Claims:We claim:
1. A device for measuring, computing and displaying real time wheel slippage of agricultural vehicle during field operations, comprising of : atleast a speed sensor (121), positioned on the drive wheel, wherein said sensor measures the speed of the drive wheel; atleast a speed sensor (122), positioned on the non-driven wheel, wherein said sensor measures the speed of the non-driven wheel; atleast a steering angle sensor (123), positioned on the steering shaft, wherein said steering angle sensor measures the steering angle of the vehicle; a computation unit (124), wherein said computation unit (124) receives input signals from said speed sensor (121) of drive wheel, speed sensor (122) of non-driven wheel and steering angle sensor (123) for computing the vehicle wheel slippage rate; a slip indication interface unit (135), position in connection with the said computation unit (124) for processing the slip measurement data received from the said computation unit (124); and a display unit (136a & 136b), positioned at the operator terminal, for relay and indicating the measured wheel slip to the operator.

2. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said computation unit (124), comprises of : a plurality of signal conditioners (131a, 131b, 131c) for conditioning the input signals from the speed sensor (121) of drive wheel, speed sensor (122) of non-driven wheel and steering angle sensor (123); a plurality of signal filters (132a, 132b, 132c) for filtering the input signals from the speed sensor (121) of drive wheel, speed sensor (122) of non-driven wheel and steering angle sensor (123); a microchip unit (125a) for receiving input signals from the speed sensor (121) of drive wheel, speed sensor (122) of non-driven wheel and steering angle sensor (123), wherein said microchip unit (125a) combines and estimates the accurate vehicle wheel slippage rate; and a power regulator (126) & an ignition switch (127) for regulating the power source to the said microchip unit (125a & 125b).

3. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said slip indication interface unit (135) is provided with a signal conditioner (131d); a filter (132d) unit; and a microchip unit (125b) for receiving the fluctuating real time slip measurement data computed by the computation unit (124) as input signals, wherein said microchip unit (125b) linearizes the fluctuating real time slip measurement data from the computation unit (124) and transmits the linearized slip data to the display unit (136a, 136b).

4. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said display unit (136a & 136b), includes a display gauge unit (136a) and a guidance unit (136b).

5. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said display gauge unit (136a) displays the linearized slip data in the form of gauge pattern indicating the current working slip position of the agricultural vehicle with respect to the threshold.

6. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said guidance unit (136b) is selected from a tell-tale LED or lamp, wherein said guidance unit (136b) provides an alert with a blinking pattern indicating the very high/very low slip position of the agricultural vehicle to the operator.

7. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said speed sensors (121 & 122) for driven and non-drive wheel is selected from inductive, magnetic, hall-effect, proximity sensors and/or combinations thereof.

8. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said steering angle sensor (123) is a potentiometer sensor.

9. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said computation unit (124) compute the vehicle wheel slippage by fusing the data of the steering angle with the actual speed of the vehicle and the theoretical speed of the vehicle to yield accurate slip measurement up to 1%.

10. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said computation unit (124) compute the real-time measurement of tractor slippage using real-time data received from the said speed sensors (121 & 122) of driven and non-drive wheel and the said steering angle sensor (123).

11. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said speed of the driven wheel is measured in the central drive axle (128).

12. A device for measuring real time wheel slippage, as claimed in claim 1, Wherein said speed of the driven wheel is measured in crown wheel (129).

13. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said speed of the non-driven wheel is measured in the front non-drive wheel (130).

14. A device for measuring real time wheel slippage, as claimed in claim 1, wherein said steering angle sensor (123) measures the articulation angle of the steered wheels.

15. A device for measuring real time wheel slippage, as claimed in claim 1, enables accurate wheel slip measurement at low vehicle speed of 0.1 kmph to 0.01 kmph.

16. A method of measuring real time wheel slippage of agricultural vehicle during field operations, comprises steps of:

a) measuring the real -time speed of the driven wheel by means of speed sensors (121) of drive wheel;
b) measuring the real- time speed of the non-driven wheel by means of speed sensors (122) of non-drive wheel;
c) measuring the steering angle of the vehicle by means of steering angle sensor (123);
d) transmitting the signals from speed sensors (121 & 122) and steering angle sensors (123) to the computation unit (124) as signal inputs (133a,133b,133c); and
e) computing real-time wheel slippage of vehicle by computation unit (124) by fusing the real-time data of speed of non-driven wheel, speed of driven wheel and steering angle of the vehicle received as inputs (133a, 133b,133c);
f) linearizing the fluctuating real time slip measurement data from the computation unit (124) by means of slip indication interface unit (135) and transmits the linearized slip data to the display unit (136a, 136b); and
g) displaying the linearized real time slip measurement data by the display unit (136a,136b). , Description:FIELD OF THE INVENTION
The present invention generally relates to an agricultural vehicle wheel slip measurement system, in particular the present invention is related to an apparatus and method for measuring wheel slippage of agricultural tractors during field operations using a combination of driven wheel, non-driven wheel and steering angle sensors and a display system thereof.
BACKGROUND OF THE INVENTION
Off-road vehicles, such as agricultural tractors are generally operated in a variety of soil conditions. For example, a tractor may be driven through a field of soft soil having high moisture content. In certain soil conditions, wheels of the tractor may slip relative to the soil surface. That is, the ground engaging surface of the wheel moves at a higher speed than the ground speed of the tractor. Slip is the distance that the drive wheel actually travels less than the distance that should be travelled during pure rolling. Primary purpose of an agricultural tractor is to perform intensive operations such as ploughing / tilling / puddling. During such operations the tractor is subjected to intentional slippage, with the goal of yielding optimal results on the soil. Tractor may successfully traverse a field while experiencing a low or medium degree of slippage, but high degree of slippage may cause the soil under the wheels of the tractor to become compacted and/or rutted. As a result, the yield from crops located within the compacted and/or rutted soil may be reduced. In addition, a high degree of slippage may cause the tractor to become rooted and get stuck in the soil. The process of extracting a stuck tractor from soil may become significantly time consuming and tedious. Further high wheel slippage also results in wastage of fuel and reduction in production capacity.
The slippage of driving wheel affects the driving speed and driving force of the vehicle, consuming more power of the engine. Excessive slipping may also cause the wheel to generate intense self-vibration and increased rolling resistance affecting the operability of the vehicle resulting huge losses in field operations and production.
The traction performance of tractors has always been important, valued and studied as it directly affects the efficiency of tractors. The main purpose of researching on the slip rate is to study the effect of slip on the performance of the vehicle, and then optimizing the performance of the vehicle by adjusting the slip rate. Furthermore if these slip rate values would be known then lot of new ways of vehicle stability improvement could be realized. The influence of the slip rate on the performance of the tractor is mainly reflected in the influence of the driving wheel slip on the traction performance of the tractor. Therefore it is of great significance to study the slippage of the driving wheel of the tractor to improve the performance of the tractor.

Conventionally, determination of wheel slippage is carried out mainly by comparing the indicators of the speed sensor mounted on the drive wheel shaft with those of the actual distance travelled, measured using track-measuring wheel or satellite navigation receiver. In another method, a device for measuring the slipping of agricultural tractors is provided with a measuring disk rigidly mounted on the shaft of the driving wheels, and a pulse counter mounted in the vehicle cab and connected to an inductive sensor and an input to the processing device. Additionally, the actual speed sensor is introduced in the form of a GPS navigator. Commonly used sensors for vehicle stability control functions are wheel speed sensors, steering wheel angle sensor, yaw rate sensor and lateral acceleration sensor. These velocity, position, angular velocity and acceleration sensor techniques are widely used and cheaply manufactured. An accurate real time capable sideslip sensing unit is approximately hundred times more expensive than these sensors.
However, the slip measurement systems are often insufficient and can provide inaccurate slip measurement. Speed sensors require the integration of noisy accelerometers which can experience drift, making velocity and slip determinations challenging. GNSS systems such as Global Positioning Systems (GPS) are often unreliable and subject to jammers, which makes the use of GPS challenging for relative velocity measurements and other computations.
US Patent Application 2018312170 provides a device of estimating a slip angle of vehicle wheel has an attitude-toward-road surface estimation section that uses a series of distances to measurement points on a road surface to estimate vehicle-body-road-surface coordinate conversion information (VCCI) for conversion from a vehicle-body coordinate system to a road-surface coordinate system, an on-road-surface inertia quantity calculation section that removes a gravity acceleration component from the vehicle-body inertia quantity to obtain inertia quantity caused by motion of a vehicle body and uses the VCCI to convert from the inertia quantity caused by the motion of the vehicle body to the road-surface coordinate system, and a wheel slip angle estimation section that estimates a sideslip angle of the vehicle wheel on the basis of a difference between a wheel acceleration vector and the acceleration vector converted to the road-surface coordinate system.
Japanese patent application 2018031690 discloses a slip ratio measurement device and method to measure the slip ratio of a tire when a car body travels on a road surface. A slip ratio measurement device includes: a plate buried in a road surface with which a tire comes into contact; at least three or more load sensors for measuring the load acting on the plate; and wheel speed measuring means for measuring the wheel speed of the tire. This slip ratio measurement device can determine a tire load center of gravity and a locus of the tire load center of gravity, and, on the basis of them, can determine the ground speed and slip ratio.
US Patent Application 2017350684 provides a system and method for the in-situ determination of vehicle wheel position using an inertial measurement unit (IMU). In one aspect as the wheel is rotating, gyroscope measurements are used to find a slip angle defined between the direction of wheel travel and the direction of vehicle travel, to determine a toe alignment condition for the wheel. System and methods are also presented for using an accelerometer to measure slip angle and camber angle. Using an accelerometer or gyroscope, instantaneous wheel angle measurements can also be made to predict vehicle movement, and aid in autonomous steering and in-situ wheel alignment adjustments.
US Patent Application 2017247038 relates to a method of estimating the side slip angle of a four-wheeled vehicle, comprising: detecting signals representing the vehicle longitudinal acceleration, lateral acceleration, vertical acceleration, yaw rate, roll rate, wheels speeds; pre-treating said signals in order to correct measurement errors and/or noises, determining an estimated vehicle longitudinal speed on the basis of at least one of the corrected measurements of the wheel speeds; determining a yaw acceleration from the signal representing the yaw rate; solving a time-depending parametrical non-linear filter, determining the vehicle estimated side slip angle from said longitudinal and lateral vehicle speeds determined by solving the non-linear filter. The present invention further relates to a computer program implementing said method, a control unit having said computer program loaded, and a vehicle comprising said control unit.
European Application 1358784 discloses a agricultural vehicle, in particular tractor comprising of: a central microprocessor box which compares the detected rotation rates of the driven wheels with the velocity of the tractor relative to the ground, for detecting drive slip and regulating the drive slip by altering the drive ratio of the continuously variable transmission and/or the engine revs, dependent on the slip and the minimal velocity entered via respective setting regulators. A mode switch allows primary control of the tractor velocity in dependence on the slip. An Independent claim for a slip regulation method for an agricultural tractor is also included.

The main disadvantages of the above methods include the question on accuracy of the calculated results and versatility of the systems used. Typically these systems utilize only single sensor to estimate speed of non-driven wheel, leading to inaccurate results, as it may give erroneous data while the vehicle is taking turns. Installation of equipment like speed sensor, measuring disk etc., involves high cost and it is also a laborious task. In order to transfer data from the sensors, it additionally requires lying information cables. Further these installations also require changes in the vehicle design and the measured slip is generally displayed directly as digits in the LCD texts. This makes the operator to entirely rely on his own interpretation on the amount and degree of wheel slippage and take appropriate actions.

To eliminate the above drawbacks, the present invention provides an apparatus for measuring slippage of agricultural vehicle especially tractors using a combination of driven wheel speed, non-driven wheel speed and steering angle. The present invention also provides a method which uses information from tractor steering angle, theoretical vehicle speed, and actual vehicle speed to accurately estimate tractor slippage up to 1% accuracy. The present invention measures the slip rate of the tractor under real time working conditions with utmost accuracy and indicates the measured slip parameter in the form of gauge and guidance pattern enabling the operator for optimal effective and dynamic control of the agricultural vehicle.
OBJECTIVES OF THE INVENTION
In view of the deficiencies of the prior art, the primary objective of the present invention is to provide a device for measuring wheel slippage of agricultural vehicle during field operations using a combination of speed of driven wheel, speed of non-driven wheel and steering angle.
Another objective of the present invention is to provide a device for measuring wheel slippage of agricultural vehicle comprising of a computation unit to compute the tractor slippage in real time kinetics.
Another objective of the present invention is to provide a slip indication and guidance unit for displaying wheel slippage of agricultural vehicle in form of gauge and guidance pattern.
Still another objective of the present invention is to provide a device for measuring wheel slippage of agricultural vehicle by fusing the data from steering angle with the actual speed and theoretical speed of the vehicle to yield accurate slip measurement of up to 1%.
Yet another objective of the present invention is to provide a device for measuring wheel slippage of agricultural vehicle wherein wheel slippage is calculated by using low cost inductive / magnetic / hall-effect / proximity speed sensors & potentiometer sensors.
Additional objective of the present invention is to provide a device which enables accurate wheel slippage of agricultural vehicle at low vehicle speeds of less than 0.1 kmph.
Accordingly it is highly desirable to provide an integrated device for measuring, computing and indicating wheel slippage of agricultural tractors. The wheel slip measurement is performed using speed sensors for measuring the speed of driven wheel and non-driven wheel and steering angle sensor for tractors. The device of the present invention is provided with a computation unit to compute the tractor slippage in real time by fusing real time data from vehicle steering angle, theoretical vehicle speed, and actual vehicle speed to accurately estimate tractor slippage up to 1% accuracy at low vehicle speeds of less than 0.1 kmph. The slip indication and display unit provides the measured real time wheel slippage to the operator in the form of gauge and guidance pattern enabling an optimal effective and dynamic operation of the agricultural vehicle.
Furthermore, other desirable features and characteristics of the devices, systems and methods of the herein described exemplary embodiments will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
SUMMARY OF THE INVENTION
The present invention provides a device for measuring real time wheel slippage of agricultural vehicle during field operations, comprises of : atleast a speed sensor, positioned on the non-drive wheel; atleast a speed sensor, positioned on the driven wheel; atleast a steering angle sensor, positioned on the steering shaft; a computation unit, wherein said computation unit receives input signals from said speed sensor of non-driven wheel, speed sensor of driven wheel and steering angle sensor for computing the vehicle wheel slippage rate; a slip indication interface unit, for processing the slip measurement received from the said computation unit; and a display unit for relay and indicating the measured wheel slip to the operator.
In the preferred embodiment, wherein said computation unit , comprises of : a plurality of signal conditioners; a plurality of signal filters; a microchip unit for receiving input signals from the speed sensor of non-driven wheel, speed sensor of driven wheel and steering angle sensor; and a power regulator & an ignition switch for regulating the power source to the said microchip unit.
In the preferred embodiment of the present invention, wherein said speed sensors for driven and non-drive wheel is selected from inductive, magnetic, hall-effect, proximity sensors and/or combinations thereof.
In the preferred embodiment of the present invention, wherein said computation unit compute the real-time measurement of vehicle slippage by fusing real-time data of the steering angle with the actual speed of the vehicle and the theoretical speed of the vehicle to yield accurate slip measurement up to 1%.
In the preferred embodiment of the present invention, wherein said slip indication interface unit (135) is provided with a signal conditioner (131d); a filter (132d) unit and a microchip unit (125b) for linearizing the fluctuating real time slip measurement data from the computation unit (124) and transmits the linearized slip data to the display unit (136a, 136b).
In the preferred embodiment of the present invention, wherein said display unit (136a & 136b), includes a display gauge unit (136a) and a guidance unit (136b). Wherein said display gauge unit (136a) displays the linearized slip data in the form of gauge pattern indicating the current working slip position with respect to the threshold. Wherein said guidance unit (136b) provides an alert with a blinking pattern indicating the very high/very low slip position of the agricultural vehicle to the operator
In an embodiment of the present invention, method of measuring real time wheel slippage of agricultural vehicle during field operations, comprises steps of : measuring the real -time speed of the non- driven wheel; measuring the real- time speed of the driven wheel; measuring the steering angle of the vehicle; transmitting the signals from speed sensors and steering angle sensors to the computation unit as signal inputs; and computing real-time wheel slippage of tractors by computation unit by fusing the real-time data of speed of non-driven wheel, speed of driven wheel and steering angle of the vehicle received as inputs.
The said slip measurement device according to the present invention enables accurate wheel slip measurement at low vehicle speed of 0.1 kmph to 0.01 kmph.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows the vehicle wheel slippage measurement device according to the present invention with the speed sensor (121), positioned on the drive wheel, in crown wheel (129).
Figure 2 shows the cross sectional view of vehicle wheel slippage measurement device according to the present invention with the speed sensor (121), positioned on the drive wheel. Theoretical vehicle speed is measured in the central drive axle (128).
Figure 3 shows the vehicle wheel slippage measurement device according to the present invention with the speed sensor (122), positioned on the non- driven wheel, in particular front drive wheel (130) and steering angle sensor (123), positioned on the steering shaft.
Figure 4 shows the computation unit (124) and slip indication interface unit (135) of the vehicle wheel slippage measurement device according to the present invention comprising of microchip unit (125a), a plurality of conditioning unit (131a,131b,131c), a plurality of filtering unit (132a,132b,132c), microchip unit (125b), display gauge unit (136a), guidance unit (136b), power regulator (126) and ignition switch (127).
Figure 5a shows the convention method of slip measurement.
Figure 5b shows vehicle wheel slippage computation and display method according to the present invention.
Figure 6a shows the symbolic denotations of steering angle measurement for agricultural vehicle turning left side.
Figure 6b shows the symbolic denotations of steering angle measurement for agricultural turning right side
Figure 7 represents the graph comparing the conventional slip measurement (B) using PA-5 and corrected slip (A) measurement according to the present invention.
Figure 8 shows the flow chart for fusing data from different sensors and computing vehicle slip according to the present invention and functioning of slip indication interface unit (135).
Figure 9 shows the gauge gain chart showing the slip range of the working agricultural vehicle with respect to the thresholds as displayed in the display gauge unit (136a).
Figure 10 shows the guidance lamp pattern as shown in display guidance unit (136b).
Figure 11a represents the graph showing reduction in average slip by providing the computed real time slip measurement data according to the present invention as feedback.
Figure 11b represents the graph showing increase in average vehicle speed by providing the computed real time slip measurement data according to the present invention as feedback.
While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
DETAILED DESCRIPTION OF THEINVENTION WITH RESPECT TO DRAWINGS
The present invention as embodied by a “Device for measuring vehicle wheel slippage and method thereof" succinctly fulfils the above-mentioned need(s) in the art. The present invention has objective(s) arising as a result of the above-mentioned need(s), said objective(s) being enumerated below. In as much as the objective(s) of the present invention are enumerated, it will be obvious to a person skilled in the art that, the enumerated objective(s) are not exhaustive of the present invention in its entirety, and are enclosed solely for the purpose of illustration. Further, the present invention encloses within its scope and purview, any structural alternative(s) and/or any functional equivalent(s) even though, such structural alternative(s) and/or any functional equivalent(s) are not mentioned explicitly herein or elsewhere, in the present disclosure. The present invention therefore encompasses also, any improvisation(s)/modification(s) applied to the structural alternative(s)/functional alternative(s) within its scope and purview. The present invention may be embodied in other specific form(s) without departing from the spirit or essential attributes thereof.
Throughout this specification, the use of the word "comprise" and variations such as "comprises" and "comprising" may imply the inclusion of an element or elements not specifically recited.
The present invention aims to overcome the defects of the existing expensive slip measurement systems, inaccuracies and sensors for agricultural tractors by providing a device for measuring and computation of wheel slippage of agricultural vehicle during field operations using a combination of speed of driven wheel, speed of non-driven wheel and steering angle. The slip measurement system according to the present invention is provided with a computation unit to compute the tractor slippage in real time by fusing real-time data from steering angle with the actual speed and theoretical speed of the vehicle to yield accurate slip measurement of up to 1%. The slip measurement system according to the present invention enables to measure the slippage of agricultural vehicles during primary / secondary field operations using a combination of magnetic / inductive/ hall-effect / proximity and potentiometer sensors. The slip measurement system further includes a slip indication and display unit which displays the measured wheel slip in the form of gauge and guidance pattern. The slip measurement system according to the present invention enables accurate slip measurement at low speed operations in less than 0.1kmph.
The present invention provides a device for measuring, computing and displaying real time wheel slippage of agricultural vehicle during field operations, comprises of : atleast a speed sensor (122), positioned on the non-drive wheel, wherein said sensor measures the speed of the non- driven wheel; atleast a speed sensor (121), positioned on the driven wheel, wherein said sensor measures the speed of the driven wheel; atleast a steering angle sensor (123), positioned on the steering shaft, wherein said steering angle sensor measures the steering angle of the vehicle; a computation unit (124), wherein said computation unit (124) receives input signals from said speed sensor (122) of non-driven wheel, speed sensor (121) of driven wheel and steering angle sensor (123) for computing the vehicle wheel slippage rate; a slip indication interface unit, position in connection with the said computation unit (124) for processing the slip measurement received from the said computation unit (124); and a display unit (136a & 136b), positioned at the operator terminal, for relay and indicating the measured wheel slip to the operator.
In the preferred embodiment of the present invention, wherein said computation unit (124), comprises of : a plurality of signal conditioners (131a, 131b, 131c) for conditioning the input signals from the speed sensor (122) of non-driven wheel, speed sensor (121) of driven wheel and steering angle sensor (123); a plurality of signal filters (132a, 132b, 132c) for filtering the input signals from the speed sensor (122) of non-driven wheel, speed sensor (121) of driven wheel and steering angle sensor (123); a microchip unit (125a) for receiving input signals from the speed sensor (122) of non-driven wheel, speed sensor (121) of driven wheel and steering angle sensor (123), wherein said microchip unit (125) combines and estimates the accurate vehicle wheel slippage rate; and a power regulator (126) & an ignition switch (127) for regulating the power source to the said microchip unit (125a, 125b).
In the preferred embodiment of the present invention, wherein said plurality of signal conditioners (131a, 131b, 131c) includes analog input signal conditioner (131a) for conditioning the input signals from steering angle sensor (123), speed signal conditioner (131b) for conditioning the input signals from the speed sensor (122) of non-driven wheel, speed signal conditioner (131c) for conditioning the input signals from the speed sensor (121) of driven wheel.
In the preferred embodiment of the present invention, wherein said plurality of signal filters (132a, 132b, 132c) includes steering angle filter (132a) for filtering the input signals from steering angle sensor (123), theoretical speed signal filter (132b) for filtering the input signals from the speed sensor (122) of non-driven wheel, actual speed signal filtering (132c) for conditioning the input signals from the speed sensor (121) of driven wheel.
In the preferred embodiment of the present invention, wherein said speed sensors (121 & 122) for driven and non-drive wheel is selected from inductive, magnetic, hall-effect, proximity sensors and/or combinations thereof.
In the preferred embodiment of the present invention, wherein said steering angle sensor (123) is a potentiometer sensor.
In the preferred embodiment of the present invention, wherein said computation unit (124) compute the slippage of tractor by fusing the data of the steering angle with the actual speed of the vehicle and the theoretical speed of the vehicle to yield accurate slip measurement up to 1%.
In the preferred embodiment of the present invention, wherein said computation unit (124) compute the real-time measurement of tractor slippage using real-time data received from the said speed sensors (121 & 122) of driven and non-drive wheel and the said steering angle sensor (123).
In the preferred embodiment of the present invention, wherein said speed of the drive wheel or the theoretical vehicle speed is measured in the central drive axle (128). Wherein said speed of the drive wheel is measured in crown wheel (129).
In the preferred embodiment of the present invention, wherein said speed of non-driven wheel or actual vehicle speed is measured in front drive wheel (130). Wherein said speed of the non-driven wheel is measured in right front drive wheel. Wherein said speed of the non-driven wheel is measured in right front drive wheel or left front drive wheel.
In the preferred embodiment of the present invention, wherein said steering angle sensor (123) measures the articulation angle of the steered wheels.
In the preferred embodiment of the present invention, wherein said slip indication interface unit (135) is provided with a signal conditioner (131d); a filter (132d) unit and a microchip unit (125b).
In the preferred embodiment of the present invention, wherein said slip indication interface unit (135) linearizes the fluctuating real time slip measurement data from the computation unit (124) and transmits the linearized slip data to the display unit (136a, 136b).
In the preferred embodiment of the present invention, wherein said display unit (136a & 136b), includes a display gauge unit (136a) and a guidance unit (136b). Wherein said display gauge unit (136a) displays the linearized slip data in the form of gauge pattern indicating the current working slip position with respect to the threshold. Wherein said guidance unit (136b) is selected from a tell-tale LED or lamp. Wherein said guidance unit (136b) provides an alert with a blinking pattern indicating the very high/very low slip position of the agricultural vehicle to the operator.
In the preferred embodiment of the present invention, wherein said slip measurement apparatus enables accurate wheel slip measurement at low vehicle speed of 0.1 kmph to 0.01 kmph.
In an embodiment of the present invention, method of measuring real time wheel slippage of agricultural vehicle during field operations, comprises steps of :
a) measuring the real -time speed of the non- driven wheel by means of speed sensors (122) of non-drive wheel;
b) measuring the real- time speed of the driven wheel by means of speed sensors (121) of drive wheel;
c) measuring the steering angle of the vehicle by means of steering angle sensor (123);
d) transmitting the signals from speed sensors (121 & 122) and steering angle sensors (123) to the computation unit (124) as signal inputs (133a,133b,133c);
e) computing real-time wheel slippage of tractors by computation unit (124) by fusing the real-time data of speed of non-driven wheel, speed of driven wheel and steering angle of the vehicle received as inputs (133a, 133b,133c);
f) linearizing the fluctuating real time slip measurement data from the computation unit (124) by means of slip indication interface unit (135) and transmits the linearized slip data to the display unit (136a, 136b); and
g) displaying the linearized real time slip measurement data by the display unit (136a,136b);

In the preferred embodiment of the present invention, wherein said speed sensors (121 & 122) for driven and non-drive wheel is selected from inductive, magnetic, hall-effect, proximity sensors and/or combinations thereof.
In the preferred embodiment of the present invention, wherein said speed of the drive wheel or the theoretical vehicle speed is measured in the central drive axle (128). Wherein said speed of the drive wheel is measured in crown wheel (129).
In the preferred embodiment of the present invention, wherein said speed of the non-driven wheel or the actual vehicle speed is measured in the front drive wheel (130). Wherein said speed of the non-driven wheel is measured in right front non-driven wheel. Wherein said speed of the non-driven wheel is measured in right front drive wheel left front non-driven wheel.
In the preferred embodiment of the present invention, wherein said steering angle sensor (123) is a potentiometer sensor.
In the preferred embodiment of the present invention, wherein said steering angle (123) sensor measures the articulation angle of the steered wheels.
In the preferred embodiment of the present invention, wherein said microchip unit (125) receives input signals from the speed sensor of non-driven wheel, speed sensor of driven wheel and steering angle sensor, combines and estimates the accurate vehicle wheel slippage rate.
In the preferred embodiment of the present invention, wherein said display unit (136a & 136b), includes a display gauge unit (136a) and a guidance unit (136b). Wherein said display gauge unit (136a) displays the linearized slip data in the form of gauge pattern indicating the current working slip position with respect to the threshold. Wherein said guidance unit (136b) is selected from a tell-tale LED or lamp. Wherein said guidance unit (136b) provides an alert with a blinking pattern indicating the very high/very low slip position of the agricultural vehicle to the operator.
In the preferred embodiment of the present invention, wherein said power regulator (126) and ignition switch (127) regulates the power source supplied to the said microchip unit (125).
In another embodiment of the present invention, Wherein computed slip measurement data is provided as a feed back mechanism in reducing the average slip of the agricultural vehicle as shown in Fig.11a.
In another embodiment of the present invention, wherein computed slip measurement data is provided as a feed back mechanism in increasing the average vehicle speed of the agricultural vehicle as shown in Fig. 11b.
EXAMPLE 1
During agricultural field operations such as ploughing, tilling, puddling, measuring real time wheel slippage of agricultural vehicle according to the present invention involves steps of, measuring the real-time speed of the drive wheel by means of speed sensors (121) mounted on the crown wheel (129) of the vehicle. Measuring the real-time speed of the non-driven wheel by means of speed sensors (122) mounted on either right side or left side front wheel of the vehicle. Wherein said speed sensors are selected from inductive, magnetic, hall-effect, proximity sensors and/or combinations thereof. Measuring the steering angle of the vehicle by means of steering angle sensor (123) mounted on the steering shaft. Wherein said steering angle sensor is a potentiometer sensor. Wherein said steering angle is measured in degrees. All the real-time sensor measurements are transferred as input signals to the computation unit (124) as shown in Fig.4. As shown in fig 4, the microchip (125) computes the vehicle slip measurement by combining and fusing all the measured data namely, the speed of non-driven speed, speed of drive speed and the steering angle. As shown in Fig. 4 the microchip (125a) computes the actual speed of the vehicle from the signals received from the speed sensor of non-drive wheel, either right side or left side front wheel of the vehicle. Theoretical speed of the vehicle is computed from the signals received from the speed sensor of drive wheel, on the crown wheel of the vehicle. Steering angle of the vehicle is computed by microchip by means of signals received from the potentiometer mounted on the steering shaft, wherein said steering angle is measured in degrees from which the turning radiuses (R1, R2) of the vehicle is computed as shown in Fig. 6a & Fig. 6b. Wherein vehicle wheel slip measurement is computed by microchip by combining and fusing the computed data of actual vehicle speed, theoretical vehicle speed and the steering angle in terms of turning radius of the vehicle (R1, R2). Wherein said computed slip measurement data in a fluctuating form is transmitted to the slip indication interface unit (135) where the slip data is linearized by means of microchip unit (125b). Linearized slip data is transmitted to the display unit comprising of, a display gauge unit (136a) which displays the linearized slip data in the form gauge pattern, and a guidance unit (136b) with a tell-tale LED lamp which provides an alert to the operator when the working agricultural vehicle is subjected to very high or very low slip position. Wherein display gauge unit (136a) displays the current working position of the vehicle with respect to the extreme thresholds.
It will be apparent to a person skilled in the art that the above description is for illustrative purposes only and should not be considered as limiting. Various modifications, additions, alterations, and improvements without deviating from the spirit and the scope of the invention may be made by a person skilled in the art.