TABLE 1.
Feedback model parameters for each model formulation
| Symbol | Description | Value |
|---|---|---|
| A. System Identification Pendulum Model | ||
| μm | Weight for maximum deviation between simulated and measured EMG signals at any time point | 1,000 N·m/s |
| μs | Weight for error between simulated and measured EMG signals over time | 10 N·m/s |
| wp | Weight for final pendulum position | 0 N |
| wv | Weight for final pendulum velocity | 0.08 N·s |
| wa | Weight for final pendulum acceleration | 0.02 N·s2 |
| B. Jigsaw Models | ||
| μm | Weight for maximum deviation between simulated and measured EMG signals at any time point | 10 N·m/s |
| μs | Weight for error between simulated and measured EMG signals over time | 1 N·m/s |
| C. Optimal Feedback Model | ||
| ρ | Weight for level of EMG activation over time | 20 N·m/s |
| qp | Weight for deviations of pendulum position over time | 0.05 N/s |
| qv | Weight for deviations of pendulum velocity over time | 50 N |
| qa | Weight for deviations of pendulum acceleration over time | 1 N·s |
| ωp | Weight for final pendulum position | 0 N |
| ωv | Weight for final pendulum velocity | 0.08 N·s |
| ωa | Weight for final pendulum acceleration | 0.02 N·s2 |
W = [wp wv wa], Q = diag [qp qv qa], and Ω = [ωp ωv ωa]. The final simulation time (tend) was 1.1 s for all models. Listed parameters are described in detail in Welch and Ting (2008).