Abstract: A failsafe device is provided to perform an operation including at least a part or all of one or more of a mechanical system, a hydraulic system, an electrical system, and a chemical system. The failsafe device includes at least one electronic system and an least one non-electronic system. The at least one electronic system is controlled by at least one computer and/or microprocessor. The at least one non-electronic system includes at least one of the mechanical, hydraulic, electrical, and chemical systems. The failsafe device is configured to operate in two modes, a normal mode and an emergency mode.

Abstract: A variable displacement pump for supplying fluid to a system is described. Controlling the variable displacement pump is determined based upon inputs from a fluidic pressure sensor and an accelerometer, and includes determining a desired fluidic pressure and monitoring, via the fluidic pressure sensor, an actual fluidic pressure. A pressure error term is determined based upon a difference between the actual fluidic pressure and the desired fluidic pressure. A time-integrated pressure error term is determined based upon the pressure error term, and a g-force is determined based upon an input signal from the accelerometer. The variable displacement pump is controlled in response to the time-integrated pressure error term when the g-force is greater than a threshold g-force.

Abstract: An electromechanical roll stabilizer for a motor vehicle includes a housing, a rotor position sensor board, and an actuator torque sensor board. The housing has a motor unit that has a stator and a rotor integrated therein. The rotor position sensor board and the actuator torque sensor board are arranged between two stabilizer halves. The actuator torque sensor board has a digitization and transmission unit for digitizing the sensed torque and transmitting the digitized torque to a data forwarding module arranged on the rotor position sensor board. The rotor position sensor board has a rotor position detection unit for sensing and digitizing the rotor position and a data processing unit. The sensing of the rotor position can be triggered by at least one command signal of a controller to the rotor position detection unit. The data processing unit is provided to process the sensed measured values.

Abstract: A method of operating a motor vehicle with a chassis system comprising at least two, preferably four vibration damper includes carrying out a body control and a wheel control with the chassis system, and controlling the energy supply for the chassis system via an energy control arrangement. A motor vehicle performing the method is also disclosed.

Abstract: Provided is a vehicle state estimation device (10) having a calculation unit (28) that calculates state quantities of at least a sprung of a vehicle based on wheel speeds of front left and right wheels and rear left and right wheels detected by detection devices. The calculation unit (28) calculates in-phase and reverse phase components of wheel speeds of left and right wheels for the front and rear wheels and calculates a pitch angular speed and a yaw angular speed of the sprung based on the in-phase and reverse phase components of the wheel speeds, respectively. The calculation unit (28) calculates in-phase and reverse phase components of vertical strokes of left and right suspensions for the front and rear wheels and calculates a vertical speed and a roll angular speed of the sprung based on the in-phase and reverse phase components of vertical strokes of the suspensions, respectively.

Abstract: System and method for operating an active suspension system of a vehicle includes actuating a switch on the vehicle, setting the active suspension system for the vehicle to a demonstration mode, setting a timer when the active suspension system is set to the demonstration mode, and setting the active suspension system for the vehicle to a normal operating mode after the timer reaches a predetermined time. Prior to expiration of the timer, the system and method determines a gear in which the vehicle is placed, determines whether an engine of the vehicle is running if the transmission gear of the vehicle is drive, reverse, or neutral, and determines a throttle angle of the vehicle if the engine is running. The active suspension system is set to a normal operating mode if the throttle angle is greater than a predetermined angle. An iterative process determines the status of the timer.

Abstract: A suspension controlling apparatus for a vehicle includes a suspension whose damping force is variably settable and a control unit capable of controlling the damping force of the suspension on the basis of a target damping force, to control the damping force of the suspension with a desired control amount and a high responsibility. A control unit includes a acceleration calculation device for calculating an acceleration in a forward and rearward direction of a vehicle on the basis of an operation input amount to the vehicle and a target damping force setting device for determining a target value of damping force on the basis of a damping force map determined in advance in response to the acceleration and a differentiation value of the acceleration.

Abstract: Provided are an electronic control suspension apparatus and a damping force controlling method thereof, which are capable of changing a damping force of a damper by just manipulating a multistep switch even during driving. The electronic control suspension apparatus for controlling a damping force of a damper installed at each of a front wheel and a rear wheel includes: a multistep switch disposed in a vehicle and configured to change the damping force of the damper in a multistep manner between a hard step and a soft step; and an electronic control unit configured to control the damping force of the damper according to a current amount corresponding to a step selected from the multistep switch, the current amount to be applied to a solenoid valve being preset for each step of the multistep switch.

Abstract: A system and method estimating a vehicle tire load identifies a change in vehicle loading condition by measuring vibration resonant frequency peaks (bounce mode and/or pitch mode) of the unsprung mass. Signals required include the chassis vertical acceleration and/or chassis pitch rate obtained from commercially available sensors mounted to the vehicle. An observer model receives the inertial signal(s) and generates a dynamic load estimation based upon observed frequency change in the sprung mass natural frequency.

Abstract: An electronic control suspension apparatus for controlling a damping force of a damper installed at each of a front wheel and a rear wheel includes: a reception unit configured to receive a vehicle manipulation signal; a driver tendency analysis unit configured to calculate a driver tendency analysis value by analyzing a driver's driving tendency based on the vehicle manipulation signal received by the reception unit; a driver mode determination unit configured to determine a driver mode to which the driver tendency analysis value calculated by the driver tendency analysis unit belongs; and a damping force control unit configured to control the damping force of the damper by changing a current value to be applied to a solenoid valve according to the determined driver mode.

Abstract: Actuator assemblies and methods and systems for using the same. One actuator assembly includes an actuator, and a controller. The controller is configured to receive a command signal from a vehicle electronic control unit, receive a data signal from a sensor, determine a control signal for the actuator based on the command signal from the vehicle electronic control unit and the data signal from the sensor, transmit the control signal to the actuator, determine a status signal based on the control signal, and transmit the status signal to the vehicle electronic control unit.

Abstract: A vehicle is described herein having a rear drive mounted to a sub-frame where the sub-frame is movable relative to the frame, and where a suspension is movable relative to the sub-frame. Thus the vertical travel of the wheels is a combination of the vertical travel of the wheels relative to the sub-frame and the vertical travel of the sub-frame relative to the frame. The sub-frame could in the front or the rear, or both.

Abstract: Suspension control and method for controlling a damper device of a bicycle that includes a damper device having a controllable damping valve. The damper device serves to dampen a relative motion between a first and a second component. A control device and a memory device are provided. The control device and the memory device define a characteristic damper curve which is characteristic of a correlation between a damping force and a characteristic parameter of the relative motion between the first and second components. At least one electric operating device is provided by means of which the defined characteristic damper curve can be modified in at least two sections of the characteristic damper curve while riding.

Abstract: A vehicle height adjustment apparatus, includes: a front wheel side changing unit capable of changing a front wheel side relative position; a rear wheel side changing unit capable of changing a rear wheel side relative position; and a control unit for adjusting a height of the main body of the vehicle by controlling the front wheel side changing unit and the rear wheel side changing unit so as to change the front wheel side relative position and the rear wheel side relative position, in which the control unit controls the front wheel side changing unit and the rear wheel side changing unit in such a manner that a rate of change of the front wheel side relative position and a rate of change of the rear wheel side relative position satisfy a predetermined relationship.

Abstract: An actuator assembly for use in an active suspension includes a drive assembly having a first portion and a second portion configured to translate relative to each other. The first portion is coupled to a sprung mass and the second portion is coupled to an unsprung mass. The actuator assembly includes an air spring assembly disposed about the drive assembly having a first portion disposed in proximity to the sprung mass and a second portion disposed in proximity to the unsprung mass, the air spring assembly defining an air volume pressurized at an air pressure greater than atmospheric pressure. The actuator assembly includes a cooling assembly having a set of drive assembly channels disposed within the air volume and in thermal communication with the drive assembly and a pump disposed in fluid communication with the set of drive assembly channels.

Abstract: Process for determining at least one state of motion of a vehicle body (10) of a vehicle (1), which has at least one wheel (2) spring-mounted on the vehicle body (10) via a wheel suspension (6), wherein an inward deflection (zrel) of the wheel (2) is measured by means of a path or angle sensor (21), an inward deflection velocity (?rel) of the wheel (2) is determined by differentiating the inward deflection (zrel) of the wheel (2) over time, a vertical acceleration ({umlaut over (z)}wheel) of the wheel (2) is measured by means of an acceleration sensor (22), a vertical velocity (?wheel) of the wheel (2) is determined by integrating the vertical acceleration ({umlaut over (z)}wheel) of the wheel (2) over time, and a vertical velocity (?body) of the vehicle body (10) is calculated by forming a difference of the vertical velocity (?wheel) of wheel (2) and the inward deflection velocity (?rel) of wheel (2).

Abstract: A control system for an adjustable damping force damper of a suspension apparatus of a vehicle, includes a lateral acceleration detecting unit detecting a lateral acceleration of the vehicle at a gravity point thereof, a yaw rate detecting unit detecting a yaw rate of the vehicle and a control unit controlling a damping force of the damper. The control unit calculates a first target damping force based on an output of the lateral acceleration detecting unit, calculates a second target damping force based on a lateral acceleration at an axel position which is estimated by an output of the yaw rate detecting unit, compares an absolute value of the first target damping force with that of the second target damping force and sets a target controlling value of the damping force in accordance with the first or second target damping force which has a larger absolute value.

Abstract: Automotive systems and methods for operating vehicles are provided. In an embodiment, when a speed sensor senses that the vehicle speed is above a first speed threshold and an ambient light sensor senses that an ambient light intensity is below a first intensity threshold, a controller provides a first command to a suspension system to lower a first end of a vehicle body to a second front trim height position relative to a horizontal plane, where the second front trim height position is below a first front trim height position, and to lower the second end of the body to a second rear trim height position relative to the horizontal plane, where the second rear trim height position is below a first rear trim height position.

Abstract: An apparatus for controlling a bicycle suspension element includes a suspension parameter controller that provides a suspension parameter controlling signal to control an operating parameter of the bicycle suspension element in response to a bicycle seat position.

Abstract: The apparatus comprises a measured signal detector 11, a vehicle parameter obtainer 12, a sideslip angle temporary estimator 13, a sideslip angle differential corresponding value computer 14 and a sideslip angle real estimator 15. A sideslip angle temporary estimate value is computed from one or plural vehicle parameters including at least the mass. A sideslip angle differential corresponding value is computed from a measured signal and the vehicle parameters including no mass. A sideslip angle is derived from the sideslip angle temporary estimate value and the sideslip angle differential corresponding value. A sideslip can be detected without a steering angle detection mechanism.

Abstract: A stabilizer system for a vehicle that includes a stabilizer bar and an actuator for changing stiffness of the stabilizer bar, an electric current to be supplied to an electric motor that is a drive source of the actuator is changed based on various parameters. The supply current is made smaller in a situation in which an operational direction of the actuator is toward a neutral position, than in another situation. Further, the supply current is made smaller with an increase in a distance of the operational position of the actuator from the neutral position. Moreover, the supply current is made larger with an increase in a steering speed. In detail, when the supply current is determined by multiplying a basic supply current by a control gain, the control gain is set to change depending upon the above-indicated parameter, whereby the supply current is changed based on the parameters.

Abstract: A vehicle (10) includes a control system (18) that is used to control a vehicle system. The control system determines a wheel normal loading in response to heave motion wheel loading, attitude-based wheel loading, and vertical motion induced wheel loading. The various wheel loadings may be indirectly determined from the sensors of the various dynamic control system outputs.

Abstract: A vehicle control system estimates the vibration states of tires by using a vehicle vibration model that is separated into a vehicle body vibration model, a chassis vibration model, and a tire vibration model with high precision. The tire vibration model in the vehicle vibration model is formed of a rear wheel tire vibration model, a front wheel tire vibration model, and a virtual coupling element vibration model that virtually couples the rear wheel tire vibration model and the front wheel tire vibration model. Influence of the vibration state that is conducted between the front wheel tires and the rear wheel tires is considered while the tire vibration model and the chassis vibration model are separated from each other, thereby making it possible to estimate the vibrations that occur in the front wheel tires and the rear wheel tires.

Abstract: A shock absorbing system includes an air container, a power source to supply a high-pressure air into the air container, a plurality of shock absorbers each provided with at least one air spring, a central controller including a plurality of control units each connected between the air container and a respective one of the shock absorbers, and a drive unit to control operation of the central controller in a wireless way. Thus, each of the shock absorbers can be lifted to lift the chassis of the car so as to prevent the chassis from being worn out or broken due to a violent hit when the car passes a rugged road and can be lowered to lower the chassis of the car so as to enhance maneuverability of the car.

Abstract: An active air suspension system includes an air spring assembly that has a piston airbag and a primary airbag mounted around the piston airbag to provide a variable force and rate dual air spring configuration. The air suspension system is configured to accurately control pressure within the piston airbags in a closed-loop manner. Continuous control of the piston pressure provides an accurate increase or decrease of spring rate or force depending on the controller inputs.

Abstract: A vehicle suspension utilizes an active air suspension system in combination with an adaptive damping system to provide a desired ride and handling output. The active air suspension and adaptive damping system can operate independently of each other, or can work in conjunction with each other to provide the desired output.

Abstract: In a rollover stability method for a vehicle in a situation which is critical with respect to the driving dynamics, a critical rollover situation is detected by analyzing a control variable and the stabilization intervention is activated or de-activated as a function of the control variable. The regulation intervention is maintained even in driving situations featuring relatively low transverse acceleration if the control variable or a characteristic property of the stability algorithm is calculated as a function of the steering angle and/or the longitudinal vehicle velocity.

Abstract: A suspension system includes four electronically controlled actuators, one at each of the four wheels. The actuators are each controlled by an electronic control unit. The left front and right front actuators are mechanically connected with each other. The left rear and the right rear actuators are also mechanically connected with each other. The only connection between the front two actuators and the rear two actuators is an electronic communication through the electronic control unit.

Abstract: A method and system for coordinating a vehicle stability control system with a suspension damper control sub-system includes a plurality of dampers, each of which are controlled directly by the suspension damper control sub-system. A plurality of sensors sense a plurality of vehicle parameters. A supervisory controller generates vehicle damper commands based on the plurality of vehicle parameters for each of the dampers. A damper controller in electrical communication with the supervisory controller receives the vehicle damper commands and generates sub-system damper commands based on a portion of the plurality of vehicle parameters for each of the dampers. The damper controller also determines if any of the vehicle damper commands for any one of the dampers has authority over the corresponding sub-system damper command.

Abstract: A hydraulic system for a suspension system for a vehicle includes at least one first pair of wheel rams (11, 12) at a first end of the vehicle and at least one second pair of wheel rams (13, 14) at a second end of the vehicle, each rams including a compression chamber (45-48) and a rebound chamber (49-52); and the system includes first and second diagonal circuits with respect to said vehicle. The hydraulic system includes at least one first and second modal resilience devices (81, 82). These devices each including at least one resilient means (107-110), at least one moveable member (105-106) and at least first and second (89, 90 and 91, 92) system modal chambers. Motion of the moveable member of each modal resilience device due to roll or pitch motion of the vehicle is controlled by the respective at least one resilient means to thereby provide respective roll or pitch resilience in the system.

Abstract: A vehicle includes a semi-active suspension including suspension dampers controllably adjustable in accordance with electronic stability control commands and ride and handling commands. Vehicle steering response states, turning direction states and vehicle dynamics states are binary coded in respective state variables and suspension control calibrations are binary coded in calibration words. Integrity and security of state variables and calibration words are ensured in efficient binary digit resource allocation schemes.

Abstract: A series arranged air compressors system includes a first air compressor and a second air compressor pneumatically connected in series in an open, closed or partially closed state of operation. The output of the second air compressor is used as a source of compressed air for an air suspension system of a motor vehicle and/or to pressurize air inflatable articles. Flow of compressed air is selectively controlled by an electronic control circuit via at least one air flow control block, and the system may further include one or more air reservoirs.

Abstract: An apparatus meant to be incorporated into a suspension system suspending a plant (i.e., an overall plant that includes a physical plant and possibly a load that the physical plant supports) of a vehicle acts to alter the spring constant of at least one spring of the suspension system in response to changes in the weight of the plant so that a resonant frequency of the at least one spring isolating the plant from a jolt encountered by the vehicle during travel remains substantially unchanged despite changes to the weight of the plant.

Abstract: A method for controlling a vehicle having a suspension is provided. The method comprises, during longitudinal oscillations of the vehicle, adjusting a suspension member to vary a normal force between the vehicle and the surface, where the suspension adjustment is based on the longitudinal oscillations.

Abstract: A rollover avoidance system for changing the damping characteristics of suspension dampers at each wheel of a vehicle so as to mitigate the potential for vehicle rollover. The system includes a plurality of vehicle parameter sensors for measuring vehicle parameters and providing vehicle parameter signals. The system also includes a controller for generating a damper suspension command signal for each damper using the vehicle parameter signals. The controller considers a roll control factor representing a rollover condition of the vehicle and a yaw stability control factor representing a yaw condition of the vehicle to set the damping of the dampers to mitigate the potential for vehicle rollover.

Abstract: A damping adjusting/controlling system is provided for a vehicle having two front shock-absorbers and two rear shock-absorbers. Each shock-absorber includes a piston rod having a central rod mounted therein. The damping adjusting/controlling system includes two front motors and two rear motors for driving the central rods of the front and rear shock-absorbers, respectively. Front and rear motor controller are mounted to front and rear portions of the vehicle and electrically connected to the front and rear motors, respectively. A main controller is operable to proceed with bidirectional information transmission/reception between a programmed chip of the main controller and programmed chips of the front and rear motor controllers to drive at least one of the front and rear motors, thereby adjusting a height of the central rod and a damping state of at least one of the front and rear shock-absorbers.

Abstract: A method of controlling a roll control system includes monitoring the position of a steering mechanism of a vehicle. A rate of change of the position of the steering mechanism is determined. The rate of change is compared to a change threshold value. The lateral acceleration of a vehicle is monitored. The lateral acceleration is compared to an acceleration threshold value. A roll control system having at least one of a front and a rear actuator is controlled based at least in part upon the comparisons of the rate of change of the steering mechanism to the change threshold value and the lateral acceleration to the acceleration threshold value. The front and rear actuators are controlled independently of each other depending upon the state of a vehicle stability index.

Abstract: A system is provided for controlling the load split between the axles and thereby the theoretical wheelbase of a vehicle having two front axles being suspended in suspension units at least some of which have springs with adjustable stiffness. A method for controlling the load split between the axles and to a motor vehicle including such a system and/or by use of such a method is also disclosed.

Abstract: A ride control suspension control system having suspension control units with a damper and a single pressure regulator that controls dampening in both the compression and rebound chambers of the damper. The fluid control circuit may include a plurality of check valves that coordinate the flow of fluid to and from both chambers through the pressure regulator. In one embodiment, the system includes a central controller that receives input from a variety of sensors and directly controls operation the pressure regulators in each of the suspension control units without the need for any remote processors. The ride control suspension system may also include wheel position sensors that are external to the accumulator.

Abstract: The present invention relates to a method of controlling a variable damper in a vehicle wherein a rear-wheel variable damper can be controlled by estimating a vertical acceleration value of a rear wheel based on the fact that there is a certain time delay in a wheel motion between front and rear wheels due to the wheelbase and vehicle speed.

Abstract: A damping adjusting/controlling system is provided for a vehicle having two front shock-absorbers and two rear shock-absorbers. Each shock-absorber includes a piston rod having a central rod mounted therein. The damping adjusting/controlling system includes two front motors and two rear motors for driving the central rods of the front and rear shock-absorbers, respectively. Front and rear motor controller are mounted to front and rear portions of the vehicle and electrically connected to the front and rear motors, respectively. A main controller is operable to proceed with bidirectional information transmission/reception between a programmed chip of the main controller and programmed chips of the front and rear motor controllers to drive at least one of the front and rear motors, thereby adjusting a height of the central rod and a damping state of at least one of the front and rear shock-absorbers.

Abstract: A hydropneumatic, level-regulated axle suspension for the front wheel axle and rear wheel axle on vehicles, in particular vehicles whose large axle load spread is large, having two double-acting hydraulic suspension cylinders, whose cylinder spaces are each connected to a first accumulator and whose annuli on the piston side are connected to a second accumulator, the axle suspension for the front axle (39) and the rear axle (40) being designed as a reversible double-function axle suspension, so that each axle (39, 40) is switchable both as an oscillating axle (in the cylinder transverse combination) and as a stabilizing axle (in the cross combination).

Abstract: A method and apparatus for controlling frame rise on a heavy duty truck having a frame, a drive axle connected to the frame, and a selectively lockable suspension component disposed therebetween for maintaining the relative position therebetween. Signals indicative of at least one of the following vehicle operating parameters: engine speed, brake pressure, vehicle speed, air bag pressure, steering wheel angle, vehicle height, or throttle position are monitored and a predicted thrust is calculated that will be applied to the drive axle based on the monitored signals. The selectively lockable suspension component is locked if the predicted thrust exceeds a predetermined threshold and is also controlled with respect to other operating parameters such as whether vehicle brakes are applied, any instantaneous change in torque, vehicle operating speed, and the length of time the selectively lockable suspension component has been locked.

Abstract: A system for adjusting a height of a first road vehicle with respect to the ground prior to impacting a second road vehicle is disclosed. The system includes a predictive crash sensor mounted to the first vehicle for sensing the second road vehicle, a control unit, and a height adjustment apparatus. The control unit is in communication with the predicative crash sensor for receiving a predictive crash signal and determining whether the first and the second road vehicles will collide. The height adjustment apparatus is mounted to the first road vehicle and in communication with the control unit. The height adjustment apparatus includes a shock absorber, a bladder, and a first valve. The shock absorber is mounted at a first end to a vehicle body of the first road vehicle and at a second end to a vehicle axle of the first road vehicle. The bladder is fixed at a first end to the first end of the shock absorber and at a second end to the second end of the shock absorber.

Abstract: An electromagnetic transducer including a stator and an armature, the armature defining a first axis and being driven to ride between first and second couplers back and forth relative to the stator along the first axis. The second coupler is configured to permit movement of the armature along a second axis orthogonal to the first axis.

Abstract: A pneumatic switching valve (1) for systems for lifting and lowering the body of a vehicle including air suspension includes a mechanical actuation element (33) for adjusting a lifting position, a lowering position, a driving position and a stop position associated with respective positions of the vehicle. An inlet valve (11), an outlet valve (12) and a locking valve (13) each include a valve body (24), a tappet (26) and a closing spring (27). The inlet valve (11) and the outlet valve (12) are arranged in one common plane to face in opposite directions. The closing springs (27) of the inlet valve (11) and of the outlet valve (12) also serve to move the actuation element (33) from the lifting position or from the lowering position to the stop position when the operator releases the actuation element (33).

Abstract: A control system that senses misalignment of components in a vehicle drive train system and adjusts the vehicle ride height to realign the components. A control unit monitors vibration, torque or other operating parameters of a vehicle's drive train or other vehicle components and determines whether the parameters are abnormal. If the monitored parameters are abnormal, then the control unit controls suspension elements on the vehicle to adjust the ride height of the vehicle and subsequently the alignment of the drive train, for example, the operating angle of the driveshaft. A ride height sensor feeds back ride height measurements as the suspension elements are adjusted to assist in finding an optimal ride height that eliminates or reduces excess vibration and/or torque. In another embodiment, the control unit adjusts the ride height based on vehicle speed or fuel economy to reduce the profile of the vehicle and improve fuel economy.

Abstract: A control system for optimizing a shock absorber having a non-linear kinetic characteristic is described. The control system uses a fitness (performance) function that is based on the physical laws of minimum entropy and biologically inspired constraints relating to mechanical constraints and/or rider comfort, driveability, etc. In one embodiment, a genetic analyzer is used in an off-line mode to develop a teaching signal. An information filter is used to filter the teaching signal to produce a compressed teaching signal. The compressed teaching signal can be approximated online by a fuzzy controller that operates using knowledge from a knowledge base. In one embodiment, the control system includes a learning system, such as a neural network that is trained by the compressed training signal. The learning system is used to create a knowledge base for use by an online fuzzy controller. The online fuzzy controller is used to program a linear controller.

Abstract: A device for stabilizing a vehicle is described. For this purpose, the device includes first determination device with which at least two vehicle motion quantities describing the vehicle motion, in particular in the direction transverse to the vehicle, are determined. Furthermore, the device includes second determination device with which a characteristic quantity is determined for each of the vehicle motion quantities. The second determination includes an adjustment device with the help of which the variation over time of the characteristic quantities is adjusted to the vehicle's behavior. In addition, the device device includes a control device with which intervention quantities are determined at least as a function of the vehicle motion quantities and the characteristic quantities, which are supplied to an actuator system for performing at least brake interventions and/or engine interventions with which the vehicle is stabilized.

Abstract: A system and method for improving the traction of a vehicle uses weight distribution control to improve wheel to driving surface friction. A driven axle and a non-driven axle support a vehicle load through adjustable suspension members. The suspension members are, for example, air bags. Actuators and controllers adjust the suspension members in a selectable predetermined manner. The selection can be based on operator preference, vehicle operating mode, or a sensed loss of traction. The driven axle carries a drive axle maximum rated load in order to maximize drive wheel traction at all times.