Player shaking when move (not the camera)

I'm making a simple game. It's a cube, walking on a floor.

I use the WASD keys to move. W and S to move foward and backward, S and D to side walking and the X mouse axis to rotation.

The camera isn't attach to the cube and use a script to follow the cube. The camera position and rotation is calculate based on the cube.

My problem it's simple... When I walk just to front, back or side walking, it's fine, but when I walk in diagonals (e.g. Sidewalking and front), the cube make a zigzag movement, him shake.

Isn't the camera, 'cause in the scene window I see making this strange movement.

I guess that I need some "Smoothing-system" somewhere in the calcs of the directional vector.

Somebody can Help me?

Here are the only two scripts used in scene

Script that control the player using UnityEngine; using System.Collections;

 public class PlayerControl : MonoBehaviour {
     private CharacterController controller;
     public float speed = 6.0f;
     public float jumpSpeed = 8.0f;
     public float gravity = 20.0f;
     private Vector3 Pdirection = Vector3.zero;
     public float mouseSens = 0.2f;
     private bool locked = true;
 
     void Start () {
         Screen.lockCursor = locked;
     }
 
     void FixedUpdate () {
         controller = GetComponent<CharacterController> ();
         if (controller.isGrounded) {
             Pdirection = new Vector3(Input.GetAxis("Horizontal"),0,Input.GetAxis("Vertical"));
             Pdirection = transform.TransformDirection(Pdirection);
             Pdirection *= speed;
         }
         Pdirection.y -= gravity * Time.deltaTime;
         print (Pdirection);
         controller.Move (Pdirection * Time.deltaTime);
         controller.transform.Rotate(0, Input.GetAxis ("Mouse X")*mouseSens*Time.deltaTime, 0);
         if (Input.GetButton ("MouseLock")) {
             locked = !locked;
             print(locked);
             Screen.lockCursor = locked;
         }
 
     }
 }

Script that control the camera:

 using UnityEngine;
 using System.Collections;
 
 public class CameraControl : MonoBehaviour {
     
     public float distancia = 10;
     public Transform target;
     
     void Start () {
     
     }
 
     void Update () {
         if (!target)
             return;
         float anguloFinal = target.transform.eulerAngles.y;
         float distanciaFinal = target.transform.position.y + distancia;
 
         float anguloAtual = transform.eulerAngles.y;
         float distanciaAtual = transform.position.y;
         
         anguloAtual = Mathf.LerpAngle (anguloAtual, anguloFinal, Time.deltaTime*0.1f);
         distanciaFinal = Mathf.Lerp (distanciaAtual, distanciaFinal, Time.deltaTime * 0.1f);
         
         Quaternion angulo = Quaternion.Euler (0, anguloFinal, 0);
 
         Vector3 posicaoFinal = transform.position;
         posicaoFinal = target.transform.position;
         posicaoFinal -= angulo * Vector3.forward * distancia;
         posicaoFinal.y = distanciaFinal;
         transform.position = posicaoFinal;
         transform.LookAt (target);
     }
 }