a "final" design so that changes can be dialed in as the season progresses. | ||
=== Durability === | === Durability === | ||
| − | Because intakes are often the only part of a robot extending past the frame perimeter, they need to be designed to take more abuse than most other robot parts. Compliant mounting and [[Polycarbonate|flexible]] parts are a popular way to keep intakes from taking damage when deployed. A robot should be able to drive into a wall at full speed without breaking | + | Because intakes are often the only part of a robot extending past the frame perimeter, they need to be designed to take more abuse than most other robot parts. Compliant mounting and [[Polycarbonate|flexible]] parts are a popular way to keep intakes from taking damage when deployed. A robot should be able to drive into a wall at full speed without breaking anything critical. |
== Major Types == | == Major Types == | ||
Revision as of 15:32, 23 June 2021
Contents
Description
(description of mechanism)
Design Considerations
Touch It, Own It
"Touch it, own it" is a concept used to describe an effective intake, although it is not a measurable metric. The moment a "touch it, own it" intake comes in contact with a game piece, it is "owned" by the robot such that it will never lose grip, fall out, or be stolen by another robot. It can be seen as somewhat of a buzzword.
Effective Intake Area
The effective intake area is the size of the area in front of the robot where reliable intaking can happen. The larger the effective intake area, the more easily game pieces can be acquired and scored. For a tank drive robot, measuring the width of the intake (parallel to the front bumper) is more important than measuring its length (perpendicular to the front bumper). For a swerve drive, the critical measurement is the total ground area under the intake where reliable intaking happens. A large intake is only valuable if the intake works reliably across the entire area. If a robot has a full width intake that jams when intaking at the sides, then a narrow intake would be more valuable.
Speed
Assuming that a roller intake is being used (as it almost always should), the surface speed of the roller(s) should be fast enough that the robot can pick up a game pieces when driving forward at full speed. For "single-contact" intake designs like the Top Roller, that means that the surface speed of the roller should be 2-4x the top speed of the robot. For "dual-contact" designs like the Top and Bottom Roller and Side Rollers, each roller's surface speed should be 1-2x the robot's top speed.
A simple equation to calculate an intake's rotational speed is:
Where:
Ω = The intake's rotational velocity in RPM
Vs = The intake's surface speed in feet per second (1-4 times the robot's maximum driving speed, depending on the type of intake used)
r = The intake's radius in inches
"Reasonable" values of rotational velocity can range from ~700 RPM (4" diameter roller used in a two-roller design on a slow robot) to ~12,000 RPM (1" diameter roller in a single-roller design on a fast robot). Once a value has been arrived at mathematically, it should be tested as much as possible. Each game piece and robot will behave differently, and will require tweaking and adjustment. Due to this, be careful to select motors and gearing capable of spinning faster than the calculated value.
Deployment
All parts of an FRC robot are typically required to start within the robot's frame perimeter. With few exceptions, an intake is unable to acquire game pieces from inside the frame perimeter. This means that intakes have to actuate outwards in order to fuction effectively. It is not always strictly necessary to be able to retract an intake, although game rules sometimes make it advantageous to do so, and parts outside the frame perimeter are always more succeptable to damage than parts protected by the bumpers.
This deployment typically happens with a linear slide, pivot, or four bar. Intake deployment is an ideal use for pneumatics as most intakes have only two positions, stowed and deployed. Deploying an intake with a motor is useful in some cases where pneumatics aren't present on the robot (such as the 2021 Robot (Oreo)), or when the intake's exact position needs to be controlled (such as the 2019 Robot (Flip)).
Choosing a deployment method is almost entirely based on the geometry of the robot, and what fits in the available space.
Compression and Compliance
In most cases in order to grip a game piece, an intake needs to provide a compression force on it. In order to provide a compression force, either the intake or the game piece needs to be able to move or flex; this movement is called compliance. If a game piece is soft (such as the balls used in 2016, 2019, or 2020), the intake can be rigid because compliance comes from the game piece (although different amounts of compliance can still help - testing is required). If a game piece is hard (such as the boxes used in 2015 or 2018), an effective intake will always have compliance because the game piece is unable to flex out of the way. An intake that is more rigid will grip the game piece harder, but will require more torque from the motor to do so. A more flexible intake will grip the game piece less forcefully, but will put less torque on the motor and may be able to acquire a game piece in a more difficult position or orientation.
The range of motion of an intake and the force required to move it are both variables that should be tested in the prototyping stages of a design. If possible, they should be adjustable on a "final" design so that changes can be dialed in as the season progresses.
Durability
Because intakes are often the only part of a robot extending past the frame perimeter, they need to be designed to take more abuse than most other robot parts. Compliant mounting and flexible parts are a popular way to keep intakes from taking damage when deployed. A robot should be able to drive into a wall at full speed without breaking anything critical.
Major Types
Over Bumper
Description
When to Use
Notable Examples
File:Example1.jpg Team #### - Year |
File:Example2.jpg Team #### - Year |
File:Example3.jpg Team #### - Year |
| Link to Info | Link to Info | Link to Info |
Through Bumper
Description
When to Use
Notable Examples
File:Example1.jpg Team #### - Year |
File:Example2.jpg Team #### - Year |
File:Example3.jpg Team #### - Year |
| Link to Info | Link to Info | Link to Info |
Top and Bottom Roller
Description
When to Use
Notable Examples
File:Example1.jpg Team #### - Year |
File:Example2.jpg Team #### - Year |
File:Example3.jpg Team #### - Year |
| Link to Info | Link to Info | Link to Info |
Top Roller
Description
Dustpans
When to Use
Notable Examples
File:Example1.jpg Team #### - Year |
File:Example2.jpg Team #### - Year |
File:Example3.jpg Team #### - Year |
| Link to Info | Link to Info | Link to Info |
Side Rollers
Description
Dustpans
When to Use
Notable Examples
File:Example1.jpg Team #### - Year |
File:Example2.jpg Team #### - Year |
File:Example3.jpg Team #### - Year |
| Link to Info | Link to Info | Link to Info |
Pinchers
Description
Dustpans
When to Use
Notable Examples
File:Example1.jpg Team #### - Year |
File:Example2.jpg Team #### - Year |
File:Example3.jpg Team #### - Year |
| Link to Info | Link to Info | Link to Info |
