更新20260622

Footwear Test methodsfor wholeshoe Slipresistanceperformance/ViewModels/MainWindowViewModel.cs

@@ -34,6 +34,14 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
         private const double StaticPeakDropToleranceN = 0.5;
         private const double SlidingStartDisplacementThresholdMm = 0.05;
         private const double MinimumAnalysisLoadRatio = 0.8;
+        // 预触发缓冲：滑动检测前持续缓存的力/位移历史长度，用于回溯真实滑动起点（保证第一个摩擦力峰值被采到）。
+        private const double PreTriggerWindowSeconds = 0.5;
+        // 滑动检测：载荷达标后，水平摩擦力较静置接触基线上升超过该值即判定已进入滑动。
+        private const double SlidingFrictionTriggerRiseN = 5.0;
+        // 回溯滑动起点：从检测点向前回溯，直到摩擦力回到基线附近（该裕度内）即认定为 onset（t=0）。
+        private const double SlidingOnsetFrictionMarginN = 2.0;
+        // 曲线/分析窗口：滑动开始后只保留该时长，剔除加载段与滑动后回程，对应标准曲线图的有效区间。
+        private const double CurveEndSeconds = 1.0;
         private const int StaticPeakDropConfirmationPointCount = 3;
         private const int MinimumDynamicWindowPointCount = 10;
         private const int StandardTrialCount = 3;
@@ -52,6 +60,7 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
         private readonly DispatcherTimer refreshTimer;
         private readonly Stopwatch runStopwatch = new();
         private readonly List<SlipDataPoint> currentRun = [];
+        private readonly List<SlipDataPoint> preTriggerBuffer = [];
         private readonly ObservableCollection<ObservablePoint> verticalLoadPoints = [];
         private readonly ObservableCollection<ObservablePoint> horizontalFrictionPoints = [];
         private readonly ObservableCollection<ObservablePoint> frictionCoefficientPoints = [];
@@ -72,6 +81,8 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
         private double runStartDisplacementMm;
         private double slidingStartDisplacementMm;
         private double? slidingStartTimeSeconds;
+        private double slidingBaselineFrictionN;
+        private bool hasSlidingBaseline;
         private int activeRunLubricantIndex;
         private DateTime lastLicenseCheckAt = DateTime.MinValue;
         private bool isLicenseLockPending;
@@ -811,6 +822,7 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
         private void BeginRun()
         {
             currentRun.Clear();
+            preTriggerBuffer.Clear();
             verticalLoadPoints.Clear();
             horizontalFrictionPoints.Clear();
             frictionCoefficientPoints.Clear();
@@ -818,6 +830,8 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
             runStartDisplacementMm = deviceService.CurrentSnapshot.DisplacementMm;
             slidingStartDisplacementMm = runStartDisplacementMm;
             slidingStartTimeSeconds = null;
+            slidingBaselineFrictionN = 0;
+            hasSlidingBaseline = false;
             activeRunLubricantIndex = SelectedLubricantIndex;
             runStopwatch.Restart();
             UploadProgress = 0;
@@ -834,7 +848,7 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
         private void RecordPoint(SlipDeviceSnapshot device)
         {
             var elapsedSinceTestStart = runStopwatch.Elapsed.TotalSeconds;
-            var detectionPoint = new SlipDataPoint(
+            var samplePoint = new SlipDataPoint(
                 device.Timestamp,
                 elapsedSinceTestStart,
                 device.VerticalLoadN,
@@ -842,25 +856,114 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
                 device.DisplacementMm,
                 device.FrictionCoefficient);
 
-            TryMarkSlidingStart(detectionPoint);
+            // 滑动起点尚未确定：把样本缓存进滚动预触发缓冲，并尝试检测滑动起点。
             if (!slidingStartTimeSeconds.HasValue)
+            {
+                UpdatePreTrigger(samplePoint);
+                return;
+            }
+
+            var standardTime = elapsedSinceTestStart - slidingStartTimeSeconds.Value;
+            // 只保留滑动开始后 CurveEndSeconds 区间，剔除滑动结束后的回程/抬升段。
+            if (standardTime > CurveEndSeconds)
             {
                 return;
             }
 
-            var standardTime = Math.Max(0, elapsedSinceTestStart - slidingStartTimeSeconds.Value);
+            AppendCurvePoint(samplePoint, standardTime);
+        }
+
+        // 滑动检测前持续缓存样本，并在载荷达标后用水平摩擦力陡升判定滑动起点。
+        private void UpdatePreTrigger(SlipDataPoint samplePoint)
+        {
+            preTriggerBuffer.Add(samplePoint);
+            var oldestAllowed = samplePoint.TimeSeconds - PreTriggerWindowSeconds;
+            while (preTriggerBuffer.Count > 0 && preTriggerBuffer[0].TimeSeconds < oldestAllowed)
+            {
+                preTriggerBuffer.RemoveAt(0);
+            }
+
+            var minimumAnalysisLoad = GetMinimumAnalysisLoad();
+            if (samplePoint.VerticalLoadN < minimumAnalysisLoad)
+            {
+                // 载荷尚未到达规定压力（静置接触前），基线需在载荷达标后重新捕获。
+                hasSlidingBaseline = false;
+                return;
+            }
+
+            if (!hasSlidingBaseline)
+            {
+                // 载荷首次达标：以当前（仅法向加载、尚未水平滑动）的摩擦力为静置接触基线。
+                slidingBaselineFrictionN = samplePoint.HorizontalFrictionN;
+                hasSlidingBaseline = true;
+                return;
+            }
+
+            var frictionRose = samplePoint.HorizontalFrictionN - slidingBaselineFrictionN >= SlidingFrictionTriggerRiseN;
+            var displacementMoved = Math.Abs(samplePoint.DisplacementMm - runStartDisplacementMm) >= SlidingStartDisplacementThresholdMm;
+            if (frictionRose || displacementMoved)
+            {
+                MarkSlidingStartFromBuffer(frictionRose ? "FrictionRise" : "DisplacementMove");
+            }
+        }
+
+        // 回溯预触发缓冲到摩擦力刚离开基线的那一刻设为 t=0，并把该时刻起的缓冲点补进曲线，保证第一个峰值被采到。
+        private void MarkSlidingStartFromBuffer(string trigger)
+        {
+            var onsetIndex = preTriggerBuffer.Count - 1;
+            while (onsetIndex > 0
+                && preTriggerBuffer[onsetIndex - 1].HorizontalFrictionN > slidingBaselineFrictionN + SlidingOnsetFrictionMarginN)
+            {
+                onsetIndex--;
+            }
+
+            // 多回退一个点（≈基线水平）作为 t=0，使曲线起点的摩擦力接近基线、随后升至首峰，与标准曲线一致。
+            onsetIndex = Math.Max(0, onsetIndex - 1);
+            var onset = preTriggerBuffer[onsetIndex];
+            slidingStartTimeSeconds = onset.TimeSeconds;
+            slidingStartDisplacementMm = onset.DisplacementMm;
+
+            for (var index = onsetIndex; index < preTriggerBuffer.Count; index++)
+            {
+                var buffered = preTriggerBuffer[index];
+                var standardTime = buffered.TimeSeconds - onset.TimeSeconds;
+                if (standardTime > CurveEndSeconds)
+                {
+                    break;
+                }
+
+                AppendCurvePoint(buffered, standardTime);
+            }
+
+            preTriggerBuffer.Clear();
+
+            CurrentStatus = "已检测到有效滑动开始：曲线从 0.000 s 开始记录";
+            Log.Information(
+                "检测到有效滑动开始并建立曲线零点：TestNumber={TestNumber}, Trigger={Trigger}, SlidingStartTime={SlidingStartTime:F3}s, BaselineFriction={BaselineFriction:F3}N, OnsetDisplacement={OnsetDisplacement:F3}mm, FlushedPointCount={FlushedPointCount}",
+                TestNumber,
+                trigger,
+                onset.TimeSeconds,
+                slidingBaselineFrictionN,
+                slidingStartDisplacementMm,
+                currentRun.Count);
+        }
+
+        // 把一个样本按标准时间（相对滑动起点）追加到数据与曲线集合，保持各曲线序列同步（节流到 SampleIntervalSeconds）。
+        private void AppendCurvePoint(SlipDataPoint source, double standardTime)
+        {
+            standardTime = Math.Max(0, standardTime);
             if (currentRun.Count > 0 && standardTime - currentRun[^1].TimeSeconds < SampleIntervalSeconds)
             {
                 return;
             }
 
             var point = new SlipDataPoint(
-                device.Timestamp,
+                source.Timestamp,
                 standardTime,
-                device.VerticalLoadN,
-                device.HorizontalFrictionN,
-                Math.Abs(device.DisplacementMm - slidingStartDisplacementMm),
-                device.FrictionCoefficient);
+                source.VerticalLoadN,
+                source.HorizontalFrictionN,
+                Math.Abs(source.DisplacementMm - slidingStartDisplacementMm),
+                source.FrictionCoefficient);
 
             currentRun.Add(point);
             verticalLoadPoints.Add(new ObservablePoint(standardTime, point.VerticalLoadN));
@@ -1091,34 +1194,6 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
             ResultSummary = $"近 3 次平均 静 {staticAverage:F2} / 动 {dynamicAverage:F2}";
         }
 
-        private void TryMarkSlidingStart(SlipDataPoint point)
-        {
-            if (slidingStartTimeSeconds.HasValue)
-            {
-                return;
-            }
-
-            var minimumAnalysisLoad = GetMinimumAnalysisLoad();
-            if (!IsSlidingStartPoint(point, runStartDisplacementMm, minimumAnalysisLoad))
-            {
-                return;
-            }
-
-            slidingStartTimeSeconds = point.TimeSeconds;
-            slidingStartDisplacementMm = point.DisplacementMm;
-            CurrentStatus = "已检测到有效滑动开始：曲线从 0.000 s 开始记录";
-            Log.Information(
-                "检测到有效滑动开始并建立曲线零点：TestNumber={TestNumber}, SlidingStartTime={SlidingStartTime:F3}s, SlidingDetectionDelay={SlidingDetectionDelay:F3}s, StandardTimeOrigin=0.000s, StartDisplacement={StartDisplacement:F3}mm, SlidingStartDisplacement={SlidingStartDisplacement:F3}mm, DisplacementDelta={DisplacementDelta:F3}mm, VerticalLoad={VerticalLoad:F3}N, MinimumAnalysisLoad={MinimumAnalysisLoad:F3}N",
-                TestNumber,
-                point.TimeSeconds,
-                point.TimeSeconds,
-                runStartDisplacementMm,
-                slidingStartDisplacementMm,
-                Math.Abs(point.DisplacementMm - runStartDisplacementMm),
-                point.VerticalLoadN,
-                minimumAnalysisLoad);
-        }
-
         private double GetMinimumAnalysisLoad() =>
             TryParseLoadValue(TargetLoadText, out var targetLoad)
                 ? Math.Max(1, targetLoad * MinimumAnalysisLoadRatio)
@@ -1132,10 +1207,6 @@ namespace Footwear_Test_methodsfor_wholeshoe_Slipresistanceperformance.ViewModel
             return double.TryParse(numeric, NumberStyles.Float, CultureInfo.InvariantCulture, out load);
         }
 
-        private static bool IsSlidingStartPoint(SlipDataPoint point, double startDisplacementMm, double minimumAnalysisLoad) =>
-            point.VerticalLoadN >= minimumAnalysisLoad
-            && Math.Abs(point.DisplacementMm - startDisplacementMm) >= SlidingStartDisplacementThresholdMm;
-
         private static StaticPeakSelection FindStaticPeak(IReadOnlyList<SlipDataPoint> points)
         {
             var searchWindow = points