Abstract: An integrated system for automatically controlling the operation of both an automated mechanical transmission and a multiple speed axle assembly in a vehicle drive train assembly includes a transmission actuator for operating the transmission in any one of a plurality of transmission gear ratios. The system further includes an axle actuator for operating the axle assembly in any one of a plurality of axle gear ratios. An electronic controller is provided for operating the transmission in a desired one of the plurality of transmission gear ratios and for operating the axle assembly in a desired one of the plurality of axle gear ratios to provide a desired overall gear ratio for the vehicle. To accomplish this, the electronic controller is responsive to one or more input signals that represent operating parameters of the vehicle.

Abstract: An autonomous vehicle includes a chassis, pair of drive wheels, a motor for driving these drive wheels, a gyrosensor provided at the chassis for detecting a direction of the chassis, and a travel control unit responsive to an output of the gyrosensor at the end of a travel of a predetermined run indicating difference from a target direction for providing control of the rotation amount of the drive wheels so that the direction of the chassis is corrected by a predetermined amount to be aligned with the target direction. A method of controlling this autonomous vehicle is also disclosed.

Abstract: A method of automatically controlling a power takeoff shaft of a work vehicle having a hitch includes automatically initiating engagement of the power takeoff shaft as the hitch is lowered such that the power takeoff shaft reaches clutch lockup approximately at a predetermined hitch position setpoint. A method of controlling the engagement of a power takeoff shaft of a work vehicle having a hitch includes calculating a hitch drop time from a first hitch position to a second hitch position based on a hitch drop rate, comparing the hitch drop time to a power takeoff shaft engagement time, and decreasing the hitch drop rate if the power takeoff shaft engagement time is greater than the hitch drop time.

Abstract: A yaw moment control system is provided to eliminate an under-steering tendency generated due to the insufficiency of a cornering force of front driven wheels of a vehicle. More specifically, in place of a longitudinal acceleration Xg and a lateral acceleration Yg used for calculating the amount of torque distributed, a corrected longitudinal acceleration Xg' larger than the value directly proportional to the longitudinal acceleration Xg and a corrected lateral acceleration Yg' larger than the value directly proportional to the lateral acceleration Yg are used, thereby increasing the amount of torque distributed to between inner and outer wheels during turning of the vehicle. A yaw moment is generated which is directed inwards in the turning direction to prevent the under-steering tendency which is generated due to the insufficiency of the cornering force of the front wheels.

Abstract: In a disengagement side control, in a power on state, a disengagement side pressure P.sub.W is output, P.sub.W being set higher than a base pressure dependent on input torque, and a disengagement side frictional engagement element is engaged and maintained. In a power off state, a disengagement side pressure lower than the base pressure is output, and the disengagement side frictional engagement element slips. In the disengagement side control, when the vehicle driving state is changed from the power off state to the power on state, the disengagement side pressure P.sub.W is changed from that for a slip state to that for a maintain state.

Abstract: A method for controlling a transfer case in a four wheel drive vehicle is provided. The transfer case has a neutral state and a plurality of drive modes. A MSS having a plurality of positions is provided for selecting the drive modes. An upshift relay and a downshift relay energize a motor to effect a shift of the transfer case to the selected drive mode. An encoder detects a value corresponding to the rotational position of the motor. The method senses if the encoder has lost power, and upon sensing the encoder has lost power, compares a current MSS position with a MSS position prior to losing power to the encoder. If the current and prior MSS positions differ, the most recent valid MSS position is determined. Whether the upshift and downshift relays are turned "on" is established. The direction of rotation of the motor is established. The desired motor destination is established.

Abstract: A working vehicle such as an agricultural tractor includes a control device having an accelerating drive mode to accelerate front wheels automatically to rotate faster than rear wheels when the front wheels are steered in excess of a fixed amount. When the rotating speed of an engine falls below a predetermined value, a shift to the accelerating drive mode is inhibited to avoid an engine stall.

Abstract: A method for controlling a transfer case in an automatic four-wheel-drive driveline for a motor vehicle includes sensing if the engine is drivably decoupled from the transfer case and setting a first variable to "T" if the engine is decoupled, otherwise setting the variable to "F". The vehicle speed is sensed to determine if the speed is substantially zero and a second variable is set to "T" if the speed is substantially zero, otherwise the second variable is set to "F". Whether the vehicle is braking is sensed, and a third variable is set to "T" if the vehicle is braking, otherwise the third variable is set to "F". If all the first, second and third variables are "T", a shift condition flag is set to "T" to permit a shift of the transfer case through a neutral state, otherwise the shift condition flag is set to "F" and a shift of the transfer case through the neutral state is not permitted.

Abstract: In a four wheel drive vehicle, a driving force distribution control apparatus estimates a road friction coefficient and controls a transfer clutch of a center differential based on the estimated road friction coefficient so that a driving force distribution on the rear wheel side becomes larger as the estimated road friction coefficient becomes small. An initial value of the road friction coefficient is established to be a low value such as 0.3 when a wiper switch is turned on, an outside air temperature is low, a traction control apparatus operates, an anti-lock brake control apparatus operates, a braking force control apparatus operates, a slip detecting apparatus detects a slip and a transmission control unit outputs a signal and is established to be an intermediate value such as 0.5 when an initial start judgment section judges an initial start of the engine after a long period of stop.

Abstract: A control system for controlling a power takeoff shaft of a work vehicle having a hitch includes a hitch position sensor and a control circuit. The hitch position sensor is configured to generate a hitch position signal. The control circuit is coupled to the hitch position sensor and is configured to receive the hitch position signal, to compare the hitch position signal to a first predetermined hitch position and a second predetermined hitch position, to engage the power takeoff shaft when the hitch crosses the first predetermined hitch position and to disengage the power takeoff shaft when the hitch crosses the second predetermined hitch position.

Abstract: A differential lock control system for controlling the locking of the various differential assemblies associated with a particular work machine wherein such system includes a first switch positionable to select any one or more of the differential assemblies for operation in their locked condition, a second switch actuatable to control the locking of the differential assemblies selected by the first switch, a ground speed sensor for determining the ground speed of the work machine, an optional steering pressure sensor for determining the steering effort required to turn the wheels associated with the front axle, and an electronic controller coupled to the first and second switches and to the respective sensors for receiving signals therefrom, the controller outputting a signal to actuate the locking mechanism of the differential assemblies selected by the position of the first switch when the controller receives a signal indicative of the second switch being actuated, and a signal indicative of the ground spee

Abstract: A process for controlling a yaw moment in a vehicle by generating a braking force in one of the left and right wheels of the vehicle and by generating a driving force in the other wheel. When a vehicle is accelerated during the turning thereof, grounding loads of rear wheels are increased in order to generate a yaw moment in a direction opposite from a turning direction. However, such yaw moment can be eliminated in order to enhance the turning performance by bringing one of the hydraulic clutches into an engaged state with a torque which is proportional to a product of longitudinal and lateral accelerations. Consequently, a braking force and a driving force in inner and outer wheels during turning of the vehicle, respectively, are generated. When the vehicle is decelerated during turning thereof, grounding loads of front wheels are increased to a yaw moment in the same direction as the turning direction.

Abstract: In a four wheel drive system for an automotive vehicle, a detected value .DELTA.V.sub.W of difference of rotating speed between the front and rear wheels is compared with a threshold .DELTA.V.sub.W0 determined in accordance with a pseudo vehicle speed V.sub.FF (S116, S213). As a result of this, when a determination is made that the pseudo vehicle speed V.sub.FF is in a directly connecting four wheel drive condition inhibiting range, a directly connecting four wheel drive condition inhibiting signal S.sub.N is sent out (S121), so that a front wheel side torque distribution instruction value T.sub.2 is determined as a value preventing the directly connecting four wheel drive condition. Thereby, in case of using of the different diameter wheel, a deterioration of stability and an increase of load of power train system caused by the directly connecting four wheel drive condition can be prevented.

Abstract: A method and system for the determining in advance of the travel corridor of a motor vehicle for an automatic system for establishing a safe tailing distance in which a signal corresponding to the speed is used to determine a turning radius of the motor vehicle, the travel corridor being determined from the turning radius.For the exact determination of the travel corridor of the motor vehicle, and in order sufficiently to take into consideration the travel dynamics of the motor vehicle, the speed of at least two wheels of the vehicle are measured and the yawing of the vehicle determined from the difference between the two wheel speeds.

Abstract: A yaw moment control system for a vehicle is provided to prevent the reduction of the turning performance during traveling of a vehicle at a low speed, which is designed, so that a driving force and a braking force are distributed to inner and outer wheels during turning of the vehicle in order to eliminate an over-steering tendency produced upon deceleration of the vehicle during turning thereof, thereby enhancing the stability during traveling of the vehicle at a high speed. A longitudinal acceleration Xg calculated in a longitudinal acceleration calculating circuit, a lateral acceleration Yg calculated in a lateral acceleration calculating circuit and a correcting factor Kv determined in a correcting factor determining circuit are multiplied by a control amount calculating circuit. Torque proportional to the resulting product is distributed to left and right wheels to eliminate the over-steering tendency produced upon deceleration of the vehicle during the turning thereof.

Abstract: A driving torque control apparatus has a first differential restraining device which restrains a rotational speed differential between front-left and front-right wheels by adjusting driving torque to be transmitted from a power source mounted on a four-wheel drive vehicle to each of the front-left and front-right wheels, and a second differential restraining device which restrains a rotational speed differential between rear-left and rear-right wheels by adjusting driving torque to be transmitted from the power source to each of the rear-left and rear-right wheels. An adjustment of driving torque by the second differential restraining device is executed in preference to an adjustment of driving torque by the first differential restraining device.

Abstract: A method of monitoring the relative effective diameters of the tires and compensating therefor in a vehicle which includes a front driveshaft for transferring motive power to a front set of wheels and a rear driveshaft for transferring motive power to a rear set of wheels, each of the wheels having an effective diameter. Front and rear driveshaft values indicative of the rotational speed of each driveshaft are generated. A difference value indicative of a difference between said front and rear driveshaft values is then generated. A low pass filtered value is generated according to the relationship of Y.sub.1p =(1-.beta.)*U(k)+.beta.*Y.sub.1p (k-1). The low pass filtered value is monitored for a predetermined period of time to determine if one of the wheels has a smaller effective diameter than the other wheels.

Abstract: For automatically controlling a differential lock in drive axles of a motor vehicle, an arrangement has a lock coupling, an actuator for actuating the lock coupling, a plurality of rotary speed sensors associated with wheels of the vehicle for forming the rotary speed signal, a control unit for receiving the rotary speed signals and forming a control signal for controlling the actuator means, the control unit including computing means for computing a nominal rotary speed value associated with each of the wheels so that a computed nominal rotary speed value is determined continuously in dependence from a corresponding traveling condition, a first comparing unit for forming a difference rotary speed value from a comparison of a measured rotary speed value with the computed nominal rotary speed value, and a second comparing unit for forming the control signal so that when the difference rotary speed value exceeds a predetermined threshold value the lock coupling is engaged and when the difference rotary speed va

Abstract: The invention provides a method for detecting the wheel rpm values of the nondriven and the driven wheels and for comparing them with one another in order to improve vehicle stability, for example when the driving torque of the engine is too high. A friction clutch located between the drive motor and the wheels in the drive train is disengaged when the rpm of the driven wheels is less than the rpm of the nondriven wheels and the difference between the two wheel rpm values exceeds a given limiting value. The friction clutch is re-engaged when the difference between the two wheel rpm values reaches or falls below a second limiting value.

Abstract: A vehicle power shift transmission (PST) is controlled by a transmission control system which implements a control method. The PST is part of the driveline of the vehicle and is shifted by an actuating mechanism. The driveline includes an engine, the PST, a clutch, a synchronized shift transmission that can be shifted by a shift lever and driven vehicle wheels. In order to simplify the operator's tasks, during the shift of the synchronized shift transmission the gear of the PST is automatically shifted so that the resulting difference in the gear ratio of the complete transmission before and after the shift is minimized. The gear of the PST is selected and shifted automatically so that the rotational speeds on both sides of the clutch differ as little as possible.

Abstract: An apparatus for controlling an automatic transmission of a vehicle in the absence of a driving mode signal indicating a driving mode of the vehicle, includes monitoring means for monitoring output from a driving mode sensor; determining means for determining whether a driving mode signal has been received from the driving mode sensor based on the monitoring; sensing means for sensing a direction in which the vehicle is traveling; transmission control means placing the automatic transmission in first gear when the determining means determines that a driving mode signal has not been received, and for controlling the automatic transmission such that the vehicle continues to travel in the detected direction.

Abstract: The invention relates to a safety system for a motor vehicle having an internal-combustion engine. Independent quantities are used for the engine control and for the monitoring of the engine control. The control of the internal-combustion engine takes place by way of an operating parameter indicative of the operating condition of the internal-combustion engine--such as the engine load. In contrast, the monitoring of the engine control takes place by means of a quantity indicative of vehicle propulsion, such as the vehicle output torque, which is determined on the basis of a rotational wheel speed. The desired values for the engine control and for the monitoring are determined from the accelerator pedal position. The detection of the corresponding actual values is based on independent input quantities.

Abstract: In a vehicle which includes a front driveshaft for transferring motive power to a front set of wheels and a rear driveshaft for transferring motive power to a rear set of wheels and a clutch to control the amount of torque provided to the driveshafts, a method is provided to control the amount of power delivered to the front and rear driveshafts. The duty cycle of the clutch is monitored and it is determined whether the clutch duty cycle passes a first lower threshold and a second higher threshold, successively, a predetermined number of times within a calibratible time period. A 4 Hi Lock mode is entered if the clutch duty cycle passes the first lower threshold and the second higher threshold, successively, a predetermined number of times within the calibratible period.

Abstract: A automatic guided vehicle which drives drive wheels differentially to change its traveling direction applies braking by imposing reverse torque to wheel drive motors when cornering or when rapid braking is demanded. This braking corrects the traveling direction of the automatic guided vehicle when the vehicle is apt to depart from its intended path, enabling a automatic guided vehicle even having a large inertia to make a smooth turn at a sharp corner.

Abstract: A method of controlling the amount of power delivered to the front driveshaft and to the rear driveshaft of a motor vehicle including the steps of generating a front driveshaft value indicative of the rotational speed of said front driveshaft and generating a rear driveshaft value indicative of the rotational speed of said rear driveshaft. A vehicle speed is generated based on the lower of said front driveshaft value and said rear driveshaft value. The amount of power delivered to said front driveshaft and to said rear driveshaft is controlled as a function of said vehicle speed.

Abstract: In one aspect of the present invention, a method for controlling the steering of a directionally steered machine having a hydrostatic system that drives a plurality of driven wheels is provided. The method includes the steps of producing a steering angle signal indicative of the angle of the steered wheels and a wheel speed signal indicative of the rotational speed of the driven wheels, and generating a programmable curve that represents the resulting driven wheel speeds as a function of the angle of the steered wheels. The generated curve is then stored in a software map to be later used to determine the driven wheel speeds based on the angle of the steered wheels.

Abstract: The present invention relates to a method for controlling a reverse shift restriction in a drive "D" range of a vehicle having an automatic transmission. The method for controlling a reverse shift restriction in a drive "D" range of a vehicle's automatic transmission, comprising the steps of generating a frequency signal representative of the vehicle speed and direction. Next, determination of whether creeping is occurring is necessary. The automatic transmission is controlled based on said determination said frequency signal.

Abstract: A method of controlling a controllable clutch in the drive train between a front axle and a rear axle of a motor vehicle having four-wheel drive including determining the rotational speed of each of the wheels with a wheel-speed sensor, supplying output signals from the sensor to an evaluation unit having a data memory, determining, from the wheel radii stored in the evaluation unit and from the difference between the averaged rotational speeds of the wheels of the front axle and the averaged rotational speeds of the wheels of the rear axle, a theoretical rotational-speed difference for cornering without wheel slip in the clutch, and generating a control signal for operation of the clutch in such a way that a constant basic transmitted torque is set in the clutch.

Abstract: A drive train assembly and monitoring system for indicating the operating condition of the drive train assembly includes a drive train assembly having a power distribution device for distributing rotative power within the drive train. A sensor is attached to a portion of the drive train assembly, the sensor being responsive to the vibration of the portion or component of the drive train assembly for generating signals indicative of the sensed vibration. A controller receives the signals from the sensor and generates an indication of the operating condition of the drive train assembly based on the vibration of the portion of the drive train assembly. Preferably the sensor is adapted to detect both the frequency and magnitude of vibration of the drive train assembly and to generate signals indicative of the sensed frequency and magnitude of vibration.

Abstract: A driving-torque control system for a four-wheel-drive vehicle includes a transfer clutch employed in a transfer of the four-wheel-drive vehicle for varying a distribution ratio of driving torque between front and rear road wheels depending on a front-and-rear wheel revolution-speed difference. A calculation unit derives a command value of the engaging force of the transfer clutch from the front-and-rear wheel revolution-speed difference. A load-condition detection unit detects an input load condition of the transfer clutch, on the basis of the front-and-rear wheel revolution-speed difference and the command value of the engaging force. A comparing unit compares the input load condition detected by the load-condition detection unit with a predetermined threshold. A compensation unit compensates the engaging force of the transfer clutch so that the transfer clutch is held in a completely engaged state for a predetermined holding time duration, when the input load condition exceeds the predetermined threshold.

Abstract: In a driving force control system for a vehicle, an angular velocity of the course direction of the vehicle body is calculated. On the other hand, a target angular velocity of the course direction is determined based on a steering angle and a vehicle speed. Then, based on the degree of the deviation of the calculated angular velocity from the target angular velocity, a correction coefficient for reducing an engine power is generated. When the vehicle traces off the course in the marginal condition on the low friction coefficient road, the correction coefficient reduces the engine power to prevent the vehicle from going out of the course.

Abstract: A system for controlling a four-wheel drive for a motor vehicle comprises a drive mode switch for detecting a drive mode of the motor vehicle selectable between a two-wheel drive mode and a four-wheel drive mode. The four-wheel drive mode is selectable between a direct-coupled four-wheel drive mode. A an auto four-wheel drive mode, a controller controls the distribution of traction between main and secondary driving wheels. A traction transmission train distributes traction between the main and secondary driving wheels. The traction transmission train has an oil pressure supply system having a friction clutch and a solenoid.

Abstract: There is disclosed a motor vehicle having a set of front wheels, a set of rear wheels, an engine, and a transmission driven by the engine and having a transmission output shaft. The motor vehicle further has a transfer including a variable torque trasmitting (VTT) clutch for varying a distribution of torque between the set of front wheels and the set of rear wheels depending upon degree of engagement thereof. A clutch activating pressure is generated and transmitted to the VTT clutch under the control of a mode selector valve.

Abstract: A wheel tachometer minimizes variances in the rate of revolution detected by the wheel velocity sensors of the tachometer due to assembling errors and improves the accuracy of the operation of driving force allocation. Sinusoidal wheel velocity signals vF and vR representing the rates of revolution of the front and rear wheels are produced respectively by front and rear wheel revolution sensors are subjected to wave shaping to obtain the rate of revolution of the front wheels nF and that of the rear wheels nR. When the rate of revolution of the front wheels nF and that of the rear wheels nR exceeds an initial threshold value V.sub.THMIN, the greater one of the rates of revolution nF and nR is used to update the threshold value V.sub.TH. Thereafter, the detected rates of revolution nF and nR are used for the wheel velocities of the front and rear wheels V.sub.F and V.sub.R when they exceed the threshold value V.sub.TH and zero is used for the wheel velocities of the front and rear wheels V.sub.F and V.sub.

Abstract: A four-wheel drive vehicle includes a transfer case for controlling the delivery of power between the front and rear wheels of the vehicle. A clutch in the transfer case controls the amount of power delivered to the front and rear wheels in response to a clutch PulseWidth Modulated (PWM) signal which is generated by an electronic powertrain controller. The powertrain controller receives a first signal which is indicative of the rotational speed of a front driveshaft, which transfers motive power from the transfer case to a pair of front wheels, and a second signal which is indicative of the rotational speed of a rear driveshaft, which transfers motive power from the transfer case to a pair of rear wheels.

Abstract: A control system for engaging, disengaging and re-engaging a front wheel drive in an agricultural vehicle includes a control circuit configured to receive signals representative of vehicle operating parameters and to generate control signals corresponding to the desired state (i.e. engaged or disengaged) of a front wheel drive engagement circuit. Sensors are associated with the rear wheels, rear service brakes, implement positioning circuit, the vehicle body and the front axle to provide parameter signals related to wheel speed, braking, implement position and vehicle speed. Control logic executed by the control circuit in a continuously cycled routine determines the desired state of the engagement circuit based upon all operating parameters. The control circuit applies an appropriate control signal to the engagement circuit causing engagement or disengagement in accordance with the desired state.

Abstract: A drive system provides a smooth start for a vehicle and converts excess kinetic energy accompanying the difference in speed between the engine and the drive wheels occurring during starting into electrical energy for storage in a battery. The drive system includes a gearbox having at least a first gear element connected to an output shaft of an engine, a second gear element connected to a drive wheel of a vehicle and a third gear element for, by applying a braking torque to the third gear element, reducing the speed of rotation input from the first gear element and outputting it to the second gear element. An engaging element provides selective connection to any of the gear elements for mechanically connecting the output shaft of the engine to the drive wheel.

Abstract: A method and apparatus for operating a power transfer device such as a vehicle transfer case having, shaft speed sensors, a two speed (high-low) drive assembly, an electrically, pneumatically or hydraulically operated shift operator and a microprocessor comprising the steps of sensing the speeds of the transfer case input shaft and output shaft, calculating the rate of change (.DELTA.S/.DELTA.t) of the speed of the input shaft, predicting, based upon such rate of change, a time when the input shaft and the output shaft will be synchronized and commencing movement of such shift operator at a time prior to such synchronization in order to effect engagement of such clutch into high gear at substantially the instant of synchronization.

Abstract: A low-cost torque detection apparatus is obtained using wheel revolution sensors which are generally provided in a conventional ABS and an engine revolution sensor which is generally provided in a conventional engine fuel jet controller. The apparatus can be used, for example, in a vehicle having a drive source, such as an engine or a motor, for driving wheels which is coupled to the right and left wheels by respective shafts having torsional stiffness for transmitting a drive torque through a differential gear. The apparatus includes a drive source revolution angle detection device for the drive source and wheel revolution angle detection means for the right and left wheels, and calculates torques of shafts such as drive shafts for coupling the differential gear to the wheels using a torque calculator.

Abstract: In a driving force transfer apparatus for a part-time four-wheel drive vehicle with a fail safe structure, a high-speed gear range shift position and a low-speed gear range shift position in a high-speed and low-speed gear range position switching mechanism in a sub transmission are determined without special position sensors. In a case where the special position sensors are installed in the transfer apparatus, a shift position sensor diagnosis operation is effected so that a failure in either of a high-speed gear range position or low-speed gear range position sensor can easily be detected. If the failure in either of the position sensor occurs, a hydraulic (oil) pressure supply for providing a clutch pressure for a frictional clutch is made effective. Furthermore, a failure of either of revolution speed sensor detecting a first output axle revolution speed or detecting a second output axle revolution speed can also be detected. The first output axle is connected to mainly driven road wheels.

Abstract: In a control system for distributing a driving force from an engine between the front and rear wheels of a vehicle, a controller is designed to decrease the driving force transmitted to the secondary drive wheels which may be the front wheels by modifying a driving force distribution control characteristic when the vehicle is in a predetermined constant speed steady state, in order to improve the fuel economy in the steady state operation while maintaining a vivid vehicle response to a driver's accelerator input. Preferably, the controller determines an offset quantity L which has at least a cubic term proportional to the third power of a vehicle speed when the predetermined steady state exists, and increases the driving force to the secondary wheels as an excess of the wheel speed difference over the offset quantity increases from zero.

Abstract: In a torque distribution control system of a four wheel drive vehicle, it is important to distribute a driving force properly between front and rear wheels according to friction coefficient of road surface. Especially when a vehicle runs on roads with low friction coefficients of road surface, it is very important to estimate friction coefficients of the road surface which vary every moment and to control the driving force according to the estimated friction coefficients. The present invention provides the torque distribution control system with means for estimating friction coefficients of road surface every moment based on data from a steering angle sensor, a vehicle speed sensor and a yaw rate sensor and for reflecting them on the calculation of torque distribution between front and rear wheels. Furthermore, yaw moment calculating means are provided to prevent the vehicle from tack-in phenomenon by properly controlling left and right wheels.