[0]RopeJoint代码动态创建 无法设置otherbody

动态生成预制体组件，要将预制体设置Laya.RopeJoint的otherbody属性，怎么设置怎么失败。
import UIcontrol from "./UIcontrol"; 
/**
*
* @ author:shiguanqing
* @ email:0110110110@qq.com
* @ data: 2022-04-09 15:53
*/
export default class fruit extends Laya.Script {
    static Fru:fruit;
    public rope:Laya.RopeJoint
    constructor() {
        super();
       fruit.Fru=this;
       
    } 
    onAwake() {
        let rig:Laya.RigidBody=this.owner.getComponent(Laya.RigidBody);
        var lala=UIcontrol.FUI.bg.getComponent(Laya.RigidBody);
        this.rope=this.owner.getComponent(Laya.RopeJoint);
        this.rope.otherBody=lala;
        console.log(lala);
        let collider:Laya.CircleCollider=this.owner.getComponent(Laya.CircleCollider);
        this.rope.otherAnchor=["540","1060"];
        this.rope.maxLength=286;
        console.log(this.owner);
        console.log(this.rope.otherBody);
    }
    onEnable() {
       
    } 
    onTriggerEnter(other: any, self: any, contact: any): void {
    //搜索黏贴在圆环上
    }
onUpdate(): void {
   
} 
onDisable(): void {
    Laya.Pool.recover("friut",this.owner);
}
}