实现流量控制前馈 + 增益调度（MFC 结构）

按 plan.md 新增三个交付物，全部默认关闭以保持与纯 PID 的 A/B 兼容：

- valve_model.py：阀特性模型 Q_ss = A_eff(x)·P1_abs·F(r)，含 ISO 6358
  椭圆 F(r)、行程/面积互逆插值、单调性校验、JSON 存取。
- identify_valve.py：从 open_loop.py 扫点 CSV 拟合 A_eff 表并输出 JSON。
- 控制器集成：config/flow_control/main/data_logger 新增阀前压读取
  （channel 2）、前馈打底 + PI 修残差、按 P1 增益调度，并记录/绘制前馈项。

新增配置 FEEDFORWARD_ENABLED / GAIN_SCHEDULE_ENABLED 默认 False，
VALVE_MODEL_PATH 默认空，未加载模型时行为与原先纯 PID 完全一致。

main.py

@@ -23,6 +23,7 @@ from controllers import IncrementalPID
 from data_logger import FlowRunRecorder
 from flow_control import FlowControlFault, FlowControlLoop
 from performance_reporter import PerformanceReporter
+from valve_model import ValveModel
 
 
 class ConsoleGate(logging.Filter):
@@ -61,7 +62,27 @@ def build_logger():
     return logger, console_gate
 
 
+def _load_valve_model(logger):
+    """按配置加载阀特性模型；配置为空或文件缺失/损坏时返回 None（纯 PID）。"""
+    if not config.VALVE_MODEL_PATH:
+        return None
+    model_path = Path(__file__).resolve().parent / config.VALVE_MODEL_PATH
+    if not model_path.exists():
+        logger.warning("阀特性模型文件不存在：%s，退化为纯 PID", model_path)
+        return None
+    try:
+        return ValveModel.load(
+            str(model_path),
+            config.MOTOR_OPEN_POSITION,
+            config.MOTOR_CLOSED_POSITION,
+        )
+    except (ValueError, OSError) as exc:
+        logger.warning("加载阀特性模型失败（%s）：%s，退化为纯 PID", model_path, exc)
+        return None
+
+
 def build_control_loop(hardware, logger):
+    valve_model = _load_valve_model(logger)
     pid = IncrementalPID(
         kp=config.PID_FAR_KP,
         ki=config.PID_FAR_KI,
@@ -77,6 +98,7 @@ def build_control_loop(hardware, logger):
         period_s=config.CONTROL_PERIOD_S,
         flow_channel=config.FLOW_INPUT_CHANNEL,
         pressure_channel=config.PRESSURE_INPUT_CHANNEL,
+        pressure_before_channel=config.PRESSURE_BEFORE_CHANNEL,
         motor_channel=config.MOTOR_OUTPUT_CHANNEL,
         motor_open_position=config.MOTOR_OPEN_POSITION,
         motor_closed_position=config.MOTOR_CLOSED_POSITION,
@@ -112,6 +134,15 @@ def build_control_loop(hardware, logger):
         pid_mode_switch_confirm_cycles=(
             config.PID_MODE_SWITCH_CONFIRM_CYCLES
         ),
+        valve_model=valve_model,
+        feedforward_enabled=config.FEEDFORWARD_ENABLED,
+        feedforward_correction_band_pct=config.FEEDFORWARD_CORRECTION_BAND_PCT,
+        gain_schedule_enabled=config.GAIN_SCHEDULE_ENABLED,
+        gain_schedule_ref_abs_kpa=config.GAIN_SCHEDULE_REF_ABS_KPA,
+        gain_schedule_floor_abs_kpa=config.GAIN_SCHEDULE_FLOOR_ABS_KPA,
+        gain_schedule_scale_change_threshold=(
+            config.GAIN_SCHEDULE_SCALE_CHANGE_THRESHOLD
+        ),
         logger=logger,
     )
 
@@ -139,12 +170,27 @@ def format_status(result):
         "--" if result.pressure_kpa is None
         else f"{result.pressure_kpa:.2f}"
     )
-    return (
-        f"状态={result.status} 目标={result.target_flow_slm:.2f} SLM "
-        f"实际={flow_text} SLM 压力={pressure_text} kPa "
-        f"开度={result.opening_pct:.2f}% "
-        f"行程={result.motor_position:.1f} dt={result.actual_dt_s:.3f}s"
+    pressure_before_text = (
+        "--" if result.pressure_before_kpa is None
+        else f"{result.pressure_before_kpa:.2f}"
     )
+    parts = [
+        f"状态={result.status}",
+        f"目标={result.target_flow_slm:.2f} SLM",
+        f"实际={flow_text} SLM",
+        f"压力={pressure_text} kPa",
+        f"阀前压={pressure_before_text} kPa",
+        f"开度={result.opening_pct:.2f}%",
+    ]
+    if result.feedforward_pct is not None:
+        parts.append(f"前馈={result.feedforward_pct:.2f}%")
+    if result.correction_pct is not None:
+        parts.append(f"修正={result.correction_pct:+.2f}%")
+    if result.gain_scale is not None and abs(result.gain_scale - 1.0) > 1e-9:
+        parts.append(f"scale={result.gain_scale:.3f}")
+    parts.append(f"行程={result.motor_position:.1f}")
+    parts.append(f"dt={result.actual_dt_s:.3f}s")
+    return " ".join(parts)
 
 
 def run(target_flow_slm):