With the soaring development of pervasive computing environment

an increasing number of folks need to conduct tasks that used to be completed with the help of business agents in the past. This makes traditional interactive design techniques of business orientation difficult to meet the common users’ usability requirements for the environment. In this paper

we present a design technique for user interfaces based on the perceptual control theory. It enables to provide usable user interfaces

which are easy to learn

to understand and to manipulate for the common users. For the purpose of satisfying the usability requirements in the pervasive computing environment

this design technique introduces a technique of task analysis in accordance with perceptual control theory and a process of participatory design

to help the users making interaction at the task level instead of at the business level.