rula-reba-assessor

rula-reba-assessor

You are rula-reba-assessor - a specialized skill for evaluating work postures using RULA and REBA methodologies.

Overview

This skill enables AI-powered posture assessment including:

• RULA scoring for upper extremity tasks
• REBA scoring for whole body postures
• Body segment angle measurement guidance
• Risk level classification
• Action level determination
• Photo/video-based assessment
• Comparative assessment reports
• Improvement recommendation generation

Capabilities

1. RULA Assessment

from dataclasses import dataclass
from typing import Optional

@dataclass
class RULAInput:
    # Upper Arm (Group A)
    upper_arm_angle: float  # degrees from vertical
    upper_arm_abducted: bool = False
    shoulder_raised: bool = False
    arm_supported: bool = False

    # Lower Arm
    lower_arm_angle: float  # degrees from vertical
    working_across_midline: bool = False
    working_outside_body: bool = False

    # Wrist
    wrist_angle: float  # degrees from neutral
    wrist_bent_from_midline: bool = False
    wrist_twist: str = "mid"  # "mid" or "extreme"

    # Neck (Group B)
    neck_angle: float  # degrees from vertical
    neck_twisted: bool = False
    neck_side_bent: bool = False

    # Trunk
    trunk_angle: float  # degrees from vertical
    trunk_twisted: bool = False
    trunk_side_bent: bool = False

    # Legs
    legs_supported: bool = True

    # Activity
    muscle_use_score: int = 0  # 0 or 1
    force_load_score: int = 0  # 0, 1, 2, or 3

def calculate_rula(inputs: RULAInput):
    """
    Calculate RULA score
    """
    # Upper Arm Score (1-6)
    if inputs.upper_arm_angle <= 20:
        upper_arm = 1
    elif inputs.upper_arm_angle <= 45:
        upper_arm = 2
    elif inputs.upper_arm_angle <= 90:
        upper_arm = 3
    else:
        upper_arm = 4

    # Adjustments
    if inputs.shoulder_raised:
        upper_arm += 1
    if inputs.upper_arm_abducted:
        upper_arm += 1
    if inputs.arm_supported:
        upper_arm -= 1

    upper_arm = max(1, min(6, upper_arm))

    # Lower Arm Score (1-3)
    if 60 <= inputs.lower_arm_angle <= 100:
        lower_arm = 1
    else:
        lower_arm = 2

    if inputs.working_across_midline or inputs.working_outside_body:
        lower_arm += 1

    lower_arm = min(3, lower_arm)

    # Wrist Score (1-4)
    if inputs.wrist_angle == 0:
        wrist = 1
    elif abs(inputs.wrist_angle) <= 15:
        wrist = 2
    else:
        wrist = 3

    if inputs.wrist_bent_from_midline:
        wrist += 1

    wrist = min(4, wrist)

    # Wrist Twist (1-2)
    wrist_twist = 1 if inputs.wrist_twist == "mid" else 2

    # Table A lookup
    table_a = get_table_a_score(upper_arm, lower_arm, wrist, wrist_twist)

    # Neck Score (1-6)
    if inputs.neck_angle <= 10:
        neck = 1
    elif inputs.neck_angle <= 20:
        neck = 2
    elif inputs.neck_angle <= 45:
        neck = 3
    else:
        neck = 4

    if inputs.neck_twisted:
        neck += 1
    if inputs.neck_side_bent:
        neck += 1

    neck = min(6, neck)

    # Trunk Score (1-6)
    if inputs.trunk_angle == 0:
        trunk = 1
    elif inputs.trunk_angle <= 20:
        trunk = 2
    elif inputs.trunk_angle <= 60:
        trunk = 3
    else:
        trunk = 4

    if inputs.trunk_twisted:
        trunk += 1
    if inputs.trunk_side_bent:
        trunk += 1

    trunk = min(6, trunk)

    # Legs Score (1-2)
    legs = 1 if inputs.legs_supported else 2

    # Table B lookup
    table_b = get_table_b_score(neck, trunk, legs)

    # Posture scores
    posture_a = table_a + inputs.muscle_use_score + inputs.force_load_score
    posture_b = table_b + inputs.muscle_use_score + inputs.force_load_score

    # Final RULA score from Table C
    final_score = get_table_c_score(posture_a, posture_b)

    return {
        "final_score": final_score,
        "group_a_score": table_a,
        "group_b_score": table_b,
        "posture_a": posture_a,
        "posture_b": posture_b,
        "component_scores": {
            "upper_arm": upper_arm,
            "lower_arm": lower_arm,
            "wrist": wrist,
            "wrist_twist": wrist_twist,
            "neck": neck,
            "trunk": trunk,
            "legs": legs
        },
        "action_level": get_rula_action_level(final_score)
    }

def get_rula_action_level(score):
    if score <= 2:
        return {"level": 1, "action": "Posture acceptable if not maintained for long periods"}
    elif score <= 4:
        return {"level": 2, "action": "Further investigation needed, changes may be required"}
    elif score <= 6:
        return {"level": 3, "action": "Investigation and changes required soon"}
    else:
        return {"level": 4, "action": "Investigation and changes required immediately"}

2. REBA Assessment

@dataclass
class REBAInput:
    # Group A (Trunk, Neck, Legs)
    trunk_angle: float
    trunk_twisted: bool = False
    trunk_side_bent: bool = False

    neck_angle: float
    neck_twisted: bool = False
    neck_side_bent: bool = False

    legs_bilateral: bool = True  # Both legs supporting
    knee_flexion: float = 0  # degrees

    # Group B (Upper Arms, Lower Arms, Wrists)
    upper_arm_angle: float
    shoulder_raised: bool = False
    upper_arm_abducted: bool = False
    arm_supported: bool = False

    lower_arm_angle: float

    wrist_angle: float
    wrist_twisted: bool = False

    # Load/Force
    load_kg: float = 0
    shock_or_rapid: bool = False

    # Coupling
    coupling: str = "good"  # good, fair, poor, unacceptable

    # Activity
    static_posture: bool = False
    repeated_actions: bool = False
    rapid_changes: bool = False

def calculate_reba(inputs: REBAInput):
    """
    Calculate REBA score
    """
    # Trunk Score (1-5)
    if inputs.trunk_angle == 0:
        trunk = 1
    elif abs(inputs.trunk_angle) <= 20:
        trunk = 2
    elif 20 < inputs.trunk_angle <= 60:
        trunk = 3
    else:
        trunk = 4

    if inputs.trunk_twisted:
        trunk += 1
    if inputs.trunk_side_bent:
        trunk += 1

    # Neck Score (1-3)
    if 0 <= inputs.neck_angle <= 20:
        neck = 1
    else:
        neck = 2

    if inputs.neck_twisted or inputs.neck_side_bent:
        neck += 1

    # Legs Score (1-4)
    legs = 1 if inputs.legs_bilateral else 2

    if 30 <= inputs.knee_flexion <= 60:
        legs += 1
    elif inputs.knee_flexion > 60:
        legs += 2

    # Table A
    table_a = get_reba_table_a(trunk, neck, legs)

    # Load/Force Score (0-3)
    if inputs.load_kg < 5:
        load = 0
    elif inputs.load_kg <= 10:
        load = 1
    else:
        load = 2

    if inputs.shock_or_rapid:
        load += 1

    score_a = table_a + load

    # Upper Arm Score (1-6)
    if inputs.upper_arm_angle <= 20:
        upper_arm = 1
    elif inputs.upper_arm_angle <= 45:
        upper_arm = 2
    elif inputs.upper_arm_angle <= 90:
        upper_arm = 3
    else:
        upper_arm = 4

    if inputs.shoulder_raised or inputs.upper_arm_abducted:
        upper_arm += 1
    if inputs.arm_supported:
        upper_arm -= 1

    # Lower Arm Score (1-2)
    if 60 <= inputs.lower_arm_angle <= 100:
        lower_arm = 1
    else:
        lower_arm = 2

    # Wrist Score (1-3)
    if abs(inputs.wrist_angle) <= 15:
        wrist = 1
    else:
        wrist = 2

    if inputs.wrist_twisted:
        wrist += 1

    # Table B
    table_b = get_reba_table_b(upper_arm, lower_arm, wrist)

    # Coupling Score (0-3)
    coupling_scores = {"good": 0, "fair": 1, "poor": 2, "unacceptable": 3}
    coupling = coupling_scores.get(inputs.coupling.lower(), 0)

    score_b = table_b + coupling

    # Table C
    table_c = get_reba_table_c(score_a, score_b)

    # Activity Score
    activity = 0
    if inputs.static_posture:
        activity += 1
    if inputs.repeated_actions:
        activity += 1
    if inputs.rapid_changes:
        activity += 1

    final_score = table_c + activity

    return {