Testing on the SATRA Pedatron

A brief overview of the workings and applications of one of SATRA’s key testing machines.

by Connor Mehew

The SATRA STM 528 Pedatron is a machine that has been engineered to accurately simulate a walking gait. This article explains how the machine works and how it can help you to test footwear durability on an accelerated timescale.

Before the Pedatron was designed, there were two main options available to test the durability of a sole unit. One possibility was to conduct a standard laboratory test on the soling compound. This provided a good idea of the material’s performance, but did not account for other aspects of a sole, such as the tread pattern. The other alternative would have been to carry out extensive human wear trials. These gave realistic wear results, but took a long time to perform and were often prohibitively expensive. 

The Pedatron simulates an accurate walking gait over an appropriate wear surface, so it provides an accelerated wear simulation under real-world conditions. Pedatron testing combines the realism of a human wear trial with the speed and cost effectiveness of laboratory materials testing.

When it was originally designed, the Pedatron was intended to be used as a sole abrasion device.

Realistic wear

It is becoming increasingly popular to use the Pedatron to realistically age internal components of footwear. Our research has shown that it can be quite challenging to tell the difference between a footbed aged using the Pedatron and one aged in real-wear scenarios. Components aged on the Pedatron could then be tested via other laboratory tests to determine how their performance changes with prolonged wear. An example of this would be the testing of electronics within insocks and sole units, as the Pedatron can repeatably expose the component to the forces involved in walking, and then the component can be inspected to determine if the electronics are still fully functional.

The standard Pedatron test programme alternates between straight steps and turning steps, during which the flooring surface rotates while the sole forepart is making contact. The combined action of walking and turning produces results that correlate closely to those found in human wear trials, while also being controlled and repeatable.

A flexible and compressive prosthetic foot form is used on the machine to fill the interior of the footwear. When fitted with hose (sock), this prosthetic produces realistic friction (allowing for natural movement inside the footwear) as the Pedatron is designed to replicate the forces present in real wear. It uses a mass, equivalent to an average person, to create friction between the surface and the footwear, complete with locomotory and torsional forces. A standard test, performed to SATRA TM362:2024 – ‘Abrasion resistance of soles – biomechanical method’, consists of 50,000 steps – taking just over 24 hours.

The mass loss in the sole unit over the specified number of steps can be measured and compared with a similar sole (usually the other half of the pair) that has been manually scoured into a fully worn condition. The lifetime of the sole can therefore be determined in terms of cycles. SATRA then uses the simple formula of 1,000 cycles to a mile to provide a predicted lifetime of the sole in walked miles. The sole can also be visually inspected for things such as wear of tread elements, the condition of any inserts and any unusual wear or breakages, such as sole bond failure.

SATRA TM362 defines many of the parameters to which the Pedatron is calibrated, allowing for a repeatable test that provides results that correlate well with wear trials. The Pedatron is a versatile machine, as most of these parameters (such as mass and surface angle) can be adjusted to customise the procedure to suit individual needs.

Publishing Data

This article was originally published on page 14 of the November 2025 issue of SATRA Bulletin.

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