Speed Vectoring Algorithms for Drivelines with Multiple Modular E-Axles

This paper discusses speed vectoring algorithms for drivelines containing multiple modular e-axles. The algorithm's purpose is to estimate the wheel and axle speeds of each e-axle in the driveline. The calculation is based on the vehicle's steering input, steering mode and driveline geometry. The algorithm is configurable for 4 × 4, 6 × 6 and 8 × 8 vehicle drivelines while also being compatible with conventional mechanical steering and electronically controlled systems. The steering modes built into the speed vectoring algorithm include front single-axle steering (FSAS), front twin-axle steering (FTAS), rear twin-axle steering (RTAS), crab steering (CBS), all-wheel-steering (AWS) and pivot steering (PTS). Each mode requires a separate steering geometry matrix. The paper highlights the main e-axle hardware considerations to be considered for speed vectoring before describing some of the steering modes implemented in the algorithm. The implications of varying wheel speeds on powertrain components are discussed and vehicle simulation for a variable radius turn is presented.