AMR Demo BAUS

Full Documentation — HTML reference with class diagram  ·  PLC Documentation — High-level PLC architecture & code guide

Autonomous Mobile Robot (AMR) demonstration project built with Beckhoff TwinCAT 3 automation platform.

Introduction

This project demonstrates a complete AMR system integrating:

• Real-time motion control for differential drive and lift mechanisms
• Navigation integration with Navitrol navigation supervisor
• Functional safety implementation with TwinCAT Safety
• Web-based HMI for monitoring and control
• Industrial communication via EtherCAT, CANopen, TCP/IP, and IO-Link

The system implements PackML (ISA-88) state machine patterns for standardized industrial automation control.

Project Structure

Component	Description
AMR_Demo/	TwinCAT System Project — PLC, Safety, Motion NC, I/O
AMR_Demo_HMI/	Web-based HMI (TwinCAT HMI framework, TypeScript)
Documentation/	Device specs, Navitrol parameters, EtherCAT/CANopen/IO-Link files
WheelScope/	TwinCAT Scope project for real-time data visualization

Getting Started

Prerequisites

• TwinCAT 3.1 Build 4026.20 or later
• Visual Studio 2015 or later with TwinCAT XAE Shell
• TwinCAT HMI Server (TE2000) for HMI functionality

Building and Running

PLC / Safety:

1. Open AMR_Demo/AMR_Demo.sln in Visual Studio
2. Right-click PLC or Safety project → Build
3. Deploy: TwinCAT → Activate Configuration

HMI:

1. Open AMR_Demo_HMI/AMR_Demo_HMI.sln in Visual Studio
2. Build → Build Solution (F6); output goes to HmiProj/bin/
3. Start TwinCAT HMI Server, then access via browser: http://localhost:1010

Simulation (no hardware):

• Set Simulated := TRUE in AMR_Demo/PLC/MAIN.TcPOU to bypass physical safety hardware

System Architecture

┌─────────────────────────────────────────────────────────────┐
│                     AMR Demo System                          │
├─────────────────────────────────────────────────────────────┤
│                                                              │
│  ┌─────────────────┐         ┌──────────────────┐          │
│  │  TwinCAT HMI    │◄───ADS──┤   TwinCAT PLC    │          │
│  │  (Web Browser)  │         │   (PackML)       │          │
│  └─────────────────┘         └────────┬─────────┘          │
│                                        │                     │
│                              ┌─────────┼─────────┐          │
│                              │         │         │          │
│                    ┌─────────▼───┐ ┌──▼─────┐ ┌▼────────┐ │
│                    │ TwinCAT NC  │ │ Safety │ │   I/O   │ │
│                    │   (Motion)  │ │  (FSoE)│ │(EtherCAT)│ │
│                    └──────┬──────┘ └───┬────┘ └─┬────────┘ │
│                           │            │        │          │
└───────────────────────────┼────────────┼────────┼──────────┘
                            │            │        │
                    ┌───────▼────────┐   │   ┌────▼────────┐
                    │ Drive Wheels   │   │   │  Sensors    │
                    │ (Left/Right)   │   │   │  (Encoder,  │
                    │ Lift Axis      │   │   │   Scanner)  │
                    └────────────────┘   │   └─────────────┘
                                         │
                                    ┌────▼────────┐
                                    │   Safety    │
                                    │  Devices    │
                                    │ (E-Stop,    │
                                    │  Scanners)  │
                                    └─────────────┘

          ┌──────────────────────────────────┐
          │   Navitrol Navigation System     │
          │   (TCP/IP Connection)            │
          └──────────────────────────────────┘

PLC Execution

MAIN.TcPOU is the sole entry point. On the first cycle it calls AmrModule.Initialize() and builds the HMI symbol tree, then every subsequent cycle calls AmrModule.CyclicLogic().

• Task: PlcTask, Priority 20, 20 ms cycle (50 Hz), AMS Port 350
• Target NetId: 5.135.212.84.1.1

AmrModule extends PackMLModule and owns all subsystems (axes, Navitrol messages, safety groups, encoder) as member variables registered via RegisterWithParent().

PackML State Machine

The robot operates under a standard ISA-88 PackML state machine with two modes: Production and Manual. Mode changes are allowed from Stopped and Aborted.

              ┌──────────┐
         ┌───►│ Aborted  │◄──────────────┐
         │    └────┬─────┘               │
         │         │ [Reset]          Aborting
         │         ▼                      │
         │    ┌──────────┐         ┌──────┴─────┐
     Abort    │ Clearing │         │  Any State │
         │    └────┬─────┘         └────────────┘
         │         │
         │         ▼
         │    ┌──────────┐
         │    │ Stopped  │◄──── Stopping ◄──────┐
         │    └────┬─────┘                      │
         │         │ [Start]               [Stop]│
         │         ▼                             │
         │    ┌──────────┐              ┌────────┴───┐
         └────┤ Starting │              │  Execute   │
              └────┬─────┘              └──────┬─────┘
                   │                           │ [scanner]
                   └──────────────────►  ┌─────▼──────┐
                                          │ Suspending │
                                          └─────┬──────┘
                                                │
                                          ┌─────▼──────┐
                                          │ Suspended  │
                                          └─────┬──────┘
                                                │ [scanner OK]
                                          ┌─────▼──────┐
                                          │Unsuspending│
                                          └────────────┘

State Descriptions

State	Description
Stopped	Idle; no active motion. Manual axis control is allowed via HMI.
Starting	Transition to automatic operation: initialize Navitrol position (x=21.23, y=36.92, θ=90°), enable all axes, enable velocity streaming, move lift to down position.
Execute	Active operation: cycles through destinations 1–4, streams Navitrol velocity setpoints to wheel axes, raises/lowers lift at each stop. Immediately triggers Suspend if either safety scanner is obstructed.
Stopping	Controlled stop: waits for Navitrol setpoint to reach zero and wheels to stop, then disables velocity streaming, stops lift, and disables all axes.
Aborting	Emergency transition: immediately disables velocity streaming, stops wheels, stops lift, disables all axes.
Aborted	Fault state; robot is idle and all axes are disabled. Operator must issue Reset command.
Clearing	Fault reset sequence: pulse safety reset → wait 200 ms for signal propagation → ResetComponents() on all subsystems → release E-Stop in Navitrol Msg3002.
Suspending	Safety obstruction detected: set E-Stop flag in Navitrol, stop lift, disable all axes.
Suspended	Waiting for scanner clearance; automatically transitions to Unsuspending when both SafetyScannerLeuze and SafetyScannerHokuyo report OK.
Unsuspending	Scanner cleared: reset Leuze and Hokuyo scanner faults, re-enable axes, release E-Stop in Navitrol, move lift to down position, then re-send GoToDestination command to resume route.

Navitrol Communication

The robot communicates with Navitrol via TCP/IP (default 127.0.0.1:2000). All message function blocks extend TcpIpCommandResultFilter and share a single TcpIpConnection instance.

Function Block	Sends	Receives	Interval	Purpose
Msg3002_NavitrolStatus	3002	3102	100 ms	Bidirectional status; carries E-Stop flag
Msg1001_InitializePosition	1001	1100/1101	On demand	Set initial robot pose
Msg1016_MeasurmentUpdateDifferentialDrive	1016	1116	30 ms	Odometry upload + receive wheel velocity setpoints
Msg3005_GoToDestination	3005	3105	On demand	Command navigation to a waypoint
Msg3024_ReturnToRoute	3024	3124	On demand	Resume an interrupted route
Msg3001_HoldRelease	3001	3101	On demand	Hold / release motion

Msg1016 interval (30 ms) must match the Navitrol parameter control_interval_us.

Velocity conversion from Navitrol (m/s) to NC (°/s):

ω = (360 × v) / (π × WHEEL_DIAMETER)    [WHEEL_DIAMETER = 0.160 m]

Safety System

Safety signals are grouped in SafetyGroup_TcEvents groups with AutoResetFaults := TRUE:

• SafetyEstop — E-Stop; sets the E-Stop flag in the Msg3002 Navitrol status message
• SafetyScannerLeuze — Leuze RSL400 safety laser scanner; triggers Suspend from within Execute
• SafetyScannerHokuyo — Hokuyo UAM-05LP laser scanner; triggers Suspend from within Execute

Safety reset sequence (in Clearing): SafetyResetPulse → 200 ms delay → ResetComponents() → release E-Stop in Msg3002.

Axes

Axis	Mode	Notes
Wheel Left / Right	NC velocity streaming	Navitrol_StreamVelocity with PT1 smoothing (τ = 100 ms); toggles two MC_MoveVelocity instances with MC_Aborting buffer for seamless setpoint changes
Lift	NC point-to-point (AxisPTP)	CANopen CSP mode (Lift_CanOpMode := 8); target positions from persistent Recipe_HMI

HMI

TypeScript ES2022 (global scope, no modules). Pages are .content files; reusable components are .usercontrol files; helpers are .js files in HmiProj/Functions/.

ADS symbol bindings:

• MAIN.AmrModule — main control module
• MAIN.AmrModule.AmrModule_HMI — HMI interface structure
• MAIN.AmrModule.Recipe_HMI — persistent recipe data (Admin only)
• MAIN.AmrModule.Navitrol_HMI — Navitrol interface

Two ADS profiles: ADS.Config.default.json (local) and ADS.Config.remote.json (remote target).

Development

Git Workflow

• Working branch: Development
• Merge target: Release

TwinCAT File Types

Extension	Description
.TcPOU	Program Organization Unit (XML wrapping Structured Text)
.TcDUT	Data Unit Type (struct / enum / union)
.TcGVL	Global Variable List
.TcIO	Interface definition
.tsproj	TwinCAT System Project
.plcproj	PLC project
.splcproj	Safety PLC project
.hmiproj	HMI project

Support

• Beckhoff Information System
• TwinCAT Documentation

Disclaimer

All sample code provided by Beckhoff Automation LLC are for illustrative purposes only and are provided "as is" and without any warranties, express or implied. Actual implementations in applications will vary significantly. Beckhoff Automation LLC shall have no liability for, and does not waive any rights in relation to, any code samples that it provides or the use of such code samples for any purpose.