bolt-tightening-quality / preprocess.py
zerozero01's picture
上传螺栓拧紧质量检测数据集(自建模拟数据,3000条)
c67e875 verified
Raw History Blame Contribute Delete
9.76 kB
# -*- coding: utf-8 -*-
"""
螺栓拧紧数据预处理与特征工程脚本
处理流程(对应「工业大数据预处理与特征工程」技术方向):
1. 数据清洗 —— 去除空行程段、3σ 异常值剔除 + 线性插值、缺失值处理
2. 特征提取 —— 从力矩-转角时序提取 12 维时域特征
3. 特征选择 —— Pearson 相关 + 共线性分析,降维至 10 维核心特征
4. 特征标准化 —— Z-score(仅基于训练集统计量,避免数据泄露)
5. 数据集划分 —— 7:2:1 分层随机抽样(按质量标签)
输入:data/raw/{benchmark,extended}/records.jsonl
输出:
data/processed/train.csv / val.csv / test.csv —— 标准化后特征集
data/processed/feature_metadata.json —— 特征元信息
用法:
python data/preprocess.py
"""
from __future__ import annotations
import json
from pathlib import Path
import numpy as np
import pandas as pd
BASE_DIR = Path(__file__).resolve().parent
RAW_DIR = BASE_DIR / "raw"
PROCESSED_DIR = BASE_DIR / "processed"
# 各规格名义最终拧紧角度(用于计算「转角偏差量」特征)
NOMINAL_ANGLE = {"M12": 95.0, "M16": 135.0, "M20": 175.0, "M24": 220.0}
# 12 维时域特征定义
FEATURE_NAMES = [
"torque_max", # 力矩最大值 (N·m)
"torque_mean", # 力矩平均值 (N·m)
"torque_std", # 力矩标准差 (N·m)
"torque_peak_angle", # 力矩峰值出现角度 (deg)
"snug_torque", # 贴合点扭矩 (N·m)
"total_angle", # 拧紧总转角 (deg)
"avg_rate", # 拧紧平均速率 (N·m/deg)
"rising_slope", # 力矩上升斜率 (N·m/deg)
"torque_fluctuation",# 力矩波动率 (无量纲)
"angle_deviation", # 转角偏差量 (deg)
"final_torque", # 最终扭矩值 (N·m)
"hold_fluctuation", # 扭矩保持段波动率 (N·m)
]
def load_raw() -> pd.DataFrame:
"""加载原始数据(基准集 + 扩展集合并)。"""
frames = []
for sub in ("benchmark", "extended"):
path = RAW_DIR / sub / "records.jsonl"
with open(path, encoding="utf-8") as f:
recs = [json.loads(line) for line in f if line.strip()]
df = pd.DataFrame(recs)
df["source"] = sub
frames.append(df)
return pd.concat(frames, ignore_index=True)
def clean_curve(angle: np.ndarray, torque: np.ndarray) -> tuple[np.ndarray, np.ndarray]:
"""数据清洗:去除空行程段 + 3σ 异常值剔除并线性插值补全。"""
angle = np.asarray(angle, dtype=float)
torque = np.asarray(torque, dtype=float)
# 1) 去除空行程段:截取从贴合点(力矩首次超过峰值 30%)到终止
if len(torque) == 0:
return angle, torque
thresh = 0.3 * np.max(torque)
snug_idx = int(np.argmax(torque >= thresh))
angle, torque = angle[snug_idx:], torque[snug_idx:]
if len(torque) < 3:
return angle, torque
# 2) 3σ 异常值剔除:基于一阶差分(跳变点)识别离群点,线性插值补全
diff = np.abs(np.diff(torque, prepend=torque[0]))
mu, sigma = diff.mean(), diff.std()
if sigma > 1e-9:
outliers = diff > (mu + 3 * sigma)
if outliers.any():
idx = np.where(outliers)[0]
valid = ~outliers
# 仅当两端存在有效点时进行插值,否则保留原值
torque_clean = torque.copy()
for i in idx:
if 0 < i < len(torque) - 1:
torque_clean[i] = (torque[i - 1] + torque[i + 1]) / 2.0
torque = torque_clean
return angle, torque
def extract_features(angle: np.ndarray, torque: np.ndarray, spec: str) -> dict:
"""提取 12 维时域特征。"""
n = len(torque)
torque_max = float(np.max(torque))
peak_idx = int(np.argmax(torque))
thresh = 0.3 * torque_max
snug_idx = int(np.argmax(torque >= thresh)) if torque_max > 0 else 0
grad = np.gradient(torque, angle)
hold_start = int(n * 0.8) # 保持段起点(末 20% 区间)
snug_torque = float(torque[snug_idx])
denom = float(angle[peak_idx] - angle[snug_idx]) if peak_idx > snug_idx else 1e-6
return {
"torque_max": torque_max,
"torque_mean": float(np.mean(torque)),
"torque_std": float(np.std(torque)),
"torque_peak_angle": float(angle[peak_idx]),
"snug_torque": snug_torque,
"total_angle": float(angle[-1] - angle[0]),
"avg_rate": float((torque_max - snug_torque) / denom),
"rising_slope": float(np.max(grad[: peak_idx + 1])),
"torque_fluctuation": float(np.std(torque) / (np.mean(torque) + 1e-6)),
"angle_deviation": float(angle[-1] - NOMINAL_ANGLE.get(spec, np.nan)),
"final_torque": float(torque[-1]),
"hold_fluctuation": float(np.std(torque[hold_start:])),
}
def select_features(feat_df: pd.DataFrame, y: pd.Series, threshold_corr: float = 0.1,
threshold_collinear: float = 0.97) -> tuple[list[str], dict]:
"""特征选择:剔除弱相关特征,合并共线性特征(连通分量聚类,保留每组代表)。"""
corr_with_label = {f: float(np.corrcoef(feat_df[f], y)[0, 1]) for f in FEATURE_NAMES}
abs_corr = {f: abs(c) for f, c in corr_with_label.items()}
# 弱相关剔除
kept = [f for f in FEATURE_NAMES if abs_corr[f] >= threshold_corr]
dropped_weak = [f for f in FEATURE_NAMES if abs_corr[f] < threshold_corr]
# 共线性合并:|corr| 高于阈值的特征对构成连通分量,每组保留与标签相关性最强的一个
parent = {f: f for f in kept}
def find(x: str) -> str:
while parent[x] != x:
parent[x] = parent[parent[x]]
x = parent[x]
return x
def union(a: str, b: str) -> None:
ra, rb = find(a), find(b)
if ra != rb:
parent[rb] = ra
collinear_pairs = []
for i in range(len(kept)):
for j in range(i + 1, len(kept)):
f_i, f_j = kept[i], kept[j]
c = float(np.corrcoef(feat_df[f_i], feat_df[f_j])[0, 1])
if abs(c) > threshold_collinear:
collinear_pairs.append((f_i, f_j, round(c, 3)))
union(f_i, f_j)
clusters: dict[str, list[str]] = {}
for f in kept:
clusters.setdefault(find(f), []).append(f)
selected, dropped_collinear = [], []
for members in clusters.values():
best = max(members, key=lambda f: abs_corr[f])
selected.append(best)
for m in members:
if m != best:
dropped_collinear.append({"kept": best, "dropped": m,
"corr": next(c for a, b, c in collinear_pairs
if {a, b} == {best, m})})
selected.sort()
meta = {
"pearson_with_label": {f: round(v, 4) for f, v in corr_with_label.items()},
"dropped_weak": dropped_weak,
"dropped_collinear": dropped_collinear,
"selected_features": selected,
}
return selected, meta
def main() -> None:
raw = load_raw()
print(f"[OK] 加载原始数据 {len(raw)} 条")
# 1) 清洗 + 2) 特征提取
feature_rows = []
for _, row in raw.iterrows():
angle, torque = clean_curve(row["angle"], row["torque"])
if len(torque) < 3:
continue
feats = extract_features(angle, torque, row["spec"])
feats.update({"id": row["id"], "spec": row["spec"], "source": row["source"],
"label": row["label"], "label_name": row["label_name"]})
feature_rows.append(feats)
feat_df = pd.DataFrame(feature_rows)
print(f"[OK] 特征提取完成,有效样本 {len(feat_df)} 条")
# 3) 特征选择
selected, meta = select_features(feat_df, feat_df["label"])
print(f"[OK] 特征选择:{len(FEATURE_NAMES)} -> {len(selected)} 维")
print(f" 剔除弱相关: {meta['dropped_weak']}")
print(f" 合并共线性: {meta['dropped_collinear']}")
# 4) 数据集划分(7:2:1 分层)
from sklearn.model_selection import train_test_split
train, temp = train_test_split(feat_df, test_size=0.3, stratify=feat_df["label"],
random_state=42)
val, test = train_test_split(temp, test_size=1 / 3, stratify=temp["label"],
random_state=42)
# 5) 特征标准化:仅基于训练集统计量
mean = train[selected].mean()
std = train[selected].std().replace(0, 1e-9)
def standardize(df: pd.DataFrame) -> pd.DataFrame:
out = df.copy()
out[selected] = (out[selected] - mean) / std
return out
train_s, val_s, test_s = standardize(train), standardize(val), standardize(test)
PROCESSED_DIR.mkdir(parents=True, exist_ok=True)
cols = ["id", "spec", "source", "label", "label_name"] + selected
train_s[cols].to_csv(PROCESSED_DIR / "train.csv", index=False, encoding="utf-8-sig")
val_s[cols].to_csv(PROCESSED_DIR / "val.csv", index=False, encoding="utf-8-sig")
test_s[cols].to_csv(PROCESSED_DIR / "test.csv", index=False, encoding="utf-8-sig")
meta["n_samples"] = {"train": int(len(train)), "val": int(len(val)),
"test": int(len(test))}
meta["standardization"] = {"mean": mean.round(6).to_dict(), "std": std.round(6).to_dict()}
with open(PROCESSED_DIR / "feature_metadata.json", "w", encoding="utf-8") as f:
json.dump(meta, f, ensure_ascii=False, indent=2)
print(f"[OK] 数据集划分 -> train {len(train)} / val {len(val)} / test {len(test)}")
print(f"[OK] 输出目录 {PROCESSED_DIR}")
if __name__ == "__main__":
main()