moving with rigidbody without acceleration

Hello, I was wondering if it is possible to move with rigidbody without acceleration. So the player has 1 consistent speed throughout, that is top speed instantly when it moves. I've looked into rigidbody.velocity but I am having issue with it since it holds a consistent speed but when jumping it floats around slowly. Also when moving onto a jumping platform that uses AddForce, the player does not register the jump when moving - it sort of does little hops when moving. If i were to stand completely still, the jump registers normally. Thank you