Steinbeis experts help ARADEX with the implementation of a functional safety standard
ARADEX is a specialist producer of efficient power transmission systems and has been working with the Steinbeis Transfer Center for System Design on a joint project looking at efficient and safe electric vehicles. The aim of both project partners was to integrate the many different process requirements into business and development systems. These are dictated by the particular focus of each sector of industry, from ships to cars (ISO standard 26262), commercial vehicles, buses, machines, and apparatus manufacturing (IEC61508).
ARADEX was founded in 1989 and has been working in the field of inverters for electric drives since 1992. In 2004 it also turned to mobile applications and in 2009 the focus shifted to traction drives. The firm is a supplier of drive chain systems used in ships but also has a focus on commercial and multipurpose vehicles. Its systems deliver between 50 kW and over 1000 kW per motor and its portfolio ranges from inverters to engines themselves, but also transmission systems and even mechanical couplings in vehicles. Overall, electric systems offer a variety of benefits: minimum particulates, the significant potential to reduce greenhouse gases, and a major reduction in engine noise. They can also be quicker when it comes to achieving financial savings than something like a car engine. One challenge that is common to all areas is achieving sufficiently high levels of efficiency – at every stage, from the battery terminals to the wheel on the road. This was especially challenging with the different loads encountered on this project. The systems have to operate for many hours at a time, albeit with low levels of partial load. To address this, ARADEX had developed a variety of drive solutions capable of delivering excellent performance, especially with low partial loads. Not only do they significantly reduce everyday electric power requirements, they also extend range – without the need for larger batteries. Sometimes they deliver such large improvements that batteries do not even need daily recharging after use. This, in turn, means that less money has to be invested in setting up the required battery charging infrastructure. The firm is currently fitting a series of 12 meter/18 ton buses that have to be capable of driving along urban bus routes for 14 hours on one battery charge. These vehicles have already been working reliably in everyday use for years.
One aspect that is not (yet) a key priority, but will be important from a strategic standpoint in the future, is when to shift to electric drives that don’t require magnets. ARADEX has been looking closely into traction motors for years, with a focus on asynchronous motors without rare earth magnets. They have been especially successful in the important partial load range, achieving respectable efficiency ratios for the otherwise extremely popular engines with permanent magnets. The top priority: the safety of products and efficiency. As a result, it was important for the company to integrate the right qualitative requirements into their business and development processes, particularly from other sectors of industry. To do this, the company approached the Steinbeis Transfer Center for System Design.
The System Design STC has been advising ARADEX on the implementation of ISO standard 26262, which governs functional safety in road vehicles. In the longer term, the clients of the systems supplier will need this standard for their components in the drive chains of electric vehicles. One important aspect of the project was for both parties to agree how best to achieve this goal. It would be necessary to combine as many elements of the quality management system as are already in use at ARADEX with the process requirements of ISO standard 26262. As the company’s activities are not limited to the automotive sector, it was also important to integrate the high standards of ISO 26262 in places where they would make sense in other industrial sectors. What this meant was that certain quality procedures could be used in all instances, while others would only have to be used as required, for a specific sector of industry.
The efficiency of an asynchronous machine co-developed by ARADEX. The machine is used as a direct drive on cardan shafts in commercial vehicles. The important parts of the graph are the green and red lines in the areas with partial loads of between 20 and 50 percent. These reflect the actual conditions encountered on country roads and in urban traffic.
The overall aim of the standard is to avoid systematic errors and minimize random errors in order to reduce residual risk. Standards play a normative role in requirements by raising sensitivity within companies to the importance of safety systems. One of the first steps for the Steinbeis experts involved in the project was to organize workshops in order to present the objectives and implementation options for such a standard on functional safety in road vehicles. This made it possible to discuss different ways to implement ISO 26262, looking not just at organizational factors but also processes. The big challenge with this project would be to fulfill different process requirements at the same time, for each specific sector of industry – for example there are ISO quality requirements, safety and quality requirements used in mechanical engineering and equipment construction, and quality standards for special vehicles. Also, processes with a bearing on quality and safety almost always involve extra work, so it would be important to integrate them efficiently into company processes. For a specialist like ARADEX, which works across several sectors, this could be a major headache, but at the same time it is a major opportunity to leverage synergies.
As the project progressed, workshops were held to analyze the different systems and processes used in management. The outcome was a gap analysis that made it possible for ARADEX to quickly put the right structures in place. The first gaps were filled by providing staff training for management through the Steinbeis Transfer Center for System Design. More evaluations will be conducted later on in the project and at that stage different approaches will be discussed and agreed again. The role of the Steinbeis Enterprise is to take on aspects relating to the analysis and optimization of technical systems in order to help companies with the implementation and optimization of their development processes and methods. Factors such as “safety” or “functional safety” have an important influence on the development, production, and maintenance of equipment, machinery, and systems. The foundations for a safe system are laid when going through the first ideas for a product, and this continues when a product enters the design stages and testing. Normative rules are laid down, capturing the state of technology a company should adopt as its minimum standard. The Steinbeis Transfer Center for System Design provides advice and expert assessments on different ways to adhere to safety-relevant requirements.
Contact
Professor Dr. Walter Commerell is the director of the Steinbeis Transfer Center for System Design at Ulm University of Applied Sciences. The services offered by the Steinbeis Enterprise include the analysis and optimization of complex systems. The emphasis of work carried out lies in energy storage, automotive systems, and energy systems. As well as providing advice on processes and a variety of topics relating to processes and development in the field of functional safety (ISO standard 26262), the center also offers model-based design and testing methods. Other services offered by the center include applied research and development, expert reports, and seminars.
Professor Dr. Walter Commerell
Steinbeis Transfer Center System Design (Deggingen)