LABCAR-MODEL Transmission

When developing transmission ECUs, the following rule applies: the earlier in the development process that it is possible to test them effectively, the more efficient that process is – and the better the subsequent performance and reliability of the transmission.

Testing transmission ECUs

The LABCAR-MODEL portfolio comprises simulation models of the combustion engine, transmission, lithium-ion battery for the powertrain, electric motor, fuel cell, vehicle dynamics and vehicle, driver, and surroundings

However, using real transmissions for testing is not always possible or a good option, as often no test components are available and critical operating states are difficult to realize. For this reason, hardware-in-the-loop (HiL) systems and the corresponding models are used for testing. They permit safe, reproducible tests – even within limit ranges.

ETAS’s LABCAR test system offers a complete solution for all types of transmission tests – from component HiL on the developer’s desk to complete vehicle simulation in the network HiL. Thanks to its PC-based simulation target, LABCAR-RTPC, and its open architecture, LABCAR can be tailored and adapted to specific customer needs and changing requirements.

ETAS’s LABCAR-MODEL-AT (automatic transmission), LABCAR-MODEL-DCT (dual clutch transmission), and LABCAR-MODEL-CVT (continuously variable transmission) models simulate the behavior of transmissions. They allow users to comprehensively test transmission ECUs in the HiL system, even in critical operating states, and to carry out an initial precalibration of control functions. Above all, they ideally combine all requirements for simulation accuracy and real-time capability.

Typical use cases

  • Integration and functional testing of TCU (transmission control unit) software
  • Testing of typical ECU functions for the offline calibration and analysis of control algorithms for mechanics and hydraulics
  • Simulation of error conditions in a transmission for testing TCU diagnostics and limp-home function

Benefits of ETAS simulation models

Because the mechanical and hydraulic parts of the transmission are built from individual components in a modular design, it is easy to modify the model. In this way, developers can adapt their simulation flexibly to their own customized system architecture and the required model granularity.

Simulation models for testing TCUs need to simulate mechanical and hydraulic components. To simulate these so-called stiff systems, advanced numerical methods have to be used. Otherwise, when simulating in real time with maximum step sizes, oscillations arise in the simulation that are not present in reality. This can lead to incorrect test results.

Simulation models of AT, CVT, and DCT drivetrains for HiL tests

ETAS offers the following simulation models of AT, CVT, and DCT drivetrains:

  • LABCAR-MODEL-AT (simulation model of an automatic transmission (AT) drivetrain for HiL tests)
  • LABCAR-MODEL-CVT (simulation model of a continuously variable transmission (CVT) drivetrain for HiL tests)
  • LABCAR-MODEL-DCT (simulation model of a dual clutch transmission (DCT) drivetrain for HiL tests)


  • The models simulate all relevant mechanical and hydraulic components of a transmission
  • Very good simulation stability thanks to optimized numerical solvers
  • Easy modification of models, as the mechanical and hydraulic parts of the transmission are built from individual components in a modular design
  • Interfaces to LABCAR-MODEL-VVTB (simulation model of a virtual vehicle test bench for HiL tests) for using the model as part of a complete vehicle simulation
  • Seamless recycling of simulations in MiL, SiL, and HiL environments

Can be combined with all ETAS simulation models in the LABCAR-MODEL product family.