gait2dc.h

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#define NDOF 9                  // number of kinematic degrees of freedom
#define NMOM 6                  // number of joint moment inputs to equation of motion
#define NGRF 6                  // number of GRF inputs to equation of motion (2D force and moment on each foot
#define NSTICK 6                // number of stick figure points generated by Autolev code
#define NFK 42                  // number of forward kinematic outputs generated by Autolev: R(2x2) and p(2) for each segment
 
typedef struct {
                // Gravity
                double gravity;
                double slope;
                
                // Air drag
                double airdrag;                 // drag coefficient, N/(m/s)^2
                double wind;                    // wind speed, m/s (positive value is a tailwind)
 
                // Body segment parameters
                double TrunkMass, TrunkInertia, TrunkCMy;
                double ThighMass, ThighInertia, ThighCMy, ThighLen;
                double ShankMass, ShankInertia, ShankCMy, ShankLen;
                double FootMass, FootInertia, FootCMx, FootCMy;
                double bodyweight;
    
    // Other parameters         
                double MinAngle[NMOM], MaxAngle[NMOM];                                                          // passive joint range of motion
    double JointK2[NMOM], JointD[NMOM];                                                                         // parameters for nonlinear joint stiffness model
    double JointK1[NMOM], JointPhi0[NMOM], JointB[NMOM];        // parameters for linear joint stiffness and damping
    
} param_struct;
 
// define struct that holds contact properties
typedef struct {
                int foot;                                                       // Which foot it is attached to: 0=right, 1=left
                double x,y;                                                     // Resting position on segment
                double k1,k2,a;                                 // Principal stiffnesses and orientation between segment and stiffness
                double kxx,kyy,kxy;                             // Stiffness matrix (symmetric)
                double b;                                                       // Damping between contact point and segment
                double c;                                                       // Friction coefficient
                double LambdaX;                                 // smoothing parameter for normal force model
                double LambdaY;                                 // smoothing parameter for friction model
                double oldcontactmodel; // set to 1 if user wants to use old contact model
                double k,d0,bo,v0,gamma;        // the parameters of the old contact model
} contactprop;
 
// prototype for the Autolev C function for multibody dynamics
void gait2dc_dynamics_al(param_struct* par,
                double q[NDOF], 
                double qd[NDOF], 
                double qdd[NDOF],
                double mom[NMOM],
                double grf[NGRF],
                double Zero[NDOF],
                double dz_dq[NDOF][NDOF], 
                double dz_dqd[NDOF][NDOF],
                double dz_dqdd[NDOF][NDOF],
                double dz_dmom[NDOF][NMOM],
                double dz_dgrf[NDOF][NGRF],
                double fk[NFK],
                double dfk_dq[NFK][NDOF],
                double fkdot[NFK],
                double dfkdot_dq[NFK][NDOF]);
 
// prototype for the Autolev C function for forward kinematics
void gait2dc_FK_al(param_struct* par,
                double q[NDOF],
                double qd[NDOF],
                double qdd[NDOF],
                double fk[NFK],
                double dfk_dq[NFK][NDOF],
                double fkdot[NFK],
                double dfkdot_dq[NFK][NDOF]);
 
// prototype for the Autolev C function for stick figure
void gait2dc_stick_al(param_struct* par,
                double q[NDOF],
                double qd[NDOF],
                double qdd[NDOF],
                double fk[NFK],
                double dfk_dq[NFK][NDOF],
                double fkdot[NFK],
                double dfkdot_dq[NFK][NDOF],
                double Stick[NSTICK][2]);
                
// prototype for the Autolev C function for contact deformation
void contact_al(contactprop* contact,                                                                                                                                                           // parameters for one contact point
                double fk[6], double fkdot[6], double xc[4], double xcdot[2],                                   // inputs for one contact point
                double f[4], double df_dfk[4][6], double df_dfkdot[4][6],
                double df_dxc[4][4], double df_dxcdot[4][2]);                                                                                                   // outputs
 
// prototype for the Autolev C function for accelerometer model
                void acc_al(param_struct* par,
                double q[NDOF],
                double qd[NDOF],
                double qdd[NDOF],
                double acc[42],
                double dacc_dq[42][NDOF],
                double dacc_dqd[42][NDOF],
                double dacc_dqdd[42][NDOF]);