Drives and Controls Magazine
Technique cuts linear stage thermal errors by up to 90%
Published:  31 July, 2017

Aeorotech has come up with a software-driven technique that, it claims, can eliminate up to 90% of the thermal errors that can affect the accuracy of precision linear positioning stages. It can be applied to both linear motor and ballscrew-driven linear stages, and operates regardless of the range of temperature change.

The most common way to tackle such thermal errors is to regulate the environment in which the machine operates. This avoids the need to design a thermally insensitive machine, which is difficult and expensive.

Although regulating the environment can reduce the thermal effects, it can be costly to maintain precise building temperature control. There is also the risk that production quality will be affected by the unreliable stability of air-conditioning systems. The level of environmental stability achieved in most industrial facilities – normally around 1°C – is not good enough for many precision manufacturing processes.

Aerotech’s new ThermoComp technology uses a combination of hardware and sensors, and a proprietary compensation algorithm, to minimise stage inaccuracies caused by thermal effects, even if temperatures vary widely. It is available on all of Aerotech’s Pro Series stages and operates via an easy-to-use set of commands integrated into the software of Aerotech’s A3200 controllers.

The graph shows internal-heating-related positioning errors measured during prolonged operation of a ballscrew stage with ThermoComp (blue line), and without it (red line)

The technology is designed to eliminate both environmental and internal heating effects. It compensates for internal self-heating – a major source of thermal-related positioning errors, especially in stages without direct feedback devices, such as ballscrew-driven stages. Aerotech claims that its technology will eliminate up to 90% of the thermal-related errors caused by self-heating in these stages.