Swerve & Steer

Swerve, but also Steer! The most reliable, easy to use, and easy to integrate swerve module for FIRST Robotics Competition teams. Swerve was once a drive style only attainable for top tier teams but now swerve is for everyone. Available assembled or in an unassembled kit these are more affordable and configurable than ever before.
These all-in-one swerve gearbox and steering module comes ready to mount and program right out of the box. It is by far the most inexpensive and most complete swerve drive solution for FRC.

Drive and Steer Motors:

The wheel propulsion is powered by your choice of several motors; CIM, Falcon 500 (using short am-6958 shaft), NEO, or even order without a drive motor and integrate your own. Rotation control by default is managed by a PG71 gearmotor. Order without the PG and use your own steering motor of choice. Both of these motors are mounted to the main motor plate, which can easily be mounted to your robot frame or other structure via the 0.5 in. hole pattern around the perimeter.

Position Sensing:

• "PG": The incremental encoder on the backside of the PG71. This encoder can be used to determine the steering angle provided that all the modules start facing forward. This encoder connects to the roboRIO via DIO ports. Each channel output goes into a different DIO port.
• "MA3": An MA3 absolute encoder and associated hardware included. The user has the option of 5 mounting locations for this encoder. This encoder connects via Analog In on the roboRIO.
• "Lamprey": A Lamprey through bore absolute encoder pre-installed and pre-calibrated into the module. This encoder works directly with a Talon SRX Motor Controller and be connected by this data port cable am-2617, not included

Wheel Rotation Sensing:

If encoder based measurement wheel rotation (ie. distance traveled) is desired, the NEO or Falcon 500 brushless motor options should be chosen as they have integrated encoders that can output this information.  

Drive Gearing Ratio:

• 12 tooth spur gear is driven by CIM Falcon 500 Motor, or 
• 40 tooth spur gear is driven by 12 tooth spur gear
• 20 tooth bevel gear is co-axial with and driven by 40 tooth spur gear
• 40 tooth bevel gear is driven by 20 tooth bevel gear
• 4" HiGrip Wheel is co-axial with and driven by the 40 tooth bevel gear
• Overall Gear Ratio: 6.67:1

Drive Speed:

• 660 or 800 Max Wheel RPM (depending on motor selection)
• 11.5 or 13.5 ft/sec (depending on motor selection)

Steer Gearing & Ratio:

• 48 tooth spur gear is driven by PG71 gearmotor
• 40 tooth spur gear is driven by 48 tooth gear
• Lower portion of the module pivots directly with the 40 tooth gear
• Max Steer Speed: 90 RPM

Programming:

Team 1640 has some example code for driving a swerve system. Their Cheif Delphi post can be found here, https://www.chiefdelphi.com/media/papers/2704. The Library and explanation can be downloaded here, https://files.andymark.com/FRC1640_2011_PivotDriveLibrary.zip

Improvements Log:

• 2022/12
  • PG Gear changed to steel
• 2021/02
  • Visual Differences
    • Some plates and gears may have small differences in look and shape but are functionally the same.
• 2021/01
  • Selectable Drive Motor Options
    • Added NEO as an out of the box option
    • Added "no drive motor" as an option to use your own motors
  • Selectable Steer Motor Options
    • Added "No Steer Motor" as an option to allow the use of already purchased motors
  • Added unassembled options for a low cost swerve experience
  • Added nut pockets in bearing plate for easier assembly 
• 2020/01
  • Choice of CIM or Falcon 500 motor
  • Choice of either PG, MA3, or Lamprey encoder
  • Thrust needle bearings replace bushings supporting the robot weight.
    • Gear plate redesigned for more supporting surface area
  • Ball bearings replace bushings on the 12T input gear shaft.
    • Bearing gear redesigned to accommodate this bearing as well as the Lamprey encoder magnet
  • Drive axle is captured with tapped ends to increase yoke rigidity.
    • Yoke redesigned to accommodate hex spacers sizes
    • Drive axle has tapped ends
• 2019/11
  • Standardized CIM pinion to 1/2 in. face width with 3/8 in. of centered tooth engagement
• 2019/09
  • Removed unused hole and adjusted thickness on bearing plate
• 2019/08
  • The motor mount plate has been widened to make mounting to box tubing frames easier and the lightning pattern has been redesigned. Note this change means they no longer 100% drop-in replacements for old modules. See CAD for details.
  • The PG71 now uses a 1/2 in. hex shaft as the 3/8 in. hex PGs are being phased out.
• 2019/01
  • The PG71 now uses a 3/8 in. hex shaft and the gear mounted to it has access holes for easy tightening and removal of the gearmotor.
    
• 2017/07
  • The keys used to transmit torque from the CIM were widened to prevent it from becoming dislodged.
  • The collar clamp on the CIM pinion was replaced with one of higher quality to improve clamping force.
• 2016/07
  • The absolute encoder, am-3308 now has mounting locations to give a 1:1 gear ratio to the module via the 40 tooth encoder gear for easier programming.
  • The 12 tooth CIM pinion now has a wider slot to allow for a 2 mm key to more securely lock the gear to the motor.