Road Access for Disabled Americans

Links to more Information about Active Suspension

• Full-active suspension, NJ Auto Site . (Short definition)
  "...replaces normal springs and shock absorbers with a double acting hydraulic actuator at each wheel, driven by a variable-rate hydraulic pump and controlled by an electronic control unit (computer)."

• "Active Suspension ala Infiniti", Bob Freudenberger . (Detailed Explanation for Laypersons)
  "The basic idea is to use a computer, sensors, a pump, and hydraulic cylinders at each corner to get the car to do things never before possible, such as leaning into a curve like a motorcycle, compensating for the dive of braking and the squat of acceleration, and raising and lowering its wheels individually to make pavement imperfections seem to disappear."

• Active Suspension . (Summary)
  "Active Suspension systems ... can store, dissipate and introduce energy to the system."

• Active Suspension, Queens U, Canada
  "Improvements to ride quality and handling performance can be achieved by employing 'active' suspensions. Active suspensions use servomechanisms to support the dynamic loads. Arbitrary forces can be applied between the wheels and vehicle body through the use of actuators. By employing a power source, these actuators are used continuously to control vehicle movement. By providing flexible control, active suspensions reduce the trade-off between handling performance and ride quality that is present with traditional passive suspensions".

• Robust Control of Active Suspensions, University of Michigan

• University of California, Berkeley - ME
  • Faculty
  • Vehicle Dynamics and Control Lab (VDL)

• Semi-Active Suspension System, Simulation Model, Nagoya University, Japan
  "In order to improve the ride comfort and drivability of cars, the active suspension system has been developed. The suspension should be soft for the ride comfort, while it should be stiff for the drivability. The active suspension systems can overcome these trade-off, but the systems are more costly, more complex and less reliable than the passive ones. The semi-active suspension system proposed by Karnopp [9] was based on the passive system in the structure and aimed to compete with active systems in achieving the reduction of the body acceleration. The semi-active system changes only the damping coefficient by controlling the electromagnetic valve inside the absorber. All the variables, the deflection, the velocity, the acceleration, and the jerk of the body must be reduced to achieve better ride comfort and drivability. Especially the jerk, the derivative of the acceleration is important to improve the ride comfort. The conventional control theory based on state variables cannot handle with all of these variables in the design procedure. For example, the jerk cannot be derived in the state equations. On the other hand, in the GA approach it is easy to implement these variables into performance index PI, as follows:..."

• Analysis of the P.A.W.S. Lorry Suspension, Abstract, University of Cambridge
  - Transportation Research Group, Technical Report Archive
  "This report compares the theoretical performance of the Pro-Active World Suspension (PAWS) to (i) a passive suspension, (ii) an active suspension with `modified skyhook damping' and (iii) an active suspension with full state feedback and optimal control."

• Research papers, J-S. Lin and I. Kanellakopoulos, UCLA

• Active Suspension Systems for Vehicles, Army Research Laboratory
  "... Generates active inputs to cancel motion & vibrations. Initial efforts are underway in the area of active vehicle suspension systems via leveraging NASA structural vibration isolation work. ..."

• Drive-by-wire Systems with Active Suspension
  "Mercedes are also investigating the combination of drive-by-wire systems with active suspension (Active Body Control, ABC) which reduces body movements during cornering to a minimum and opens up new dimensions in terms of handling, stability and road-holding."

• Motorola / microcontrollers
  "Suspension control improves vehicle stability during high speed manouvers by the use of actuators in the vehicle's ride control elements. In order to achieve full vehicle dynamic control, information such as angular speed and direction, vehicle speed, transmission settings, wheel slip and brake pressure will be required in order to determine proper action. Motorola is leading the industry in developing microcontrollers for these functions."

• Active Cab Suspention, Luleå University of Technology, Sweden
  "A number of studies show that operators on forest machinery are exposed to severe whole-body vibration. At present, damping of the vibration is incorporated in the cab seat. The seat however, are primarily designed for road vehicles, although some modifications have been made to make them more suitable for off-road operation.
  "Another way in which the operator can be isolated from vibration is to damp the entire cab, in which case the existing seats are quite suitable. Yet the best solution would be to equipe the machine with an active cab suspension system; in other words, to input energy into the suspension system in order to equalize the vibrations introduced from the machine. Active suspension systems do already exist for cars..."

• CSA Engineering
  This is a bit of a stretch - but it looks like we have a better chance for a smooth ride on a space launch then in our neighborhoods.

• SoloTrek SFV
  Another way to avoid the bumps and undulations...

© Rada Project, 2000
February 7, 2000 / last update: April 21, 2000 (Version 1.b)