I am playing with the example from the RigidBodyDynamic.jl documentation with the MeshCatMechanisms.jl. No major changes. How do I get the last link to show? using RigidBodyDynamics using LinearAlgebra using StaticArrays using MeshCatMechanisms using Random g = -9.81 # gravitational acceleration …

With Skeleton(inertias = false), MechanismGeometries.jl generates a box geometry (‘rod’) between the origins of each pair of joints that is attached to the same rigid body. This is handy as a quick and dirty visualization for for closed-loop mechanisms, like the four-bar linkage example. But for kin…

The Skeleton geometry source is pretty basic–it only draws sticks between joints, so a terminal link will only be obvious if you allow it to draw the inertias. If you set inertias=true, do you see the link?

with inertias=true I get an error ERROR: Principal inertias [-0.25, 0, 0.083] do not satisfy the triangle inequalities, so the equivalent inertial ellipsoid is not well-defined [image]

Ugh, yeah, that’s https://github.com/JuliaRobotics/RigidBodyDynamics.jl/issues/399 which we haven’t gotten around to. Instead of moment=I_1 * axis * axis' you should be able to use moment=I_1 * [0.01, 1, 1], for example.

SDiagonal() produces the same error. I will move to URDF files

RigidBodyDynamics visualization not working

General Usage

tkoolen August 21, 2020, 3:06am 7

See Adding external force RigidBodyDynamics mechansms - #4 by tkoolen.

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RigidBodyDynamics visualization not working

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