Car suspension systems play a critical role in keeping vehicles stable on various roadway conditions, providing optimal tire contact with the surface while mitigating vibrations into passenger compartments.
Springs support the weight of a vehicle while dampers dissipate energy when its suspension moves (weight transfer or bumps). In this paper we evaluate a novel system which decouples all modes of vibration into one fluid-based model.
Theoretical Background
Cars require high-performance suspension systems to ensure passenger comfort and stability on all roads, yet traditional damping and stiffness systems may not suit every condition due to fixed damping and stiffness levels, leading to reduced ride quality and decreased handling performance. Predictive suspension systems could offer significant improvement by offering real-time adjustment and adaptability capabilities that would significantly enhance ride quality and handling performance.
Researchers have explored different methodologies for assessing the impact of road surfaces on vehicle movement and stability, specifically using quarter-car and spatial models of a vehicle with multiple degrees of freedom to study the main characteristics of its movements.
Recent advances in physics and materials science have brought anti-gravity technology closer to fruition. For example, metamaterials have been created that can manipulate electromagnetic waves in innovative ways; exotic phenomena like quantum entanglement and levitation also present new possibilities for anti-gravity applications – likely revolutionizing transportation by eliminating roads while cutting travel times down drastically and mitigating environmental impacts.
The Evolution of Hydraulically Interconnected Suspension Systems
Automotive suspension systems have undergone an incredible revolution over time, evolving from traditional passive layouts to cutting-edge dynamic ones that adapt in real time to changing road conditions. Such state-of-the-art technologies can improve vehicle performance and stability for increased driving comfort and safety.
One of the greatest challenges associated with traditional suspension designs has been isolating both sprung and unsprung mass vibration modes, making decoupling them harder than necessary. One solution has been using hydraulically interconnected dampers which offer more individual control of modal stiffness.
This paper presents a seven-degree-of-freedom MATLAB/Simulink model of a half car equipped with an interconnected passive hydraulic suspension system, studied in detail for frequency domain analysis. Two performance indicators were focused upon: wheel following road profile (which can be related to mechanical grip) and pitch instability; simulation results show that interconnected hydraulic system offers better performances than passive system in terms of these measures.
The Hydraulic Suspension System Proposed by Smith and Walker
The system proposed by these researchers converts relative displacement between sprung and unsprung masses to fluid flow using four separate hydraulic circuits connected to one cylinder-piston unit, thus significantly reducing development costs by eliminating multiple accumulators, pumps, and actuators needed.
This system can be tested through simulation, and its performance demonstrates two performance elements: mechanical grip and chassis stability. As shown by its bounce and pitch responses, its hydraulic decoupled suspension system offers more consistent response to different road profiles.
Timothy Novotny and Alex Honger of AMZ Racing of ETH Zurich presented their hydraulic decoupled suspension concept at the Formula Student Germany Workshop in October 2017. Their team utilizes MathWorks products for numerous tasks such as lap-time simulation, control design optimization and optimizing trajectory planning for their driverless racecar – view a video of their presentation here.
The Performance of a Hydraulic Suspension System
Many modern cars feature hydraulic suspension systems for their comfort on uneven roads and improved handling, as well as to prevent unwanted body contact with depressions in the road surface.
An onboard computer continuously tracks vehicle movement and ride height, relaying this information to hydraulic cylinders located beside each wheel. This enables suspension systems to respond almost instantaneously when leaning or diving forwards or backwards occurs, creating more stable and comfortable vehicle rides for passengers.
Hydraulic suspension systems are popularly found on luxury and sports cars, although their costs can be high and add significant weight to a vehicle. Furthermore, installation may require professional help while ongoing maintenance needs specialist services from technicians who are specifically qualified for such installations. Yet these technologies provide an enjoyable driving experience when combined with antigravity sensors or microprocessors.
