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Questions tagged [drake]

Drake is an open-source toolbox for planning, control, and analysis of nonlinear systems, developed in C++ with bindings available in Python.

Drake is an open-source toolbox for planning, control, and analysis of nonlinear systems, developed in C++ with bindings available in Python.

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692 questions
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Rigid Body Plant - State vs. Kinematics and Accelerations

Suppose that my rigid body plant is generated from a URDF file and represents a manipulator such as the Kuka arm in the examples. I have two questions: 1.) Are the generalized positions and velocities from state_output_port() and…
Felix Crazzolara
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High memory usage when doing direct transcription with sympy equations

I used sympy to derive, via lagrange, the equations of motion of my 3 link robot. The resultant equation of motion in the form (theta_dot_dot = f(theta, theta_dot)) turned out very complicated with A LOT of cos and sin. I then lambdified the…
Rufus
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Class implementation in Python

I'm trying to create a class in Python and having some issues. First I tried inheriting a VectorSystem to do trajectory optimization and I get the error regarding it not having 'AutoDiff' RuntimeError: The object named [] of type …
GuyS
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Tracking time_step and recording geometry logic errors at runtime

With my simulations, I keep running into errors which only occur at runtime, such as terminate called after throwing an instance of 'std::logic_error' what(): Vector appears to be nearly zero. and abort: Failure at…
Joaquin Giraldo-Laguna
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Visualising the motion of multiple robots

I am trying to add multiple robot instances and visualising their motions. I tried a couple of ways to do this and I ran into errors/issues. They are as follows: I tried adding another model instance after the system is created.…
sutej kulgod
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How can I fix the "undefined reference to" error in cpp, when call for functions in rigidbodytree, like doKinematics, CreateKinematicCache

I am a starter of drake. I use urdf parser to extract my robot model to RigidBodyTree. Then I use doKinematics function to create kinematic cache. However, the builder give me the error below. This is one case, in some cases, I cannot use other…
Junda Huang
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Issues installing Drake on Ubuntu 18.04

Followed through installation tips, but after typing $ python underactuated/src/double_pendulum/simulate.py I get ImportError: dynamic module does not define init function (init_module_py). If I run python3 I get ImportError: cannot import name…
cvobok
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Is there a way of visualising a line in drake visualizer

I am currently working with the compass-gait example. I am trying to visualise a planned path for a robot. Is there a way to visualise a few lines dynamically during the simulation on the visualizer as the robot traces a path? I am looking into…
sutej kulgod
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Events changing visual geometries

I'm trying to visualize collisions and different events visually, and am searching for the best way to update color or visual element properties after registration with RegisterVisualGeometry. I've found the GeometryInstance class, which seems like…
Joaquin Giraldo-Laguna
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world body BodyIndex is non-zero?

I have a simple check once I add all my models to my plant to review every BodyIndex and its corresponding name. I noticed that the worldbody registers in each call to GetBodyIndices() regardless of model instance index, and, alarmingly, with a…
Joaquin Giraldo-Laguna
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Is there a way of storing vectors of varying size in context as discrete states

I am working with compass gait and I am looking at storing some motion primitives/obstacle descriptions. Since all the functions in the class are constant, I cannot add a variable to the class to store this information. Hence I was wondering if…
sutej kulgod
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rqt_graph functionality for drake + LCM

I'm working with drake and LCM messaging in a robotic manipulation context and would like to know if there exists an LCM functionality similar to rqt_graph for ROS, which visualizes inputs and outputs to different nodes.
Joaquin Giraldo-Laguna
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Error control wants to select step smaller than minimum allowed

I'm getting the following error when I run my simulation terminate called after throwing an instance of 'std::runtime_error' what(): Error control wants to select step smaller than minimum allowed (1e-14)
Rufus
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Can I visualize a Multibody pose without explicitly calculating every body's full transform?

In the examples/quadrotor/ example, a custom QuadrotorPlant is specified and its output is passed into QuadrotorGeometry where the QuadrotorPlant state is packaged into FramePoseVector for the SceneGraph to visualize. The relevant code segment in…
Rufus
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No entry for variable u0_0 when converting from state_output to RollPitchYaw

Background In order to control my MultibodyPlant, I need to know the current roll, pitch, yaw and x, y, z of a particular link. I believe I obtain this information from my MultibodyPlant's get_state_output_port(). The plant is floating, i.e. it…
Rufus
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