Player Controls

I wrote a script and attached it to a cube, expecting the cube to move when the arrow keys or wasd keys are pressed, and jump when the space bar is pressed, I have no erros in my console, but the cube wont work. This is my script:

using UnityEngine; using System.Collections;

public class PlyerControl : MonoBehaviour {

 Rigidbody rb;
 public float Speed = 10f;
 public float jumpSpeed = 10f;
 bool OnGround;
 // Use this for initialization
 void Start () {
     rb = GetComponent<Rigidbody>();
     
 }
 
 // Update is called once per frame
 void Update () {

     OnGround = transform.position.y == 0.5f;

     float h = Input.GetAxis("Horizontal");
     float v = Input.GetAxis("Vertical");

     Vector3 move = new Vector3(h, 0f, v) * Speed;

     Vector3 movemt = move + transform.position;

     rb.AddForce(movemt);

     if(Input.GetKeyDown("space") && OnGround)
     {
         Vector3 up = Vector3.up * jumpSpeed;

         Vector3 upMove = up + transform.position;

         rb.AddForce(upMove);
     }

 }

}