CAN on Parallel Robots: How to Control a Stewart Platform using CAN based motor controllers

Abstract

The Stewart Platform is a well known and studied parallel robot. It is composed by an upper ring and six linear actuators. The actuators can be hydraulic, pneumatic or electrical, being the last used on applications where moderated forces and moments are required. In this paper a control of a Stewart Platform with electrical motors is described, the motors are regulated by CANopen based controllers. A CAN network is built to communicate and synchronize the motion of the six motors. A PC104 board and a Real Time Operating System (RTOS) are selected to create a fast and reliable CANopen master. The software running in the PC104 is developed from scratch; however some basic features are ported from open-source software. The PC104 board is connected to a desktop PC through an Ethernet network, allowing a remote controlled system. The Stewart platform control is running on the desktop PC due to its high computational requirements.