Jonathan Newell finds out how robots are being used for quality and accelerated life testing of commercial vehicle upholstery.
Spending most of your working hours sat behind the wheel of a commercial vehicle brings a whole new level of importance to the phrase “Are you sitting comfortably…”. This importance is reflected in the technology applied to the testing of seats to ensure they can withstand the rigours of constant usage over the expected life-span of the vehicle whilst still retaining the level of comfort expected by the driver.
This isn’t about pandering to personal expectations of a luxurious workplace, it’s about ensuring that professional drivers can expect reasonable working conditions and that their performance and safety isn’t compromised by distracting levels of discomfort or the inability to customise the ergonomics of their workplace to fit productivity needs.
Robotic accelerated life testing
On a recent visit to the Millbrook Leyland Technical Centre, Managing Director Dr Paul Wilkinson showed me the upholstery testing laboratory with its robotic accelerated life testing equipment. Steeped in decades of commercial vehicle testing heritage, the Leyland Technical Centre continues to be the centre of expertise in the UK for bus, van and lorry testing and verification.
The organisation is constantly investing in the latest technology and deploying advanced test processes, the upholstery testing facility being one such example.
“The robot is able to accurately replicate the cycle of movements and actions of the driver”, Wilkinson explains. These actions include the end conditions of getting into and alighting from the cab, both of which include twist and lateral slide components across the surface of the seat. By replicating these actions as well as the repetitive bounces of moving across different road surfaces, a profile can be achieved which can simulate the usage cycle of the seat that can be repeated to accelerate the whole life of the upholstery.
The use of robots in upholstery testing has a number of advantages relating to flexibility, repeatability, the ability to programme test profiles into the equipment and the ability to use sensors to measure drifts in parameters during the test to indicate changes in upholstery condition.
German automation specialist, Battenberg Robotic, provides a range of robotic seat testing equipment that perform a number of functions, including:
* Firmness testing
The test uses pre-determined points on the seat upholstery and an indenter is applied to each point with a constant force, measuring displacement over a fixed period of time to gain a visualisation of the firmness profile over the surface of the seat or backrest.
* Haptic testing
Haptic testing can be used to determine the force profile required to activate a function. This could be headrest positioning, recline lever activation or seat squab height adjustment controls. A carefully designed haptic test can build a force / distance profile to determine the range of forces and distances needed to trigger the function under test.
* Control testing
For production quality control, robots can be used to test the variety of seat controls in one pass through the test cell. Calibration points on the seat itself are positionally matched to markers on the seat holding fixture to provide the robot with a datum, from which it can then find all the controls and check their operation.
* Ingress / egress testing
Similar to the accelerated life testing robot at Leyland, ingress / egress testing robots are designed to test the resilience of upholstery fabrics to the repeated action of entering and exiting the vehicle.