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77 lines
2.6 KiB
C++
77 lines
2.6 KiB
C++
#include <matrix/math.hpp>
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#ifndef EKF_UTILS_HPP
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#define EKF_UTILS_HPP
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// return the square of two floating point numbers - used in auto coded sections
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static constexpr float sq(float var) { return var * var; }
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// converts Tait-Bryan 312 sequence of rotations from frame 1 to frame 2
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// to the corresponding rotation matrix that rotates from frame 2 to frame 1
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// rot312(0) - First rotation is a RH rotation about the Z axis (rad)
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// rot312(1) - Second rotation is a RH rotation about the X axis (rad)
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// rot312(2) - Third rotation is a RH rotation about the Y axis (rad)
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// See http://www.atacolorado.com/eulersequences.doc
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matrix::Dcmf taitBryan312ToRotMat(const matrix::Vector3f &rot312);
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// Use Kahan summation algorithm to get the sum of "sum_previous" and "input".
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// This function relies on the caller to be responsible for keeping a copy of
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// "accumulator" and passing this value at the next iteration.
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// Ref: https://en.wikipedia.org/wiki/Kahan_summation_algorithm
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float kahanSummation(float sum_previous, float input, float &accumulator);
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// calculate the inverse rotation matrix from a quaternion rotation
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// this produces the inverse rotation to that produced by the math library quaternion to Dcmf operator
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matrix::Dcmf quatToInverseRotMat(const matrix::Quatf &quat);
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// We should use a 3-2-1 Tait-Bryan (yaw-pitch-roll) rotation sequence
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// when there is more roll than pitch tilt and a 3-1-2 rotation sequence
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// when there is more pitch than roll tilt to avoid gimbal lock.
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inline bool shouldUse321RotationSequence(const matrix::Dcmf &R) { return fabsf(R(2, 0)) < fabsf(R(2, 1)); }
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inline float getEuler321Yaw(const matrix::Dcmf &R) { return atan2f(R(1, 0), R(0, 0)); }
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inline float getEuler312Yaw(const matrix::Dcmf &R) { return atan2f(-R(0, 1), R(1, 1)); }
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float getEuler321Yaw(const matrix::Quatf &q);
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float getEuler312Yaw(const matrix::Quatf &q);
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inline float getEulerYaw(const matrix::Dcmf &R)
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{
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if (shouldUse321RotationSequence(R)) {
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return getEuler321Yaw(R);
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} else {
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return getEuler312Yaw(R);
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}
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}
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matrix::Dcmf updateEuler321YawInRotMat(float yaw, const matrix::Dcmf &rot_in);
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matrix::Dcmf updateEuler312YawInRotMat(float yaw, const matrix::Dcmf &rot_in);
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// Checks which euler rotation sequence to use and update yaw in rotation matrix
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matrix::Dcmf updateYawInRotMat(float yaw, const matrix::Dcmf &rot_in);
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namespace ecl
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{
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inline float powf(float x, int exp)
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{
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float ret;
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if (exp > 0) {
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ret = x;
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for (int count = 1; count < exp; count++) {
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ret *= x;
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}
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return ret;
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} else if (exp < 0) {
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return 1.0f / ecl::powf(x, -exp);
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}
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return 1.0f;
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}
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}
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#endif // EKF_UTILS_HPP
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