High Fidelity Dog Clutch Model for Transmission Software Validation on a HiL System

Dog clutch is a type of mechanical clutch that are widely used in automotive transmissions for their ability to engage and disengage gear pairs rapidly between two rotating shafts or components without slippage, providing a direct mechanical connection. They offer positive no-slip engagement, higher efficiency, durability and can handle high torques. A real-time dog clutch model is necessary in software validation of transmission used in Electric Vehicles (EVs) on Hardware in Loop (HiL) Testing platform to ensures the data exchanged between electronic control unit (ECU) and the virtual environment occurs at the same rate as the actual system's operation, making the simulation as close to real-world performance as possible in a time-synchronized manner. However, modelling the behaviour of such dog clutch poses unique challenges due to their nonlinear dynamics, high-impact engagements, and as it needs precise control during shift operations. This paper describes a robust physics-based model of the dog clutch developed in MATLAB/Simulink suitable for testing the behaviour of transmission ECU on HiL testbench. Dog Clutch engagement process comprises of four primary states. Each state exhibit distinct dynamic behaviour. Dog clutch is modelled in two parts - first part is to simulate the model of dog clutch engagement and disengagement and second part explains modelling of dog clutch integrated with the automatic transmission system. Finally, the model was validated using data collected from the testbed measurements. Furthermore, the simulated results for engagement, disengagement and the transitions among the intermittent states of dog clutch were validated by comparing with actual measurement from testbeds. Such modelling methodology of dog clutch can be used on HiL which plays an important role in verification & validation (V & V) in development phase of EVs.