Pneumatics: Double Solenoid

[archiver]

Posted by Elliot Johnson at 2/1/2001 1:15 PM EST


Student on team #218, HP Robotics Team, from Highland Park High School and Double-E Inc..


In Reply to: Pneumatics: Double Solenoid
Posted by Suneet Upadhyay on 1/31/2001 8:22 PM EST:



We had a gripper last year on our robot powered by a cylinder that could be stopped at any position. The double solenoid was hooked up with a flow control valve after each of the outputs, and then that went to the cylinder inputs.

Solenoid Port A -> Flow Control Valve #1 -> Top of Cylinder
Solenoid Port B -> Flow Control Valve #2 -> Bottom of Cylinder

The Solenoid is then hooked up to a relay using the two diode scheme shown in the robot manual. To move the cylinder in one direction, turn the relay on in one direction. To move it the other way, reverse the relay. To stop the cylinder while its moving, just turn off the relay. When the solenoid is stopped, the pressure in the cylinders is locked in.
The valves are used to slow down the speed of the cylinder so that you can stop it in time. If the cylinder is fired at full pressure, it reaches the other state too quickly.
This set up worked for us reliably in all of our matches, but we didn't have a huge load on the cylinders, just the force of the ball pushing back.

hope that helps,
Elliot Johnson