Methodological proposal for Accelerated Screening Test design on stepper motors

• A methodology for Accelerated Screening Test (AST) is proposed.
• AST has the aim to precipitate early failures, to evaluate infant mortality.
• A mechatronic subsystem under accelerated operating conditions is described.
• To process the data the frequency domain analysis is used.
• This approach guarantees improvement in test design quality and result evaluation.

In the industrial world the need to guarantee a product out of the infant mortality zone has become almost imperative. Stress screening testing of mechatronic subsystems under nominal operating conditions may be time- and resource-consuming, making sometimes such procedures expensive and impractical. As a result, technologies for accelerated testing have been developed, to design high level stress tests (e.g. temperature, voltage, pressure, corrosive media, load, vibration, etc.) by means of thermal chambers and shakers which stimulate the device under test with external stresses. However, not all industries have access to such expensive equipment.In this research, a methodology for implementing Accelerated Screening Test by varying internal system variables is proposed and applied to a subsystem with a stepper motor. Some interesting preliminary experimental results are reported and commented. Accelerated Screening Test has the aim to precipitate early failures without inducing fatigue failure mechanisms. Actually this kind of procedure is difficult to optimize and requires some concern to model the infant mortality. This paper investigates also the use of Accelerated Screening Test for the characterization of a subsystem, to demonstrate the general validity of the proposed methodology.