drake | Model-based design and verification for robotics | Robotics library

Installation steps were:

I have limited experience in drake and currently trying to learn and implement some simple algorithms. The code I have is based on an example from the Underactuated Robotics course by R. Tedrake. The code is a slightly modified version of this example here, where the goal is to design a Lyapanuv Control Function for the unicycle robot model.

To simulate the robot model, an instance of SymbolicVectorSystem from drake is used.

As I understand this is just a building block for the "prototyping" and designing a suitable controller, is this correct?, is SymbolicVectorSystem still needed if there is a real robot?.

Now that I am happy with the controller, I would like to deploy this controller to a ROS2 robot. For that, I have written a simple script that subscribes to the current robot states from the localization system that I have. I am not really sure how to proceed from here, I think I need to connect the received robot state messages to the input of the controller, then publish the output of the controller back to the robot. The problem is I couldn't find any examples that suit this use case.

An approach I think of, could be that I create another class that inherits from VectorSystem, and this class wraps the ros stuff to subscribe publish ROS messages. In overridden DoCalcVectorOutput function of my wrapper class, I assign/retrieve the I/O and publish retrieved control commands. Finally, I connect the I/O of controller and wrapper classes with a DiagramBuilder

I am not sure if this will work, or if this is will be the recommended approach, I will appreciate your help.

Here is what the current code looks like;

I'm a bit unfamiliar with Drake and I've been trying to write a function to return the body indices involved in collisions in my MultibodyPlant. I'm having some trouble getting the correct collision results. I'm currently trying to get the contact results from the plant using a LeafSystem:

I am working on a simple 2D peg-in-hole example in which I want to directly control the peg (which is just a box) in 2D. In order to do that, I add a planar joint to attach the peg to the world as in the Manipulation course's example.

For example I can build a model using functions like AddRigidbody and AddJoint. After the model is built, can I save the model into a URDF file or other xml type file? Drake can load model from URDF or SDF using parser but I haven't find function for saving the MultibodyPlant into URDF or SDF. Thank you for your answer!

I try to build drake1.0.0 from source using bazel. However I encounter the following error:

I have data like this:

I have freshly installed drake using pip and while going through tutorials about mathematical programs, I cannot use the example with IpoptSolver. I am getting this error message, however, I cannot find information in the documentation how to compile it. Could you point me to the right direction?

ValueError: IpoptSolver cannot Solve because IpoptSolver::available() is false, i.e., IpoptSolver has not been compiled as part of this binary. Refer to the IpoptSolver class overview documentation for how to compile it.

One of Drake's selling points is the easy availability of gradients via AutoDiff, but I'm struggling to see how to easily compute second-order derivatives in pydrake.

Given a function f(x), I know of two ways to compute the Jacobian. The first way uses the forwarddiff.jacobian helper function, e.g.: