Advances in company’s software enables tuning of vehicle steering feel to suit local driver expectations
PARIS – Specialist electric power steering supplier Nexteer Automotive is enabling global vehicle manufacturers to create custom steering calibrations to suit different local market requirements. The company’s ride and handling experts and in-house software engineers have provided the first customers with electric power steering (EPS) systems tuned to provide certain markets with different levels of feel, feedback and refinement.
“The perceived quality of a vehicle’s steering by drivers in key markets is a critical part of any global vehicle platform’s commercial success,” said Laurent Bresson, Nexteer’s President and COO. “Drivers in some markets, such as the UK, expect higher levels of road-feedback than drivers in other markets. Nexteer’s high precision mechanical design and the strength of our in-house software expertise is making it viable for manufacturers to commission custom steering set-ups for some markets.”
A vehicle’s steering feel is influenced by a range of parameters, including suspension geometry, tire and bushing stiffness, spring rates, mass distribution, but the quality of the EPS system is critical. The basis for good steering feel is a mechanical system with low levels of inertia and friction, combined with a high-resolution steering sensor and a smooth assist motor. With intelligent control algorithms and ride and handling engineers adept in tuning the software, it is then possible to create custom set-ups that meet both global brand characteristics and local market requirements.
“Designing the complete system and developing the software entirely in-house gives Nexteer precise control of all the variables, allowing us to calibrate the steering more quickly,” Bertram Moeller, EPS Technology Manager., Nexteer Automotive. “Using our own specialist software, a custom set-up for a specific local market can be very fast. Much of the driver’s perception of the vehicle’s behaviour and the road’s surface is communicated through the steering system, so the effect on the finished vehicle can be significant, helping to ensure a successful model launch and higher levels of customer satisfaction.”
Nexteer’s developed the algorithms in its control software in-house to provide the necessary range of control and operational robustness for all its EPS systems, regardless of whether the application is a large off-road SUV or small city car. While the algorithms define the system’s functionality, the calibration determines the actual timings and levels of the key system outputs, such as damping levels and the filtration of unwanted vibration.
“Our development process begins by creating the necessary mechanical properties in the system to ensure that no unwanted vibrations can interfere with the system’s response,” said Moeller. “The mechanical tuning is defined early in the programme, when interfaces, bearings and the mechanical links that determine the system’s friction levels are all specified. The subjective tuning of the vehicle’s steering feel then takes place behind the wheel with a laptop.”
A pioneer in steering technologies, Nexteer was the first company to introduce EPS for volume applications in 1999.
Nexteer Automotive is a multi-billion dollar global steering and driveline business solely dedicated to electric and hydraulic steering systems, steering columns and driveline products for original equipment manufacturers. Its 10,000 employees serve more than 60 customers in every major region of the world. The company has 20 manufacturing plants, six engineering centers and 15 customer service centers strategically located in North and South America, Europe and Asia. Nexteer Automotive’s customers include GM, Fiat, Ford, Toyota, Chrysler and PSA Peugeot Citroen, as well as automakers in India, China and South America. www.nexteer.com
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