Durai, R., Thirupathi, A., Shetty, M., and Mampilly, D., "Design of Feedback Rock Crawl Controller with Engine Torque Optimization for Off-road Vehicle," SAE Technical Paper 2015-01-2839, 2015, doi:10.4271/2015-01-2839.
In this paper Longitudinal Force Slip (LFS) controller will be designed for controlling the traction force in each wheel when Rock Crawl Scenario prevails for commercial vehicles working in Off-Road condition. During Rock Crawling the wheels can have more longitudinal slip than lateral slip. Slip is caused by relative movement of tires with the rock.PID controller (Longitudinal Force Controller) will be designed in order to stabilize the traction force on individual wheels. Individual Lateral and Longitudinal force will be calculated for each wheel from Tire modeling. Optimal longitudinal force will be determined based on fuzzy model with the help of determined Mue.The designed LFS controller which controls the individual traction force by applying active braking. Active braking on individual wheel will be realized with the hydraulic system associated with Vehicle Stability Control ECU (VSC - ECU). Optimal engine torque will be calculated based on driver pedal request. With the combination of optimal engine torque manipulation and Active braking, longitudinal slip can be controlled. The Electronic Differential Locking by LFS will additionally enhance the vehicle to come out of slip observed in wheels and hence the designed LFS Controller will be used to control the optimal traction force on wheels individually along with optimal engine torque.