Vehicle stabilization system and method of operating the same

Abstract

An aspect of stabilizing a vehicle is described. A vehicle speed (ν), a roll angle (φ), and a roll rate of the vehicle are determined. Based on the vehicle speed (ν), gain values ​​(G1, G2) are determined for the roll angle (φ) and the roll rate, respectively, and a stabilizing torque (T) is determined based on applying the respective gain values ​​(G1, G2) to the roll angle (φ) and the roll rate. s ) is determined. In one example, the tuning parameters are the resultant torque (T) and the steering torque (T r ) and may be determined based on a comparison with the stabilizing torque (T s ) to be applied to the vehicle steering wheel by the actuator. s ) is provided to an actuator to stabilize the vehicle.

Description

Technical Field

[0001] The subject of the present invention generally relates to a vehicle stabilization system and a method of operating the same.

Background Art

[0002] Saddle-type vehicles, including two-wheeled and three-wheeled vehicles, are steered by operating a steering handle so as to rotate a front fork that supports a front wheel around a steering system / shaft. Generally, the vehicle is steered by a steering force applied to the steering handle by the rider. While moving at a very low speed, it is particularly necessary to apply a high steering force. For example, in slow traffic, the rider is generally forced to ride at a very low speed and is often forced to make sudden stops and restarts. In such a state, when the vehicle loses its stability at a very low speed, it becomes very difficult for the rider to balance the vehicle. Therefore, it becomes difficult for the rider, especially a beginner, to balance the vehicle. Furthermore, vehicles having single-track wheels, such as two-wheeled vehicles, often have a potential risk of falling, also referred to as a rollover accident. When the vehicle loses its stability, the rider, especially a beginner, tends to make sudden steering movements unconsciously and apply a greater steering torque, and the rider becomes fatigued. Also, it can be seen that the rider generally has difficulty in balancing the vehicle when encountering road bumps or depressions. Furthermore, depending on the riding conditions including sharp curves, a high steering force is also required. In order to balance the vehicle under such conditions, the rider generally applies a sudden steering movement to the steering handle and may fall with the vehicle while doing so. Therefore, a system for assisting the rider, which can help balance the vehicle, has been researched and developed.

[0003] Recently, driverless vehicles, i.e., vehicles equipped with autonomous driving and self-balancing capabilities and which do not require a rider to control or steer the vehicle, have also been developed. Even in such vehicles, it is particularly difficult to balance the vehicle, especially at low speeds.

[0004] The prior art describes a steering support system for two-wheeled vehicles that provides additional steering force to support the steering force applied by a rider so that the rider can properly balance the vehicle. However, applying additional steering force by the steering support system requires determination of several dynamic vehicle parameters, such as the steering angle, the instantaneous steering torque applied by the rider, and the instantaneous acceleration of the entire vehicle or just some components of the vehicle. For example, a yaw rate sensor, a roll rate sensor, or an acceleration sensor may be used to detect lateral acceleration, longitudinal acceleration, and / or vertical acceleration. As a result, the steering support system uses multiple sensors, such as force sensors, acceleration sensors, etc. Further, the support system also utilizes other vehicle dynamic parameters, such as a control signal from an antilock braking system, to ascertain the amount of torque that will be applied to the actuator.

[0005] Also, conventional systems used to balance a vehicle require the use of yaw rate parameters to determine the stabilizing / balancing torque that will be applied. However, the yaw rate parameters have a shorter lead time with respect to the steering torque. The fact that only a short lead time is obtained for applying the balancing torque may interfere with the rider's intervention that may be required to perform some maneuver while riding.

[0006] Using several vehicle dynamic parameters to determine the additional steering torque required to balance the vehicle tends to affect the accuracy and precision of the calculation of the additional steering torque required under various vehicle riding conditions, and is a complex and costly proposition. Further, the number of sensors used to determine the additional steering torque required also results in an increase in the cost of the product, longer assembly times, and complex manufacturing cum assembly.

[0007] Furthermore, in some other prior arts, attempts have been made to balance two-wheeled vehicles by giving minimal significance to the interaction between the two wheels and the rider when there are various riding conditions. However, it is important to consider such interactions in order to understand the comfort / discomfort felt by the rider when the vehicle is steered / controlled by an additional / support steering stabilization system.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] This summary is provided to introduce concepts related to vehicle stabilization further described in the detailed description below. This summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used to determine or limit the scope of the claimed subject matter.

[0009] The present subject matter provides a system and method for improving the stability of a vehicle at various vehicle speeds, including very low vehicle speeds, and under various riding conditions, particularly for saddle-type vehicles.

MEANS FOR SOLVING THE PROBLEM

[0010] In one example, the system includes a plurality of sensors, the plurality of sensors including a position sensor for determining a vehicle speed (ν), and an angular displacement sensor for determining a roll angle (φ) and a roll rate of the vehicle, where the roll angle (φ) corresponds to the angular displacement of the vehicle in the roll direction and the roll rate corresponds to the angular velocity of the vehicle in the roll direction. The system further includes a stabilization unit for providing an actuation signal to an actuator, the actuation signal being a stabilization torque (T s ) that will be applied by the actuator to the vehicle's steering wheel to stabilize the vehicle, and the stabilization unit is coupled to the plurality of sensors. The stabilization unit determines gain values (G1, G2) for the roll angle (φ) and the roll rate respectively based on the vehicle speed (ν), and determines the stabilization torque (T s ) based on applying the respective gain values (G1, G2) to the roll angle (φ) and the roll rate.

[0011] In another example, the system includes a plurality of sensors, the plurality of sensors including a position sensor for determining a vehicle speed (ν), a roll angle (φ) corresponding to the angular displacement of the vehicle in the roll direction, an angular displacement sensor for determining a roll rate corresponding to the angular velocity of the vehicle in the roll direction, and a steering torque sensor for determining a steering torque (T r ) applied to the vehicle's steering wheel. The system further includes a stabilization unit coupled to the plurality of sensors, the stabilization unit determining a combined torque based on the roll angle (φ), the roll rate, and the vehicle speed (ν), determining tuning parameters based on a comparison of the combined torque and the steering torque (T r ), determining a stabilization torque (T s ) based on the tuning parameters and the combined torque, and providing to the actuator an actuation signal corresponding to the stabilization torque (T s ) to apply the stabilization torque (T s ) to the vehicle's steering wheel to stabilize the vehicle.

[0012] In various examples, methods for vehicle stabilization are also discussed based on determining a stabilization torque from a synthetic torque, where the synthetic torque is determined based on roll parameters and vehicle speed.

[0013] A detailed description of the subject matter will be set forth with reference to the accompanying drawings. The same reference numerals are used throughout the drawings to refer to like features and components.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4a

Figure 4b

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0015] The present subject matter relates to a vehicle stabilization system and method for improving the stability of a saddle-riding type vehicle under various riding conditions, and particularly at very low speeds. It helps ensure the ease of vehicle operation, ride comfort, and rider safety at various vehicle speeds, including very low vehicle speeds. The system and method are capable of providing accurate and precise steering support to the vehicle without interfering with the rider's steering intention. Further, the system and method are capable of mimicking the rider's steering action / input while balancing the vehicle. Additionally, embodiments of the present subject matter are simple and economical to manufacture, install, and operate. Thus, the present subject matter also helps optimize the cost of manufacturing vehicles that use the stabilization system.

[0016] Aspects of the present subject matter are discussed with reference to a rider operating a vehicle as an example, but it should be understood that the principles of the present subject matter may also apply to autonomous vehicles where a vehicle controller, rather than a rider, steers or navigates the vehicle. Thus, the present stabilization system and method can assist the vehicle controller in maintaining stability and improving safety and maneuverability, similar to assisting a rider.

[0017] According to one aspect of the present subject matter, the system uses a steering handle (handlebar) to mechanically support the movement of the vehicle and uses an actuator to apply a driving force / balancing force to the steering handle based on a stabilization torque (T s ), and the stabilization torque (T s ) is obtained from a resultant torque (T) determined by a stabilization unit. In one example, the resultant torque (T) is determined from a first resultant torque (T1), and the first resultant torque is determined based on a roll angle and a roll rate measured by an inertial measurement unit. The first resultant torque (T1) can be determined by multiplying a roll angle (φ) and a roll rate ( measured by an angular displacement sensor by their respective gain values and then adding the products together.

[0018] The gain value can be derived from experiments by statistical analysis and can be obtained as a function of vehicle speed (v), vehicle specifications, and delay time. Specifically, the delay time referred to in this specification is the time difference for a second (subsequent) dynamic parameter that lags behind a first (preceding) dynamic parameter and is measured in seconds. For example, in the case of low-speed maneuvering when the vehicle has a tendency to roll due to instability, the rider provides steering torque to balance, which will balance the vehicle. As can be understood, the dynamic parameter "steering torque" will have a delay time associated with the "roll angle", which is one of the dynamic parameters obtained when the vehicle rolls.

[0019] Therefore, while determining the combined torque (T), the stabilization unit takes into account the vehicle speed (v) used to determine the gain values (G1 and G2). General vehicle parameters such as vehicle layout, mass inertia, and its distribution, subsystem characteristics, etc. can also affect the combined torque (T) and can be considered. In one example, the first combined torque (T1) can be the combined torque (T) applied to stabilize the vehicle.

[0020] In another example, the stabilization unit is configured to determine the advance time (τ) at which the first combined torque (T1) will be applied and to consider that advance time to obtain a second combined torque (T2) as the combined torque (T). Typically, the advance time (τ) selected to apply the first combined torque (T1) is such that the time point of applying the combined torque (T) precedes the time point of a normal rider's steering operation. Selecting the advance time (τ) in this way to apply the combined torque (T) helps to improve the rider's confidence level in the vehicle, even while being assisted to balance at particularly low vehicle speeds.

[0021] In one example, the combined torque (T) can be applied as a stabilization torque (T s ) to stabilize the vehicle. In another example, the stabilization torque (T s) can be determined based on the comparison between the combined torque (T) and the steering input / torque (T r ) typically measured by a steering torque sensor provided in the vehicle. Further, the stabilization unit can determine the stabilization torque (T r ) to be applied to the steering wheel based on determining different riding conditions and corresponding tuning parameters from the steering torque (T s ). The tuning parameters can be in the range from 0 to 1 depending on the riding conditions and can be gradually changed to improve the rider's comfort and safety.

[0022] In one example, for instance, during a lane change, when steering the vehicle, or when overtaking another vehicle, or when the rider is temporarily changing the steering torque to avoid a pothole, since the applied steering torque (T r ) continues to change continuously, it can be seen that the combined torque (T) is typically not equal to the steering torque (T r ). Thus, it can be seen that the difference between the combined torque (T) and the steering torque (T r ) is not equal to zero. In such a state, the stabilization torque (T s ) to be applied by the actuator to ensure that the vehicle remains balanced is calculated by multiplying the combined torque (T) by a first tuning parameter "A" stored in the stabilization unit. The first tuning parameter is determined in advance as a function of the vehicle speed (v), rider behavior, and vehicle specifications including vehicle layout, mass distribution, and inertia.

[0023] In another example, when the vehicle is cornering, a constant steering torque (T r ) can be applied by the rider. The stabilization unit can determine the stabilization torque (T r ) to be applied to the steering wheel based on the comparison between the combined torque (T) and the rider's steering input / torque (T s) is multiplied, and further, by multiplying the second tuning parameter "B" stored in the stabilization unit by the synthetic stabilization torque (T1), accurate and precise steering support can be provided to the vehicle during cornering. The second tuning parameter B can also be determined in advance as a function of the vehicle speed (v) and the turning radius.

[0024] In yet another example, when the vehicle is cruising, the rider may not apply the steering torque (T r ) except for maintaining balance. In such a case, the steering torque (T r ) is essentially zero and constant, and the stabilization unit can add the synthetic torque (T) as the stabilization torque (T s ), that is, use a tuning parameter of 1. When the stabilization unit applies the balancing torque, the rider does not even need to apply the balancing torque, thus further improving the rider's comfort.

[0025] Therefore, the system according to the principles of the present subject matter helps to balance the vehicle by applying the stabilization torque (T s ) in advance under various riding conditions without interfering with the steering intention of the rider / vehicle controller. Further, since roll parameters such as roll rate and roll angle are used to determine the synthetic torque (T), it can be seen that the advance time available for applying the stabilization torque can sufficiently apply the stabilization torque in a time shorter than the response time taken when the rider makes a steering correction to balance the vehicle at a low speed. Therefore, the stabilization system, in a sense, mimics the rider's balancing of the vehicle, while ensuring that the rider only needs to make minimal effort to balance the vehicle and can feel confident under various riding conditions, especially while riding at low speed.

[0026] This subject matter will be further described with reference to the accompanying drawings. It should be noted that the description and drawings are merely illustrative of the principles of the subject matter. Although not explicitly described or shown herein, various configurations incorporating the principles of the subject matter can be devised. Further, all descriptions in this specification regarding the principles, aspects, and examples of the subject matter, as well as specific examples thereof, are intended to encompass their equivalents.

[0027] FIG. 1 shows an exemplary saddle-ride type vehicle 100 using a system 200 for stabilizing the vehicle 100. The saddle-ride type vehicle 100 includes a head tube 101 and a main tube (not shown) extending rearward and downward from the head tube 101. As understood, the head tube 101 and the main tube form part of the body frame of the saddle-ride type vehicle. The steering system of the vehicle includes a steering shaft 102, a pair of front forks 103, and a steering handle 104. The steering shaft 102 is connected to the head tube 101 and has one end fixedly attached to the steering handle 104 so as to have a rotational joint with the head tube 101. Specifically, the pair of front forks 103 and the steering handle 104 rotatably support the front wheel 105 through the steering shaft 102. The steering handle 104 serves as a means for the rider to mechanically stabilize the movement of the vehicle.

[0028] The saddle-riding type vehicle 100 includes a system 200 that helps to balance the vehicle 100 at various vehicle speeds and under various riding conditions. The system 200 may include a stabilization unit 202 and a plurality of sensors communicably coupled to the stabilization unit 202. The stabilization unit 202 can be, for example, a controller. The system 200 interacts with an actuator 201 and in some examples can include the actuator 201, and the actuator 201 is connected to a steering handle 104 such that the actuator 201 can rotate the steering handle 104 around a steering axis. For example, the actuator 201 may be directly connected to the steering system along the steering axis or indirectly connected to the steering system through a linkage member, and the weight and dimensions of the linkage member will form part of the vehicle specifications. Using a linkage member to connect the actuator 201 to the steering system can help reduce the weight and cost of the actuator and can also help facilitate assembly and maintenance.

[0029] In one example, the actuator 201 can be a motor and can be connected to a rotating shaft 207 fixed to the steering handle 104. Further, a motor fixture 206 may be used to fixedly link the actuator 201 to the head tube 101. Using the motor fixture 206 to fix the actuator 201 can help reduce the weight of the actuator 201. Further, mounting the actuator 201 above the steering handle 104 can also help save space. The actuator 201 is configured to apply a stabilization torque (T s ) to the steering handle to balance the vehicle 100 / support the vehicle 100 at various speeds and under various riding conditions.

[0030] The actuator 201 can receive an actuation signal from the stabilization unit 202 of the system 200. In one example, the stabilization unit 202 may be located in the main tube (not shown) of the vehicle. However, the stabilization unit 202 may be arranged anywhere else on the frame of the vehicle 100. In one example, as shown in the figure, the stabilization unit 202 may be arranged within the utility box 107 of the vehicle 100.

[0031] In one embodiment, the stabilization unit 202 may include one or more processors / processing units and one or more memories. For example, the stabilization unit 202 may include a first processing unit and a second processing unit that can be communicatively coupled to each other. In one example, the first processing unit and the second processing unit may be arranged at the same location within the vehicle 100, such as within the utility box. In another example, the first processing unit and the second processing unit may be arranged at different locations within the vehicle 100. For example, the first processing unit may be arranged within the utility box, and the second processing unit may be arranged in proximity to the steering wheel 104 or the actuator 201.

[0032] The stabilization unit 202 may be communicatively coupled to a plurality of sensors for receiving dynamic vehicle inputs such as vehicle speed, vehicle state, angular displacement inputs in the roll direction of the vehicle such as roll angle and roll rate, steering torque and angle, etc.

[0033] In one example, the plurality of sensors may include an inertial measurement unit (IMU) as the angular displacement sensor 203, a steering torque sensor 204, and a position sensor 205. In one example, the angular displacement sensor 203 may also be disposed in the utility box and can detect the angular displacement of the vehicle in the roll direction (i.e., roll angle) and the angular velocity of the vehicle in the roll direction (i.e., roll rate). In other examples, the angular displacement sensor 203 may be disposed at other locations on the vehicle 100. The angular displacement sensor 203 can supply an input signal corresponding to the roll angle and roll rate to the stabilization unit 202. The position sensor 205 can be a global positioning system (GPS)-based sensor. In one example, the position sensor 205 may be disposed on an outward extension member 108 extending outward from the utility box 107, but the position sensor 205 may also be disposed at other locations on the vehicle 100 as will be appreciated.

[0034] The position sensor 205 can supply a signal corresponding to the speed of the vehicle and a signal regarding the instantaneous state of the vehicle to the stabilization unit 202. The instantaneous state is the translational and angular (roll, pitch, yaw) positions of the motorcycle at that instant, which will change at the next instant when the vehicle moves, and at that time the state of the vehicle (in this case, roll angle, roll rate) changes continuously with the movement of the vehicle. The torque provided at the next instant is determined based on the instantaneous state at the current instant.

[0035] The steering torque sensor 204 can sense and provide an input corresponding to the force or torque with which the rider rotates the steering handle 104 in the steering direction. For this purpose, the steering torque sensor may be disposed on the steering shaft 102. In one example, the inputs from the angular displacement sensor 203 and the position sensor 205 may be received by the first processing unit of the stabilization unit 202, while the input from the steering torque sensor 204 may be received by the second processing unit together with the output from the first processing unit.

[0036] Based on the signals generated by the above-described sensors that provide information regarding the dynamic parameters of the vehicle, the stabilization unit 202 can determine a stabilization torque (T s ). Specifically, in the present subject matter, roll parameters such as roll angle and roll rate are considered rather than yaw parameters in order for the stabilization torque (T s ) to reach the resultant torque (T) that can be obtained to stabilize the vehicle. As understood and shown in FIG. 1, the roll axis corresponds to the longitudinal axis of the vehicle, the yaw axis corresponds to the vertical axis of the vehicle, and the pitch axis corresponds to the lateral axis of the vehicle. Accordingly, the roll angle and roll rate correspond to the angular displacement and angular velocity about the roll axis. Typically, the measurement of roll parameters is faster than that of yaw parameters. By using roll parameters, the delay associated with the use of yaw parameters is eliminated. According to one aspect of the present subject matter, the resultant torque (T) is synthesized based on the roll angle and roll rate measured by the angular displacement sensor 203 using coefficients determined based on regression analysis of experimental data.

[0037] The resultant torque (T) may also reflect the delay time when adding the stabilization torque (T s ) in response to the roll parameters, and the lead time for adding the resultant torque (T) so that the stabilization torque is added before the rider adds the steering torque. In one example, the resultant torque (T) can be added as the stabilization torque (T s ). In another example, the resultant torque may be compared with the steering torque (T r ), and the stabilization torque (T s ) to be added may be determined based on this comparison.

[0038] Various examples and details regarding the determination of the resultant torque and the stabilization torque are described with reference to FIGS. 2, 3, 4a, and 4b in combination.

[0039] As shown in FIG. 2, in one example, the stabilization unit 202 may include a first processing unit 202a and a second processing unit 202b. The first processing unit and the second processing unit may be implemented as a processor, a microcontroller, etc. Further, the stabilization unit 202 may include one or more memories (not shown) associated with the first processing unit and the second processing unit. The first processing unit 202a can receive the vehicle speed, roll rate, and roll angle from the position sensor 205 and the angular displacement sensor 203, and can determine the combined torque (T).

[0040] In one example, as shown in FIG. 3, the combined torque (T) is determined by multiplying the roll angle (φ) and the roll rate () by gain values G1 and G2, respectively, and adding the products thus determined. In order to ensure a precise determination of the combined torque (T), delay times dt1 and dt2 corresponding to the roll angle (φ) and the roll rate (, respectively, are introduced, and the delay times are determined with respect to the steering torque (T r ) applied by the rider. Accordingly, the time t1 for calculating the roll angle at time t is obtained as (t1 = t - dt1), where dt1 is the roll angle delay time. Similarly, the time t2 for calculating the roll rate at time t is obtained as (t2 = t - dt2), and dt2 is the roll rate delay time.

[0041] The delay time reflects the time difference by which the steering torque lags behind the roll angle (φ) and the roll rate (, and is measured in seconds. For example, in the case of low-speed maneuvering when the vehicle has a tendency to roll due to instability, the rider applies a steering torque (T rcan be provided, which will balance the vehicle. Since the steering torque is provided in response to the roll parameter, the steering torque will have a delay time with respect to the roll angle (φ) and the roll rate (). Also, the delay times introduced for the two roll parameters will be different because the roll rate () is the rate of change of the roll angle (φ), and thus the delay of the roll rate () will be different compared to the delay of the roll angle (φ). Furthermore, the delay time can vary based on the speed of the vehicle, and the delay time will be larger for lower speeds.

[0042] In one example, the gain values G1 and G2 are obtained as functions of the vehicle speed (v), vehicle specifications, and the delay time. In one example, as can be seen in FIGS. 4a and 4b, the gain values G1 and G2 decrease non-linearly with an increasing vehicle speed (v) and increase non-linearly with a decreasing vehicle speed (v). As a result, a higher gain, and thus a larger combined torque (T), is obtained at a low vehicle speed where the requirements for stabilization are greater, while a smaller gain, and thus a smaller combined torque (T), is obtained for a higher speed where the requirements for stabilization are smaller. In one example, the gain values G1 and G2 are pre-determined and can be stored, for example, in the memory of the stabilization unit 202 as a mapping table together with the vehicle speed and the delay time. In one example, the coefficients for determining the gain values G1 and G2 can be pre-determined based on a regression analysis of experimental data for different vehicle speeds and delay times for different vehicle specifications. Thus, the gain values G1 and G2 can themselves be represented as mathematical functions and can be calculated instantaneously.

[0043] In one example, the stabilization unit 202 can use Equation 1 shown below to determine the first combined torque (T1) at time t in order to determine the combined torque (T).

[0044]

Equation

[0045] In one example, the first combined torque can be determined by the first processing unit 202a of the stabilization unit 202 shown in FIG. 2. In one example, the first processing unit 202a may include a gain adjuster block (not shown) that obtains and outputs the first combined torque (T1) by adding the products of the gain values G1 and G2 with the roll angle φ(t1) and the roll rate, respectively, and the roll angle (φ) and the roll rate () are detected by the angular displacement sensor 203. Further, the first processing unit 202a may also include a lead time calculation block (not shown) for determining the second combined torque (T2) by applying a lead time (τ) for adding the first combined torque (T1) as shown in Equation 2. T2(t)=T1(t + τ) ··· Equation 2

[0046] The lead time (τ) helps to improve the rider's confidence level in the vehicle, even while being assisted to balance at particularly low vehicle speeds, and is selected such that the point in time when the balancing torque is applied precedes the normal rider steering operation point in order to reduce the amount of effort the rider has to make to balance. In one example, the lead time (τ) can be predetermined based on the vehicle specifications and stored in the memory of the stabilization unit 202.

[0047] The second processing unit 202b receives the combined torque (T r ) from the first processing unit 202a for comparison with the steering torque (T r) can be the combined torque (T) received by the second processing unit 202b for comparison. In another example, the second combined torque (T2) is the steering torque (T r ) can be the combined torque (T) received by the second processing unit 202b for comparison.

[0048] Furthermore, the second processing unit 202b determines a stabilization torque (T r ) based on the comparison of the combined torque (T) and the steering torque (T s ) and provides an actuation signal to the actuator 201 to cause the actuator 201 to apply the stabilization torque (T s ) on the steering wheel. In one example, the second processing unit 202b can determine the product of the combined torque (T) and a tuning parameter based on the comparison to determine the stabilization torque.

[0049] The value of the selected correction factor / tuning parameter can vary within the range of 0 to 1 according to various riding conditions that can be determined based on the steering torque (T r ). The stabilization unit 202 typically encounters at least three different riding scenarios while comparing the combined torque (T) with the steering torque (T r ).

[0050] For example, in a first condition where the rider is not operating the vehicle 100 and the saddle - riding type vehicle is in a straight - running state, the calculated combined torque (T) will be the same as the torque that a rider tends to apply under non - assisted riding conditions. Thus, the tuning parameter is selected to be 1, that is, the combined torque (T) is applied as the stabilization torque (T s ) on the steering wheel by the actuator 201. Thus, the steering torque (T r ) that would be applied by the rider is zero, and at this time, the system 200 provides a stabilization torque (T s which is equal to the combined torque (T) in this case.Completely control the vehicle by adding [[ID=]]. Typically, in a straight - driving state, the only need for balancing torque is typically felt at low vehicle speeds. Since G1 and G2 are functions of vehicle speed, even at very low speeds, for example, less than 7 km / h, the system 200 automatically helps to balance the vehicle without the rider having to make steering corrections / apply steering torque to balance the vehicle. This is useful because at very low speeds, the rider response during rapid steering adjustments / corrections is typically slow. Thus, at low speeds and during cruising, it improves the riding experience and safety.

[0051] A second condition where the rider transiently maneuvers the vehicle, for example, during traffic situations or when the rider attempts to avoid a dip or an obstacle on the road, at that instant, the applied steering torque (T r ) will not be the same as the combined stabilization torque (T1) calculated by the stabilization unit. Furthermore, the rate of change of the applied steering torque (T r ) will not be zero during transient maneuvers, that is, the difference (T r) is not approximately equal to 0 (not ≒). In one example, the differential steering torque is determined based on the difference between the steering torque determined at the current instant and the steering torque determined at the immediately preceding instant. In one example, the signal corresponding to the roll parameter may have noise and may be filtered before processing. In this case, the difference may be determined from the filtered values of the steering torque obtained for the previous and current instants. In one example, when the second condition is applicable, the stabilization unit triggers the actuator to add the stabilization torque A×T (i.e., the product of the values of the tuning parameters A and T). The value of the tuning parameter A depends on the instantaneous values of the roll angle (φ) and the roll rate ( and varies between 0 and 1 depending on the riding conditions. For example, after riding stably for a certain distance with the assistance of the system 200 (i.e., with tuning parameter 1), when the rider is changing lanes or maneuvering transiently to avoid a depression, the rider is enabled to apply the torque required for the maneuver, the stabilization torque (T r) The value of the tuning parameter (A) applied to calculate s ) will be reduced from 1 to near 0. Reducing the value of the first tuning parameter A to near zero is done gradually so that the rider does not experience a sudden discomfort of additional torque being applied. Further, after a transient maneuver, when the rider continues to ride straight, i.e., when the steering torque is zero or near zero, the value of A is gradually increased to near 1. Thus, from providing assistance in the straight - running state, through providing reduced assistance during transient maneuvers, to returning to the assisted state during straight running, a smooth transition is made. By using the tuning parameter, the rider can surely control the vehicle, while also ensuring that the vehicle does not lose balance. Thus, the present subject matter helps the rider feel in control of the vehicle even while the vehicle is still being assisted by the system to maintain balance. This is advantageous because if the system completely takes away the steering of the vehicle instead of reducing the assistance, the rider may tend to over - steer or apply additional unnecessary torque. Thus, the stabilization unit is configured to temporarily apply A≈0 when the rider makes a sudden maneuver, changing the value of the tuning parameter between 0 and 1 with the maneuver, so that the stabilization torque (T s ) becomes near zero and enables the rider to take over.

[0052] In a third condition where the rider is stably cornering, the stabilization unit determines the combined torque (T) based on the roll angle (φ) of the vehicle. Since continuous roll occurs during cornering, it can be seen that the applied steering torque (T r ) becomes approximately equal to the combined torque (T). Further, the rate of change of the applied steering torque (T r ) is zero during stable cornering, i.e., the difference (T r )≈0. Under such conditions, the stabilization unit 202 provides the stabilization torque T s=B×T, that is, trigger the motor to add the product of the second tuning parameter B and T. The stabilization unit 202 is configured to select "B" as a correction factor or tuning parameter that needs to be applied to the torque (T). The value of the tuning parameter B varies between 0 and 1. For example, when the rear rider of a stable ride starts cornering, it is initially detected as a transient maneuver, and the tuning parameter can be reduced to zero as discussed above. Further, when the steering torque remains constant while the rider continues to corner, it can be determined that the tuning parameter B will be applied. When the rider continues to corner, the value of B gradually increases towards 1. As a result, the stabilization torque (T become ) is equal to B times that of the combined torque (T). While the value of B is maintained between zero and 1, the rider may or may not apply minimal effort for cornering. Further, when the rider returns to the stable driving state, the tuning parameter is maintained as 1 as discussed above for the first condition. s )

[0053] In one example, the tuning parameters that will be used are pre-determined and can be stored in the memory within the stabilization unit 202, for example, as a mapping table or a mathematical function. Although the above discussion states that the tuning parameters change gradually (increase or decrease), it should be understood that the variation of the tuning parameters can be implemented in units of milliseconds and the speed of variation can also depend on the vehicle speed.

[0054] In one example, various coefficients / factors such as gain, delay time, advance time, tuning parameters, etc. can be pre-determined based on regression analysis of experimental data for various vehicle specifications and pre-stored in the memory of the stabilization unit 202. In one example, the stabilization unit 202 may implement machine learning to learn and fine-tune various coefficients as the vehicle is driven to improve performance over time.

[0055] Accordingly, in various operational dynamic riding conditions, vehicle balance is maintained, efficient assistance is provided by system 200 with minimal parameters, and the rider experience is improved.

[0056] Next, with reference to FIGS. 5, 6, and 7, which respectively show methods 500, 600, and 700 for stabilizing a vehicle according to the present subject matter, a description will be given.

[0057] The order in which methods 500 to 700 are described is not intended to be construed as limiting, and some of the described method blocks may be combined in different orders to implement these methods or alternative methods. Further, these methods may be implemented by processing resources through any suitable hardware, non-transitory machine-readable instructions, or a combination thereof. It should be understood that the steps of these methods may be executed based on instructions stored in a non-transitory computer-readable medium. The non-transitory computer-readable medium may include, for example, digital memory, magnetic storage media such as magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media. Further, methods 500 to 700 may be implemented in various systems, but these methods are described in relation to system 200 and vehicle 100 for ease of explanation.

[0058] Referring to FIG. 5 and method 500, at block 502, the vehicle speed (ν) is received from a vehicle position sensor. For example, the stabilization unit 202 receives the vehicle speed from the position sensor 205 of the vehicle 100.

[0059] In block 504, the roll angle (φ) and roll rate of the vehicle are received from the angular displacement sensor of the vehicle. The roll angle (φ) corresponds to the angular displacement of the vehicle in the roll direction, and the roll rate corresponds to the angular velocity of the vehicle in the roll direction. For example, the stabilization unit 202 can receive the roll angle (φ) and roll rate from the angular displacement sensor 203 of the vehicle 100.

[0060] In block 506, the gain values (G1, G2) can be determined by the controller based on the vehicle speed (ν). For example, the stabilization unit 202 can be the controller and can determine the gain values from a mapping table or mathematical function stored in the memory or implemented as a hardware circuit.

[0061] In block 508, the stabilization torque (T s ) that is to be applied to the steering wheel of the vehicle to stabilize the vehicle can be determined by the controller based on applying the respective gain values (G1, G2) to the roll angle (φ) and roll rate. For example, the stabilization unit 202 can determine the stabilization torque (T s ) based on the gain values. As discussed above, the first gain value (G1) and the second gain value (G2) increase non-linearly with a decrease in the vehicle speed (ν) and decrease non-linearly with an increase in the vehicle speed (ν). The gain values (G1, G2) can be functions of the vehicle speed (ν), vehicle specifications, roll angle delay time (dt1), and roll rate delay time (dt2).

[0062] In one example, to accurately estimate the steering torque, respective delay times dt1, dt2 are introduced into the roll angle and roll rate. If the delay times are changed, the gain values will also change. This is because the gain values are calculated from the analysis of experimental measurement values for a given first combined torque (T1) based on Equation 1.

[0063] In one example, the controller can determine a first combined torque (T1) as the sum of a first product of a roll angle (φ) and a first gain value (G1), and a second product of a roll rate and a second gain value (G2). Further, to determine the gain values (G1, G2), respective delay times (dt1, dt2) can be applied to the roll angle (φ) and the roll rate to reflect the delay of the steering torque with respect to the roll parameter. The first combined torque can be used, in one example, to determine a stabilizing torque (T s ).

[0064] In one example, a second combined torque (T2) can be determined based on the first combined torque (T1) and a lead time (τ), where the lead time enables adding the stabilizing torque (T r ) before the steering torque (T s ) is applied to the steering wheel. The second combined torque can be used, in another example, to determine a stabilizing torque (T s ).

[0065] In block 510, an actuation signal is provided to an actuator by the controller to add a stabilizing torque (T s ) to the vehicle's steering wheel to stabilize the vehicle. For example, the stabilization unit 202 can provide the actuation signal to the actuator 201.

[0066] In one example, to stabilize the vehicle, as discussed with reference to FIG. 6, the steering torque (T r ) can also be considered to reflect various riding conditions.

[0067] Referring to FIG. 6 and method 600, at block 602, the vehicle speed (ν) is received from a position sensor, and a roll angle (φ) corresponding to the angular displacement of the vehicle in the roll direction and a roll rate corresponding to the angular velocity of the vehicle in the roll direction are received from an angular displacement sensor, and the steering torque (T r) is received from the steering torque sensor. For example, the stabilization unit 202 can receive the vehicle speed from the position sensor 205, the roll angle and roll rate from the angular displacement sensor 203, and the steering torque (T r ) from the steering torque sensor 204.

[0068] In block 604, a combined torque (T) based on the roll angle (φ), roll rate, and vehicle speed (ν) is determined by the controller. For example, the stabilization unit 202 can be the controller and can determine the combined torque (T).

[0069] In one example, the combined torque (T) determines a first combined torque (T1) as the sum of a first product of the roll angle (φ) and a first gain value (G1) and a second product of the roll rate and a second gain value (G1). The first gain value (G1) and the second gain value (G2) increase non-linearly with a decrease in the vehicle speed (ν) and decrease non-linearly with an increase in the vehicle speed (ν). Further, as discussed above, respective delay times (dt1, dt2) are introduced into the roll angle (φ) and roll rate to determine the first combined torque (T1). Further, a second combined torque (T2) is determined based on the first combined torque (T1) and the lead time (τ), and the lead time enables the addition of a stabilization torque (T r ) before the steering torque (T s ).

[0070] In block 606, a tuning parameter is determined by the controller based on a comparison of the combined torque (T) and the steering torque (T r ). The value of the tuning parameter can be within the range from 0 to 1.

[0071] In one example, the tuning parameter is maintained at 1 when the steering torque is zero such that the stabilizing torque applied to the steering wheel when no steering torque is applied to the steering wheel is equal to the combined torque. This corresponds to a stable driving state of the vehicle where the rider may not be steering the vehicle.

[0072] In one example, when the steering torque is not equal to the stabilizing torque and the steering torque varies over time, the tuning parameter is gradually changed from 1 to 0 such that the stabilizing torque applied to the steering wheel decreases from the combined torque to zero. Further, the tuning parameter is gradually increased from 0 to 1 when the steering torque becomes zero. This corresponds to a driving state where a transient maneuver is performed from a steady state ride and then returns to the steady state after the transient maneuver.

[0073] In one example, when the steering torque is equal to the stabilizing torque and the steering torque is constant over time, the tuning parameter is gradually changed from 0 to 1 such that the stabilizing torque applied to the steering wheel increases from zero to the combined torque. This corresponds to stable cornering ride conditions.

[0074] At block 608, a stabilizing torque (T s ) is determined by the controller based on the tuning parameter and the combined torque.

[0075] At block 610, an actuation signal corresponding to the stabilizing torque (T s ) is provided to an actuator to apply the stabilizing torque (T s ) to the steering wheel of the vehicle to stabilize the vehicle.

[0076] FIG. 7 shows a particular exemplary method 700 for stabilizing a vehicle. At block 702, vehicle speed (ν), roll angle (φ), roll rate, and steering torque (T r) is received, for example, by the stabilization unit 202 from a plurality of sensors.

[0077] In block 704, a first synthetic torque (T1) is determined by applying respective gains (G1, G2) and delay times (dt1, dt2) to the roll angle (φ) and roll rate. For example, the first synthetic torque can be determined using Equation 1 discussed above.

[0078] In block 706, a second synthetic torque (T2) is determined by applying a lead time (τ) to the first synthetic torque (T1) to obtain a synthetic torque (T). For example, the second synthetic torque can be determined using Equation 2 discussed above. The second synthetic torque is used as the synthetic torque for determining the stabilization torque.

[0079] In block 708, the synthetic torque (T) is compared with the steering torque (T r ) and based on that comparison, a stabilization torque (T s ) is determined. Three possible conditions in the comparison are shown in blocks 710, 712, and 714. Since these conditions may be evaluated in any order, they are shown as parallel branches originating from block 708 in method 700.

[0080] In block 710, it is determined whether the steering torque (T r ) is zero, and if so, in block 716, the stabilization torque (T s ) is determined to be equal to the synthetic torque (T) to assist the rider in operating / cruising in a stable state.

[0081] In block 712, it is determined whether the steering torque (T r ) is not equal to the synthetic torque (T), and whether the steering torque (T r) is determined whether it varies with time (i.e., the difference in steering torque is not zero), and if so, in block 718, to enable the rider to take over for transient maneuvers, the stabilizing torque (T s ) is gradually reduced from the combined torque to zero. In one example, to obtain the stabilizing torque (T s ), a first tuning parameter may be multiplied by the combined torque (T).

[0082] In block 714, it is determined whether the steering torque (T r ) is equal to the combined torque (T), and whether the steering torque (T r ) is constant over time (i.e., the difference in steering torque is zero), and if so, in block 720, to assist in stable cornering, the stabilizing torque (T s ) is gradually increased from zero to the combined torque (T). In one example, to obtain the stabilizing torque (T s ), a second tuning parameter may be multiplied by the combined torque (T).

[0083] Therefore, the stabilizing torque (T s ) determined from block 716 or 718 or 720 is used in block 722 to provide an actuation signal to an actuator, such as motor actuator 201, to apply the stabilizing torque on the steering wheel of the vehicle.

[0084] Therefore, the present subject matter helps to balance the vehicle by applying a stabilizing torque ahead of the rider under various riding conditions without interfering with the rider's steering intention. Although described in detail with reference to a rider, it should be understood that it is also applicable to an autonomous vehicle that is automatically controlled and maneuvered.

[0085] As can be understood from the foregoing discussion, the systems and methods according to the teachings of the present subject matter are capable of not only estimating the stabilization torque required to balance a vehicle under various riding conditions, but also ensuring that a rider can effectively control the vehicle while the balance of the vehicle is being achieved with the assistance from the present systems and methods. Further, the present subject matter uses some easily determinable vehicle parameters, such as vehicle speed, roll angle, and roll rate, unlike other systems known in the art that use more complex inputs and calculations. Also, the number of sensors required for the present subject matter to function is reduced compared to complex prior art systems, thereby making it possible to reduce the overall manufacturing and operating costs of the system.

[0086] While embodiments of the present subject matter have been described in structural features and / or language specific to methods, it should be understood that the present subject matter is not necessarily limited to the specific features or methods described. Rather, these specific features and methods are disclosed and described as exemplary embodiments.

Claims

1. A system (200) for stabilizing a vehicle (100), comprising: A position sensor (205) for determining a vehicle speed (ν), a roll angle (φ) corresponding to an angular displacement of the vehicle (100) in the roll direction, and a roll rate corresponding to an angular velocity of the vehicle (100) in the roll direction, and a steering torque sensor for determining a steering torque (T r ) applied to the steering wheel of the vehicle, and a plurality of sensors including; A stabilization unit (202) coupled to the plurality of sensors; The stabilization unit (202) is configured to: Determine a combined torque based on the roll angle (φ), the roll rate, and the vehicle speed (ν); Determine a tuning parameter based on a comparison between the combined torque and the steering torque (T r ); Determine a stabilization torque (T s ) based on a product of the tuning parameter and the combined torque; Provide an actuator (201) with an actuation signal corresponding to the stabilization torque (T s ) to apply the stabilization torque (T s ) to the steering wheel of the vehicle (100) to stabilize the vehicle (100).

2. The system (200) according to claim 1, wherein the tuning parameter is in the range from 0 to 1.

3. The system (200) according to claim 2, wherein the stabilization unit (202) maintains the tuning parameter at 1 when the steering torque is zero such that the stabilization torque applied to the steering wheel when no steering torque is applied to the steering wheel is equal to the combined torque.

4. The stabilization unit (202) is, when the steering torque is not equal to the stabilization torque and the steering torque varies with time, gradually changing the tuning parameter from 1 to 0 so that the stabilization torque applied to the steering handle decreases from the combined torque to zero, The system (200) according to claim 2, wherein the tuning parameter is gradually increased from 0 to 1 when the steering torque becomes zero.

5. The stabilization unit (202) is, when the steering torque is equal to the combined torque and the steering torque is constant over time, gradually changing the tuning parameter from 0 to 1 so that the stabilization torque applied to the steering handle increases from zero to the combined torque, the system (200) according to claim 2.

6. To determine the combined torque, the stabilization unit (202) determines a first combined torque (T 1 ) as the sum of a first product of the roll angle (φ) and a first gain value (G 1 ) and a second product of the roll rate and a second gain value (G2), and the first gain value (G 1 ) and the second gain value (G 2 ) increase non-linearly with a decrease in the vehicle speed (ν) and decrease non-linearly with an increase in the vehicle speed (ν), the system (200) according to claim 1.

7. To determine the combined torque, the stabilization unit (202) introduces a roll angle delay time (dt1) to calculate the roll angle (φ) and a roll rate delay time (dt2) to calculate the roll rate. The roll angle delay time (dt1) and the roll rate delay time (dt2) are determined with respect to the steering torque (Tr) applied by the rider. The time t1 for calculating the roll angle at time t is obtained as (t1 = t - dt1), and the time t2 for calculating the roll rate at time t is obtained as (t2 = t - dt2). The system (200) according to claim 6.

8. To determine the combined torque, the stabilization unit (202) is the first combined torque (T 1 ) and, based on the advance time (τ), which is the time difference between the time when the stabilization torque (Ts) is applied and the time when the steering torque (Tr) is then applied, the second combined torque (T 2 ) is determined according to the formula T2(t) = T1(t + τ). The system (200) according to claim 7.

9. The position sensor determines the instantaneous state of the vehicle. The system (200) according to claim 1.

10. The stabilization unit includes one or more controllers and one or more memories. The system (200) according to claim 1.

11. The actuator (201) is a motor, and the actuation signal controls the motor torque applied by the motor on the steering wheel. The system (200) according to claim 1.

12. A vehicle (100) comprising a steering wheel, an actuator (201), and a system (200) for stabilizing the vehicle (100) according to claim 11.

13. A method for stabilizing a vehicle (100), comprising The vehicle speed (ν) from the position sensor (205), the roll angle (φ) corresponding to the angular displacement of the vehicle (100) in the roll direction from the angular displacement sensor (203), and the roll rate corresponding to the angular velocity of the vehicle in the roll direction, and the steering torque (T r ) applied to the steering wheel of the vehicle (100) from the steering torque sensor (204). Determining a combined torque by a controller based on the roll angle (φ), the roll rate, and the vehicle speed (ν). Determining a tuning parameter by the controller based on a comparison between the combined torque and the steering torque (T r ). Determining a stabilizing torque (T s ) by the controller based on a product of the tuning parameter and the combined torque. Applying the stabilizing torque (T s ) to the steering wheel of the vehicle (100) to stabilize the vehicle (100), and providing an actuation signal corresponding to the stabilizing torque (T s ) to an actuator (201). A method comprising:

14. The method according to claim 13, wherein the tuning parameter is in a range from 0 to 1.

15. The method according to claim 14, comprising maintaining the tuning parameter as 1 when the steering torque is zero such that the stabilizing torque applied to the steering wheel when no steering torque is applied to the steering wheel is equal to the combined torque.

16. When the steering torque is not equal to the stabilizing torque and the steering torque varies with time, gradually changing the tuning parameter from 1 to 0 so that the stabilizing torque applied to the steering wheel decreases from the combined torque to zero, and gradually increasing the tuning parameter from 0 to 1 when the steering torque becomes zero The method according to claim 14, comprising:

17. The method according to claim 14, comprising gradually changing the tuning parameter from 0 to 1 so that the stabilizing torque applied to the steering wheel increases from zero to the combined torque when the steering torque is equal to the combined torque and the steering torque is constant over time.

18. Determining the combined torque includes determining a first combined torque (T 1 ) as the sum of a first product of the roll angle (φ) and a first gain value (G 1 ) and a second product of the roll rate and a second gain value (G2), wherein the first gain value (G 1 ) and the second gain value (G 2 ) increase non-linearly with a decrease in the vehicle speed (ν) and decrease non-linearly with an increase in the vehicle speed (ν). The method according to claim 13.

19. Determining the combined torque includes introducing a roll angle delay time (dt1) to calculate the roll angle (φ) and a roll rate delay time (dt2) to calculate the roll rate, where the delay times (dt1, dt2) are determined with respect to the steering torque (Tr) applied by the rider. The time t1 for calculating the roll angle at time t is obtained as (t1 = t - dt1), where dt1 is the roll angle delay time, and the time t2 for calculating the roll rate at time t is obtained as (t2 = t - dt2), where dt2 is the roll rate delay time. The method according to claim 18.

20. Determining the combined torque includes 1 adding the first combined torque (T 2 ) and determining a second combined torque (T 2 ) according to the formula T2(t) = T1(t + τ), where τ is the advance time, which is the time difference between the time when the stabilizing torque (Ts) is added and the time when the steering torque (Tr) is added thereafter. The method according to claim 19.

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