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

A Mechanical Hardware in the Loop (mHIL) system provides a laboratory method of evaluating the effects of physical chassis elements (in this case the damper sub-system) on vehicle-level attributes (in this case vehicle handling).

• An MTS damper test system or systems with customer dampers installed on it represents the mechanical hardware, which is put in place of modeled damper element(s) within a vehicle simulation model
• The damper sub-system consists of the damper itself including necessary infrastructure and fixturing to simulate a realistic vehicle configuration. 
• The damper system can be passive or actively controlled by an ECU. 
• The damper system and the ECU are driven in the modeled vehicle on a modeled track as if they were on a real vehicle and track.

The damper test system applies loads and/or displacements to the mechanical damper hardware based on inputs from the vehicle simulation model, measures the hardware response, and then sends these responses back to the vehicle simulation mode. The mechanical hardware is included “in the loop” with the simulated vehicle.

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

Hybrid System Response Convergence (HSRC) is an iterative technique developed by MTS that makes hybrid simulation practical for more complex, high-bandwidth applications where the use of a sequential, offline iterative technique is necessary.

Durability Test Load Generation

This application of the HSRC technique combines a simulator-mounted test vehicle with virtual tires and scanned digital road surfaces to create a digital, three-dimensional proving ground over which the test vehicles can be “driven” to simulate braking and maneuvering events.

• RPC iteration processes coordinate the dynamics between the physical and virtual systems to find a force and motion solution that satisfies both simultaneously.
• Sequential iterations yield test drive files that have proven to correlate well with actual road load measurements
• Eliminates need for a prototype, a proving ground or a comprehensive digital model 
• Enable the generation of accurate durability test road loads without an instrumented prototype, a proving ground or a comprehensive digital model 
• Iterative process does not require the system components to be operated in real time; works with standard test systems and existing vehicle models

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