Wheelie determining device and wheelie determining method

1. A wheelie determining device comprising:

an electronic control unit configured to determine a start of a lift-off of a front wheel of a vehicle from a ground surface, based on a traveling state value indicating a traveling state of the vehicle,

wherein the electronic unit is configured to:

calculate a lift-off trend value indicating a degree of easiness of the lift-off of the front wheel from the ground surface, based on an operation value indicating a rate of change over time of a request by a rider's driving operation for increasing power of a driving source of the vehicle,

change a threshold level of a lift-off condition so as to meet the lift-off condition earlier, as the lift-off trend value increases, and

determine the start of the lift-off of the front wheel in a case where the traveling state value meets the lift-off condition.

2. The wheelie determining device according to claim 1 ,

wherein the traveling state value includes a rotational acceleration rate of the front wheel, and the lift-off condition includes a front wheel acceleration rate condition in which the rotational acceleration rate of the front wheel is equal to or less than a threshold, and

wherein the electronic control unit is configured to set the threshold to a larger value as the rate of change over time of the request for increasing the power of the driving source is greater.

3. The wheelie determining device according to claim 1 ,

wherein the traveling state value includes a front wheel state value indicating a state of the front wheel, and an estimated value of power of the driving source, and

wherein the electronic control unit is configured to determine whether or not the lift-off of the front wheel has started, based on the front wheel state value and the estimated value of the power of the driving source.

4. The wheelie determining device according to claim 1 , wherein the electronic control unit is further configured to calculate

as a wheelie amount which is an amount of the lift-off of the front wheel from the ground surface, a change amount of an angle of a vehicle body in a rotational direction in which the front wheel is away from the ground surface after a time point at which the electronic control unit has determined that the lift-off of the front wheel has started.

5. The wheelie determining device according to claim 4 ,

wherein the electronic control unit is further configured to suppress power of the driving source based on the wheelie amount.

6. The wheelie determining device according to claim 1 , wherein the electronic control unit is further configured to:

compare the traveling state value to a threshold to determine whether or not the lift-off of the front wheel has started; and

variably set the threshold according to the rate of change over time of the request for increasing the power of the driving source.

7. The wheelie determining device according to claim 1 , wherein the electronic control unit is further configured to:

calculate as a wheelie amount which is an amount of the lift-off of the front wheel from the ground surface, a change amount of an angle of a vehicle body in a rotational direction in which the front wheel is away from the ground surface after a time point at which the electronic control unit has determined that the lift-off of the front wheel has started; and

suppress power of the driving source based on the wheelie amount.

8. A method of determining occurrence of a wheelie in a vehicle, comprising:

calculating a lift-off trend value indicating a degree of easiness of a lift-off of a front wheel of the vehicle from a ground surface, based on an operation value indicating a rate of change over time of a request by a rider's driving operation for increasing power of a driving source of the vehicle,

change a threshold level of a lift-off condition so as to meet the lift-off condition earlier, as the degree of easiness of the lift-off of the front wheel increases, and

determining a start of the lift-off of the front wheel in a case where a traveling state value indicating a traveling state of the vehicle meets the lift-off condition.

9. A wheelie determining device comprising:

an electronic control unit configured to determine a start of a lift-off of a front wheel from a ground surface, based on a traveling state value indicated a traveling state of a vehicle,

wherein the electronic control unit is configured to:

calculate a lift-off trend value indicating a degree of easiness of the lift-off of the front wheel from the ground surface, based on an operation value indicating a stroke amount of a front suspension or a rate of change over time of the stroke amount,

change a threshold level of a lift-off condition so as to meet the lift-off condition earlier, as the degree of easiness of the lift-off increases, and

determine the start of the lift-off of the front wheel in a case where the traveling state value meets the lift-off condition.