[LayaAir 2.0]物理引擎，刚体施加力效果错误，有人帮忙看下吗

物理引擎，刚体施加力效果错误
给cube添加单一方向的作用力，物理运动中旋转角度和位置发生了偏移，unity中不会
 
//添加3D场景
var scene:Scene3D = Laya.stage.addChild(new Scene3D()) as Scene3D;
 
//添加照相机
var camera:Camera = (scene.addChild(new Camera(0, 0.1, 100))) as Camera;
camera.transform.translate(new Vector3(0, 10, 0));
camera.transform.rotate(new Vector3(-30, 0, 0), true, false);
 
//添加地板
var floor:MeshSprite3D = scene.addChild(new MeshSprite3D(PrimitiveMesh.createPlane(10, 2000, 100, 100))) as MeshSprite3D;
//给地板添加物理组件
var floorCollicar:PhysicsCollider = floor.addComponent(PhysicsCollider);
// 添加collidershape
floorCollicar.colliderShape = new BoxColliderShape(10,0,2000);
 
//加载精灵
Sprite3D.load("LayaScene_cu_demo/Conventional/Cu.lh", Handler.create(null, function(sp:Sprite3D):void {
cu = scene.addChild(sp) as Sprite3D;
cu.transform.rotate(new Vector3(0, -90, 0), true, false);
_rb = cu.getComponent(Rigidbody3D) as Rigidbody3D;
}));
 
//施加作用力或冲量
btn_a.on(Event.CLICK,this, function():void{
_rb.applyImpulse(new Vector3(0, 0, -2000));
})