WO2016039197A1 - Method and device for speed change control of a bicycle - Google Patents

Abstract

In a conventional speed change control method, a speed change operation is performed by pushing a bar-shaped switch fixed to a handlebar of a bicycle. However, during such an operation, it is necessary to move a hand and move a finger to the position of the switch. When an operator is concentrating on pedaling a bicycle such as during a hill climb, movement of the body accompanying such an operation or temporary distraction due to a button operation may lead to stress. The timing for a speed change operation is also determined sensorially by an operator, but in terms of improving movement efficiency, the timing for a speed change operation is preferably determined on the basis of an objective physical indicator. In the present invention, a speed change is performed automatically by measuring the rocking of a bicycle/person generated during pedaling and detecting a change in the rocking, and thereby a button operation during a speed change is unnecessary. Further, the pedaling efficiency and the speed change timing are indicated to the operator on the basis of the rocking condition, and thus the bicycle training efficiency is improved.

Description

Bicycle shift control method and apparatus

The present invention relates to a bicycle shift control method and apparatus.

In recent years, a device for electrically controlling a bicycle transmission has been put into practical use (Patent Document 1). Synchronous shift (Patent Document 2) that shifts the rear gear (or reverses the front / rear operation) in conjunction with the shift operation of the front gear, which was difficult with conventional mechanical shift control, It can be easily realized with a transmission that is controlled automatically. In the synchro shift, one gear shift operation can synchronize the front and rear gear shifts to optimize the front / rear gear ratio and improve pedaling efficiency.

In the conventional shift control method, a bar-shaped switch fixed to a bicycle handle is pressed to perform a shift operation. At the time of the operation, it is necessary to move the hand to move the finger to the switch position. If you are struggling on a bicycle during a hill climb, you will be stressed by temporarily taking care of your body movements (changes in posture and movement of the center of gravity) and button operations. The driver also sensibly determines the timing of the speed change operation, but it is desirable to determine the timing of the speed change operation based on an objective physical index in order to improve exercise efficiency. In addition, when the synchro shift is installed, when one gear shift operation of the front / rear gear is performed, the program shifts the front / rear gear in one operation to adjust the gear ratio of the front / rear gear. Therefore, when canceling or changing the synchro shift, it is necessary to perform the switch operation again.

In the present invention, the swing of a bicycle / person occurring at the time of pedaling is measured, and a change in the swing is detected to automatically perform a shift, thereby eliminating the need for button operation during the shift. In addition, the efficiency of bicycle training is improved by showing the driver the timing of the pedaling efficiency and the timing of the shift from the state of swinging.

In general, pedaling of a bicycle is classified into a stepping angle range (mainly from 2 o'clock to 3 o'clock angle) and a pulling angle range (from 8 o'clock to 10 o'clock) according to the rotation angle of the crank. However, it is possible to improve pedaling efficiency by considering the strength of the stepping / pulling force in each area. Also, in the vicinity of the bottom dead center of the crank (angle range from 5 o'clock to 7 o'clock), a force pulling in the circumferential direction is applied (so-called winding leg), and near the top dead center (angle from 11 o'clock to 1 o'clock) In the area, pedaling can be made more efficient depending on the driving situation (hill climb, high-speed cruise, etc.) by applying a force pushing in the circumferential direction (so-called push foot).

When pedaling, the bicycle changes due to changes in force according to the crank angle, left and right crank angle offsets (generally 180 degrees), and left and right foot position shifts (depending on the Q factor, the presence or absence of the front shifting gear, etc.) And swinging in the human body. When constant pedaling is performed, this oscillation is a regular reciprocating motion in the lateral direction (direction perpendicular to the traveling direction). This reciprocating motion is synchronized with the crank rotation. It can be said that the movement of human beings linked with the swing of the car body is a feature not found in cars and motorcycles.

The regular reciprocating motion of the car body due to pedaling loses regularity due to changes in cruising conditions (acceleration / deceleration) and changes in the road surface (corners / slopes). That is, at the timing when the driver is willing to accelerate or decelerate or when the road surface condition changes, the power required for pedaling increases or decreases, so that the swing of the bicycle / person accompanying pedaling changes.
Lagrange's equation of motion, which expresses the movement of a bicycle or person swinging in the horizontal direction, is shown in Equation 1.
[Equation 1]

Here, q is a generalized coordinate, the first term on the left side is the inertia term, the second term on the left side is the center / Coriolis force term, and the third term on the left side is the gravity term. τ is generalization force, Fc is restraining force, restraining wheel on the ground, Coriolis force due to wheel rotation, weight on driver's hand on handle, force on foot from pedal, sitting on saddle This is a term that represents the resultant force of the force that is generated due to the state of contact. The efficiency of movement may be reduced by applying a force to consciously or unconsciously suppress the swinging of both hands on the handle, but the point is that natural swinging occurs so as not to decrease.
An expression in the case of modeling as a two-degree-of-freedom inverted pendulum limitedly is shown in Patent Document 2 and the like.

At the time of acceleration or when the climbing slope on the slope increases, the power required for pedaling increases and the swing of the person and the vehicle increases. Conversely, when decelerating or downhill, the power required for pedaling is reduced and the swinging of the person / body is reduced. Since pedaling stops at a sharp corner, the vehicle does not reciprocate. The formula for calculating the swing index is shown in Equation 2. Equation 15 in Patent Document 3 corresponds to the case where n = 2 and q = θ in Equation 2.
[Equation 2]

Here, Wq, i (s) and Wq ^ dot, i (s) represent weighting functions (s is a variable of Laplace transform). The weighting includes a time constant (filter) and weighting for each term, and changes depending on road conditions (gradient / paving conditions, etc.) and pedaling conditions (acceleration / deceleration, dancing, etc.). When the pavement is rough like a stone pavement, high frequency components are removed.
An evaluation function ψ for the speed change operation is defined by Equation 3.
[Equation 3]

In this equation, t is a time [second], and W1, W2,... Wn are time series (or q ′) weighting functions. As the time t increases, n = 1, 2... A speed change operation is performed by this evaluation function ψ and a threshold value (initial value or user set value).

In the present invention, it is possible to automatically change gears by measuring the swing of a bicycle / person and capturing the change. After a certain level of acceleration, rear side gear upshift (speed increase, front / rear gear speed ratio becomes large) or front side gear and rear side gear synchro shift equivalent to rear side gear upshift, constant After decelerating the level, the rear side gear is downshifted (deceleration, the front / rear gear ratio becomes smaller), or the front side gear and the rear side gear are synchronously shifted corresponding to the rear side gear downshift. In situations where the uphill slope is large on the slope or the heart rate is rising, the rear side gear downshift or the rear side gear downshift equivalent to the rear side gear downshift and the rear side gear downshift to suppress changes in power required for pedaling. Perform side gear synchro shift. The reverse shift is performed at the timing when the ascending slope becomes smaller on the slope and on the downhill. In addition, a crank rotation speed (cadence) region that is difficult to row due to a change in gear ratio occurs after a shift, but in the case of an electrically assisted vehicle, it can be made easy to row by adding electric assist in this rotation speed region.

When dancing (so-called standing) or sprinting, the bicycle handle may be slightly swung to ensure efficient pedaling. In these cases, since the hand is holding the handle, it is difficult to move the hand or finger to the position of the shift switch. In the present invention, the movement of the driver's hand, body or head is detected, and automatic shifting is possible even during dancing or sprinting. Shifts automatically when braking (generally, the gear ratio of the front / rear gear is reduced during down-shifting = downshifting) to smooth the starting after braking. Further, when braking suddenly, the driver moves such as stopping pedaling. Therefore, the intention of sudden braking is detected from the movement of the driver / bicycle, and the electric brake (option) is controlled. By synchronizing braking with electric brakes and shifting (deceleration, downshift), pedaling after braking can be performed smoothly.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a bicycle and a driver wearing a gyroscope.
In order to measure the swing of a bicycle or person, it is sufficient that at least one gyroscope is attached. However, since there is a movable part between the handle and the bicycle frame, in FIG. Wearing. An acceleration sensor and a three-axis gyroscope (vibrating gyroscope) are used to capture changes in bicycle speed and azimuth angle. In addition, two gyroscopes are worn to capture the movement of the driver's upper body and head. As an option, a power meter and a crank tachometer are installed. The signal processing unit in the control device 3 processes the sensor data, and the control unit outputs shift signals for the front and rear gears.

Accelerometers and vibratory gyroscopes are smaller and less expensive (especially manufactured with MEMS technology), and can detect angular velocities and accelerations in two or even three axes in one package. Acceleration / deceleration, gradient, etc. can be measured with an acceleration sensor. The measurement data is evaluated and used by a threshold filter or an evaluation function based on statistics. The sensor signal is analyzed by digital filter (IIR filter, etc.) or frequency analysis (Fourier transform).

Also, as an option, a sensor such as a touch panel is attached to the handle, frame, saddle, or pedal, and the movement of the hand or body in contact with the sensor is detected to control the speed change operation or the electric brake. The touch panel can technically realize a curved sensor that matches the handle and the vehicle body, and has the advantage that the sensor can be mounted while maintaining the aerodynamic performance of the bicycle.

When a human motion is detected by a gyroscope or a touch panel, there are a case where the motion is detected due to a motion of the bicycle and a case where a motion of the bicycle / body is intentionally detected like a gesture. In any case, the shift operation, the electric brake, and the like are controlled by the sensor measurement data.

Formula 4 is illustrated for the case where the calculation formula (Formula 2) of the swing index is simplified.
[Equation 4]

In this equation, t is time [second], and θn ^ dot is angular velocity [radian / second] at time t (time differentiation of angle θ from the upright state of the frame shown in FIG. 1). The evaluation function ψ can be expressed as in Equation 5.
[Equation 5]

In this equation, t is the time [second], θ is the angle [radian] from the upright state of the frame, and W1, W2,... Wn are weighting functions. It is possible to mount on a small portable terminal by suppressing the calculation cost by a simple evaluation function such as Equation 5.
The evaluation function ψ is illustrated in FIG. Automatic shift is performed by this evaluation function ψ and a threshold value (initial value or user set value). In FIG. 2, when the swing is small, that is, when the value of the evaluation function ψ is small and the swing of the bicycle is small (= θ is also small), and when the swing is large, “automatic shift range” ". A curve other than the curve having the lead line of ψ (θ) is the value of En, and in the case of the figure, n = 1 to 4 are illustrated. θ1 to θ4 and ψ0 are threshold values and are given as preset values / user set values. An area where automatic shifting is not possible can be set near the origin. Also in the case of Formula 2 swing calculation formula and Formula 3 evaluation function ψ, a plurality of “automatic shift regions” are set according to the function form.

In this automatic shift region, the front / rear gear ratio is increased (the force applied to the foot feels heavy) or the gear ratio is decreased. The gear ratio is increased when the pedaling power is changing in a more necessary direction in a certain driving situation, and conversely, the gear ratio is reduced when the pedaling power is changing in the direction of suppressing the pedaling power. Non-Patent Document 1 shows the relationship between the front and rear gears of a bicycle and the gear ratio, and the relationship between the gear ratio and power transmission efficiency. For example, when shifting in a state where the heart rate is fully raised during hill climbing, it is necessary to suppress pedaling power, and therefore the gears before and after are shifted (downshifted) in synchronization so that the gear ratio becomes small. Further, when the pedaling power is continuously changing in a more necessary direction during sprinting or the like, the front and rear gears are shifted (upshifted) in synchronization so that the gear ratio is increased.

The traveling speed of the bicycle can be determined from the relationship between the yaw rate (turning speed), curvature (steering angle), and forward speed, as well as the speed measured by the vehicle speed sensor and the GPS received data. In this case, the steering angle and the yaw rate are measured by a gyro attached to the steering wheel and the frame, and the forward speed is obtained from the relational expression.

In the synchronized shift, a gear ratio deviation as shown in FIG. 3 occurs depending on the combination of the front and rear gears. In the present invention, not only when the gear ratio divergence is combined so as to simply minimize the gear ratio divergence, but even when the gear ratio divergence increases, pedaling more efficiently depending on the driving situation (gradient, etc.). Select a possible gear ratio. For example, a gear ratio with good power transmission efficiency is selected from the shift map during hill climbing. The shift map is based on data created in advance corresponding to the number of gears and the number of teeth of the front gear and the number of gears and the number of teeth of the rear gear.

FIG. 4 shows a flowchart of the signal processing unit in the control device.
When measuring the gradient etc. with the acceleration sensor, the gear matched to the road gradient is selected at the time of the sync shift. If the gear shift is synchronized to the same gear ratio as when flat when the vehicle is climbing up (power output decreases during the shift), the pedaling power required after the shift increases, so a gear ratio lighter by one is selected from the shift map. On the other hand, when the slope is down, the gear ratio that is the same as that at the time of flatness or one heavier is selected.
FIG. 5 shows a flowchart of the control processing unit in the control device.

Bicycle and human rocking can also be measured by analyzing video from an in-vehicle camera such as an action camera. In Non-Patent Document 2, the motion analysis of an automobile is performed by analyzing the image of an in-vehicle camera and the optical flow. FIG. 6 shows an example of the optical flow of swinging the bicycle. When going straight, there is a vanishing point near the center of the image, and the motion vector v (matrix) of the pixel due to rocking is indicated by an arrow. The rocking index E is calculated by replacing q and q ^ dot in Equation 2 with the matrix v. When an obstacle is detected, braking is performed by an electric brake.

When the power meter is attached, the power output can be used as a kind of data on the driving situation for selecting the transmission gear. For example, when automatically shifting at 300W (Watt), it is close to the upper limit load of a general cyclist. This threshold value (depending on driving conditions such as gradient and wind direction; 300W, etc.) depends on preset values or user settings.

As an option, when a sensor such as a touch panel is installed on the handle (FIG. 7), the intention of shifting can be read by the movement of the hand / finger on the touch panel. If the position of the hand / finger on the touch panel is p1 and p2 corresponding to the left and right, q and q ^ dot in Equation 2 can be replaced with p1 and p2, and Equation 6 can be expressed as follows.
[Equation 6]

The rocking index E for the touch operation is calculated from Equation 6.

The industrial applicability of the present invention is useful for automating bicycle shift control.

It is a figure which shows the relationship between a bicycle, various sensors, and a driver | operator. It is a figure which shows the relationship between a rocking | fluctuation index | exponent, the evaluation function, and the threshold value of a transmission. It is a figure which shows the example of a transmission map. It is a flowchart explaining the signal processing method for automation of gear shifting. It is a flowchart explaining the process in a control part. It is a figure which shows the example of the optical flow of the rocking | fluctuation of a bicycle. It is a figure which shows the relationship between a touch sensor and a driver | operator.

1: Body
21, 22, 23: Gyro sensor 3: Control device 4: Crank tachometer 5: Speedometer 61, 62: Power meter 7: Heart rate monitor 11: Front gear 12: Rear gear

US Patent No. 7900946 JP 2012-164061 "Track Planning Method, Track Control Method, Track Planning System, and Track Planning / Control System" JP 2011-068216 "Control device for omnidirectional vehicle"

Claims (6)

1. A device for controlling a bicycle transmission,
   A sensor that detects movement of both the driver and the bicycle, or either,
   A signal processing unit for determining a shift from the operation detected by the sensor unit;
   A control unit that operates the transmission based on shift determination data in the signal processing unit;
   A control device comprising:
2. 2. The control device according to claim 1, further comprising means for transmitting shift determination data in the signal processing unit to a display unit.
3. 2. The control apparatus according to claim 1, further comprising means for transmitting and / or receiving the data from / to a vehicle-mounted computer.
4. 2. The control device according to claim 1, further comprising means for operating the plurality of transmissions in synchronization.
5. The control apparatus according to claim 1, wherein the bicycle includes an electric brake, and includes means for applying the electric brake from the operation detected by the sensor unit.
6. 2. The control apparatus according to claim 1, further comprising an electric brake, and means for operating the electric brake and the transmission in synchronization with each other based on the operation detected by the sensor unit.

Images