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msm/TOOLBOX_Force_Estimation/ESTIMATION_TOOL_maximum_muscle_forces.m
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ESTIMATION_TOOL_maximum_muscle_forces.m
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function FMAX = ESTIMATION_TOOL_maximum_muscle_forces(ESTDATA, DYDATA, MWDATA)
% Initialise the Output
FMAX = [];
% Initialise a local indexing variable
k = 0;
Pesh = 50;
% Use the Model which depends on the muscle length and velocity
if isequal(ESTDATA.FmaxOption, 'on') % it would not be on anymore
for MuscleId = 1:42
for SegmentId = 1:MWDATA{MuscleId, 1}.MSCInfo.NbSegments
k = k+1;
% Get the Muscle Length
Lm = ESTDATA.Muscle_Length(MuscleId, SegmentId);
% Get the Muscle Velocity (invert muscle velocity, positive = contraction, negative = elongation)
dLmdt = -ESTDATA.Moment_Arm_Matrix(:,k)'*DYDATA.dJEAdt;
% Define the Maximum and Minimum muscle lengths
Lm_max = 2.5*MWDATA{MuscleId, 1}.MSCInfo.Lmax;
Lm_min = 0.4*MWDATA{MuscleId, 1}.MSCInfo.Lmin;
% Get the Optimum Fiber Length
Lopt = 0.7;
% All these parameters are guessed...
Lsh = 0.6; % [m]
Ver = 0.5; % [-]
Vml = 1.3; % [-]
Lt = 0.02; % [m]
Lce0 = Lm_min + Lopt*(Lm_max - Lm_min) - Lt; % [m]
Vvm = 6*Lce0; % [m/s]
Vsh = 0.3; % [-]
Vshl = 0.23; % [-]
Lce = Lm - Lt; % [m]
Lcesh = Lsh*(Lm_max - Lm_min); % [m]
% Compute the Length Function
Flce = exp(-((Lce - Lce0)/Lcesh)^2);
% Compute the Muscle Velocity Function
Fvce = Flce;
Vmax = Vvm*(1 - Ver*(1 - Flce));
if dLmdt <= -Vmax
Fvce = 0;
elseif dLmdt > -Vmax && dLmdt < 0
Fvce = Vsh*(Vmax + dLmdt)/(Vsh*Vmax - dLmdt);
elseif dLmdt >= 0
Fvce = (Vsh*Vshl*Vmax + Vml*dLmdt)/(Vsh*Vshl*Vmax + dLmdt);
else
Fvce = 0;
end
% Compute the Maximum Muscle Force (Activation is set to 1)
FMAX(k,1) = Flce.*Fvce.*MWDATA{MuscleId, 1}.MSCInfo.Fmax + MWDATA{MuscleId, 1}.MSCInfo.Fmax/exp(Pesh)*(exp(Pesh/Lm_max*Lm) - 1);
end
end
% Simply use the maximum forces as is
else
for MuscleId = 1:42
for SegmentId = 1:MWDATA{MuscleId, 1}.MSCInfo.NbSegments
k = k+1;
FMAX(k,1) = MWDATA{MuscleId, 1}.MSCInfo.Fmax;
end
end
end
return;
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