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Testing ekf implementation for Quadro_1.
Diff: EKF_RP.cpp
- Revision:
- 0:a0e9705be9c4
- Child:
- 1:6b803652d032
diff -r 000000000000 -r a0e9705be9c4 EKF_RP.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/EKF_RP.cpp Fri Oct 18 14:55:53 2019 +0000 @@ -0,0 +1,126 @@ +#include "EKF_RP.h" + +using namespace std; +using namespace Eigen; + +EKF_RP::EKF_RP(float Ts) +{ + this->Ts = Ts; + /* [n_gyro; n_b_g; n_v] */ + var_fx << 1000, 1000, 20, 20, 10, 10; + /* [n_acc] */ + var_gy << 40, 40; + rho = 5000; + kv = 0.5; /* k1/m */ + g = 9.81; + reset(); +} + +EKF_RP::~EKF_RP() {} + +void EKF_RP::reset() +{ + u.setZero(); + y.setZero(); + x.setZero(); + update_F(); + update_H(); + initialize_Q(); + initialize_R(); + P = Q; + K.setZero(); + I.setIdentity(); +} + +void EKF_RP::update(float gyro_x, float gyro_y, float accel_x, float accel_y) +{ + // u << gyro_x, gyro_y; + // y << accel_x, accel_y; + + // update_F(); + // update_H(); /* H remains constant */ + // update_Q(); + + // x = fxd(); + // P = F * P * F.transpose() + Q; + + // K = P * H.transpose() * ( H * P * H.transpose() + R ).inverse(); + + // x = x + K * (y - gy()); + // P = (I - K * H) * P; +} + +float EKF_RP::get_est_state(uint8_t i) +{ + /* x = [ang; b_g; v] */ + return x(i); +} + +void EKF_RP::update_angles() +{ + s1 = sinf(x(0)); + c1 = cosf(x(0)); + s2 = sinf(x(1)); + c2 = cosf(x(1)); +} + +void EKF_RP::update_F() +{ + F << (Ts*c1*s2*(u(1) - x(3)))/c2 + 1, -(Ts*s1*(u(1) - x(3)))/(s2*s2 - 1), -Ts, -(Ts*s1*s2)/c2, 0, 0, + -Ts*s1*(u(1) - x(3)), 1, 0, -Ts*c1, 0, 0, + 0, 0, 1, 0, 0, 0, + 0, 0, 0, 1, 0, 0, + 0, Ts*c2*g, 0, 0, 1 - Ts*kv, 0, + -Ts*c1*c2*g, Ts*g*s1*s2, 0, 0, 0, 1 - Ts*kv; +} + +void EKF_RP::update_H() +{ + H << 0, 0, 0, 0, -kv, 0, + 0, 0, 0, 0, 0, -kv; +} + +void EKF_RP::initialize_R() +{ + R << rho*var_gy(0)/Ts, 0, + 0, rho*var_gy(1)/Ts; +} + +void EKF_RP::initialize_Q() +{ + Q << Ts*(var_fx(0) + (s1*s1*s2*s2*var_fx(1))/(c2*c2)), (Ts*c1*s1*s2*var_fx(1))/c2, 0, 0, 0, 0, + (Ts*c1*s1*s2*var_fx(1))/c2, Ts*c1*c1*var_fx(1), 0, 0, 0, 0, + 0, 0, Ts*var_fx(3), 0, 0, 0, + 0, 0, 0, Ts*var_fx(4), 0, 0, + 0, 0, 0, 0, Ts*var_fx(5), 0, + 0, 0, 0, 0, 0, Ts*var_fx(6); +} + +void EKF_RP::update_Q() +{ + Q(0,0) = Ts*(var_fx(0) + (s1*s1*s2*s2*var_fx(1))/(c2*c2)); + Q(0,1) = Ts*c1*s1*s2*var_fx(1)/c2; + Q(1,0) = Q(0,1); + Q(1,1) = Ts*c1*c1*var_fx(1); +} + +Matrix <float, 6, 1> EKF_RP::fxd() +{ + Matrix <float, 6, 1> retval; + retval << x(0) + Ts*(u(0) - x(2) + (s1*s2*(u(1) - x(3)))/c2), + x(1) + Ts*c1*(u(1) - x(3)), + x(2), + x(3), + x(4) + Ts*(g*s2 - kv*x(4)), + x(5) - Ts*(kv*x(5) + c2*g*s1); + return retval; +} + +Matrix <float, 2, 1> EKF_RP::gy() +{ + Matrix <float, 2, 1> retval; + retval << -kv*x(4), + -kv*x(5); + return retval; +} +