Land vehicles – Wheeled – Running gear
Patent
1991-12-13
1993-06-08
Rice, Kenneth R.
Land vehicles
Wheeled
Running gear
280840, 280772, 280DIG1, 180 41, 36442405, B60G 1701
Patent
active
052172465
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a control system for controlling the suspension system of a land vehicle, in particular a motor vehicle. By "land vehicle" is meant all classes of vehicle capable of powered motion over the land, including motor cars, motor cycles, tractors and tracked vehicles.
In particular, the invention relates to a control system for controlling a motor vehicle having an active suspension system.
An active suspension system is a motor vehicle suspension system in which the conventional suspension components, such as springs and dampers, are assisted or replaced by actuators operable in response to command signals from a microprocessor in order to correct, change or control the attitude of the vehicle. The aim of such a system is to minimise variations in the forces experienced by the vehicle body, thereby improving vehicle safety and enhancing driver and passenger comfort.
The command signals are produced as a result of the measured values of a number of variables defining the motor vehicle's attitude. In a truly active suspension system, there is the capability not merely of operating the actuators in response to previously measured changes in the values of the variables, but also of, for example, biassing the attitude of the vehicle in some way to offset the effects of a steady-state or dynamic loading; and even of operating the actuators in a manner predictive of expected road conditions.
Active suspension systems are now well known. For example, European Patent Application number EP-A-0114757 discloses an active suspension system for a four-wheeled motor vehicle in which force measurements are taken at the points of support of the vehicle body on each wheel/hub assembly and processed to produce a demanded output of the actuator secured to operate between each wheel/hub assembly and the body of the vehicle.
A control system for controlling the attitude of a motor vehicle having an active suspension system is known to include means for converting the forces measured at the points of support of the vehicle body or the wheel/hub assemblies to a set of modal forces which act on the vehicle body as a whole relative to the wheel/hub assemblies. The required actuator outputs may then be calculated to overcome the combined modal forces in order to maintain the desired attitude of the vehicle. The modal forces are the heave, pitch, roll and warp forces.
A significant advantage of an active suspension system is that the suspension characteristics of a vehicle may be continuously altered to accommodate varying road conditions and operating conditions of the vehicle. This facility permits the constructions of a vehicle which has improved safety characteristics, since it is possible to maintain a greater degree of contact of the vehicle tyres with a road surface, and the vehicle is likely to be more predictable to the driver, than in the case of a vehicle not having an active suspension system.
However, a disadvantage of an active suspension system which resolves the forces measured at the points of support of the vehicle body on each wheel/hub assembly into modal forces is that the resulting modal force values do not accurately reflect the net forces experienced by the vehicle body as a result of road inputs. (By "road inputs" is meant the force effect of the vehicle passing over irregularities in a road surface, such irregularities being, for example, bumps and depressions.)
The active suspension systems currently available lack precision since they do not take into account all of the loads transmitted from the unsprung matters of the vehicle, the wheel and hub assemblies, to the sprung matter of the vehicle, the chassis or body of the vehicle. The suspension linkage arrangement commonly used by vehicles transmits load from the unsprung masses to the sprung mass by a plurality of load paths. To date, active suspension system have only considered those loads which can be measured, that is to say the loads on the actuator and spring assembly.
According to the invention, there is therefore provided a co
Davis John P.
Williams David A.
Wright Peter G.
Group Lotus PLC
Rice Kenneth R.
LandOfFree
Control system for controlling the suspension of a land vehicle does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Control system for controlling the suspension of a land vehicle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control system for controlling the suspension of a land vehicle will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1929232