Unity player movement, speed not fixed - unity3d

Question

I'm making an isometric 3d game like Brawl Stars, and I'm trying to get the same movement, but I have some troubles. My player moves without a fixed speed,but it seem to be increased. How can solve it? The first script if of the virtual joystick and the second one is of the player movement.
Could be a problem of mass?
Joystick script:
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using System.Collections;
public class VirtualJoystick : MonoBehaviour, IDragHandler, IPointerUpHandler, IPointerDownHandler
{
private Image bgImg;
private Image joystickImg;
private Vector3 inputVector;
private void Start()
{
bgImg = GetComponent<Image>();
joystickImg = transform.GetChild(0).GetComponent<Image>();
}
public virtual void OnDrag(PointerEventData ped)
{
Vector2 pos;
if (RectTransformUtility.ScreenPointToLocalPointInRectangle(bgImg.rectTransform, ped.position, ped.pressEventCamera, out pos))
{
pos.x = (pos.x / bgImg.rectTransform.sizeDelta.x);
pos.y = (pos.y / bgImg.rectTransform.sizeDelta.x);
inputVector = new Vector3(pos.x * 2 + 1, 0, pos.y * 2 - 1);
inputVector = (inputVector.magnitude > 1.0f) ? inputVector.normalized : inputVector;
// Move joystickImg
joystickImg.rectTransform.anchoredPosition =
new Vector3(inputVector.x * bgImg.rectTransform.sizeDelta.x / 3
, inputVector.z * (bgImg.rectTransform.sizeDelta.y / 3));
}
}
public virtual void OnPointerDown(PointerEventData ped)
{
OnDrag(ped);
}
public virtual void OnPointerUp(PointerEventData ped)
{
inputVector = Vector3.zero;
joystickImg.rectTransform.anchoredPosition = Vector3.zero;
}
public float Horizontal()
{
if (inputVector.x != 0)
return inputVector.x;
else
return Input.GetAxis("Horizontal");
}
public float Vertical()
{
if (inputVector.x != 0)
return inputVector.z;
else
return Input.GetAxis("Vertical");
}
}
Player movement's script:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Move : MonoBehaviour
{
public float moveSpeed = 20f;
public VirtualJoystick moveJoystick;
public Rigidbody rb;
private Vector3 dir = Vector3.zero;
private bool wasMoving = false;
private void Update()
{
dir.x = moveJoystick.Horizontal();
dir.z = moveJoystick.Vertical();
if (dir.magnitude > 0)
{
wasMoving = true;
}
}
private void FixedUpdate()
{
if (wasMoving && dir.magnitude == 0f)
{
wasMoving = false;
rb.Sleep();
}
rb.AddForce(dir * moveSpeed);
}
}

Answer 1

How to handle character movement in Unity:
Your character is affected by physics? Use Rigidbody as you have, and use Vector3.ClampMagnitude to ensure you don't pass terminal velocity.
Your character isn't affected by physics, but affects other physical objects? Use a kinematic Rigidbody and use RigidBody.MovePosition to move.
Your character has no physics at all? Directly move it via Transform
So in your case, I'm guessing solutions 1 or 2 will work for you.

Answer 2

If you intend on adding force to your rb you'll have to manually limit the maximum speed your character is allowed to achieve, otherwise it will increase indefinitely or until drag is too high. Easiest way is using rb.velocity.magnitude to set a limit and only if your character is below that limit you add force.
Edit, in order to change directions:
rb.AddForce(dir * moveSpeed);
if(rigidbody.velocity.magnitude > maxSpeed){
rigidbody.velocity = Vector3.ClampMagnitude(rigidbody.velocity, maxSpeed);
}
This clamps the maximum velocity of the rigidbody after applying a force, this way you will change directions but not speed up.
Also be aware that using the joystick directions like you are doing might make your character move faster when moving diagonally.

Answer 3

I solved by myself changing "rb.AddForce(dir * moveSpeed);" to "rb.position+= dir*(moveSpeed/10);"