To my knowledge, nobody is working on this right now. If you want to implement something at submit a PR, we'd be happy to consider it for inclusion in the library.

There are some existing Python-based block diagram editors out there. In particular, take a look at pysimCoder by @robertobucher.

BDSim includes a graphical block diagram editor.

Its format is a JSON file. It might be possible to convert that into an interconnect command, or create some other way to integrate with python-control, such as by use python-control system objects in BDSim.

Thank you for your kind reply. I apologize for the delay, as I have been evaluating our technical options.

A major advantage of python-control is that it is cross-platform (Windows, Mac, and Linux) and licensed under the BSD 3-Clause license. I want to ensure that my implementation preserves these benefits.

It appears that pysimCoder only runs on Linux. And, I would prefer not to adopt BDSim because it depends on PyQt5, which has a more restrictive license.

So, I am considering using one of the following tools for the plotting functionality. I would appreciate hearing your thoughts on this.

Mermaid + browser / IPython

Features

• License: MIT
• Merits
  • Very beautiful
  • No additional Python libraries required
• Demerits
  • Depends on mermaid.min.js, so it only works online / you need to place mermaid.min.js locally

# mermaid-test.ipynb
import tempfile
import webbrowser

def generate_mermaid_code():
    # some jobs to do ...
    return r"""
<pre class="mermaid">
graph LR
    input@{ shape: stadium, label: "input" }
    output@{ shape: stadium, label: "output" }
    sumJun1@{ shape: sm-circ }
    K["$$K$$"]
    P["$$P\ :\begin{cases}\begin{aligned} \dot{x}(t) & = Ax(t) + Bu(t) \\\\ y(t) & = Cx(t) + Du(t) \end{aligned}\end{cases}$$"]
    sep1@{ shape: f-circ }
    input -->|"$$r$$"| sumJun1
    sumJun1 --> |"$$e$$"| K
    P --> |"$$y$$"| sep1
    sep1 --> |"$$y$$"| output
    K --> |"$$u$$"| P
    sep1 --> |"$$-1 \times y$$"| sumJun1

classDef inout fill:#7ca;
class input,output inout
</pre>
    """

class InterconnectedSystem:
    def _repr_html_(self):
        html = f"""
<script src="https://cdn.jsdelivr.net/npm/mermaid@11.9.0/dist/mermaid.min.js"></script>
{generate_mermaid_code()}
<script>
if (window.mermaid) {{
    mermaid.initialize({{startOnLoad:true}});
    mermaid.init(undefined, document.querySelectorAll(".mermaid"));
}}
</script>
        """
        return html

InterconnectedSystem()  # Draws the block diagram in Jupyter Notebook

NetworkX

Features

• License: 3-clause BSD
• Merits
  • Since it is a Python graph library, everything can be done in Python code
• Demerits
  • It does not produce block diagrams.
    • Text may not fit inside nodes, and rectangular nodes cannot be drawn
    • Feedback arrows are troublesome

# networkx-test.ipynb
import networkx as nx
import matplotlib.pyplot as plt

plt.rcParams.update({
    "mathtext.fontset": "cm",
    'pdf.fonttype': 42,
    'ps.fonttype': 42,
})

# define node and labels
labels = {
    1: r"$P$",
    2: r"$\frac{s-1}{(s+1)(s-2)}$",
    3: "TransferFunction()",
    4: "K"
}

G = nx.DiGraph()
for n, label in labels.items():
    G.add_node(n, label=label)
G.add_edges_from([(1, 2), (2, 3), (3, 1), (1, 4)])

# calculate node sizes based on label size
font_size = 16

pos = nx.spring_layout(G)
nx.draw(G, pos, with_labels=False)
nx.draw_networkx_labels(G, pos, labels, font_size=font_size)

plt.show()

I've started developing a test library at https://github.com/knttnk/pyctrl-block-diagram.
You can now display diagrams like the images below.

I think there are too many arrows in the diagrams. Do you have any suggestions for names, too many arrows, and others?