6.875 in. Turret Assembly

The 6.875 inch Turret Assembly is an input ready turntable component ready for integration into your next robot project. This assembly utilizes a bearing stack design to provide smooth rotational motion with a large center pass through design for various sized objects to move through. The primary drive component for this assembly is a 200 tooth 20DP gear paired with a 20 tooth pinion to provide a large gear reduction for flexibility in motor usage. With #10 mounting holes on a ½ inch pitch, fastening this assembly is no problem and matches perfectly with common FRC structural components.

Sensor Integration

There are a few methods teams can use to keep track of the heading of their turret.

• Built In Motor Encoder - For motor inputs that have a built in encoder, using the motors existing encoder is an easy to implement option. Teams should consider either starting with the turret facing a specific direction (often aligning a sharpie mark between the base plate and the moving component) or by having a zeroing procedure (rotating into limit switch or using current monitoring for current spikes).
• Absolute Encoders - An absolute encoder is a great tool for keeping track of the position of a component regardless of its position when the robot is turned on. Due to the non 1:1 ratio of the large turret gear and the input gear, the input gear/sensor is likely not going to be 1:1 with the rotation of the turret gear causing incorrect alignment. This can be overcome by mounting the absolute encoder on a 1:10 overdrive so that the rotation of the sensor spins one time for every rotation of the turret gear. Alternatively, using Chinese Remainder Theorem and our offset sensor mount files, teams can utilize two absolute encoders to track the absolute rotation of the turret gear with offset gear teeth (19T/21T).

Use without Extrusion:

This turret is not intended to be used without sufficient structure supporting it. Without a firm structure holding it in place, the polycarb may flex and misalign the bearings, causing movement to be unpredictable and rough. AndyMark recommends installing the turret base plate to a solid structure, such as box tube, to support the plate around the perimeter.