Challenges and Opportunities of Integrating a Stowable Steering Column with a Steer-by-wire Handwheel Actuator

As the automotive industry continues its rapid evolution to fully autonomous driving, automakers and suppliers are working to develop safe and advanced autonomous features while maintaining costs that are acceptable to the consumer. Efficiently integrating multiple sub-systems to support this transformation provides opportunities for optimizing performance and cost. A stowable steering column assembly integrated with a steer-by-wire handwheel actuator is one example of such an integration opportunity. While a traditional power-actuated steering column enhances driver comfort by providing relatively minor adjustments to the steering wheel location, a stowable steering column transforms a vehicle cockpit during an autonomous steering mode by significantly moving the steering wheel out of a driver’s way. This transformation is further enhanced when integrated with a steer-by-wire handwheel actuator, which enables technology like Quiet Wheel™ Steering, where the steering wheel does not rotate during vehicle lateral motion. While there are significant benefits of implementing a stowable steering column with a steer-by-wire system, it comes with many challenges. These challenges include creating a mechanical design to provide the large movements required for stowing the steering wheel, maintaining typical steering column performance constraints such as natural frequency, stiffness, and acoustic performance, achieving the desired stow path and speeds, and fitting the steering column assembly hardware within a vehicle’s packaging space environment. Other electrical design challenges include thermal management, system packaging, fail-operational performance, pinch detection, software function partitioning, diagnostics, software throughput, and safety. These challenges provide additional opportunities for hardware cost reduction, optimized validation effort, and implementation of advanced software features. Strategic planning between an OEM and a supplier helps mitigate and address these challenges.