altb_pmic / Mbed 2 deprecated Test_ekf

Testing ekf implementation for Quadro_1.

Dependencies:   mbed Eigen

EKF_RP.cpp@13:2e03d9c03409, 2019-10-22 (annotated)

Committer:
pmic
Date:
Tue Oct 22 20:21:04 2019 +0000
Revision:
13:2e03d9c03409
Parent:
9:be2e1d2f683d
Child:
15:53485bd1ff28
Implement iterative covariance update in EKF_RP and EKF_RPY. Tunestate and noise covariance.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
pmic 0:a0e9705be9c4 1 #include "EKF_RP.h"
pmic 0:a0e9705be9c4 2
pmic 0:a0e9705be9c4 3 using namespace std;
pmic 0:a0e9705be9c4 4 using namespace Eigen;
pmic 0:a0e9705be9c4 5
pmic 0:a0e9705be9c4 6 EKF_RP::EKF_RP(float Ts)
pmic 0:a0e9705be9c4 7 {
pmic 0:a0e9705be9c4 8 this->Ts = Ts;
pmic 0:a0e9705be9c4 9 /* [n_gyro; n_b_g; n_v] */
pmic 13:2e03d9c03409 10 var_fx << 0.1f, 0.1f, 0.002f, 0.002f, 0.002f, 0.002f;
pmic 0:a0e9705be9c4 11 /* [n_acc] */
pmic 13:2e03d9c03409 12 var_gy << 40.0f, 40.0f;
pmic 13:2e03d9c03409 13 rho = 1.0f;
pmic 5:676cbc33c81b 14 kv = 0.5f; /* k1/m */
pmic 5:676cbc33c81b 15 g = 9.81f;
pmic 0:a0e9705be9c4 16 reset();
pmic 0:a0e9705be9c4 17 }
pmic 0:a0e9705be9c4 18
pmic 0:a0e9705be9c4 19 EKF_RP::~EKF_RP() {}
pmic 0:a0e9705be9c4 20
pmic 0:a0e9705be9c4 21 void EKF_RP::reset()
pmic 0:a0e9705be9c4 22 {
pmic 0:a0e9705be9c4 23 u.setZero();
pmic 0:a0e9705be9c4 24 y.setZero();
pmic 0:a0e9705be9c4 25 x.setZero();
pmic 4:e50e18eac72b 26 update_angles();
pmic 4:e50e18eac72b 27 calc_F();
pmic 4:e50e18eac72b 28 calc_H();
pmic 0:a0e9705be9c4 29 initialize_Q();
pmic 0:a0e9705be9c4 30 initialize_R();
pmic 0:a0e9705be9c4 31 P = Q;
pmic 0:a0e9705be9c4 32 K.setZero();
pmic 0:a0e9705be9c4 33 I.setIdentity();
pmic 13:2e03d9c03409 34 e.setZero();
pmic 0:a0e9705be9c4 35 }
pmic 0:a0e9705be9c4 36
pmic 4:e50e18eac72b 37 float EKF_RP::get_est_state(uint8_t i)
pmic 4:e50e18eac72b 38 {
pmic 7:bcbcc23983de 39 /* x = [ang; v; b_g] = [0: phi
pmic 7:bcbcc23983de 40 1: theta
pmic 7:bcbcc23983de 41 2: vx
pmic 7:bcbcc23983de 42 3: vy
pmic 7:bcbcc23983de 43 4: b_gx
pmic 7:bcbcc23983de 44 5: b_gy] */
pmic 4:e50e18eac72b 45 return x(i);
pmic 4:e50e18eac72b 46 }
pmic 4:e50e18eac72b 47
pmic 0:a0e9705be9c4 48 void EKF_RP::update(float gyro_x, float gyro_y, float accel_x, float accel_y)
pmic 0:a0e9705be9c4 49 {
pmic 4:e50e18eac72b 50 u << gyro_x, gyro_y;
pmic 4:e50e18eac72b 51 y << accel_x, accel_y;
pmic 4:e50e18eac72b 52 update_angles();
pmic 0:a0e9705be9c4 53
pmic 4:e50e18eac72b 54 calc_F();
pmic 5:676cbc33c81b 55 // calc_H(); /* H remains constant */
pmic 4:e50e18eac72b 56 calc_Q();
pmic 0:a0e9705be9c4 57
pmic 4:e50e18eac72b 58 x = fxd();
pmic 5:676cbc33c81b 59 P = F * P * F.transpose() + Q;
pmic 13:2e03d9c03409 60 e = y - gy();
pmic 0:a0e9705be9c4 61
pmic 13:2e03d9c03409 62 /* only valid if R is diagonal (uncorrelated noise) */
pmic 13:2e03d9c03409 63 for(uint8_t i = 0; i < 4; i++) {
pmic 13:2e03d9c03409 64 K.col(i) = ( P * (H.row(i)).transpose() ) / ( H.row(i) * P * (H.row(i)).transpose() + R(i,i) );
pmic 13:2e03d9c03409 65 x = x + K.col(i) * e(i);
pmic 13:2e03d9c03409 66 P = (I - K.col(i)*H.row(i)) * P;
pmic 13:2e03d9c03409 67 }
pmic 0:a0e9705be9c4 68 }
pmic 0:a0e9705be9c4 69
pmic 0:a0e9705be9c4 70 void EKF_RP::update_angles()
pmic 0:a0e9705be9c4 71 {
pmic 5:676cbc33c81b 72 s1 = sinf(x(0));
pmic 5:676cbc33c81b 73 c1 = cosf(x(0));
pmic 5:676cbc33c81b 74 s2 = sinf(x(1));
pmic 5:676cbc33c81b 75 c2 = cosf(x(1));
pmic 0:a0e9705be9c4 76 }
pmic 0:a0e9705be9c4 77
pmic 4:e50e18eac72b 78 void EKF_RP::calc_F()
pmic 0:a0e9705be9c4 79 {
pmic 7:bcbcc23983de 80 F << Ts*c1*s2*(u(1) - x(3))/c2 + 1.0f, Ts*s1*(u(1) - x(3))/(c2*c2), -Ts, -Ts*s1*s2/c2, 0.0f, 0.0f,
pmic 7:bcbcc23983de 81 -Ts*s1*(u(1) - x(3)), 1.0f, 0.0f, -Ts*c1, 0.0f, 0.0f,
pmic 7:bcbcc23983de 82 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
pmic 7:bcbcc23983de 83 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f,
pmic 7:bcbcc23983de 84 0.0f, Ts*c2*g, 0.0f, 0.0f, 1.0f - Ts*kv, 0.0f,
pmic 7:bcbcc23983de 85 -Ts*c1*c2*g, Ts*g*s1*s2, 0.0f, 0.0f, 0.0f, 1.0f - Ts*kv;
pmic 0:a0e9705be9c4 86 }
pmic 0:a0e9705be9c4 87
pmic 4:e50e18eac72b 88 void EKF_RP::calc_H()
pmic 0:a0e9705be9c4 89 {
pmic 5:676cbc33c81b 90 H << 0.0f, 0.0f, 0.0f, 0.0f, -kv, 0.0f,
pmic 5:676cbc33c81b 91 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -kv;
pmic 0:a0e9705be9c4 92 }
pmic 0:a0e9705be9c4 93
pmic 0:a0e9705be9c4 94 void EKF_RP::initialize_R()
pmic 0:a0e9705be9c4 95 {
pmic 5:676cbc33c81b 96 R << rho*var_gy(0)/Ts, 0.0f,
pmic 5:676cbc33c81b 97 0.0f, rho*var_gy(1)/Ts;
pmic 0:a0e9705be9c4 98 }
pmic 0:a0e9705be9c4 99
pmic 0:a0e9705be9c4 100 void EKF_RP::initialize_Q()
pmic 0:a0e9705be9c4 101 {
pmic 5:676cbc33c81b 102 Q << Ts*(var_fx(0) + s1*s1*s2*s2*var_fx(1)/(c2*c2)), Ts*c1*s1*s2*var_fx(1)/c2, 0.0f, 0.0f, 0.0f, 0.0f,
pmic 5:676cbc33c81b 103 Ts*c1*s1*s2*var_fx(1)/c2, Ts*c1*c1*var_fx(1), 0.0f, 0.0f, 0.0f, 0.0f,
pmic 5:676cbc33c81b 104 0.0f, 0.0f, Ts*var_fx(2), 0.0f, 0.0f, 0.0f,
pmic 5:676cbc33c81b 105 0.0f, 0.0f, 0.0f, Ts*var_fx(3), 0.0f, 0.0f,
pmic 5:676cbc33c81b 106 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(4), 0.0f,
pmic 5:676cbc33c81b 107 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, Ts*var_fx(5);
pmic 0:a0e9705be9c4 108 }
pmic 0:a0e9705be9c4 109
pmic 4:e50e18eac72b 110 void EKF_RP::calc_Q()
pmic 0:a0e9705be9c4 111 {
pmic 4:e50e18eac72b 112 Q(0,0) = Ts*(var_fx(0) + s1*s1*s2*s2*var_fx(1)/(c2*c2));
pmic 0:a0e9705be9c4 113 Q(0,1) = Ts*c1*s1*s2*var_fx(1)/c2;
pmic 0:a0e9705be9c4 114 Q(1,0) = Q(0,1);
pmic 0:a0e9705be9c4 115 Q(1,1) = Ts*c1*c1*var_fx(1);
pmic 0:a0e9705be9c4 116 }
pmic 0:a0e9705be9c4 117
pmic 0:a0e9705be9c4 118 Matrix <float, 6, 1> EKF_RP::fxd()
pmic 0:a0e9705be9c4 119 {
pmic 0:a0e9705be9c4 120 Matrix <float, 6, 1> retval;
pmic 0:a0e9705be9c4 121 retval << x(0) + Ts*(u(0) - x(2) + (s1*s2*(u(1) - x(3)))/c2),
pmic 0:a0e9705be9c4 122 x(1) + Ts*c1*(u(1) - x(3)),
pmic 0:a0e9705be9c4 123 x(2),
pmic 0:a0e9705be9c4 124 x(3),
pmic 0:a0e9705be9c4 125 x(4) + Ts*(g*s2 - kv*x(4)),
pmic 0:a0e9705be9c4 126 x(5) - Ts*(kv*x(5) + c2*g*s1);
pmic 0:a0e9705be9c4 127 return retval;
pmic 0:a0e9705be9c4 128 }
pmic 0:a0e9705be9c4 129
pmic 0:a0e9705be9c4 130 Matrix <float, 2, 1> EKF_RP::gy()
pmic 0:a0e9705be9c4 131 {
pmic 0:a0e9705be9c4 132 Matrix <float, 2, 1> retval;
pmic 0:a0e9705be9c4 133 retval << -kv*x(4),
pmic 0:a0e9705be9c4 134 -kv*x(5);
pmic 0:a0e9705be9c4 135 return retval;
pmic 0:a0e9705be9c4 136 }
pmic 0:a0e9705be9c4 137