Im just using the basic code to move the player added Clamp values and my player automatically going towards top left corner im not using any gravity

using UnityEngine; using System.Collections;

[System.Serializable] public class Boundary { public float xMin, xMax, zMin, zMax;

}

public class PlayerMovement : MonoBehaviour { public float speed; public float tilt; public Boundary boundary; private Rigidbody rb;

 void Start()
 {
     rb = GetComponent<Rigidbody> ();
     
 }
 
 void FixedUpdate ()
 {
     float moveHorizontal = Input.GetAxis ("Horizontal");
     float moveVertical = Input.GetAxis ("Vertical");
     
     Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);
     rb.velocity = movement * speed;
     
     Vector3 tempPos = rb.position;
     
     tempPos.x = Mathf.Clamp(rb.position.x, boundary.xMin, boundary.xMax);
     tempPos.y = 0.0f;
     tempPos.z = Mathf.Clamp (rb.position.z, boundary.zMin, boundary.zMax);
     
     rb.position = tempPos;
     
     rb.rotation = Quaternion.Euler (0.0f, 0.0f, rb.velocity.x * -tilt);
 }

}