diff --git a/agv_app/app.py b/agv_app/app.py
index f06983d..42a21da 100644
--- a/agv_app/app.py
+++ b/agv_app/app.py
@@ -1130,14 +1130,14 @@ def api_camera_capture():
 
 @app.route("/api/camera/arm_refresh")
 def api_arm_camera_refresh():
-    """从机械臂拉一张 JPEG（流式读第一个完整帧，超时则降级）"""
+    """从机械臂拉一张 JPEG（流式读第一个完整帧）"""
     import requests
     try:
-        r = requests.get(ARM_CAMERA_CONFIG["url"], stream=True, timeout=5)
+        r = requests.get(ARM_CAMERA_CONFIG["url"], stream=True, timeout=8)
         if r.status_code != 200:
             return "", 404
         data = b""
-        for chunk in r.iter_content(chunk_size=4096):
+        for chunk in r.iter_content(chunk_size=8192):
             data += chunk
             # 在累积数据中找 JPEG 完整帧
             s = data.find(b"\xff\xd8")
@@ -1145,8 +1145,8 @@ def api_arm_camera_refresh():
             if s >= 0 and e > s:
                 r.close()
                 return Response(data[s:e+2], mimetype="image/jpeg")
-            # 数据太长还没找到 JPEG 也直接返回（可能是空流）
-            if len(data) > 1024 * 1024:
+            # 累积超过 5MB 还没找到完整帧，说明流异常，放弃
+            if len(data) > 5 * 1024 * 1024:
                 r.close()
                 return "", 404
         r.close()
@@ -1460,6 +1460,16 @@ if __name__ == "__main__":
     gs.qr_scanner = QRScanner(CAMERA_CONFIG["device_index"])
     gs.camera_opened = gs.qr_scanner.open()
     logger.info(f"AGV 摄像头初始化: {'成功' if gs.camera_opened else '失败'}")
+    # 启动时自动检测机械臂摄像头
+    try:
+        import requests as _startup_req
+        r = _startup_req.get(ARM_CAMERA_CONFIG["url"], stream=True, timeout=5)
+        gs.arm_camera_opened = (r.status_code == 200)
+        r.close()
+        logger.info(f"机械臂摄像头检测: {'成功' if gs.arm_camera_opened else '失败'}")
+    except Exception as _e:
+        gs.arm_camera_opened = False
+        logger.warning(f"机械臂摄像头检测失败: {_e}")
     app.run(
         host=SERVER_CONFIG["host"],
         port=SERVER_CONFIG["port"],
diff --git a/arm_server/arm_server.py b/arm_server/arm_server.py
index 596c977..1723b46 100644
--- a/arm_server/arm_server.py
+++ b/arm_server/arm_server.py
@@ -35,39 +35,47 @@ ARM_CAMERA_INDEX = 0   # 机械臂端摄像头设备号
 _ffmpeg_proc = None
 
 
+def _ensure_ffmpeg():
+    """确保 ffmpeg 进程在运行，自动重启崩溃的进程"""
+    global _ffmpeg_proc
+    if _ffmpeg_proc is None or _ffmpeg_proc.poll() is not None:
+        logger.info(f"启动 ffmpeg 视频流 (Video{ARM_CAMERA_INDEX})")
+        _ffmpeg_proc = subprocess.Popen(
+            [
+                "ffmpeg",
+                "-f", "v4l2",
+                "-input_format", "mjpeg",
+                "-i", f"/dev/video{ARM_CAMERA_INDEX}",
+                "-vf", "rotate=PI",
+                "-q:v", "8",
+                "-f", "mjpeg",
+                "-"
+            ],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.DEVNULL,
+        )
+        time.sleep(2.0)  # 等待 ffmpeg 初始化完成（设备冷启动可能需要更久）
+
+
 @arm_video_app.route("/api/camera/preview")
 def arm_camera_preview():
     """机械臂摄像头 MJPEG 流 (ffmpeg)"""
-    global _ffmpeg_proc
+    _ensure_ffmpeg()
 
     def generate():
         global _ffmpeg_proc
-        # 启动 ffmpeg 进程（如果尚未运行）
-        if _ffmpeg_proc is None or _ffmpeg_proc.poll() is not None:
-            logger.info(f"启动 ffmpeg 视频流 (Video{ARM_CAMERA_INDEX})")
-            _ffmpeg_proc = subprocess.Popen(
-                [
-                    "ffmpeg",
-                    "-f", "v4l2",
-                    "-input_format", "mjpeg",
-                    "-i", f"/dev/video{ARM_CAMERA_INDEX}",
-                    "-vf", "rotate=PI",
-                    "-q:v", "8",
-                    "-f", "mjpeg",
-                    "-"
-                ],
-                stdout=subprocess.PIPE,
-                stderr=subprocess.DEVNULL,
-            )
-            time.sleep(0.5)  # 等待 ffmpeg 初始化
-
         try:
             while True:
                 if _ffmpeg_proc is None or _ffmpeg_proc.poll() is not None:
-                    break
+                    _ensure_ffmpeg()
                 jpeg = _ffmpeg_proc.stdout.read(65536)
                 if not jpeg:
-                    break
+                    # ffmpeg 无数据输出，重启它
+                    logger.warning("ffmpeg stdout 空，重启")
+                    _ffmpeg_proc.terminate()
+                    _ffmpeg_proc = None
+                    _ensure_ffmpeg()
+                    continue
                 yield (b"--frame\r\nContent-Type: image/jpeg\r\n\r\n" + jpeg + b"\r\n")
         except Exception as e:
             logger.error(f"视频流异常: {e}")
@@ -92,6 +100,7 @@ def arm_camera_restart():
     if _ffmpeg_proc:
         _ffmpeg_proc.terminate()
         _ffmpeg_proc = None
+    _ensure_ffmpeg()
     return jsonify({"ok": True})