Particularly intensive – that’s how Aard Tuenter of VB-Airsuspension and Maarten Meulen of Sioux describe their collaboration to develop an advanced air suspension controller for light commercial vehicles. The high standards for technical and functional safety, in the automotive sector in particular, drive the complexity of the process and the technology. ‘The bar is set high and that frequently generates considerable pressures within the project’, says Tuenter. ‘But we are always there for each other and you can see that in the result.’
VB-Airsuspension was founded in 1993. There was a growing demand in the market for commercial vehicles for greater comfort, better handling and improved safety. Air suspension can make a significant contribution to that. Whereas this technology was already being deployed in the heavier segment, the drivers of light commercial vehicles still had to deal with ‘dumb’ mechanical systems. The founders of VB-Airsuspension saw a gap in the market and rushed to fill it.
VB-Airsuspension is the European market leader in its niche. The firm serves both OEMs and the aftermarket. Its products are used worldwide in light vans and minibuses, but also in special vehicles such as ambulances, camper vans and Wheelchair Accessible Vehicles.
‘We derive our raison d’être from our collaboration with customers and from our technological lead’, says Tuenter, R&D manager at VB-Airsuspension. ‘The automotive market is always in motion. New models are constantly being introduced and the degree of innovation is high, especially in the market for commercial vehicles. That is partly due to the high expectations of users and increasingly stringent regulations. It means we have to innovate constantly. We recently took a big stride in that regard with the development of a new Electronic Control Unit (ECU) for complete air suspension systems. We decided to work with Sioux on that, due to their expertise in integrated software and electronics solutions for the car industry.’
The air suspension controller may be regarded as the heart of VB-Airsuspension’s technology. It monitors and controls the various components of the complete air suspension system, such as compressors, valve blocks and sensors. It is precisely in the interplay of these components that there are opportunities to improve the handling and stability of a vehicle and create new functionalities – for example, raising and lowering the access to the car and loading ramp.
Tuenter: ‘So it is a high-tech device that allows VB-Airsuspension to set itself apart. However, we have been building on our original product for 25 years. For this reason we began developing an advanced new ECU in 2016 and contracted Sioux to do the engineering for us. This project revolved around safety, and with good reason. In the automotive sector, critical technologies such as airbags and brake systems need to comply with the most stringent Safety Integration Level. The requirements for air suspension are only slightly lower: in the ASIL C category. That’s not surprising: if something goes wrong here, it can really go wrong. If the handling of a vehicle suddenly changes, that can result in accidents and potentially serious consequences for users and manufacturers alike.’
The required safety certificate has had a huge impact on the development of the suspension controller. It began with laying down the technical and functional safety requirements in detail in accordance with the ISO-26262 standards for developing software and electronics in the automotive sector.
Maarten Meulen, project manager automotive: ‘That means that for each step in the process, from concept and design through to testing and manufacturing, you make use of strict procedures and methodologies. These are primarily aimed at systematically identifying safety risks and ensuring that they are adequately addressed. So, for example, everything needs to be extensively recorded in documents and there is a strong focus on testing. Naturally, we are familiar with that within Sioux’s automotive department. The ECU for VB-Airsuspension is absolutely not a straightforward product. Safety is everything in the automotive sector and it has therefore had a substantial impact on this project. For example, the safety-critical part had to be executed with built-in redundancy. The dual-core microcontroller is configured in lock step, which means that all the instructions are executed and checked in parallel. In addition, with a view to the many components that need to work together within an air suspension system, all kinds of diagnostic mechanisms have been built in. This makes it possible to detect any software or hardware errors and make sure the system automatically reverts to a safe setting.’
Following a development process lasting three and a half years, a prototype of the new air suspension controller is ready. It will be tested and developed into a complete product next year. ‘During this project, there was considerable time pressure’, says Tuenter. ‘The demands were high, both in terms of quality as in speed. What’s more, Sioux works for a fixed fee. The consequence is an intensive partnership. We are always there for one another. I’ve never had the feeling of being part of a customer-supplier relationship in which everything has to be done exactly according to the rules. Our partnership is based on trust, transparency and working towards a common goal. That’s really great, and it has absolutely contributed to our success.’
