Understanding CTE Workcell Pneumatics – VEX Library

This article introduces the pneumatic components in the CTE Workcell Kit, including details on issues that may arise and need troubleshooting.

CTE Workcell pneumatic system showing the air supply, solenoid valve, tubing, and cylinder connections.

Kit Exploration

The CTE Workcell Pneumatics Kit can be broken down into 5 different functional categories.

Air Stowage: This pertains to the components responsible for storing and distributing the pressurized air within the system, like the Air Pump and the Air Tank.
Cylinders: These dual-action cylinders (2x Pitch Stroke and 4x Pitch Stroke Pneumatic Cylinders) create mechanical movement through the use of compressed air.
Tubing: This includes the tubes that transport the pressurized air throughout the system.
Electronic Control: This category includes the Pneumatic Solenoid that control the operation of the pneumatic system electronically.
Fittings: This category includes the Tee Fitting, which connects and routes the Tubing throughout the system.

Air Stowage

70 Milliliter (mL) Air Tank

The Air Tank gives compressed air to the pneumatics system. This lets air flow continuously. With the tank, many cylinders can work at the same time without needing the air pump to do all the work.

Air Pump

The Air Pump works like an engine by compressing air and mainly sends it to the Cylinders through the Solenoid.

Cylinders

2 Pitch Stroke Pneumatic Cylinder

4 Pitch Stroke Pneumatic Cylinder

The CTE Workcell Kit comes with two types of Pneumatic Cylinders: the 2x Pitch and 4x Pitch. These cylinders use air pressure to extend or retract, creating a push or pull motion.

'Pitch' refers to how far the cylinder can extend, not its starting size. They connect to the Tubing through built-in fittings and use the power of pressurized air to create linear movement. Select either the 2 or 4 Pitch Stroke Pneumatic Cylinder for your design based on how far you need it to move.

Tubing

4 Millimeter (mm) Tubing

The 4mm Tubing in your CTE Workcell Kit moves pressurized air between components. It can be cut to any length with scissors, making it adaptable for any project.

Electronic Control

Pneumatic Solenoid

The Pneumatic Solenoid is an important control part, working like an electronic valve. It receives instructions from your Robot Brain and turns them into pneumatic actions by directing compressed air to the cylinders.

It can control up to four pneumatic circuits at the same time, directing air to make cylinders extend (push) or retract (pull). This part is key in managing how your pneumatic system works.

Fittings

Tee Fitting

The Tee Fitting, shaped like the letter 'T', directs air from one source to two different points in your pneumatic system. This allows you to send air to multiple locations simultaneously, enabling multiple cylinders to work together or managing complex routes.

Pneumatic Devices

The CTE Workcell Kit includes two devices designed for use with the pneumatic cylinders. These devices help manage the flow of Disks on CTE Workcell conveyors: Disk Feeders, which place Disks onto the conveyors, and Diverters, which remove Disks from the conveyors.

Disk Feeders

Disk Feeder device.

Disk Feeders are devices used to deploy Disks onto a Linear Conveyor, which then transports the Disks towards a Serpentine Conveyor Track.

To control the Disk Feeder, push the plunger forward (by retracting the cylinder) to force a Disk out of the feeder and onto the Linear Conveyor. To deploy additional Disks, extend the plunger, allowing the next Disk to fall to the bottom of the device before being pushed out when the cylinder is again retracted.

Diverters

Diverter device.

Diverters are devices used on Serpentine Conveyor Tracks to redirect Disks from one conveyor to another at junctions where multiple conveyors intersect.

They can be controlled by pushing the Diverter up, allowing Disks to continue on their current path, or pulling it down to block the conveyor's path and redirect the Disks onto a different track.

Troubleshooting Pneumatics

Problem: Disks overshoot the Entry Conveyor

When coding the pneumatic Disk Feeder on the CTE Workcell, a problem may occur where the pressure is too great and the pneumatic cylinder pushes the Disk over the edge of the Entry Conveyor. Here are two potential solutions for this problem:

Potential Solution 1: Reduce the air pressure in the system by removing one of the sides of tubing from the Disk Feeder pneumatic cylinder. This will reduce the force coming from the cylinder until the Air Compressor works to get the system back to the designated PSI.
Potential Solution 2: Create a barrier using additional pieces on the other side of the Entry Conveyor. By adding this backing, the Disks can bounce off of the backing and back onto the Conveyor.