how to keep rigidbody2D upright unity
Rigidbody hoverRB; // hovercraft's rigidbody
...
void FixedUpdate()
{
Quaternion deltaQuat = Quaternion.FromToRotation(hoverRB.transform.up, Vector3.up);
Vector3 axis;
float angle
deltaQuat.ToAngleAxis(out angle, out axis);
float dampenFactor = 0.8f; // this value requires tuning
hoverRB.AddTorque(-hoverRB.angularVelocity * dampenFactor, ForceMode.Acceleration);
float adjustFactor = 0.5f; // this value requires tuning
hoverRB.AddTorque(axis.normalized * angle * adjustFactor, ForceMode.Acceleration);
}