Digital twin of a safe system

Sammanfattning

At Epiroc’s drill rigs a safe system is installed to make sure the vehicle is driven in a safe manner. In the development both machine tests and hardware-in-the-loop (HIL) tests have been performed but when changes are made the firmware in the safe modules has to be updated. To speed up the process a digital twin would be beneficial. This enables testing of parameters and formulation of criteria detecting faults. The purpose of the work is to develop a digital twin for steering and braking safe functions and evaluate the performance using data from machines as well as data from a HIL-rig. Also, the impact of the hydraulic model used in the HIL-rig is investigated. When the model is built two test cases are used to investigate how well the model replicates the behaviour of the real system and how sensitive it is to what input data is used. The biggest difference in the data is the sampling time, machine logs have 80 ms interval while logs from the rig are logged every 5 ms. It is discovered that some of the fault detection functions work very well no matter what data is used while others must have the better resolution to be trusted. The complexity of the hydraulic model used impacts the pressures but seem to have little effect on which fault codes are activated. With this the main purpose is partly achieved and further investigation is needed before the model can be used for all fault codes.