controling air cylinder with a joystick.

thank reading this.

i having problems controlling air cylinder moving heavy weight joystick.  program below cylinder overshooting , undershooting desired positions in gradually decreasing amounts 3 or 4 times until reaches desired position.  part of must compressibility of air in cylinder (the cylinder reacts kind of spring).  love other ways of looking @ problem.

code: [select]


// control dual acting air cylinder (one way pushes/ 1 way pulls) joystick

void setup() {
  int joystickpot =0;
  int aircylinderpot =0;
  pinmode(5,output);  //retract cylinder valve
  pinmode(6,output);  //extend cylinder valve
}

void loop() {

  int joystickpot=analogread(a0);       //reads joystick potentionmeter
  int aircylinderpot=analogread(a1);   //reads positional pototentionmeter on air cylinder
  int diff=joystickpot-aircylinderpot;  //is difference between joystick , aircylinder positions
 
if (diff<-100){analogwrite(6,250);}   // open air cylinder extend valve fully
if (diff<=-50 && diff>-100){analogwrite(6,100);}  //open air cylinder extend valve halfway
if (diff<=-10 && diff>-50){analogwrite(6,50);}    //open air cylinder extend valve slightly
if (diff>-10 && diff<10){analogwrite(6,0);analogwrite(5,0);}  //if joystick , cylinder position close each other close air cylinder valves.
if (diff>=10 && diff<50){analogwrite(5,50);}      //open air cylinder retract valve slightly
if (diff>= 50 && diff<100){analogwrite(5,100);}   //open air cylinder retract valve halfway
if (diff>=100){analogwrite(5,250);}   //open air cylinder retract valve fully 

}

you have answer. need develop way anticipate movement location want weight , reverse air slow , stop weight. can joystick? don't know. problems three: compressiblity of gas, temperature of gas , inertia of weight. guess there fourth, distance move weight. perhaps 5th, direction move weight.

quite list.

paul

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