Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:


Field of the invention:
[0001] The present disclosure relates to a controller and method to determine slip in a drive wheel of a vehicle.

Background of the invention:
[0002] A rider safety is a very important parameter to consider while designing a two-wheeler. As the rider is exposed to the environment, accidents or even falls cause severe injuries or turn fatal. Thus, improving rider safety is paramount and needs to be concentrated on. A loss of rear wheel traction occurs when the rider requests power but due to less friction with the road surface (loose sand, oil patches, wet roads, bad tires etc.), the rear wheel spins freely. This can have two effects: in first, the rear wheel never finds traction and the bike falls in the direction lean (low side). In second, the rear wheel finds sudden traction and the bike moves aggressively in the opposite side of lean like a pendulum and throws the rider away (high side). If these traction loss events can be detected, the power to the wheels can be cut to avoid these events and the bike can find traction.

[0003] According to existing prior art, there exists a system and method for estimating turning circle diameter and traction loss of a vehicle. The system controls the air pressure of the ride air springs of the lift axle based on the vehicle steering angle. It increases the traction automatically in the vehicle during a sever turn. The prior art uses two wheel speed sensors to detect the slip situation at all times. Similarly, another prior art discloses a “Joint Wheel-Slip and Vehicle-Motion Estimation Based on Inertial, GPS, and Wheel-Speed Sensors” by Karl Berntorp. This is for a four-wheeler and discloses about different sensors (GPS, wheel speed sensor and IMU) used for determining the wheel slip and vehicle motion. The paper concentrates on connectivity between and sensors and using the sensors data as an estimator. In yet another prior art, a “tire Modeling and Friction Estimation” by Jacob Svendenius is disclosed. The tire modelling and friction is modelled at different instances of driving such as cornering, cambers, and braking. One of the main inputs for all this is wheel slip information. A feedforward filter on the brake torque that predicts the disturbances on the wheel speed due to the application of the brakes is present. But still this is only during braking and the actual slip is still calculated using sensors on all wheels. In all the above-mentioned prior arts, wheel speed sensors are still used for determining the wheel slip scenario. The current Traction Control (TC) feature uses two wheel speed sensors front and back. If the rear wheel speed is more than the front, after multiple processing steps the event is considered as a wheel slip event.

[0004] According to a prior art US6577944, a traction control system is disclosed. There is provided a method for controlling the driving traction of a wheel on a surface to reduce slippage of the wheel on the surface without the need to monitor the rotational speed of the wheel where the wheel is driven by a power unit. A threshold value of maximum acceptable acceleration for the power unit is established. The rotational speed of the power unit is measured for a first selected time interval. The rotational speed of the power unit is measured for a second selected time interval. The difference between the rotational speed of the power unit in the second time interval and the rotational speed of the power unit in the first time interval is determined. The difference between the rotational speed of the power unit in the second and first time intervals are compared with the established threshold value. If the difference in rotational speed of the power unit is greater than the established threshold value, a corrective action is initiated to reduce the rotational speed of the power unit.

Brief description of the accompanying drawings:
[0005] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0006] Fig. 1 illustrates a block diagram of a controller to determine slip in a drive wheel of a vehicle, according to an embodiment of the present invention, and
[0007] Fig. 2 illustrates a method flow diagram for determining slip in the drive wheel of the vehicle, according to the present invention.

Detailed description of the embodiments:
[0008] Fig. 1 illustrates a block diagram of a controller to determine slip in a drive wheel of a vehicle, according to an embodiment of the present invention. The controller 110 configured to receive crankshaft position signal from a crankshaft position sensor 102 when the vehicle 100 is in motion, characterized in that, the controller 110 further configured to process the crankshaft position signal through a computational module 106, compare output of the computational module 106 with a threshold value, and determine slip in the drive wheel 114 of the vehicle 100 based on the comparison. The controller 110 is configured to monitor angular acceleration of the crankshaft instead of engine RPM, as the crankshaft undergoes different speeds within a combustion cycle based on the stroke, but engine speed would be an average (approx..) of these varying speeds.

[0009] According to an embodiment of the present invention, the computational module 106 performs at least one operation selected from a group comprising a differentiation 108 and Discreet Fourier Transform (DFT) 112 to the crankshaft position signal. The output of the differentiation 108 is angular acceleration of a crankshaft of the vehicle 100. The output of the DFT 112 is magnitude component and phase component.

[0010] According to the present invention, the threshold value is corrected by a correction factor which is selected based on vehicle speed. In other words, there exists a map or table which comprises vehicle speed and corresponding correction factor, which is applied to the threshold value. Thus the controller 110 uses a dynamic threshold value instead of static/fixed threshold value.

[0011] According to an embodiment of the present invention, the controller 110 is applicable for two-wheeler vehicle such as motorcycle, scooter, three wheeler vehicle such as auto-rickshaw, four-wheeler vehicle such as cars and other vehicles 100. Specifically, the controller 110 is applicable for vehicle 100 with or without Anti-lock Braking System (ABS).

[0012] According to an embodiment of the present invention, the controller 110 configured to adjust torque to eliminate the slip. The torque adjustment is implemented through at least one of an injection control, an ignition control, and an air flow control.

[0013] According to the present invention, the controller 110 continuously determines slip or initiates the slip determination only after boundary conditions comprising parameters such as engine RPM, engine torque, clutch status are satisfied with respective preset values.

[0014] In accordance to an embodiment of the present invention, the controller 110 is provided with necessary signal detection, acquisition, and processing circuits. The controller 110 is the one which comprises input interface, output interfaces having pins or ports, the memory element 104 such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and a Digital-to-Analog Convertor (DAC), clocks, timers, counters and at least one processor (capable of implementing machine learning) connected with each other and to other components through communication bus channels. The memory element 104 is pre-stored with logics or instructions or programs or applications or modules/models and/or threshold values/ranges, reference values, predefined/predetermined criteria/conditions, which is/are accessed by the at least one processor as per the defined routines. The internal components of the controller 110 are not explained for being state of the art, and the same must not be understood in a limiting manner. The controller 110 may also comprise communication units such as transceivers to communicate through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, and the like. The controller 110 is implementable in the form of System-in-Package (SiP) or System-on-Chip (SOC) or any other known types. Examples of controller 110 comprises but not limited to, microcontroller, microprocessor, microcomputer, etc.

[0015] Further, the processor may be implemented as any or a combination of one or more microchips or integrated circuits interconnected using a parent board, hardwired logic, software stored in the memory element 104 and executed by a microprocessor, firmware, an application specific integrated circuit (ASIC), and/or a field programmable gate array (FPGA). The processor is configured to exchange and manage the processing of various Artificial Intelligence (AI) modules.

[0016] According to the present invention, the controller 110 is part of at least one of an internal device and an external device. The internal device is at least one Electronic Control Unit (ECU) selected from a group comprising is at least one of an Engine Management System (EMS) controller, a Tire Pressure Monitoring System (TPMS) controller, a Telematics Control Unit (TCU) controller, an Anti-lock Braking System (ABS) controller, an Electronic Stability Program (ESP) controller and a combination thereof. The external device is at least one of a cloud based device and a communication device. The external device is connected through a Telematic Control Unit (TCU) of the vehicle 100 through at least one a wired and wireless means known in the art. The communication device corresponds to electronic computing devices which enable a rider or driver or a user to communicate with others such as smartphone, wearable electronics such as smart watch, etc. The cloud based device corresponds to cloud computing architecture having network of servers, databases connected with each other and vehicle 100 for processing of inputs and providing outputs. Thus, the processing is done by any one of the internal device and the external device or both. In case of both, the processing is shared as per the respective loading and capacity of processing.

[0017] Fig. 2 illustrates a method flow diagram for determining slip in the drive wheel of the vehicle, according to the present invention. The method comprises plurality of steps of which a step 202 comprises receiving, by the controller 110, crankshaft position signal from the crankshaft position sensor 102 while the vehicle 100 is in motion. The crankshaft position signal is continuously received in real time. The method is characterized by a step 204 which comprises processing, by the controller 110, the crankshaft position signal through the computational module 106. A step 206 comprises comparing, by the controller 110, output of the computational module 106 with the threshold value. A step 208 comprises determining, by the controller 110, slip in the drive wheel 114 of the vehicle 100 based on the comparison. The method is adapted to monitor angular acceleration of the crankshaft instead of engine RPM, as the crankshaft undergoes different speeds within the combustion cycle based on the stroke, but engine speed would be an average (approx..) of these varying speeds.

[0018] According to the step 204, the computational module 106 performs at least one operation selected from a group comprising the differentiation 108 and the Discreet Fourier Transform (DFT) 112 to the crankshaft position signal. The output of the differentiation 108 is angular acceleration of the crankshaft, and the output of the DFT 112 is magnitude component and phase component.

[0019] In the step 206, the method also comprises correcting the threshold value based on the correction factor. The correction factor is selected depending on vehicle speed. Thus, there exists the map or the table which comprises vehicle speed and corresponding correction factor, which is applied to the threshold value.

[0020] The method comprises adjusting torque to eliminate the slip. The torque adjustment is implemented through at least one of the injection control, the ignition control, and the air flow control.

[0021] According to the present invention, the method is implemented for the vehicle 100 such as the two-wheeler vehicle. However, the method is implementable for other vehicles 100 as mentioned above.

[0022] According to the present invention, the controller 110 is configured/adapted to determine the wheel slip event with the help of crankshaft position sensor 102 (or crankshaft speed sensor) by exploiting the effect of the wheel slip on the crankshaft, thus eliminating the need for wheel speed sensors and the encoder wheel assemblies at the wheels. The engine speed that is read in the controller 110 is not only a function of the power delivered by the engine but is also indirectly shows the state of the rear wheel. The controller 110 monitors the crankshaft position signal (or engine speed) to detect traction loss/wheel slip events. The threshold value have the correction factor which is based on vehicle speed. The disadvantage of having a fixed threshold is that the slip varies due different factors and the dynamics involved in motorcycles due to lean etc. The present invention provides wheel-slip detection based on engine parameters.

[0023] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:We claim:
1. A controller (110) to determine slip in a drive wheel (114) of a vehicle (100), said controller (110) configured to:
receive crankshaft position signal from a crankshaft position sensor (102) when said vehicle (100) is in motion, characterized in that,
process said crankshaft position signal through a computational module (106),
compare output of said computational module (106) with a threshold value, and
determine slip in said drive wheel (114) of said vehicle (100) based on said comparison.

2. The controller (110) as claimed in claim 1, wherein said computational module (106) performs at least one operation selected from a group comprising a differentiation (108) and Discreet Fourier Transform (DFT) (112) to said crankshaft position signal.

3. The controller (110) as claimed in claim 2, wherein output of said differentiation (108) is angular acceleration of a crankshaft of an engine of said vehicle (100), wherein output of said DFT (112) is magnitude component and phase component.

4. The controller (110) as claimed in claim 1, wherein said threshold value is corrected based on a correction factor, said correction factor is selected based on vehicle speed.

5. The controller (110) as claimed in claim 1, configured to adjust engine torque to eliminate said slip, wherein said engine torque adjustment is implemented through at least one of an injection control, an ignition control, and an air flow control.

6. A method for determining slip in a drive wheel (114) of a vehicle (100), said method comprising the steps of:
receiving crankshaft position signal from a crankshaft position sensor (102) while said vehicle (100) is in motion, characterized by,
processing said crankshaft position signal through a computational module (106),
comparing output of said computational module (106) with a threshold value, and
determining slip in said drive wheel (114) of said vehicle (100) based on said comparison.

7. The method as claimed in claim 6, wherein said computational module (106) performs at least one operation selected from a group comprising a differentiation (108) and Discreet Fourier Transform (DFT) (112) to said crankshaft position signal.

8. The method as claimed in claim 7, wherein output of said differentiation (108) is angular acceleration of a crankshaft of an engine of said vehicle (100), and output of said DFT (112) is magnitude component and phase component.

9. The method as claimed in claim 6, comprises correcting said threshold value based on a correction factor, said correction factor is selected depending on vehicle speed.

10. The method as claimed in claim 6, comprises adjusting engine torque to eliminate said slip, wherein said engine torque adjustment is implemented through any one of an injection control, an ignition control, and an air flow control.