JPH0843423A - Method and device for detecting acceleration and the like - Google Patents

Abstract

PURPOSE:To obtain an acceleration detection device with simple configuration and at low cost. CONSTITUTION:Acceleration sensors 1 and 2 provided with detection axes an and a2 inclined at thetas against an installation plane P are used. If the installation plane P is inclined against horizontal plane H, in the case acceleration a is applied in horizontal direction, the component of gravitational acceleration appears besides the component of acceleration alpha in the detection value of the acceleration sensors 1 and 2. Based an the detection values of the acceleration sensors 1 and 2, numeral calculation is performed, so that, inclination thetap of the installation plane P against the horizontal plane H is detected, and influence of gravitational acceleration is excluded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration detecting device and method for detecting acceleration, velocity, moving distance, etc. of a moving body or the like.

[0002]

2. Description of the Related Art As a vehicle distance sensor used in a dead reckoning device or the like, there is a configuration utilizing a wheel speed sensor. In this configuration, the rotation speed of the wheel is detected by the wheel speed sensor, and the detected rotation speed is integrated (integrated).
To be done. However, when such a configuration is used, an error occurs due to wheel slip, wear, etc., and the movement distance cannot be accurately known. Further, since it is not easy to attach the wheel speed sensor, it is very difficult for a vehicle user to attach and replace the wheel speed sensor.

As a method of avoiding such a problem, the acceleration applied to the vehicle is detected, and the detected acceleration is changed depending on time.
One method is to obtain the moving distance by integrating twice. When this method is carried out, there is no need to monitor the rotation of the wheels, so there is no room for error due to slip or wear of the wheels, and there is no need to attach them to the wheels. Further, in recent years, a small acceleration sensor such as an acceleration sensor manufactured by a semiconductor micro process has been developed, which is significant for downsizing the device.

[0004]

However, the method based on the acceleration detection has a problem that an error occurs due to the inclination of the mounted moving body.

For example, it is assumed that an acceleration sensor is mounted on a vehicle and the detection axis of the acceleration sensor is set so as to be horizontal when the vehicle body is in a horizontal posture. Since an ordinary acceleration sensor has a function of detecting only a component in a predetermined direction (detection axis) of applied acceleration, if the vehicle is always traveling in a horizontal posture, the detection axis is By setting such a direction, it is possible to detect the acceleration applied to the vehicle as the vehicle starts, accelerates, brakes, or the like. Further, by integrating the acceleration detected in this way, information such as speed and movement distance can be accurately obtained.

However, in reality, the vehicle leans due to causes such as luggage loading, personnel boarding, and road inclination. When the detection axis of the acceleration sensor is set to be horizontal when the vehicle body is in the horizontal posture as described above, the detection axis of the acceleration sensor is displaced from the horizontal direction when the vehicle is tilted. Turn to. As the acceleration applied to the vehicle, not only the acceleration applied due to the start, acceleration, braking, etc., but also the gravitational acceleration is present. I will detect it. This causes an error.

In an inertial navigation system for aviation, etc.,
A device that uses a 3-axis acceleration sensor and a 3-axis yaw rate gyro sensor to correct an acceleration detection error caused by a change in the attitude of the aircraft based on the detected values of the attitude change (yaw, pitch, roll) of the aircraft is adopted. ing. By using a configuration similar to this, it is possible to correct the error due to the inclination of the vehicle body. However, when such a configuration is applied, the tilt of the vehicle body must be detected separately, resulting in enlargement of the device configuration, complication of the configuration, cost demerit, and the like.

[0008] The present invention has been made to solve the above problems, and by devising the arrangement of the acceleration sensor, while ensuring the ease of mounting,
An object of the present invention is to enable acceleration detection, speed detection, and movement distance detection with a small error with a relatively simple device configuration.

[0009]

In order to achieve such an object, the acceleration detecting device of the present invention has a component α _{a1 in the} direction a ₁ which forms an angle θ _s with respect to the installation surface P among the applied acceleration.
And a second acceleration sensor that detects a component α _a2 of the applied acceleration that forms an angle θ _s with respect to the installation surface P and that is in the direction a ₂ that is coplanar with the direction a ₁ . Based on the components α _a1 and α _a2 detected by the first and second acceleration sensors, while eliminating the influence of the inclination θ _p of the installation surface P with respect to the horizontal plane H, the plane including the directions a ₁ and a ₂ and the horizontal plane H And means for calculating the acceleration α in the direction of the intersection line.

The acceleration detecting device of the present invention may be arranged such that, in the applied acceleration, a direction a forming an angle θ _s with respect to the installation plane P.
_{A first} acceleration sensor for detecting a component α _a1 of ₁ and a first acceleration sensor for detecting a component α _{a2 of} a direction a ₂ which forms an angle θ _s with respect to the installation plane P and is coplanar with the direction a _{1 in} the applied acceleration. Two acceleration sensors, a means for detecting the inclination θ _p of the installation surface P with respect to the horizontal plane H based on the components α _a1 and α _a2 detected by the first and second acceleration sensors, and the means detected by the first and second acceleration sensors. And a means for calculating the acceleration α in the direction of intersection of the horizontal plane H with the plane including the directions a ₁ and a ₂ based on the detected components α _a1 and α _a2 and the detected inclination θ _p. .

The speed detecting device of the present invention is characterized by including the acceleration detecting device of the present invention and means for calculating the speed v by integrating the acceleration α once with time.

The moving distance detecting device of the present invention is characterized by including the acceleration detecting device of the present invention and means for calculating the moving distance 1 by integrating the acceleration α twice with time.

In the acceleration detecting method of the present invention, among the applied accelerations, the components α _a1 and α _a2 of the directions a ₁ and a _{2 that form} an angle θ _s with the installation plane P and belong to the same plane, respectively. Detecting step and detected component α
calculating the acceleration α in the direction of intersection between the plane including the directions a ₁ and a ₂ and the horizontal plane H while eliminating the influence of the inclination θ _p of the installation surface P with respect to the horizontal plane H based on _a1 and α _a2 ; It is characterized by having.

[0014]

In the acceleration detecting device and the acceleration detecting method of the present invention, the acceleration components α _a1 and α _{a2 in the} directions a ₁ and a ₂
Is detected. Since the directions a ₁ and a ₂ both form an angle θ _s with the installation plane P, the detected acceleration component α _a1
And α _a2 include the component of the gravitational acceleration g when the installation surface P is horizontally arranged. Even when the installation surface P is inclined with respect to the horizontal plane H, the direction a ₁ or a
Unless ₂ is horizontal, the acceleration components α _a1 and α _a2 include the component of gravitational acceleration g. Further, the direction a ₁
Since a and a ₂ are on the same plane, only the inclination θ _p of the installation surface P with respect to the horizontal plane H appears as variables in the relational expression of the acceleration vector in addition to the acceleration α to be detected. Therefore, by performing the calculation based on this relational expression using the components α _a1 and α _a2 , it is possible to eliminate the influence of the inclination θ _p of the installation surface P with respect to the horizontal plane H and to obtain a plane including the directions a ₁ and a _2. The acceleration α in the direction of the intersection of the horizontal plane H can be calculated. As a result, acceleration detection with less error is realized with a relatively simple device configuration. At that time, there is no problem in mounting the acceleration sensor or the like.

In the speed detecting device of the present invention, the acceleration α detected as described above is integrated once with time to obtain the speed v. In the moving distance detecting device of the present invention, the acceleration α detected as described above is integrated twice with time to obtain the moving distance l. Therefore, it is possible to detect the velocity and the moving distance without the influence of the inclination θ _p of the installation surface P with respect to the horizontal plane H.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a functional configuration of an apparatus according to an embodiment of the present invention. Further, FIG. 2 shows an arrangement mode of the acceleration sensor in this embodiment. As shown in these figures, in the present embodiment, the installation surface P
On the other hand, two acceleration sensors 1 and 2 arranged back to back on the installation base 3 are used so as to form an angle θ _s . Further, the detection axes a ₁ and a _{2 of} the acceleration sensors 1 and ₂
Is set in a plane vertical to the installation plane P. The accelerations α _a1 and α _a2 detected by the acceleration sensors 1 and 2 are supplied to the moving acceleration calculation unit 4. The moving acceleration calculation unit 4 performs the calculation described below based on the accelerations α _a1 and α _a2 , and detects the acceleration α in the left-right direction (that is, the direction of the intersection of the plane including the detection axes a ₁ and a ₂ and the horizontal plane H) in FIG. To do. The moving speed calculation unit 5 integrates the detected acceleration α while using the initial speed v ₀ given from the outside as an integration constant, thereby detecting the speed v. The moving distance calculation unit 6 performs a calculation based on the acceleration α and the speed v to detect the moving distance l.

This embodiment is characterized by the sensor arrangement shown in FIG. 2 and the acceleration sensors 1 and 2.
The inclination α _p of the installation surface P with respect to the horizontal plane H is compensated by using the accelerations α _a1 and α _a2 detected by
The point is that the error caused by is prevented.

Here, as shown in FIG. 3, it is assumed that the moving body on which the apparatus of this embodiment is mounted is in a state in which the front portion is lifted and the rear portion is depressed. In this state, the directions of the detection axes a ₁ and a ₂ are θ _s + θ _p or θ _s −θ _p , respectively, when the horizontal plane H is used as a reference. Therefore, when the horizontal acceleration α is applied in this state, the acceleration sensor 1
The accelerations α _a1 and α _a2 detected by 2 and 2 are expressed as follows, taking the influence of the gravitational acceleration g into consideration.

[0020]

[Alpha] _a1 = [alpha] .cos ([theta] _s + [theta] _p ) -g * sin ([theta] _s + [theta] _p ) (1) [alpha] _a2 =-[alpha] .cos ([theta] _{s- [} theta] _p ) -g * sin ([theta]) _s −θ _p ) (2) The variables in these equations are the acceleration α and the inclination θ _p of the moving body. Both sides of the equation (1) have cos (θ _s −
multiplied by θ _p ) and cos (θ _s + on both sides of equation (2)
θ _p ) multiplied by and added, the variable α is eliminated and the following equation is obtained.

[0021]

[Number 2] _{f (θ p) = α a1} · cos (θ s -θ p) + α a2 · cos (θ s + θ p) -g · sin2θ s = 0 ... (3) In addition, variable both sides of this equation Differentiating with respect to θ _p gives the following equation.

[0022]

Equation 3] _{f'(θ p) = α a1} · sin (θ s -θ p) -α a2 · sin (θ s + θ p) = 0 ... (4) moving acceleration calculator 4, a stopping criterion

F (θ _p + Δθ _p ) = f (θ _p ) + f ′ (θ _p ) · Δθ _p = 0 That is,

[Number 5] while using _{Δθ p = -f (θ p)} / f' a (θ _p), run the Newton Raphson method, the slope θ
Calculate _p numerically. Specifically, the initial value θ _p0 is substituted into θ _p in the convergence determination condition to calculate Δθ _p = Δθ _p0 , and θ _p1
= Θ _p0 + Δθ _p0 is substituted for θ _p in the convergence judgment condition and Δθ
Calculate _p = Δθ _p1 and substitute θ _p2 = θ _p1 + Δθ _p1 into θ _p in the convergence judgment condition to calculate Δθ _p = Δθ _p2, and so on until Δθ _p becomes smaller than a predetermined value. Repeat (until it converges sufficiently). The moving acceleration calculation unit 4 calculates Δ
Equation theta _p at the time the theta _p is smaller than a predetermined value (1)
Alternatively, by substituting in (2), the acceleration α is obtained and output.

Moving speed calculator 5 and moving distance calculator 6
Calculates the velocity v and the moving distance l using the other initial velocity v ₀ of the obtained acceleration α. Calculation timing is subscript i
If it is expressed by, the arithmetic expression is expressed as follows. However, at the timing i = 0 when the acceleration α is first detected, the velocity v and the moving distance l are not calculated, and the acceleration α = α ₀ obtained at this timing is used as the initial velocity at the next timing i = 1. velocity v and movement distance l together with v ₀
It is used to calculate.

[0024]

[6] _{v i = v i-1 +} α i-1 t l i = v i-1 t + α i-1 t 2/2 In the above description, the plane including the detection axis a ₁ and a ₂ is placed Although the configuration orthogonal to the plane P has been described, the plane including the detection axes a ₁ and a ₂ may intersect the installation plane P at a known angle. Further, in the above description, it is assumed that the plane including the detection axes a ₁ and a ₂ is parallel to the traveling direction of the moving body, but the plane including the detection axes a ₁ and a ₂ is the traveling direction of the moving body. Any direction may be used as long as the direction is not orthogonal to. Any known material may be used for the materials and configurations of the acceleration sensors 1 and 2. Applications of the present invention include a navigation device, a vehicle body control device, an engine control device,
A speed display device, a mileage display device, etc. can be mentioned. However, the present invention is not limited to a vehicle, but can be used for other moving bodies, and is suitable for any application other than the moving body as long as the inclination θ _p of the installation surface P with respect to the horizontal plane H can occur. Can be applied to.

[0025]

As described above, according to the acceleration detecting device and the acceleration detecting method of the present invention, the directions a ₁ and a ₂
The acceleration components α _a1 and α _a2 are detected, and the acceleration α in the direction of the intersection of the plane including the directions a ₁ and a ₂ and the horizontal plane H is calculated based on the detected acceleration components α _a1 and α _a2. The influence of _p can be eliminated, and acceleration detection with less error can be realized. At that time, since it is not necessary to separately provide the posture detection means, the device configuration is relatively simple, which is advantageous in terms of cost. Further, it is possible to obtain a device which is easy to use and easy to replace and repair without mounting the acceleration sensor or the like.

Further, according to the speed detecting device and the moving distance detecting device of the present invention, the acceleration α detected as described above is used.
Since the speed v or the moving distance 1 is obtained by integrating once or twice depending on time, it is possible to detect the speed and the moving distance with less error by eliminating the influence of the inclination θ _p of the installation surface P with respect to the horizontal plane H. become.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of acceleration sensors in this embodiment.

FIG. 3 is a diagram showing the occurrence of inclination and a vector relationship.

[Explanation of symbols]

1, 2 Acceleration sensor 3 Installation base 4 Moving acceleration calculation unit 5 Moving speed calculation unit 6 Moving distance calculation unit P Installation surface H Horizontal plane a ₁ , a ₂ Detection axis θ _s Detection axis inclination relative to installation surface θ _p Installation surface relative to horizontal surface Slope α _a1 , α _a2 Acceleration detected by acceleration sensor α Acceleration to be detected v Velocity l Moving distance

Claims (5)

[Claims] 1. A applied without a first acceleration sensor for detecting the component alpha _a1 direction a ₁ to to installation surface P forms an angle theta _s of acceleration, the angle theta _s to the installation surface P of the acceleration applied And the component α _{a2 of the} direction a ₂ that is coplanar with the direction a ₁
A second acceleration sensor for detecting the component α _a1 detected by the first and second acceleration sensors
And α _a2 , the inclination θ of the installation plane P with respect to the horizontal plane H
An acceleration detecting device comprising: means for calculating an acceleration α in a direction of an intersection of the plane including the directions a ₁ and a ₂ and the horizontal plane H while eliminating the influence of _p . 2. A applied without a first acceleration sensor for detecting the component alpha _a1 direction a ₁ at an angle theta _s to installation surface P of the acceleration, the angle theta _s to the installation surface P of the applied acceleration And the component α _{a2 of the} direction a ₂ that is coplanar with the direction a ₁
A second acceleration sensor for detecting the component α _a1 detected by the first and second acceleration sensors
And α _a2 , the inclination θ _p of the installation plane P with respect to the horizontal plane H
And a component α _a1 detected by the first and second acceleration sensors.
And α _a2 and the detected inclination θ _p , the direction a ₁
And means for calculating an acceleration α in the direction of the intersection of the horizontal plane H and the plane including a ₂ and a ₂ . 3. A speed detecting device comprising: the acceleration detecting device according to claim 1; and a means for calculating a speed v by integrating the acceleration α once with time. 4. A moving distance detecting apparatus, comprising: the acceleration detecting apparatus according to claim 1; and a unit that calculates a moving distance 1 by integrating acceleration α twice with time. 5. Among the applied acceleration, a step of detecting components α _a1 and α _a2 of directions a ₁ and a ₂ that both form an angle θ _s with respect to the installation surface P and belong to the same plane, respectively, Based on the components α _a1 and α _a2 , while eliminating the influence of the inclination θ _p of the installation surface P with respect to the horizontal plane H, the acceleration α in the direction of the intersection of the plane including the directions a ₁ and a ₂ and the horizontal plane H
An acceleration detection method comprising the step of: