hector_exploration_controller publishs twist really slowly

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 Hello everyone,
    I try to use `hector_exploration_node` and `hector_exploration_controller` to let robot explore the unknown environment in the stage_ros.
    I simulate the environment by `stage_ros` and create the map by `gmapping` .

    The problem is that I can get the topic `/exploration_path` published by `hector_exploration_node` , but no goals topic . And  there is a trajectory from the robot to the unknown environment .
But the robot only rotate and cant move forward. And the  it costs `hector_exploration_node` 20 more seconds every cycle.

I also find similar problems here.

Here is the rviz.

So , please give me some advice. Thanks first!