Webots：ERROR: “E:/**/wheelfinready.wbt”：33：23：错误：Expected ‘浮点值‘, found ‘[‘. {1‘?} {2:23:?}

Webots：ERROR: “E:/**/wheelfinready.wbt”：33：23：错误：Expected ‘浮点值’, found ‘[’. {1’?} {2:23:?}

问题描述

昨天新建了一个世界用来仿真最近在做的一个机器人，晚上回去的时候就保存之后关闭了，今天来了之后发现打开世界之后是空的，人直接傻掉了，还以为忘记保存了，但是仔细看了文件最后的保存时间确实是昨晚走的时候，重新打开了一下，发现还是不行，并发先下面显示如下错误：

ERROR: “E:/Webots/wheelFinRobot/worlds/wheelfinready.wbt”：33：23：错误：Expected ‘浮点值’, found ‘[’. {1’?} {2:23:?}
ERROR: ‘E:/Webots/wheelFinRobot/worlds/wheelfinready.wbt’: Failed to load due to syntax error(s).

问题解决

似乎是读取保存的世界文件wbt文件的时候出现了一些问题，网上搜了一下也没有什么解决方法，只能自己想办法了，想到了之前看到的Webots使用的语音是VRML（Virtual Reality Modeling Language）即虚拟现实建模语言。因此可以用文本编辑器打开.wbt文件，寻找解决办法。
打开后可以很明确的看到世界的结构

#VRML_SIM R2020b utf8
WorldInfo {basicTimeStep 1coordinateSystem "NUE"contactProperties [ContactProperties {coulombFriction [0.4]}]
}
Viewpoint {orientation -0.14560678248228257 -0.9759251935056109 -0.16238436370597023 1.6114345810625152position -15.057677608988085 3.0920645357548664 -0.24588279808939442
}
TexturedBackground {}
TexturedBackgroundLight {}
UnevenTerrain {size 100 0 100appearance SandyGround {colorOverride 0.698039 1 0.760784textureTransform TextureTransform {scale 0 0}}
}
DEF Build Group {children [HelicoidalRoadSegment {roadBorderWidth [0.1]translation 6 0.001 20rotation 0 1 0 1.570796327name "road(1)"width 2roadBorderHeight 0.05roadBorderWidth 0.1bottom TRUEheight 5radius 20roadBoundingObject TRUE}SpeedLimitSign {translation 0.075001 0 -1.5901rotation 0 1 0 2.0944}SnackStand {translation -8.9 0 5.35}SimpleBench {translation 7.37999 0 2.37rotation 0 -1 0 1.5708}Bench {translation -1.64 0 -7.47}SwingCouch {translation -3.93 0 5.34rotation 0 1 0 -1.5707953071795862}Slide {translation -18.7755 0 13.2498rotation 0 -1 0 1.5708}Swing {translation 3.08 0 -8.69}PicketFenceWithDoor {translation -2.79 0 -8.1}DogHouse {translation -11.33 0 -12.91rotation 0 1 0 3.14159}Pergolas {translation 16.05 0 -11.03}Windmill {translation 16.19 0 -17.73rotation 0 -1 0 -1.8325953071795862}SuburbanHouse {translation 6.01036e-05 0 -22.65rotation 0 1 0 3.14159}BungalowStyleHouse {translation 8.92 0 18.98floor FALSE}RoadIntersection {translation 3 0.001 0rotation 0 1 0 0.7853981635roadsWidth 2startRoadsLength [2]startRoadBorderHeight 0.05startRoadBorderWidth 0.1}StraightRoadSegment {translation -10 0.001 0rotation 0 1 0 1.570796327width 2roadBorderHeight 0.05startingRoadBorderWidth 0.1endingRoadBorderWidth 0.1}Oak {translation 8.53 0 4.02}Oak {translation 23.38 0 2.04name "oak tree(1)"}Oak {translation 23.38 0 -1.96name "oak tree(3)"}Oak {translation 23.38 0 -5.96name "oak tree(4)"}Oak {translation 28.68 0 9.41name "oak tree(5)"}Oak {translation 30.22 0 13.19name "oak tree(6)"}Oak {translation 31.53 0 16.81name "oak tree(7)"}Oak {translation 28.77 0 6.04name "oak tree(2)"}]
}
Robot {translation -9.5 0.07 0children [DEF wheelFin1 HingeJoint {jointParameters HingeJointParameters {axis 0 0 1anchor 0.24 0.0365 0.16...

其中DEF Build Group 是插入的给世界做装饰作用的一些东西，考虑到其中有些东西之前没有用过，所以会不会是某些模块有些问题，因此决定一个一个注释掉试试

#VRML_SIM R2020b utf8
WorldInfo {basicTimeStep 1coordinateSystem "NUE"contactProperties [ContactProperties {coulombFriction [0.4]}]
}
Viewpoint {orientation -0.14560678248228257 -0.9759251935056109 -0.16238436370597023 1.6114345810625152position -15.057677608988085 3.0920645357548664 -0.24588279808939442
}
TexturedBackground {}
TexturedBackgroundLight {}
UnevenTerrain {size 100 0 100appearance SandyGround {colorOverride 0.698039 1 0.760784textureTransform TextureTransform {scale 0 0}}
}
DEF Build Group {children [
#    HelicoidalRoadSegment {#      roadBorderWidth [
#        0.1
#      ]
#      translation 6 0.001 20
#      rotation 0 1 0 1.570796327
#      name "road(1)"
#      width 2
#      roadBorderHeight 0.05
#      roadBorderWidth 0.1
#      bottom TRUE
#      height 5
#      radius 20
#      roadBoundingObject TRUE
#    }SpeedLimitSign {translation 0.075001 0 -1.5901rotation 0 1 0 2.0944}SnackStand {translation -8.9 0 5.35}SimpleBench {translation 7.37999 0 2.37rotation 0 -1 0 1.5708}

其中这个旋转的高速公路是最复杂的一个模块，之前也没用过，所以先把他注释掉，注释之后保存，再次打开发现问题解决。

进一步确定问题范围，注意到报错中显示的
错误：Expected ‘浮点值’, found ‘[’. {1’?} {2:23:?}
应该与
[
有关，注意到代码中

#    HelicoidalRoadSegment {#      roadBorderWidth [
#        0.1
#      ]
#      translation 6 0.001 20
#      rotation 0 1 0 1.570796327
#      name "road(1)"
#      width 2
#      roadBorderHeight 0.05
#      roadBorderWidth 0.1
#      bottom TRUE
#      height 5
#      radius 20
#      roadBoundingObject TRUE
#    }

只有roadBorderWidth参数带
[
将其删除后

    HelicoidalRoadSegment {roadBorderWidth 0.1translation 6 0.001 20rotation 0 1 0 1.570796327name "road(1)"width 2roadBorderHeight 0.05roadBorderWidth 0.1bottom TRUEheight 5radius 20roadBoundingObject TRUE}

再次运行，发现旋转高速路显示出来了，但是参数roadBorderWidth 失去了作用

总结

问题的原因可能是因为新做的模块测试不够，所以存在一些bug。