Nexteer Automotive – A Leader in Intuitive Motion Control

Torque Overlay Solutions

Nexteer Automotive’s torque overlay solutions analyze input from multiple vehicle systems to determine the appropriate response to various conditions. The result is a pleasant driving experience with reduced driver workload, increasing customer satisfaction while reducing warranty costs.

Nexteer Automotive’s torque overlay is applied to a steering system through software programming and enhancements to existing hardware.

What is Torque Overlay?

Torque Overlay can add or subtract torque to the steering system, independent of driver input, in either direction.

What are Torque Overlay Features?

Torque Overlay features include the following:

  • Return
  • Damping
  • Lead/Pull Compensation
  • Wind Gust Mitigation
  • Lane Keeping Assistance
  • Park Assist
  • Vehicle Stability Control
  • Yaw Stability Control

In order to apply these commands, these advanced algorithms must be developed using inputs from various sensor subsystems within the steering system and for certain features from alternate sensors and subsystems. These features must be integrated into the EPS or HPS control system to provide a seamless control to the driver maximizing performance and driver comfort. In the figure below, the driver provides the input and receives feedback from the road and additional feedback from the torque overlay algorithms command to the steering unit.

The Torque Overlay Features applied to EPS and HPS must be highly engineered to determine:

  • Determination of appropriate response
  • Integration with base steering functions to provide transparency to the driver

Determination Of Response:

While it may seem simple to take a command from external sensors and or subsystems and apply a command to the EPS or HPS system, it takes the experience of Nexteer with critical systems to:

  • Define requirement of the incoming Torque Overlay signal
  • Apply appropriate Firewall Limits
  • Firewall limits will constrain the amount of command to the steering motor
  • Perform various analysis and tests to insure the system is compliant to the latest ISO 26262 requirement