The PG71 has an encoder on the back side of the 775 motor, which can help keep track of the steering location. In order to use this method of closed-loop encoder tracking, use a 3/16" allen wrench or pin/screw to ensure that the motor plate, bearing plate, and gear plate are all aligned before operation. Alternatively, there is a location to mount an optional absolute encoder (am-3308).
- 8/2019 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.
- 8/2019: The PG71 now uses a 1/2 in. hex shaft as the 3/8 in. hex PGs are being phased out.
- 1/2019: 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.
- 7/2017: The keys used to transmit torque from the CIM were widened to prevent it from becoming dislodged.
- 7/2017: The collar clamp on the CIM pinion was replaced with one of higher quality to improve clamping force.
- 7/2016: 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 programing.
- 7/2016: The 12 tooth CIM pinion now has a wider slot to allow for a 2mm key to more securely lock the gear to the motor.
Drive Gearing & Ratio:
- 12 tooth spur gear is driven by CIM Motor
- 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
- 660 rpm
- 11.5 ft/sec
- 48 tooth spur gear is driven by PG71 gearmotor
- 40 tooth spur gear is driven by 48 tooth gear
- Lower portion of module pivots directly with the 40 tooth gear
- Steer Speed: 90 rpm
- A hall effect encoder is included on the PG71
- An optional absolute encoder could be added to this assembly using this 40 tooth Encoder Gear. The encoder we suggest is MA3-A10-250-N Absolute Encoder (am-2899).
- 1 CIM motor for Driving
- 1 PG71 for Steering
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, http://files.andymark.com/FRC1640_2011_PivotDriveLibrary.zip
- Overall Height: 12.04 in.
- Weight: 9.4 lbs
- Ratio: 6.67:1
There all right
It is a simple design that seems to work fine but just fine. The encoders that are included work but not well. We had problems in 2017 with the encoders slipping causing the wheels to be misaligned causing the robot to be difficult to drive. They are much better when you add absolute encoders. But there is still a problem with the fact the the wheel isn't in the center of the pivot point. its off to the side so the robot jiggles if your just spinning the module
AM Swerves led to game dominance
These drives, with a little attention to detail between matches, gave team 3707 one of the most agile bots on the field last year. We added the absolute encoders and CIMcoders. Take care to make sure the shaft keys stay in place when installing CIMcoders. Thanks AndyMark.
We were building a prototype t-shirt shooter with a swerve drive as an off-season FIRST robotics project and this product made it all possible! We were up against a grant deadline and the whole AndyMark team went above and beyond for us. From sales, to customer support, to the mechanical assembly personnel - all were a pleasure to work with!
Big robot? Just the thing!
This is one of THE HIGHEST QUALITY and MOST COMPLETE AND CONVENIENT parts I have EVER PURCHASED in my 25 YEARS of robotics experience! I cannot STRESS THIS ENOUGH! It will make your next robot build a JOY! Worth EVERY PENNY. Period. And Customer Service and support are BAR NONE. Shop here. Buy here. Support this company.