Hybrid Simulation: ImHIL Tire

The Iterative mechanical Hardware-in-the-Loop (mHIL) Tire solution allows the combination of physical tires and a virtual vehicle for investigating the interaction between tires and vehicles at the vehicle level. This technique improves over pure computer vehicle simulation by replacing simplified tire models with real physical tires.

• To avoid the need for a specialized four-tire test rig, the hybrid simulation is performed sequentially instead of simultaneously, which requires an iterative technique to achieve the same results as a simultaneous four-tire, real-time hybrid simulation.
• Each corner is simulated independently and the results combined with the vehicle dynamic simulation (which could be real time or not) to create a complete hybrid simulation.
• The model calculates the wheel orientation angles (slip and toe angle), spindle torque and normal tire force. These are incorporated as signals into a drive file, which is then executed once per corner. The tire forces and moments are acquired and used as inputs for the vehicle simulation.
• Only a handful of iterations are typically required to achieve convergence, making this method quick and more efficient than creating a tire model to use with a vehicle simulation.
• A tire test rig with sufficient performance to meet the maneuver requirements is necessary. No special real-time platform or high-speed communication network is required to run the vehicle simulation.

The advantages of using the MTS mHIL Hybrid Simulation technique in the vehicle development process include:

• Analysis / CAE 
  • Real physical parts can be substituted for difficult-to-model components when performing virtual simulations
  • Enhanced characterization to support better model development
• Objective and repeatable results 
  • Very repeatable tool to support a more efficient track program
• Generate accurate test results faster and earlier in the development process: 
  • Don’t need to wait for road loads or full vehicle prototypes
  • Evaluation and validation at both the sub-system and vehicle level
  • Rapid testing of platform and geographic variations
  • Fast validation cycles
• Safer and less costly alternative to the track: 
  • Expected and unexpected fault conditions easily and safely evaluated in a laboratory environment
  • Reduce the number of vehicle prototypes required
  • Reduce vehicle instrumentation and data acquisition costs
  • Reduce track dependency associated costs