参考：http://wiki.ros.org/actionlib/DetailedDescription 
setAccepted – After inspecting a goal, decide to start processing it
setAccepted – 检查目标后，决定开始处理
setRejected – After inspecting a goal, decide to never process it because it is an invalid request (out of bounds, resources not available, invalid, etc)
setRejected – 检查目标后，决定不要处理它，因为它是一个无效的请求（超出界限，资源不可用，无效等）
setSucceeded – Notify that goal has been successfully processed
setSucceeded – 通知该目标已成功处理
setAborted – Notify that goal encountered an error during processsing, and had to be aborted
setAborted – 通知目标在处理过程中遇到错误，并且必须中止
setCanceled – Notify that goal is no longer being processed, due to a cancel request
setCanceled – 由于取消请求，通知该目标不再被处理
The action client can also asynchronously trigger state transitions: 动作客户端也可以异步触发状态转换：
CancelRequest: The client notifies the action server that it wants the server to stop processing the goal.
CancelRequest：客户端通知操作服务器它希望服务器停止处理目标。
Intermediate States 中间状态
Pending – The goal has yet to be processed by the action server
待处理 – 目标尚未由操作服务器处理
Active – The goal is currently being processed by the action server
活动 – 目标正在由操作服务器处理
Recalling – The goal has not been processed and a cancel request has been received from the action client, but the action server has not confirmed the goal is canceled
回想 – 目标没有被处理，并且已经从操作客户端收到取消请求，但是操作服务器尚未确认目标被取消
Preempting – The goal is being processed, and a cancel request has been received from the action client, but the action server has not confirmed the goal is canceled
抢占 – 正在处理目标，并从行动客户端收到取消请求，但是行动服务器尚未确认目标已取消
Terminal States 最终状态
Rejected – The goal was rejected by the action server without being processed and without a request from the action client to cancel
被拒绝 – 目标被操作服务器拒绝，而不被处理，没有来自操作客户端的请求取消
Succeeded – The goal was achieved successfully by the action server
成功 – 动作服务器成功实现了目标
Aborted – The goal was terminated by the action server without an external request from the action client to cancel
中止 – 目标被操作服务器终止，没有来自操作客户端的外部请求取消
Recalled – The goal was canceled by either another goal, or a cancel request, before the action server began processing the goal
回想起来 – 在行动服务器开始处理目标之前，目标被另一个目标或取消请求取消
Preempted – Processing of the goal was canceled by either another goal, or a cancel request sent to the action server
抢占 – 目标的处理被另一个目标或发送到操作服务器的取消请求取消
