Modelling, parametrisation and validation of a truck steering-system to predict the steering-wheel torque

The prediction of the steering-wheel torque in a steering-system is a challenging subject. The steering-system of a truck consists of many components, including a hydraulic power-steering system. A model is developed that includes the most important components. A Wheatstone bridge is used to model the hydraulic valve system. A flexible supply hose and compressible fluid in the cylinder chamber are taken into account. The model is parametrised using test-bench measurements. The model is validated by means of additional measurements on the same test-bench. The model is verified for quasi-static conditions and up till a frequency higher than a driver will ever use. The predictions of the steering-wheel torque, steering-wheel angle and pressures in the system are accurate for high torque amplitude inputs. For small inputs the model is still able to predict the steering-wheel torque with an error smaller than 10%.