derivative filter in PID control loop

Hi, I am using a driving cycle and a PID driver that follows the velocity in the driving cycle as a reference. I have the Kp,Ki,Kd values 15,10,1 respectively. However my loop doesn't follow the speed properly. I may require to implement a filter in the derivative part which I am not sure how to do. Please , help me out how to define the derivative term with the filter using MATLAB only . I am not using any transfer functions neither Simulink . It works in a FOR loop and give results.

Kp=15;         % Proportional gain
Ki=10;         % Integral gain
Kd=1;          % Derivative gain

tauI=1/Ki;
tauD=1/Kd;

    e(i)  = v_cycle(i)-v_act(i);
    deriv =    (v_act(i)-v_act(i-1))/dT;
    integ =       integ+e(i)*dT;

u(i)=(Kp*e(i)) + ((Kp/tauI)*integ) - (Kp*tauD*deriv);

This is some part of my code...