Solution: Variable position of cylinder in compliance with <R74>

[Roboman01]

Originally Posted by PAR_WIG1350

(emphasis added by me)

1) {response to bold text} These facts are what allows such a system to work. The entire operating principle of the design relies on a variable force being counteracted by a controlled variable force. The two forces cancel out at equilibrium. A constant force spring would not work in this system, the description specifically calls for a variable force device.

2) {response to underlined text} This was a problem with the system as originally described, but I edited the description to account for the force applied by the mechanism being actuated. The forces will still cancel out at equilibrium, assuming the correct bore and spring are chosen based on the direction and magnitude of the forces that will be applied by the mechanism.

3) {response to first line of quoted text} It is somewhat jury rigged. The system is meant to be implemented on a robot that had previously used multiple solenoids to control a single cylinder, to make it fit within the rules. Your system would be preferable in this situation, since it requires little to no change to the code and minimal changes to the hardware. however, if I were building the system from nothing, I would prefer my system based on the fact that it would appear easier to program (plus my team has been successful in positioning a rotary device with pots, but has little/no experience with linear positioning, as far as I am aware).

4){red paragraph} It wouldn't be terribly difficult to use a window motor or a RS-395 (with an appropriate transmission, possibly from a servo [minus the mechanical stops]) to control the regulator, assuming fairly accurate pots are used and/or the values used in the code are properly adjusted.

1: Good point, I hadn't thought of that.

2: That makes sense, but the system will not be as authoritative in its movements, if you're varying the pressure, and therefore, the output force.

3: If you're entirely set of using the adjustable regulator, why not go with an electronic one? That would cut down on your overall weight immensely. Also, my team is not measuring the extent of the cylinder directly; rather, we're actuating an arm. The arm has an encoder at the joint, which obviously measures the position of the arm itself. For our purposes, my system will work far more efficiently, since we won't have a variable output force. Also, my system will most likely weigh far less than yours, as we don't need a motor, gearbox, or secondary regulator. This is important, at least for my team, since we are within a few pounds of the limit.

4: Actually, my system could possibly be easier to program for, at least, in my team's application. For us, we either need the valve in one extreme or the other, or simply off. Also, we can gain higher positioning accuracy without any extra electronics, other than the single encoder on the joint of the arm. In order to make sure that you are positioned correctly, you would need both an encoder/potentiometer on the regulator, as well as an encoder/potentiometer on the arm, assuming you're using this for an arm.