DESC:FIELD OF THE INVENTION
[001] Present invention relates a steer assist assembly for a vehicle. Embodiments of the present invention also discloses a method of assisting steering of the vehicle.

BACKGROUND OF THE INVENTION
[002] Typically, a vehicle is provided with a steering assembly, that is coupled to one or more wheels of the vehicle. As such, the vehicle is customarily steered by forces exerted onto the steering assembly by a rider. Generally, the rider exerts minimal force onto the steering assembly while driving the vehicle in a straight line. However, forces exerted on the steering assembly vary during cornering of the vehicle. In certain instances, such as a low speed cornering, the rider exerts a greater force on the steering assembly. In certain instances, such as a high speed cornering, the rider may exert a minimal force on the steering column while leaning or inclining the vehicle. Further, the scenario pertaining to force exerted on the steering assembly completely changes when the rider is braking while cornering. Thus, in order to maintain vehicle stability during riding, the rider needs to consider and control plurality of variables, wherein a single error may prove to be fatal.
[003] In order to overcome the aforesaid limitation, steer assistance systems are provided in the art. These systems incorporate plurality of sensors such as a steering angle sensor, a steering torque sensor and the like in the vehicle for procuring vehicle data. An assist torque is then provided to the steering assembly for ensuring balance of the vehicle. However, these systems are associated with plurality of sensors for procuring vehicle data making the system expensive. Also, the conventional steer assist systems are bulky in nature due to large number of components, rendering packaging issues in the vehicle, particularly in two-wheeled vehicle. Further, bulky construction of the conventional steer assist systems also adds on weight in the vehicle, which is undesirable in view of performance and efficiency of the vehicle.
[004] Additionally, in two-wheeled vehicles, instability at low-speeds requires continuous steering inputs for providing the balance. As such, torque required for providing such steering inputs in conventional steering systems can be provided through an actuator device. However, the torque required for balancing the two-wheeled vehicle is high and frequent, and thus a bulkier or a larger sized actuator is required to be used in the two-wheeled vehicle, which is undesirable in view of packaging constraints, weight and costs involved.
[005] In view of the above, there is a need for a steer assist assembly that addresses at least some of the limitations mentioned above.

SUMMARY OF THE INVENTION
[006] In one aspect, a steer assist assembly is disclosed. The steer assist assembly comprising a first member connected to a second member. The second member configured to provide a steer assist torque to the first member when one or more vehicle operating parameters reach a threshold limit. The one or more vehicle operating parameters are sensed by one or more sensing units. The one or more sensing units are operably connected to at least one of the first member or the second member.
[007] In an embodiment, the first member is one of a handlebar assembly and a steering wheel, and the second member is an actuator.
[008] In an embodiment, the second member is coupled to the first member through a transmission assembly. The transmission assembly comprises a primary member coupled to an intermediate member and a secondary member coupled to the first member (102). The secondary member is connected with the primary member for receiving the steer assist torque from the second member.
[009] In an embodiment, the transmission assembly comprises the intermediate member coupled to the secondary member and to the first member. The intermediate member is engaged with a movable member provided to the first member. The movable member is movable on the intermediate member corresponding to actuation of the first member.
[010] In an embodiment, the one or more sensing units comprise a steering sensor unit. The steering sensor unit is provided with a sensor shaft. The sensor shaft is engaged to a movable member, wherein the sensor shaft is adapted to move corresponding to actuation of the movable member for determining steering angle information of the first member.
[011] In an embodiment, the second member is communicably coupled with a control unit. The control unit is communicably coupled to the one or more sensing units and the second member. The control unit is adapted to operate the second member for providing the steer assist torque to the first member based on the one or more vehicle operating parameters.
[012] In another aspect, a method of assisting steering of a vehicle is disclosed. The method comprises detecting by the one or more sensing units the one or more vehicle operating parameters. The control unit thereafter is configured to estimate a steer assist torque when one or more vehicle operating parameters reach a threshold limit. The control unit is then configured to operate the second member for providing the steer assist torque to the vehicle.
[013] In an embodiment, the one or more vehicle operating parameters comprises vehicle speed, a roll rate of the vehicle, a steering angle, a lean angle, and an angle of a sensor shaft.
[014] In an embodiment, the control unit is configured to estimate a balance steer assist torque when the vehicle speed is below a threshold limit. Thereafter, the control unit is configured to operate the second member to provide the balance steer assist torque to the first member for maintaining balance of the vehicle.
[015] In an embodiment, the control unit is configured to estimate a power steer assist torque when the vehicle speed is above the threshold limit. The control unit is then configured to operate the second member to provide the power steer assist torque to the first member for maintaining balance of the vehicle.
[016] In an embodiment, the control unit is configured to determine a constant voltage to be 0 Volts, when the angle of the sensor shaft is determined to be less than 5 degrees. The control unit is configured to determine a linear voltage from 0 Volts to 5 Volts, when the angle of the sensor shaft is determined to be between 5 degrees to 125 degrees. The control unit is configured to determine a constant voltage to be 5 Volts, when the angle of the sensor shaft is determined to be greater than 125 degrees. The control unit is configured to supply one of the constant voltage of 0 Volts, the linear voltage of 0 Volts to 5 Volts and the constant voltage of 5 Volts to the second member corresponding to the angle of the sensor shaft.
[017] In an embodiment, the control unit is configured to determine a mean of an actual steering angle over a predetermined time. The control unit is then configured to identify the control unit a change in the actual steering with respect to the steering angle over the pre-determined time period.
[018] In an embodiment, the control unit is configured to determine a hysteresis torque. The control unit is configured to determine a mean of an actual steering angle and the hysteresis torque over a predetermined time. The control unit is then configured to determine a change in the actual steering and the hysteresis torque with respect to the steering angle and hysteresis torque over the pre-determined time period.
[019] In an embodiment, the control unit is configured to compare the hysteresis torque with a threshold value. The control unit then determines a motor torque to be provided, if the mean hysteresis torque is greater than the threshold value or if the hysteresis torque is greater than the threshold value. The control unit is then configured to operate the second member corresponding to the determined motor torque. The control unit then determines that the vehicle is assisted upon operating the second member.
[020] In an embodiment, the control unit is configured to compare the hysteresis torque with the threshold value. The control unit is then configured to determine a motor torque to be zero, if the mean hysteresis torque is less than the threshold value or if the hysteresis torque is less than the threshold value.

BRIEF DESCRIPTION OF ACCOMAPNYING DRAWINGS
[021] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 is a perspective view of a front portion of a vehicle including a steer assist assembly, in accordance with an exemplary embodiment of the present invention.
Figure 2 is a top view of the front portion of the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 3 a left-rear perspective view of the front portion of the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 4 is an exploded view of a first member of the vehicle including the steer assist assembly, in accordance with an exemplary embodiment of the present invention.
Figure 5 is a perspective view of the steer assist assembly mounted onto a steering column of the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 6 is an exploded view of the steer assist assembly mounted onto the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 7 is a left side view of the steer assist assembly mounted the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 8 is a top view of the steer assist assembly mounted onto vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 9 is a perspective view of the steer assist assembly mounted onto the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 10 is a flow diagram of a method of assisting steering of the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 11 is a flow diagram of a method of assisting steering of the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 12 is a flow diagram of a method of assisting steering of the vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 13 is a graphical illustration of a steering torque with respect to time applied on a conventional steer assist assembly, in accordance with an exemplary embodiment of the present invention.
Figure 14 is a graphical illustration of a steering torque with respect to time in the steer assist assembly, in accordance with an exemplary embodiment of the present invention.
Figure 15 is a graphical illustration of a steering torque with respect to a Root Mean Square (RMS) Value when a steer assist is OFF and when the steer assist is ON in the steer assist assembly, in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[022] Present invention discloses a steer assist assembly for a vehicle. The steer assist assembly comprises a first member, which can be a handlebar assembly or a steering wheel, connected to a second member, wherein the second member is an actuator. The second member is adapted to provide an assist to the first member when one or more vehicle operating parameters reaches a threshold limit. In an embodiment, the second member is adapted to provide the assist through a transmission assembly connected between the first member and the second member.
[023] The steer assist assembly of the present invention is adapted to improve rider experience, as less effort is required for steering the vehicle, thereby reducing rider fatigue. Also, minimal number of parts are provided in the steer assist assembly, reducing the overall cost as well as mitigating packaging issues.
[024] Figure 1 is a perspective view of a front portion of a vehicle 122 including a steer assist assembly 100, in accordance with an exemplary embodiment of the present invention. For ease of reference and for sake of brevity, the portion of the vehicle 122 comprising the steer assist assembly 100 is depicted in the figures. In the present embodiment, the steer assist assembly 100 is mounted above a front wheel 124 of the vehicle 122, and thus the portion above the front wheel 124 is depicted as the front portion of the vehicle 122. The vehicle 122 can be a two-wheeled vehicle, a three-wheeled vehicle or a multi-wheeled vehicle as per requirement. In the present embodiment, the vehicle 122 is a two-wheeled vehicle.
[025] Referring to Figures 2 and 3 in conjunction with Figure 1, the vehicle 122 has a first member 102, which can be a handlebar assembly or a steering wheel. In the present embodiment, the first member 102 is the handlebar assembly. The first member 102 is also coupled to the front wheel 124 through a suspension assembly 126 (as shown in Figure 2) known in the art and a steering column 130 (shown in Figure 5). The first member 102 is also pivotally supported on a headtube 128 (as shown in Figure 3) of a frame assembly (not shown) of the vehicle 122. As such, the first member 102 is mounted or positioned on top of the front wheel 124 (as shown in Figure 2). The pivotal actuation of the first member 102 by a rider (not shown) of the vehicle correspondingly actuates the front wheel 124, thereby enabling steering of the vehicle.
[026] In an embodiment, referring to Figures 4 and 5 in conjunction with Figures 1-3, the first member 102 (i.e. the handlebar assembly) comprises an upper triple clamp 132a, a lower triple clamp 132b and the steering column 130. The upper triple clamp 132a is mounted on a top portion (not shown) of the headtube 128. The lower triple clamp 132b is mounted to a bottom portion (not shown) of the headtube 128. The upper triple clamp 132a and the lower triple clamp 132b are provided with slots at either ends for receiving the suspension assembly 126. As such, the upper triple clamp 132a engages with a top end of the suspension assembly 126, while the lower triple clamp 132b engages with a central portion of the suspension assembly 126. At the central portion of the upper triple clamp 132a and the lower triple clamp 132b, the steering column 130 is supported. Further, on the upper triple clamp 132a a holder 134 is provided for supporting the first member 102. Thus, pivotal actuation of the first member 102 correspondingly actuates the front wheel 124, through the upper triple clamp 132a, the lower triple clamp 132b and the steering column 130 thereby enabling steering of the vehicle.
[027] Figure 6 provides an exploded view of the steer assist assembly 100 mounted onto the vehicle 122. The steer assist assembly 100 comprises the first member 102 connected to a second member 104. The second member 104 is adapted to provide an assist to the first member 102 when one or more vehicle operating parameters reach a threshold limit. In the present embodiment, the second actuator 104 is an actuator such as a motor. Alternatively, the second actuator 104 can be a hydraulic actuator or a pneumatic actuator as per requirement.
[028] The second member 104 (i.e. the actuator) is coupled with the first member 102 through a transmission assembly 108. The transmission assembly 108 is adapted to enhance the torque supplied to the first member 102 by the second member 104, thereby mitigating the need for a larger second member 104. Also, cost of larger second member 104 is mitigated, thereby making the steer assist assembly 100 of the present invention inexpensive.
[029] The transmission assembly 108 comprises a primary member 110 coupled to the second member 104. In an embodiment, the second member 104 may be provided with a shaft 104a. Accordingly, the primary member 110 is connected to the second member 104 through the shaft 104a by conventional connecting techniques known in the art such as clamping, fastening and the like. Further, a central axis B-B’ (shown in Figures 5, 7 and 9) of the primary member 110 is oriented parallelly to a central axis A-A’ (shown in Figures 5, 7 and 9) of the steering column 130. In an embodiment, the primary member 110 is a spur gear member.
[030] Further, the transmission assembly 108 comprises a secondary member 112 coupled to the first member 102 (also shown in Figure 8). In the present embodiment, the secondary member 112 is coupled to the steering column 130 of the first member 102 through conventional coupling techniques known in the art such as fastening, clamping and the like. Alternatively, the secondary member 112 may be coupled directly to the handlebar. In an embodiment, the secondary member 112 has a central axis (not shown) that is parallel to the central axis B-B’ and overlaps with the central axis A-A’ (shown in Figures 5, 7 and 9). Also, the primary member 110 is coupled to the secondary member 112. Therefore, torque from the second member 104 is transferred to the first member 102 through the secondary member 112 and the primary member 112. In an embodiment, size of the primary member 110 is smaller than that of the secondary member 112 in order to amplify the torque transfer to the first member 102 from the second member 104. In an embodiment, the size of the primary member 110 with respect to the secondary member 112 is selected basis the torque transfer requirement to the first member 102 from the second member 104. In an embodiment, the secondary member 112 is a spur gear member.
[031] Further, an intermediate member 114 is coupled to the secondary member 112 and to the first member 102 through the conventional coupling techniques known in the art. In an embodiment, the intermediate member 114 is coupled concentrically to the steering column 130 of the first member 102 and to the secondary member 112. As such, a central axis (not shown) of the intermediate member 114 overlaps with the secondary member 112 and the steering column 130 (as shown in Figure 6). In an embodiment, the intermediate member 114 comprises a hollow shaft portion 114a that concentrically mounts onto the steering column 130 and the secondary member 112. In an embodiment, on an outer surface (not shown) of the hollow shaft portion 114a, a plurality of guide grooves 114b are provided. The plurality of guide grooves 114b enable vertical movement of any member that is in contact with or engaged to the intermediate member 114. In an embodiment, the plurality of guide grooves 114b corresponds to helical gear teeth provided on the outer surface of the hollow shaft portion 114a. In an embodiment, the intermediate member 114 is a helical gear member.
[032] The intermediate member 114 is also engaged with a movable member 116 provided to the first member 102. The movable member 116 may be disposed below the intermediate member 114 along a top-down direction of the vehicle 122. In an embodiment, the movable member 116 is a collar member that is disposed on the steering column 130 of the first member 102. The movable member 116 is movable vertically (arrow indication provided in Figure 6) on the intermediate member 114 corresponding to actuation of the first member 102. In an embodiment, the movable member 116 is provided with inner guide grooves 116a that engage with the plurality of guide grooves 114b provided to the intermediate member 114. As such, rotation of the first member 102 (that is the handlebar assembly) causes rotation in the steering column 130. Correspondingly the intermediate member 114 rotates along with the second member 112 in the direction of actuation of the first member 102. Such a rotation of the intermediate member 114 induces vertical movement of the movable member 116 on the intermediate member 114 due to the plurality of guide grooves 114b. In an embodiment, the movable member 116 may move vertically upwards when the first member 102 is actuated in a clockwise direction, while the movable member 116 may move vertically downwards when the first member 102 is actuated in an anti-clockwise direction. In an embodiment, the intermediate member 114 and the movable member 116 are constructed based on extent of actuation of the first member 102 (i.e. the handlebar assembly) in the clockwise direction and in the anti-clockwise direction. In an embodiment, the inner guide grooves 116a of the movable member 116 corresponds to internal helical gear splines corresponding to the helical gear teeth provided on the intermediate member 114.
[033] Further, a steering sensor unit 106a of the one or more sensing units 106 is coupled to the movable member 116. The steering sensor unit 106a is positioned behind the steering column 130 along a front-rear direction of the vehicle 122. As such, the steering sensor unit 106a is adapted to procure information pertaining to extent of actuation of the first member 102 based on vertical movement of the movable member 116. In an embodiment, the steering sensor unit 106a is provided with a sensor shaft 118 that engages with the movable member 116. The sensor shaft 118 is adapted to rotate about its axis corresponding to vertical movement of the movable member 116, thereby procuring information pertaining to extent of actuation of the first member 102.
[034] In an embodiment, the steering sensing unit 106a is also coupled to the second member 104. As such, the steering sensor unit 106a is capable of determining a steering angle ‘a’ (shown in Figure 2) of the vehicle based on the rotation of the primary member 110 due to rotation of the secondary member 112, during actuation of the first member 102. In an embodiment, the steering angle ‘a’ is positive (i.e. ‘+a’) when the first member 102 is rotated away from rider of the vehicle 122, and the steering angle ‘a’ is negative (i.e. ‘-a’) when the first member 102 is rotated towards the rider of the vehicle 122.
[035] A holder assembly 138 is positioned on the intermediate member 112 along the top-down direction of the vehicle 122. In an embodiment, the holder assembly 138 is provided over a housing 140 (as shown in Figure 5) that is adapted to enclose the transmission assembly 108. The holder assembly 138 engages with the steering column 130. As such, the holder assembly 138 acts as an anchor for the transmission assembly 108 provided on the steering column 130.
[036] Further, the steer assist assembly 100 comprises a control unit 120 disposed in the vehicle 122, and communicably coupled with the second member 104 (i.e. the actuator). The control unit 120 may be coupled through a wired connection or a wireless connection with the second member 104 as per requirement. The control unit 120 is adapted to operate or actuate the second member 104 for providing a steer assist torque to the first member 102 based on the one or more vehicle operating parameters, thereby enhancing balance to the vehicle 122 with minimal effort from the rider. In an embodiment, the one or more vehicle operating parameters comprises a vehicle speed, the steering angle ‘a’ of the first member 102 and a lean angle ‘?’ of the vehicle 122.
[037] In an embodiment, the control unit 120 is coupled to the one or more sensing units 106 for procuring information pertaining to the one or more vehicle operating parameters. On receiving the information from the one or more sensing units 106, the control unit 120 is adapted to determine the one or more vehicle operating parameters. In an embodiment, the control unit 120 is coupled through wired connection or a wireless connection with the one or more sensing units 106.
[038] In an embodiment, the control unit 120 receives the information pertaining to the steering angle ‘a’ of the first member 102 from the steering sensor unit 106a. The steering sensor unit 106a provides the information pertaining to the steering angle ‘a’ of the vehicle basis rotation of the sensor shaft 118 corresponding to the vertical movement of the movable member 116. Upon receiving the information from the steering sensor unit 106a, the control unit 120 is adapted to determine the steering angle ‘a’ of the first member 102. In an embodiment, the steering sensor unit 106a is a potentiometer. In an embodiment, the steering sensor unit 106a may procure information pertaining to the steering angle ‘a’ of the first member 102 about a central axis (not shown) of the vehicle 122.
[039] In an embodiment, the control unit 120 is coupled to an Inertial Measurement Unit (IMU) (not shown in Figures), wherein the IMU is adapted to procure information pertaining to the lean angle ‘?’ of the vehicle 122. Basis the information provided by the IMU, the control unit 120 is adapted to determine the lean angle ‘?’ of the vehicle 122. In an embodiment, the IMU may be mounted onto the frame assembly of the vehicle. In an embodiment, the IMU may procure information pertaining to the lean angle ‘?’ of the vehicle 122 about a vertical axis.
[040] In an embodiment, the control unit 120 is coupled to a vehicle speed sensor (not shown in Figures), wherein the vehicle speed sensor is adapted to procure information pertaining to vehicle speed. Basis the information provided by the vehicle speed sensor, the control unit 120 is adapted to determine the vehicle speed. In an embodiment, the vehicle speed sensor is mounted onto the front wheel 124. In an embodiment, the vehicle speed sensor can be a hall effect sensor.
[041] The control unit 120 upon determining the one or more vehicle operating parameters is adapted to compare these parameters with reference parameters. In an embodiment, the reference parameters may be stored within the control unit 120. As such, when the one or more vehicle operating parameters reach a threshold limit, the control unit 120 is adapted to estimate steer assist torque required to be provided to the first member 102. Upon estimation of the steer assist torque, the control unit 120 is adapted to operate the second member 104, which accordingly rotates the first member 102 through the transmission assembly 108, thereby providing the steer assist torque to the first member 102. As an example, if the control unit 120 determines the vehicle speed to be 10 kmph, with the steering angle ‘a’ being 2 degrees and the lean angle ‘?’ of the vehicle 122 being 1 degree with respect to the central axis (X-X’) of the vehicle, the control unit 120 determines that the vehicle is relatively in a straight line driving condition. Thus, the control unit 120 determines that the vehicle operating conditions are within or yet to reach the threshold limit and thus does not provide any steer assist torque to the first member 102. However, if the vehicle speed is 10 kmph, the steering angle ‘a’ is 2 degrees and the lean angle ‘?’ is 30 degrees, the control unit 120 determines that the lean angle ‘?’ has reached the threshold limit and accordingly estimates the steer assist torque. The steer assist torque is then provided to the first member 102 through actuation of the second member 104, thereby ensuring balance of the vehicle 122. The control unit 120 may provide the steer assist torque until the lean angle ‘?’ is within the limits for the corresponding vehicle speed and the steering angle ‘a’. In other words, the control unit 120 may provide the steer assist torque until the lean angle ‘?’ is 2 degrees for the vehicle speed being 10 kmph and steering angle ‘a’ being 2 degrees. In an embodiment, the steer assist torque may counter rotate the first member 102 for ensuing balance of the vehicle 122.
[042] In an embodiment, the steer assist torque corresponds to the counter rotation of the first member 102 for ensuring balance of the vehicle 122. In an embodiment, the steer assist torque provided by the control unit 120 during a low vehicle speed may be a balance assist torque. In an embodiment, the steer assist torque provided by the control unit 120 during a high vehicle speed may be a power assist torque.
[043] In an operational embodiment, when the first member 102 is actuated by the rider in the clockwise direction, the steering column 130 rotates along with the first member 102. As such, the intermediate member 114 rotates along with the steering column 130. At this scenario, the movable member 116 moves vertically upwards on the intermediate member 114. Due to the vertical movement, the sensor shaft 118 rotates in the clockwise direction, thereby procuring information pertaining to the steering angle ‘a’ of the first member 102. In an embodiment, the steering angle ‘a’ of the first member 102 can also be determined based on the rotation of the primary member 110 due to rotation of the secondary member 112 mounted to the steering column 130. At this juncture, the information from the steering sensor unit 106a is provided to the control unit 120, which determines the steering angle ‘a’ of the first member 102.
[044] Further, the control unit 120 determines the vehicle speed and the lean angle ‘?’ along with the lean rate of the vehicle 122. If the vehicle speed, the lean rate, the lean angle ‘?’ and the steering angle ‘a’ reaches the threshold limit, the control unit 120 provides/supplies power to the second actuator 104. The primary member 110 connected to the second actuator 104 thus rotates in a direction opposite to that of rotation of the first member 102 provided by the rider. Accordingly, the rotation or the steer assist torque from the primary member 110 is transferred to the secondary member 112 and then to the steering column 130, thereby maintaining balance of the vehicle 122.
[045] Figure 10 is a flow diagram of a method 1000 of assisting steering of the vehicle 122 in accordance with an exemplary embodiment of the present invention. The method 1000 is carried out by the control unit 120.
[046] At step 1002, the control unit 120 detects the one or more vehicle operating parameters basis the information provided by the one or more sensing units 106.
[047] At step 1004, the control unit 120 is adapted to compare the determined one or more vehicle operating parameters with the reference parameters. As such, if the one or more vehicle operating parameters reach a threshold limit, the control unit 120 is adapted to estimate the steer assist torque required for balancing the vehicle 122.
[048] At step 1006, the control unit 120 is adapted to operate the second member 104 for providing the steer assist torque to the first member 102. In an embodiment, the control unit 120 is adapted to enable supply power or electric current to the second member 104 from a battery pack (not shown) in the vehicle 122. Supply of the power or electric current to the second member enables actuation, thereby supplying steer assist torque to the first member 102.
[049] In an embodiment, the control unit 120 is adapted to provide the balance steer assist torque to the first member 102, when the vehicle speed is less than the threshold speed. The control unit 120 provides the balance steer assist torque, due to the low vehicle speed. In this scenario, due to lower vehicle speed, the rate of adjustment of the steering angle ‘a’ through the balance steer assist torque is high. As such, the control unit 120 tries to rapidly adjust the steering angle ‘a’ for regaining balance of the vehicle in low speed scenario.
[050] In an embodiment, the control unit 120 is adapted to provide the power steer assist torque to the first member 102, when the vehicle speed is greater than the threshold speed. The control unit 120 provides the power steer assist torque, due to the high speed of the vehicle. In this scenario, due to higher vehicle speed, the rate of adjustment of the steering angle ‘a’ through the power steer assist torque is low. As such, the control unit 120 tries to steadily adjust the steering angle ‘a’ for regaining balance of the vehicle in high speed scenario.
[051] Referring to Figure 11 in conjunction with Figure 10, an exemplary embodiment of the method assisting steering of the vehicle 122 is provided.
[052] At step 1102, the control unit 120 is adapted to determine the vehicle speed. As mentioned in description pertaining to Figure 6-9, the control unit 102 determines the vehicle speed through the information provided by the vehicle speed sensor. In an embodiment, the control unit 120 may determine the vehicle speed based on the information provided by a vehicle control unit (not shown).
[053] At step 1104, the control unit 120 determine the roll rate or the lean rate of the vehicle based on the information provided by the IMU. In an embodiment, the roll rate or lean rate refers to inclination of the vehicle 122 with respect to a vertical axis for a given time. As an example, the control unit 120 may determine the roll rate to be 1 degree per second based on the information provided by the IMU. Subsequently, at step 1106, the control unit 120 determines or estimates the lean angle ‘?’ of the vehicle 122 with respect to the vertical axis based on the information provided by the IMU. The determination of the roll rate along with the vehicle speed enables the control unit 120 to understand if the vehicle 122 is falling or loosing balance in the low speed scenario or in the high speed scenario. Such a determination enables the control unit 120 to provide the steer assist torque based on the vehicle speed to avoid further imbalance in the vehicle 122.
[054] At step 1108, the control unit 120 determines the steering angle ‘a’ of the first member 102 based on information provided by the steering sensor unit 106a. Subsequently, at step 1110 the control unit 120 also determines the position of the sensor shaft 118 due to the actuation of the first member 102. The control unit 120 determines the angle (or mechanical angle) of the sensor shaft 118 between 0 degrees to 130 degrees. The determination of the angle of the sensor shaft 118 provides accurate determination of the steering angle ‘a’ of the first member 102.
[055] The method moves to step 1112, if the angle of the sensor shaft 118 is determined to be less than 5 degrees, the method moves to step 1114 where the constant voltage is determined to be 0 V by the control unit 120.
[056] The method moves to step 1116 If the angle of the sensor shaft 118 is determined to be between 5 degrees to 125 degrees. At this scenario, the method moves to step 1118, where a linear voltage from 0 Volts to 5 Volts is determined by the control unit 120. Accordingly, the linear voltage may be provided to the second member 104 through the battery pack. The term linear voltage pertains to gradual increase of voltage from 0 Volts to 5 Volts that is provided to the second actuator 104.
[057] The method moves to step 1120 If the angle of the sensor shaft 118 is determined to be greater than 125 degrees. At this scenario, the method moves to step 1122, where a constant voltage of 5 Volts is determined by the control unit 120. Accordingly, the constant voltage may be provided to the second member 104 through the battery pack.
[058] Thereafter, at step 1124 the control unit 120 determines a hysteresis torque (referenced by ‘T’) from the second member. Particularly, the control unit 120 determines if the hysteresis torque ‘T’ is between 2 Nm to 50 Nm.
[059] In an embodiment, the method further comprises of determining a mean of the actual steering angle and hysteresis torque ‘T’ over a pre-determined time. The mean of the actual steering angle and hysteresis torque ‘T’ taken over the pre-determined time eliminates any error value in the actual steering and hysteresis torque ‘T’ (for example, error values that may occur due to unintentional manoeuvres or fluctuation due to road surfaces or other parameters). Through the mean value of the actual steering angle and hysteresis torque ‘T’, the control unit 120 identifies the change in actual steering angle and hysteresis torque ‘T’ with respect to the steering angle ‘a’ and hysteresis torque ‘T’ over the pre-determined time period.
[060] In an embodiment, the method further comprises of determining a mean of the actual steering angle over a pre-determined time. The mean of the actual steering angle taken over the pre-determined time eliminates any error value in the actual steering (for example, error values may occur due to unintentional manoeuvres or fluctuation due to road surfaces or other parameters). Through the mean value, the control unit 120 identifies the change in actual steering angle with respect to the steering angle ‘a’ over the pre-determined time period. Further, the hysteresis torque ‘T’ is compared with the threshold value ‘Tth’ (threshold hysteresis) at step 1126.
[061] If the mean hysteresis torque ‘T’ is greater than the reference torque ‘Tth’ (threshold torque), or the hysteresis torque ‘T’ is greater than the reference torque ‘Tth’ (threshold torque), the method moves to step 1128 to determine the motor torque to be provided. In one embodiment, at step 1128, the motor torque has a gain factor A, which is multiplied with the motor torque. The gain factor A is being a value between 0 and 1. The gain factor is chosen is chosen based on rate at which the control action has to be taken. For an immediate control, the gain factor is chosen to be maximum.
[062] The control unit 120 based on above mentioned conditions operates the actuator 104 accordingly for providing the motor torque. Once the steer assist torque is provided, the control unit 120 moves to step 1130 and determines that the vehicle is assisted and ends the method. If the mean hysteresis torque ‘T’ is less than the reference torque (threshold torque), the control unit 120 moves to step 1132 and does not determine the motor torque required. In other words, the control unit determines a steady manoeuvre condition. Thus, the system identifies that there is no input from the rider side and the vehicle is also in the steady manoeuvring condition.
[063] Figure 12 is a flow diagram of a method 1200 of assisting steering of the vehicle 122, in accordance with an exemplary embodiment of the present invention. In the present embodiment, the control techniques employed in the control unit 120 for providing the steering assistance is provided.
[064] At step 1202, the control unit 120 determines actuation of the first actuator 102 by the user, which may be essentially a state of the vehicle 122. The actuation of the first actuator 102 may enable the control unit 120 to determine the steering angle ‘a’ of the first member 102 as well as the steering torque applied by the user of the vehicle 122 on the first member 102. The control unit 120 then moves to step 1204 to the lean or roll angle ‘?’ and the roll rate from the IMU. Subsequently, the control unit 120 moves to step 1206 for determining steering angle ‘a’ of the first member 102.
[065] At step 1208, the control unit 120 is adapted to employ one or more control techniques for providing the necessary steering assistance to the user of the vehicle 122. In an embodiment, any function that operates in a closed loop environment needs to be fed using "control law”. The control unit 120 is adapted to generate a feedback signal corresponding to the determined the determined steering angle ‘a’ and the steering torque. Additionally, the feedback signal generated by the control unit 120 is also generated based on the vehicle speed, thereby enabling assistance to the user. In an embodiment, the feedback signal is generated by the control unit 120 through steps 1124-1120 as already described.
[066] Subsequently, at step 1210, the control unit 120 provides the feedback signal to the second member 104, directing it to operate in the desired RPM to help the transmission assembly 108 so that the output roll and roll rate, or the vehicle state, remain within the minimal range of fluctuations. In an embodiment, A power electronics driver (not shown) is provided for sending and receiving signals from the control unit 120 to the second member 104. The power electronics driver is powered by a vehicle battery (not shown), which can be a 12V battery.
[067] Figure 14 provides a graphical representation of a plot of a steering torque with respect to time in the vehicle 122, in accordance with an exemplary embodiment of the present invention. The control unit 120 is adapted to determine the steering torque provided by the user for steering or actuating the first member 102. The steering torque provided by the user (or user torque) is depicted by the plot referenced as ‘146’. Based on the user torque, the control unit 120 determines the torque provided by the second member 104 (i.e. the actuator) for ensuring balance or minimal fluctuations in the vehicle 122 during riding. The torque provided by the second member 104 (or assist torque or actuator torque) is depicted by the plot referenced as ‘148’. The user torque and the assist torque are provided to the first member 102 for ensuring balance or minimal fluctuations in the vehicle 122 during riding. Accordingly, the total torque acting on the first member 102 is sum of user torque and the assist torque and is referenced as ‘150’. The term ‘total torque’ corresponds to the amount of torque required to steer the vehicle.
[068] The total torque acting on the first member 102 through the steer assist assembly 100 is identical to the total torque of the conventional steering assemblies (referenced as ‘152’ in Figure 13). However, in the steer assist assembly 100 of the present invention, the assist torque is provided along with the user torque to the first member 102, thereby reducing the effort for the user.
[069] Referring to Figure 15, a Root Mean Square (RMS) value of torque (referenced as ‘154’ in Figure 15) applied by the user is reduced when the assist torque is provided by the steer assist assembly 100, as compared to the torque (referenced as ‘156’ in Figure 15) applied by the user without the assist torque from the steer assist assembly 100.
[070] The claimed invention as disclosed above is not routine, conventional, or well understood in the art, as the claimed aspects enable the following solutions to the existing problems in conventional technologies. Specifically, the claimed aspect of the steer assist assembly of the present invention improves handling, performance and rider experience, as less effort is required for steering the vehicle, thereby reducing rider fatigue. Also, minimal number of parts are provided in the steer assist assembly, reducing the overall cost as well as mitigating packaging issues. Additionally, the transmission assembly multiplies the torque supplied by the second member, thereby mitigating the need for a larger actuator, thereby reducing costs and packaging constraints that are associated with the larger actuator.
[071] In light of the abovementioned advantages and the technical advancements provided by the disclosed method, the claimed steps as discussed above are not routine, conventional, or well understood in the art, as the claimed steps provide solutions to the existing problems in conventional technologies. Further, the claimed steps clearly bring an improvement in the functioning of the assembly itself as the claimed steps provide a technical solution to a technical problem.
[072] Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present disclosure. A computer-readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term “computer-readable storage medium” should be understood to include tangible items and exclude carrier waves and transient signals, i.e., be non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, non-volatile memory, hard drives, CD ROMs, DVDs, flash drives, disks, and any other known physical storage media”.
[073] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

Reference Numerals and Characters
100 – Steer assist assembly
102 – First member
104 – Second member
106 – One or more sensing units
108 – Transmission assembly
110 – Primary member
112 – Secondary member
114 – Intermediate member
116 – Movable member
118 – Sensor shaft
120 – Control unit
122 – Vehicle
124 – Front wheel
126 – Suspension assembly
128 – Headtube
130 – Steering column
132a – Upper triple clamp
132b – Lower triple clamp
134 – Holder for the handlebar
138 – Holder assembly
140 – Housing for the transmission assembly
A-A’ – Central Axis of steering column
B-B’ – Central axis of primary member
,CLAIMS:WE CLAIM
1. A steer assist assembly (100) comprising:
a first member (102), the first member (102) being connected to a second member (104), the second member (104) being configured to provide a steer assist torque to the first member (102) when one or more vehicle operating parameters reach a threshold limit,
wherein the one or more vehicle operating parameters being sensed by one or more sensing units (106), the one or more sensing units (106) being operably connected to at least one of the first member (102) or the second member (104).

2. The steer assist assembly (100) as claimed in claim 1, wherein the first member (102) is one of a handlebar assembly and a steering wheel, and the second member (104) is an actuator.

3. The steer assist assembly (100) as claimed in claim 1, wherein the second member (104) being coupled to the first member (102) through a transmission assembly (108), the transmission assembly (108) comprising:
a primary member (110), the primary member (110) being coupled to an intermediate member (114); and
a secondary member (112), the secondary member (112) being coupled to the first member (102), the secondary member (112) being connected with the primary member (110) for receiving the steer assist torque from the second member (112).

4. The steer assist assembly (100) as claimed in claim 3, wherein the transmission assembly (108) comprises the intermediate member (114), the intermediate member (114) being coupled to the secondary member (112) and to the first member (102),
wherein the intermediate member (114) being engaged with a movable member (116) provided to the first member (102), the movable member (116) being movable on the intermediate member (114) corresponding to actuation of the first member (102).

5. The steer assist assembly (100) as claimed in claim 1, wherein the one or more sensing units (106) comprise a steering sensor unit (106a), the steering sensor unit (106a) being provided with a sensor shaft (118), the sensor shaft (118) being engaged to a movable member (116),
wherein the sensor shaft (118) being adapted to move corresponding to actuation of the movable member (116) for determining steering angle information of the first member (102).

6. The steer assist assembly (100) as claimed in claim 1, wherein the second member (104) being communicably coupled with a control unit (120), the control unit (120) being communicably coupled to the one or more sensing units (106) and the second member (104),
the control unit (120) being adapted to operate the second member (104) for providing the steer assist torque to the first member (102), based on the one or more vehicle operating parameters.

7. A method (1000) of assisting steering of a vehicle (122), the method (1000) comprising:
detecting (1002), by one or more sensing units (106), one or more vehicle operating parameters;
estimating (1004), by a control unit (120), a steer assist torque when one or more vehicle operating parameters reaches a threshold limit; and
operating (1006), by the control unit (120), the second member (104) to provide the steer assist torque to the vehicle (122).

8. The method (1000) as claimed in any of the preceding claims, wherein the one or more vehicle operating parameters comprises vehicle speed, a roll rate of the vehicle (122), a steering angle (a), a lean angle (?), and an angle of a sensor shaft (118).

9. The method (1000) as claimed in any of the preceding claims comprising:
estimating, by the control unit (120), a balance steer assist torque when the vehicle speed is below a threshold limit; and
operating, by the control unit (120), the second member (104) to provide the balance steer assist torque to the first member (102) for maintaining balance of the vehicle (122).

10. The method (1000) as claimed in any of the preceding claims comprising:
estimating, by the control unit (120), a power steer assist torque when the vehicle speed is above a threshold limit; and
operating, by the control unit (120), the second member (104) to provide the power steer assist torque to the first member (102) for maintaining balance of the vehicle (122).

11. The method (1000) as claimed in any of the preceding claims comprising:
determining (1114), by the control unit (120), a constant voltage to be 0 Volts, when the angle of the sensor shaft (118) is determined to be less than 5 degrees;
determining (1116), by the control unit (120), a linear voltage from 0 Volts to 5 Volts, when the angle of the sensor shaft (118) is determined to be between 5 degrees to 125 degrees;
determining (1122), by the control unit (120), a constant voltage to be 5 Volts, when the angle of the sensor shaft (118) is determined to be greater than 125 degrees; and
supplying, by the control unit (120), one of the constant voltage of 0 Volts, the linear voltage of 0 Volts to 5 Volts and the constant voltage of 5 Volts to the second member (104) corresponding to the angle of the sensor shaft (118).

12. The method (1000) as claimed in any of the preceding claims comprising:
determining, by the control unit (120), a mean of an actual steering angle over a predetermined time; and
identifying, by the control unit (120), a change in the actual steering with respect to the steering angle (a) over the pre-determined time period.

13. The method (1000) as claimed in any of the preceding claims comprising:
determining (1124), by the control unit (120), a hysteresis torque (T);
determining, by the control unit (120), a mean of an actual steering angle and the hysteresis torque (T) over a predetermined time; and
identifying, by the control unit (120), a change in the actual steering and the hysteresis torque (T) with respect to the steering angle (a) and hysteresis torque (T) over the pre-determined time period.

14. The method (1000) as claimed in any of the preceding claims comprising:
comparing (1126), by the control unit (120), the hysteresis torque (T) with a threshold value (Tth);
determining (1128), by the control unit (120), a motor torque to be provided, if the mean hysteresis torque (T) is greater than the threshold value (Tth) or if the hysteresis torque (T) is greater than the threshold value (Tth);
operating, by the control unit (120), the second member (104) corresponding to the determined motor torque; and
determining (1130), by the control unit (120), that the vehicle (122) is assisted upon operating the second member (104).

15. The method (1000) as claimed in any of the preceding claims comprising:
comparing (1126), by the control unit (120), the hysteresis torque (T) with the threshold value (Tth); and
determining (1128), by the control unit (120), a motor torque to be zero, if the mean hysteresis torque (T) is less than the threshold value (Tth) or if the hysteresis torque (T) is less than the threshold value (Tth).
Dated this 07th day of February 2024
TVS MOTOR COMPANY LIMITED
By their Agent & Attorney

(Nikhil Ranjan)
of Khaitan & Co
Reg No IN/PA-1471