为什么四轮的添加阿克曼一直报错未初始化

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controller_manager:
ros__parameters:
update_rate: 100 # Hz
use_sim_time: true
fishbot_joint_state_broadcaster:
type: joint_state_broadcaster/JointStateBroadcaster
use_sim_time: true
update_rate: 50
rear_wheels_velocity_controller:
type: ackermann_steering_controller/AckermannSteeringController

  # left_wheel: "lbj"  # 后左轮关节名
  # right_wheel: "rbj" # 后右轮关节名
  # left_steering: "lftj"      # 前轮转向关节
  # right_steering: "rftj"
  #front_steering_joints: ["lftj", "rftj"]  # 必须匹配 URDF
  rear_wheel_joints: ["rbj", "lbj"]
  front_wheel_joints: ["rfj", "lfj"]
  wheelbase: 0.63  # 前后轮轴距（米）
  wheel_radius: 0.075
  wheel_separation: 0.88 # 左右轮距（米）
  max_steer_angle: 0.52 
  cmd_vel_topic: "/cmd_vel"  # 订阅的cmd_vel话题
  odom_topic: "/odom"        # 发布的里程计话题
  odom_frame_id: odom
  base_frame_id: base_footprint
  pose_covariance_diagonal: [0.001, 0.001, 0.0, 0.0, 0.0, 0.01]
  twist_covariance_diagonal: [0.001, 0.0, 0.0, 0.0, 0.0, 0.01]
  enable_odom_tf: true      # 启用odom到base_link的TF变换
  cmd_vel_timeout: 0.5     # 指令超时时间（秒）
  publish_rate: 50.0        # 发布频率（Hz）
  use_stamped_vel: false    # 不使用时间戳速度指令
  open_loop: true
# 前轮转向控制器（位置控制）
fishbot_front_wheels_position_controller:
  type: position_controllers/JointGroupPositionController

fishbot_front_wheels_position_controller:
ros__parameters:

joints: 
   ["lftj","rftj"]
command_interfaces: ["position"]
state_interfaces: ["position"]