Vehicle Suspension Control part 1 Dr. Khisbullah Hudha

Classification of Vehicle Suspension System Passive: Parallel arrangement between passive damper and spring Semi-active: Parallel arrangement between adjustable damper and spring Slow Active: Parallel arrangement between passive damper, spring and force generation device Active: Parallel arrangement between spring and force generation device Fully Active: Force generation device only

Passive damper: unable to generate force, able to dissipate energy at a constant rate Semi-active damper: unable to generate force, able to dissipate energy at a variable rate - Variable orifice - Variable fluid viscosity Force generation device: able to generate external force to oppose unwanted motion of vehicle - Hydraulic actuator - Pneumatic system

Passive damper

Semi-Active Damper

Force generation devices Hydraulic: - expensive - suitable for precision control Pneumatic: - cheaper - more difficult to control due to springing effect of air

Basic Structure of Suspension Control

Outer loop control / vehicle control: used to compute the ideal target force to cancel out unwanted vibratory motions of a vehicle Inner loop control / actuator control: used to control the actuator in such a way that the actuator will produce the actual force as close as possible with the target force Vehicle states: position and speed of sprung and un-sprung masses

Outer Loop Controller / Vehicle Controller Some well-known approaches for outer loop controller: - skyhook - groundhook - hybrid skyhook groundhook

Csky Cground Csky Cground