CAN in service robots
- Fig. 1: The Asimo robot by Honda is already ten years old; it uses a decentralized control system to achieve a “human” walking
Source: CAN Newsletter March 2011
CAN as embedded network in service robots is especially in battery-powered systems an optimal solution. Service robots don’t require very high-speed networks. They need a low-power consumption network technology, which is reliable and robust – features that CAN provides. In 1920 Karel Čapek for the first time used the word ‘robot’ in one of his plays (Rossum’s Universal Robots). His brother Josef Čapek proposed the term. The idea is not new: Since the beginnings of civilization, we have been pondering on a human-like creation that would serve us. Early societies were engaged in slavery and used those slaves to perform the tasks, which were dirty, dangerous, or scarring. When most of the slaves were freed, the idea of humanoid machines was born, so-to-say a mechanic slave. Nowadays, we regard a robot as a virtual or mechanical artificial agent. In practice, it usually is an electro-mechanical machine, which is guided by electronic controllers.
CAN interface in detail
Mobile robots have the capability to move around in their environment and are not fixed to one physical location. An example of a mobile robot that is in common use today is the automatic guided vehicle (AGV). An AGV is a mobile robot that follows markers or wires in the floor, or uses vision or lasers. Some of them are controlled by CAN-based systems (see CAN Newsletter 4/2010, page 40). Mobile robots are also found in military and security environments. A typical example is the EOD robot by Telerob. It is used for investigating dangerous areas from a safe distance and diffusing explosive charges. It can be used, for example, on aircrafts with a suspected bomb on board. A CAN network is used to communicate between embedded modules. The CANopen protocol was crucial in helping to make the development of the device quicker, simpler and more modular. The axes are largely controlled on a time-independent basis, which means that the bus performance easily meets requirements. The largest drives are located in the four drive tracks, which are each fitted with a 40‑mm diameter DC motor with braking and encoder. Smaller motors with sensors are used in the seven-axis manipulator with an adjustable tower. The battery-powered robot can be used completely autonomous for a wide range of applications.
