JPH02107916A - Apparatus and method for detecting body position - Google Patents

Abstract

PURPOSE:To enable highly accurate detection of a position of a body by detecting and computing a rolling distance with right and left wheels for measurement which are connected with a shaft to be built in a one-piece construction. CONSTITUTION:Right and left wheels 2 for measurement are connected to a shaft 5 to be built in a one-piece construction. These wheels are free to rotate with a bearing, each provided with an encoder for detecting rolling distance. Then, the current position of a body 1 is computed sequentially from the rolling distance detected and based on the computed value thus obtained, an automatic operation of an unmanned vehicle is performed. With such an arrangement, as a higher parallel accuracy is achieved in direction of rolling of the right and left wheels when the wheels 2 are mounted on the body 1, in an expression of the position of the body, a term attributed to amounting deviation of the wheels 2 is made constant with respect to the axis 3 aligning the centers of turning of the body. Thus, by determining a constant properly beforehand, the position of the body can be detected at a high accuracy regardless of any position at which a positional deviation and an angular deviation may occur in the wheels 3 from the shaft 3.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to automatic guided vehicles that detect the vehicle body position using only the rolling distance detection values of the left and right measurement wheels of the vehicle body and control automatic steering, etc. The present invention relates to a vehicle body position detection device and method.

(Prior Art) Conventional vehicle body position detection devices and methods of this type use an encoder or the like to measure the rolling distance of the left and right wheels of the vehicle body on axes aligned with the turning centers of the vehicle body. Alternatively, as shown in Fig. 3, two dedicated left and right measurement wheels were individually installed to detect rolling distance.

In the latter vehicle body position detection method, the rolling distance is detected by the vehicle body position detection device described above, and the vehicle body position is calculated using the following equation (1).

However, (in formula 11, i is a sequential value for each minute unit time, X", y", 0 weight is the vehicle body position, △lL, Δ1.l
i indicates the detected rolling distance of the left and right measurement wheels, and W indicates the distance between the left and right measurement wheels.

(Problem to be Solved by the Invention) (The calculation using Equation 11 assumes that the left and right measurement wheels 2 are mounted with high accuracy on the shaft 3 where the turning centers of the vehicle body are aligned, as shown in Fig. 3. Therefore, each of the left and right measuring wheels 2 has a positional deviation uL + as shown in FIG.
If it is installed with an angular deviation α5.α, uR+v(+v, ), the result of calculating the vehicle body position according to the above equation (1) will include an error.

Therefore, in the conventional method, in order to accurately detect the vehicle body position The problem was that accuracy also had to be improved.

(Means for Solving the Problems) In order to eliminate these problems, the present invention has an integral structure in which the left and right measuring wheels for detecting rolling distance are connected by a shaft, and the center of rotation of the vehicle body of each of the left and right measuring wheels is fixed. The mounting on the parallel axes is configured to perform calculations by converting the terms in the calculation formula for the vehicle body position caused by the amount of deviation into constants.

(Example) One embodiment will be described in detail below with reference to the drawings.

FIG. 2 shows the position deviations uL I uR-Vl, VR, and angular deviation α from the state where the measurement wheel 2 is accurately mounted on the shaft 3 where the turning centers of the vehicle body 1 in FIG. 3 are aligned.
3. This shows a state where α8 is occurring.

The rolling distance Δβ,'' of the left measurement wheel when the vehicle body 1 turns by a turning angle Δθt1 with point A as the turning center can be expressed by the following equation (2).

Based on the formulas △β and 5 obtained above, the capacitance corresponding to the right measuring wheel 2 is similarly expressed with the subscript R, and △
Find β, , △β8゛ and apply it to equation (1), Δθ1,
When Δp· is calculated, each includes an error and can be expressed by the following equation (3).

However, in the above equation (3), r is the successive turning radius of the vehicle body l, uL + vL + uR+ vR+
αL and αR are the positional deviation and angular deviation of the mounting of the left and right measurement wheels 2, and △θ, ``, △7!t'(=r'' · △θ, ゛) are the true values. Here, if α,=α8−α, the above equation (3) is expressed as the following equation (4).

Substituting △θ engineering and △11 in equation (11) into equation (5), △θ1
, △β1・ are rewritten as △θ1. If we replace it with △Il', we get equation (6).

In the above equation (4), k, , and 2. : indicates that l is a constant term.

1/k+, 1/kz, k3/kz to θ, to 7! ,.

Replace kJ2 with (4) △θ, , △6. The calculation of i is as shown in equation (5) below.

Therefore, appropriately select θ, kA, , kN2 as constants (6)
By substituting the values calculated by the equation (1) into the calculation equations for X·, yl, and θi, the calculated vehicle body position value does not include any error.

The condition of α1-α arm-α, which is the condition of equation (4), is that the left and right measuring wheels 2 have an integral structure in which the wheels are connected by the shaft 5 as shown in Fig. 1, and the left and right rolling when installed on the vehicle body 1. This can be achieved by increasing the parallelism accuracy of the directions. In FIG. 1, the left and right measurement wheels 2 are rotatable with respect to the shaft 5 via bearings (not shown), and encoders and the like for detecting rolling distance are attached to each of the left and right wheels.

In addition, the values of the constants θ, kN, . It can be determined in advance by comparing.

For example, when installing a wheel for measuring kθ, β, , and β2, the value when there is no positional deviation or angular deviation is kθ=1. β is set to =1.7!2=O, first the vehicle body 1 is made to turn, and θ is determined by the following equation (7) from the values of θ゛ and θ゛ at that time.

θ to θ −−−−−−−−−−−・−−−−−(7
+θ amount Next, after setting θ to the value determined by equation (7), the vehicle body 1 is driven straight in the X-axis direction, and β is determined from the values of xl and X at that time using equation (8) below.

X′ k fi , = −−
---(81X') Next, set klI to the value determined by formula (8), and
is rotated at a constant radius, and y゛θ4. Yi
From the value of , 7!2 is determined using the following equation (9).

Note that calculations of the vehicle body position in equations (1) and (6) are performed by a computer or the like (not shown) mounted on the vehicle body 1.

(Effects of the Invention) As explained above, the left and right measurement wheels have an integral structure connected by a shaft, and by increasing the parallelism accuracy of the left and right rolling direction when attached to the vehicle body, the left and right measurement wheels can be easily adjusted to the vehicle body. When mounting to the axes where the turning centers are aligned, the term in the vehicle body position calculation formula caused by the amount of deviation can be made into a constant, so if the constant is properly determined in advance, the left and right measurement wheels can be mounted on the vehicle body in the same state. The vehicle body position can be detected with high accuracy even if the vehicle body position is at any position where there is a positional deviation or angular deviation with respect to the axes on which the turning centers of the vehicle body are aligned.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the structure of the left and right measuring wheels applied to the vehicle body position detection method of the present invention and the state of attachment to the vehicle body, and FIG. 2 shows the positional deviation of the measuring wheels from the state of FIG. 3. FIG. 3 is an explanatory diagram showing a state in which an angular deviation occurs, and FIG. 3 is a configuration diagram showing a state in which left and right measuring wheels are attached to a vehicle body, which is required in a conventional vehicle body position detection method. 1 Vehicle body 2 Left and right measurement wheels 3 --- Axes on which the turning centers of the vehicle body are aligned 4 Points to be calculated for vehicle body position 5 ---
−−−Single shaft 6−・−・−・−Wheel

Claims (2)

[Claims] 1. In an automated guided vehicle, two measurement wheels on the left and right for detecting rolling distance are attached to the vehicle body, the current position of the vehicle body is sequentially calculated from the detected rolling distance, and automatic steering etc. are controlled based on the calculated value. A vehicle body position detection device characterized by an integral structure in which left and right measurement wheels for detecting rolling distance are connected by a shaft. 2. An unmanned system that installs left and right measuring wheels that detect rolling distance on the vehicle body as an integrated structure connected by a shaft, sequentially calculates the current position of the vehicle body from the detected rolling distance, and controls automatic steering etc. based on the calculated value. In the transport vehicle,
A method for detecting a vehicle body position, characterized in that a term in a calculation formula for a vehicle body position, which is caused by an amount of mounting deviation of each left and right measuring wheel with respect to the axes on which the turning centers of the vehicle body are lined up, is converted into a constant and calculation is performed.