Self Propelled modular unit

SPMU is an abbreviation for self-propelled modular unit, a moving platform for heavy loads up to 1200 tons.

To control it, 2 hardware components have been developed and completely new software has been developed.

A fully equipped SPMU has 4 power packs and 12 trailers: this corresponds to 64 SCC modules, 4 panel pc’s and a remote control. This system can control 72 axles, 144 wheels! These axles can be controlled in 3 modes: normal, carousel and crab. In normal and carousel modes, the steering point can be set to the operator’s discretion. The layout of the trailers can be adjusted freely! Driving and steering is done with two joysticks where the speed of driving and steering can be infinitely adjusted.

System design

The system has a modular design, whereby a connection is made between different communication layers (Ethernet, Wireless, CAN and RS485), different platforms (panel PC and embedded) and also the hydraulics and the mechanical configuration have a modular structure

SPMU Smart Gateway

SPMU Smart Gateway

The Smartgateway takes care of the central part of the control of the SPMU and also provides the connection of the control to the HMI. Thanks to its powerful Cortex-M4 processor, the gateway is able to take care of the calculations for the wheel steering and at the same time provide the wired or wireless connection to the remote control.

The smart gateway is equipped with an RS485 fieldbus with which it communicates with the rest of the control system; this control is based on the SCC and IO extender modules, which it also developed itself.

Smart gateway


  • Designed for Industrial Applications
  • DIN Rail mounting
  • Industrial Temperature Range (-20 / +85 degrees)


The HMI consists of a remote control and a panel PC. The remote is used to control the SPMU. The panel PC is used for making settings and as a display, diagnosis and logging tool. The application that is developed in-house and runs on it displays the status of the power packs and the positions of the wheels, among other things.