Robotics - OPC UA for Robotics MotionDeviceSystem model

Layer: L7-Application · Flags: PC_ENABLE_OPCUA + PC_ENABLE_ROBOTICS

Turns the board into an OPC UA for Robotics server. OPC 40010-1 ("OPC UA for Robotics - Part 1: Vertical Integration", VDMA / OPC Foundation) is the OPC UA companion specification for industrial robots: it standardizes how a motion device reports its identity and live motion state so any OPC UA client reads the same structure across every vendor. This example exposes that model over OPC UA on TCP/4840 - the twin of example Umati (machine tools).

What it exposes

A MotionDeviceSystem object under the Objects folder, with the standard OPC 40010-1 components (faithful BrowseNames):

MotionDeviceSystem
  MotionDevices (Folder)
    MotionDevice     Manufacturer, Model, ProductCode, SerialNumber, MotionDeviceCategory
      ParameterSet   OnPath, InControl, SpeedOverride
      Axes (Folder)
        Axis_1..N    ActualPosition, ActualSpeed, ActualAcceleration, MotionProfile
  Controllers (Folder)
    Controller       Manufacturer, Model, ProductCode, SerialNumber
      Software       Manufacturer, Model, SoftwareRevision
  SafetyStates (Folder)
    SafetyState
      ParameterSet   OperationalMode, EmergencyStop, ProtectiveStop

You fill a RoboticsMotionDeviceSystem struct and refresh its live fields each loop() from your robot I/O; the server reads straight out of it. pc_robotics_install(&mds) binds the struct and registers the OPC UA Browse + Read resolvers - that is the whole wiring. The axis count is parametric (PC_ROBOTICS_AXES, default 6): each bound axis becomes an Axis_k object with its four live variables.

What you teach

One companion-spec model, one struct. The values carry the standard OPC 40010-1 BrowseNames, so a generic OPC UA client discovers and reads them the same way it would on a real robot cell. It is a read-only monitoring model (the robot reports, the client observes), built on the OPC UA Binary server from example OpcUa.

Configure and flash

1. Set SSID / PASSWORD at the top of Robotics.ino.
2. Build with both flags set (already in build_opt.h for the Arduino IDE):

   pio ci examples/L7-Application/Robotics --board esp32dev --lib "." \
     --project-option="build_flags=-DPC_ENABLE_OPCUA=1 -DPC_ENABLE_ROBOTICS=1"

3. Flash, open Serial @115200, note the IP.

Verify with an OPC UA client

Any OPC UA client works. With python asyncua:

import asyncio
from asyncua import Client
 
async def main():
    async with Client("opc.tcp://<BOARD_IP>:4840") as c:
        objects = c.nodes.objects
        for system in await objects.get_children():            # MotionDeviceSystem
            print("System:", await system.read_browse_name())
            for folder in await system.get_children():         # MotionDevices / Controllers / SafetyStates
                print(" ", await folder.read_browse_name())
 
asyncio.run(main())

Browse from Objects to MotionDeviceSystem, then into MotionDevices -> MotionDevice -> Axes -> Axis_1 -> ActualPosition and read it a few times - it tracks the simulated robot. UaExpert and open62541 browse the same tree.

Scope

A single MotionDevice / Controller / SafetyState and PC_ROBOTICS_AXES parametric axes are exposed (the common embedded robot). The values are faithfully named per OPC 40010-1; full companion-spec TypeDefinitions, PowerTrains, and advertising the Robotics namespace in the server's NamespaceArray (which needs array-Variant support in the base OPC UA server) are a documented follow-on - a generic OPC UA client still browses the structure and reads every value by BrowseName today.