Trying to derive left error with noise (equation 30 in paper - left version). Similar to how paper does noise free derivative of error.

d/dt n = g(n) - w^ n <- this is what we seek and is the left version of equation 30 in the paper.

Definitions: d/dt x = f(x) + x w^ n = x^-1 xbar x n = xbar g(n) = f(n) - f(I) n

Start by taking derivative: d/dt(n) = d/dt (x^-1) xbar + x^-1 d/dt xbar Substitute d/dt(x ^x-1) = d/dt I = 0 -> d/dt x^-1 = -x^-1 (d/dt x) x^-1 = -x^-1 d/dt x x^-1 xbar + x^-1 d/dt xbar Insert dynamics "f": = -x^-1 (f(x) + x w^) x^-1 xbar + x^-1 (f(xbar) + xbar w^) = -x^-1 f(x)x^-1 xbar + -x^-1 x w^ x^-1 xbar + (x^-1 f(xbar) + x^-1 xbar w^) Put n back in = -x^-1 f(x)n -w^ n + x^-1 f(xbar) + n w^ Eliminte xbar = -x^-1 f(x)n -w^ n + x^-1 f(x n) + n w^ Set x = I = -f(I)n -w^ n + f(n) + n w^ Insert defintion of g = f(n) - f(I)n -w^ n + n w^ = g(n) -w^ n + n w^

Almost but not quite. I can't get rid of "n w^". What am I missing? Paper derives noise free error derivative but only states results of the noisey version.

Has this repository compiled on Mac? I'm using Mac to compile this repository and I got following error message:clang: error: linker command failed with exit code 1 (use -v to see invocation) make[2]: *** [../lib/libinekf.dylib] Error 1 make[1]: *** [CMakeFiles/inekf.dir/all] Error 2 make: *** [all] Error 2 I have installed the requirement package already. Thanks in advance!

The IEKF system noise Qt=Adx*Cov (wt)*Adx^T . where Adx=[R 0 0 0] [(vt)xR R 0 0] [(pt)xR 0 R 0] [(dt)xR 0 0 R] if the position pt is large, for example the robot moves to a certain location (1000,1000,1000),and its velocity is (100,100,100) ,then Qt is very large. Namely IEKF's system noise is very large and this is unreasonable. Why is this happening? 　

Hi, thanks for making this code available.

I am trying to use it with a pre determined map of ceiling mounted apriltag markers. (corner positions known).

Would you be able to give me a few tips on how to use your example and add marker corners?

Would I give each corner an id , and set them as landmarks?

Where is the camera / robot pose added?

Thanks!

hello,When I run simulink, I meet the following problems. Simulink cannot propagate the variable-size mode from the 'Output Port 1' of 'RIEKF_test/Landmark Spoofer' to the 'Input Port 1' of 'RIEKF_test/Orientation EtherCAT Rate Transition6'. This input port expects a fixed-size mode. The variable-size mode originates from 'RIEKF_test/Landmark Spoofer/MATLAB Function1'. Examine the configurations of 'RIEKF_test/Orientation EtherCAT Rate Transition6' for one of the following scenarios: 1) the block does not support variable-size signals; 2) the block supports variable-size signals but needs to be configured for them.

Hi, I'm trying to reproduce your results on my own to make sure that I really understand your paper Contact-Aided Invariant Extended Kalman Filtering for Robot State Estimation*. When I look into the KINEMATIC measurement in imu_kinematic_measurements.txt, I find it is quite strange. Here is my understanding: instead of measuring the joint encoder of the Cassie, the imu_kinematic_measurements.txt provides the relative position between the foot and the robot directly, which I can understand. However, The imu_kinematic_measurements.txt also provides the covariance matrix, which I really don't understand. Can the covariance matrix be measured? This is really strange to me. I would be really appreciated if you can answer this question for me. Thank you so much in advance for your time! Best Yuan

Hello,

I want to implement ZUPT (zero velocity updates). I first thought it would be a piece of cake but I came to the realisation that I have to master the theory first... which is not out of reach, but certainly going to take least a couple of days. Still, the solution might be really simple so I'm taking a chance here. Perhaps someone could provide the solution in just a few key lines of code.

Thanks to anyone! And a big thanks to Ross Hartley for sharing.