Chief Delphi - Help with shooter angle closed loop

My team has been having a little difficulty with the accuracy of our shooter angle.

Our shooter angle has a bit of a knock back when we fire a disk, and just the 'P' loop was not enough to move the shooter that couple degrees back to position. I tried getting a 'PI' loop and now the slightest of bump will cause our angle to go unstable.

Code:



float bias = 1.1932;         

float brads = 0;

float cop2axis = (copjoy.GetRawAxis(2));  //this is the co-pilot joystick that is controlling the angle.



if (ds->GetDigitalIn(7) == true) {

        if (cop2axis > 0.15){

                potsetpoint = potsetpoint + .0001;

                last = true;

                randomtimer.Start();

        }

        if (cop2axis < -0.15){

                potsetpoint = potsetpoint - .0001;

                last = true;

                randomtimer.Start();

        }

        if (randomtimer.Get() >= 0.1){

                last = false;

                randomtimer.Stop();

        }

        

        float potdiff = (abs(potsetpoint - anglepot.GetVoltage()));

                                

        brads = (anglepot.GetVoltage()*50);

        if (potdiff <=.02000){

                                

        bias = ((bias * cos(brads))/128);

        potset = potset + bias;

                        

        }else {

        if (potsetpoint < anglepot.GetVoltage()){

                potset = ((potsetpoint-anglepot.GetVoltage())*3.5);

        }

        if (potsetpoint > anglepot.GetVoltage()){

        potset = ((potsetpoint-anglepot.GetVoltage())*4);

        }

        }

                if (potset>=1){

                        potset= 1;

                }

                if (potset<=-1){

                        potset= -1;

                }

                angle.Set(potset*-1);

also, my code was adapted from the attached pdf file.

If I'm missing any info, please post below.