Comparison of control strategies for the cervical muscles of an average female head-neck finite element model

Figures & data

Figure 1. Implementation of Angular Positioned Feedback (APF) control and Muscle Length Feedback (MLF) Control.

Figure 2. Simulation setup and sign convention.

Table 1. PID Gains from calibration simulation.

Active muscle control strategy	Proportional gain KP	Integral gain KI	Derivative gain KD	Neural delay
Angular Positioned Feedback (APF)	0.60 (% contraction/rad)	0 (% contraction/rad ms)	412.62 (%contraction/rad ms^−1)	15.00 (ms)
Muscle Length Feedback (MLF)	0.45 (% contraction/mm)	0 (% contraction/mm ms)	6.71 (%contraction/mm ms^−1)	53.21 (ms)
Passive	All gains zero

Figure 3. Time-series comparison of model with APF, MLF and without muscle activation.

Table 2. Sprague-Geers metrics evaluation and CORA rating evaluation of calibration simulation.

Rating Evaluation of Kinematics	Head linear x-displacement			Head linear z-displacement			Head rotation y-displacement
	Passive	APF	MLF	Passive	APF	MLF	Passive	APF	MLF
Sprague-Geers Magnitude (%)	28.5	−2.9	20.4	191.5	51.9	147.8	44.1	13.9	48.9
Sprague-Geers Phase (%)	1.3	3.3	3.3	18.4	25.5	21.3	3.5	8.8	4.4
Sprague-Geers Comprehensive (%)	28.6	4.4	20.6	192.4	57.8	149.3	44.3	16.4	49.1
CORA Evaluation	0.707	0.940	0.782	0.324	0.344	0.321	0.681	0.707	0.615