Fig. 7
From: Performance-based robotic assistance during rhythmic arm exercises
Comparison of the performance-based assistance with simulated data. The simulated data is composed of a succession of 5 periods of unperturbed sinusoidal movements and 5 periods of simulated pathological movements. The pathological movements are first small movements, followed by slow movements, jerky movements with lateral errors, and finally jerky movements with longitudinal errors. The upper panel shows the position signal along the x-axis, and the second panel shows the velocity along the x-axis. The third and fourth panels display the signals used to assess the motor performance. The third panel shows the signals involved in computing the smoothness metric (η, ξ, ε sm and ε s m,m i n ), and the bottom panel shows the adaptive oscillator state variables ω osc and α osc together with the corresponding minimum desired values ω d and α d . The corresponding assistance gain increases when the performance is lower than the desired threshold, as displayed in the bottom panel. This panel shows the evolution of the three assistance gains k %,s m , k %,v e l , and k %,a m p l . When the corresponding error is above the threshold, a color background is added (smoothness in blue, velocity in green, and amplitude in red)