---
id: wiki-2026-0508-neuromuscular-control
title: Neuromuscular Control
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [신경근 조절, Motor Control, NMS Control]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [neuroscience, biomechanics, motor-control, robotics, biomedical]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: python
  framework: opensim
---

# Neuromuscular Control

## 매 한 줄
> **"매 brain plans, spine reflexes, muscle executes"**. Neuromuscular control 은 CNS 가 motor neuron 을 통해 muscle 활성화를 조절해 movement 를 produce 하는 hierarchical process. 2026 perspective 에서 EMG-driven simulation, exoskeleton control, BCI prosthetics 의 핵심.

## 매 핵심

### 매 hierarchy
- **Cortex (M1, PMC, SMA)**: motor planning.
- **Cerebellum**: timing, coordination, error correction.
- **Basal ganglia**: action selection, gain modulation.
- **Spinal cord**: reflex circuits, central pattern generators (CPG).
- **Motor unit**: α-MN + muscle fibers (final common pathway).

### 매 control principles
- **Size principle (Henneman)**: small MN 먼저, large 나중.
- **Co-contraction**: agonist + antagonist 동시 활성화 → stiffness 조절.
- **Stretch reflex**: muscle spindle Ia → α-MN monosynaptic.
- **Equilibrium point hypothesis**: descending command = desired length.

### 매 응용
1. Prosthetic / exoskeleton control.
2. Rehabilitation robotics.
3. Surgical motor mapping.
4. Sport biomechanics.

## 💻 패턴

### Hill-type muscle model
```python
import numpy as np

def hill_muscle(activation, length, velocity,
                F_max=1000, l_opt=0.1, v_max=10):
    f_l = np.exp(-((length - l_opt) / (0.5 * l_opt))**2)
    if velocity <= 0:
        f_v = (v_max + velocity) / (v_max - 4 * velocity)
    else:
        f_v = (1.8 - 0.8 * (v_max + velocity) / (v_max - 7.56 * velocity))
    return F_max * activation * f_l * f_v
```

### Motor unit recruitment (size principle)
```python
def recruit(excitation, n_units=100, threshold_max=1.0):
    thresholds = np.linspace(0.05, threshold_max, n_units)
    return np.where(excitation > thresholds,
                    (excitation - thresholds) / (1 - thresholds), 0)
```

### EMG → activation mapping
```python
from scipy.signal import butter, filtfilt

def emg_to_activation(emg_raw, fs=1000):
    b, a = butter(4, [20, 450], btype="band", fs=fs)
    emg = filtfilt(b, a, emg_raw)
    emg = np.abs(emg)
    b, a = butter(4, 6, btype="low", fs=fs)
    env = filtfilt(b, a, emg)
    return env / env.max()
```

### Inverse dynamics (joint torque)
```python
def inverse_dynamics(theta, theta_dot, theta_ddot, m=5, l=0.4, g=9.81):
    I = m * l**2 / 3
    return I * theta_ddot + 0.5 * m * g * l * np.sin(theta)
```

### CPG (Matsuoka oscillator)
```python
def matsuoka_step(x1, x2, v1, v2, u=1.0, beta=2.5, tau=0.1, dt=0.001):
    y1, y2 = max(0, x1), max(0, x2)
    dx1 = (-x1 - beta*v1 - 2.0*y2 + u) / tau
    dx2 = (-x2 - beta*v2 - 2.0*y1 + u) / tau
    dv1 = (-v1 + y1) / (tau * 12)
    dv2 = (-v2 + y2) / (tau * 12)
    return x1 + dx1*dt, x2 + dx2*dt, v1 + dv1*dt, v2 + dv2*dt
```

### EMG-driven prosthetic control
```python
class MyoelectricController:
    def __init__(self, n_channels=8):
        self.classifier = train_lda()
    def predict(self, emg_window):
        feat = extract_features(emg_window)  # MAV, ZC, WL, AR4
        return self.classifier.predict(feat)
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Whole-body simulation | OpenSim / MyoSuite |
| Single joint, real-time | Hill-type + LDA EMG |
| Locomotion robot | CPG + reflexes |
| Pathology study | Inverse dynamics + EMG |

**기본값**: Hill-type muscle + size-principle recruitment + EMG envelope.

## 🔗 Graph
- 변형: [[Perceptual-Motor-Skills]]
- Adjacent: [[Reinforcement Learning]] · [[BCI]]

## 🤖 LLM 활용
**언제**: simulation parameter tuning, EMG feature engineering, paper synthesis.
**언제 X**: clinical motor diagnosis — neurologist 필수.

## ❌ 안티패턴
- **Linear EMG-force assumption**: 매 force 는 nonlinear (length × velocity × activation).
- **Ignoring co-contraction**: stiffness control 무시 → unstable model.
- **Pure feedback control**: feed-forward (internal model) 누락 → laggy.

## 🧪 검증 / 중복
- Verified (Zajac 1989, Delp OpenSim 2018, Henneman 1965).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — Hill model + EMG + CPG 패턴 |
