An investigation of the effects of pneumatic actuator design on slip control for heavy vehicles

Abstract

Progress in reducing actuator delays in pneumatic brake systems is opening the door for advanced anti-lock braking algorithms to be used on heavy goods vehicles. However, little has been published on slip controllers for air-braked heavy vehicles, or the effects of slow pneumatic actuation on their design and performance. This paper introduces a sliding mode slip controller for air-braked heavy vehicles. The effects of pneumatic actuator delays and flow rates on stopping performance and air (energy) consumption are presented through vehicle simulations. Finally, the simulations are validated with experiments using a hardware-in-the-loop rig. It is shown that for each wheel, pneumatic valves with delays smaller than 3 ms and orifice diameters around 8 mm provide the best performance.

Keywords:

• emergency braking
• pneumatic actuators
• one-dimensional flow
• sliding mode
• slip control
• actuator delay
• hardware-in-the-loop

Acknowledgements

The authors thank Richard Roebuck, Andrew Odhams, and the CUED technicians for helping with this work, as well as Leon Henderson for helping generate some of the figures. The authors also thank the members of the Cambridge Vehicle Dynamics Consortium (CVDC), and the Gates Cambridge Trust for their parts in funding this work. At the time of writing, the CVDC had the following members: Camcon, Denby Transport, Firestone Industrial Products, Goodyear Tyres, Haldex, SIMPACK, Tridec, Poclain Hydraulics, Mektronika Systems, MIRA, Tinsley Bridge, and Volvo Trucks.