JP4089344B2 - Guided driving method for omnidirectional automated guided vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a guided traveling method for an omnidirectional automatic guided vehicle.
[0002]
[Prior art]
As shown in FIG. 3, an omnidirectional automatic guided vehicle (hereinafter simply referred to as an automatic guided vehicle) includes driving wheels 11 and 12 and free casters 31 and 32 on the front and rear sides, and induction sensors 21, 22, 23, and 24. It is prepared in four directions so that it can travel in all directions along the guide line.
Here, the automatic guided vehicle calculates the steering angles ψ ₁ and ψ ₂ and the traveling speeds V ₁ and V ₂ of the two drive wheels 11 and 12 from the input value of the guidance sensor 21 in the traveling direction with respect to the guide line. Yes.
[0003]
First, the turning radius R is obtained from the input value of the induction sensor 21 from the equation (1).
R = (H / 2 + δ) L / ε (1)
Here, the turning radius R is the distance from the pivot point O to the pivot center point P _O AGV, H is the front and rear between the steering center point P _r of the drive wheel 12 and the steering center point P _f of the drive wheel 11 A wheel base which is a directional distance, L is a longitudinal distance between the induction sensor 21 and the target point P ₁ ′, and δ is a sensor mounting length which is a longitudinal distance between the drive wheel 11 and the induction sensor 21.
Further, ε is a guidance deviation indicating the traveling direction, and is input as a distance from the guidance sensor center point P _{1 of} the guidance sensor 21 to the guidance line.
[0004]
Next, from the obtained turning radius R, the steering angles ψ ₁ and ψ ₂ and the traveling speeds V ₁ and V ₂ of the drive wheels 11 and 12 are calculated from the equation (2).
ψ ₁ = arctan (P / (R + T / 2)) (2)
ψ ₂ = arctan (P / (R−T / 2)) (3)
V ₁ = V {P ² + (R + T / 2) ² } ^1/2 / R (4)
V ₂ = V {P ² + (R−T / 2) ² } ^1/2 / R (5)
However, P = H / 2 + δ.
T is a tread indicating the distance in the left-right direction between the drive wheel 11 and the free caster 31 (the distance in the left-right direction between the drive wheel 12 and the free caster 32).
[0005]
Guided traveling is performed by independently controlling the motors using these steering angles ψ ₁ , ψ ₂ and traveling speeds V ₁ , V ₂ as command values.
That is, as shown in the control block diagram of FIG. 4, the steering angle command values ψ ₁ ^* and ψ ₂ ^* and the travel speed command values V ₁ ^* and V ₂ ^* are obtained from the guidance control unit 40 for each drive wheel 11 and 12. The driving wheel control units 51 and 52 are given control amounts θ ₁ , θ ₂ and v ₁ and v ₂ from the driving wheel control units 51 and 52 to the steering motors 61 and 62 and the drive motors 71 and 72, respectively. Feedback control is performed so that ψ ₁ , ψ ₂ and traveling speeds V ₁ , V ₂ are obtained, and the automatic guided vehicle 80 is caused to travel at a speed V in the direction indicated by the induction deviation ε.
[0006]
[Problems to be solved by the invention]
In an omnidirectional automatic guided vehicle, in order to improve the turning performance by guided traveling, if the target point P ₁ ′ in FIG. 3 is set in front, that is, if the distance L is reduced, the turning radius is smaller than the equation (1). Thus, as shown in FIG. 5, the straight running performance is impaired, causing meandering.
On the other hand, when the target point P ₁ ′ is set at the back, that is, when the distance L is increased, the turning radius is increased from the expression (1), and the course is out of the curve section with a small curvature as shown in FIG.
[0007]
[Means for Solving the Problems]
The guided traveling method of the omnidirectional automatic guided vehicle according to claim 1 of the present invention for solving the above-described problem is to detect the distances from the guide lines as the guidance deviations ε ₁ and ε _{2 at} the front part and the rear part of the vehicle body, respectively. For an omnidirectional automated guided vehicle having sensors and front and rear steering wheels, as a precondition, a target point P ₁ ′ that is a distance L ahead from the guide line sensor at the front of the vehicle body is set. Based on the distance L and the induced deviations ε ₁ and ε ₂ detected by the guidance sensor, the steering angle ψ _{1 of the} steered wheel on the front side with respect to the traveling direction and the steering on the rear side with respect to the traveling direction In the control of guiding the omnidirectional automatic guided vehicle by calculating the wheel steering angle ψ ₂ by calculation ,
When | ε ₁ −ε ₂ | ≦ Δε holds for the induced deviations ε ₁ and ε ₂ , the steering angles ψ ₁ and ψ ₂ are obtained according to the following equation (where ε = ε ₁ ) ,
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L−εT / 2}]
When | ε ₁ −ε ₂ |> Δε holds for the induced deviations ε ₁ and ε ₂ , the center offset amount γ = F (ε ₁ −ε ₂ ) / ε _{1 is} added to the numerator and denominator terms on the right side as shown in the following equation. To correct the steering angles ψ ₁ and ψ ₂ ,
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ + γ) / [ (H / 2 + δ + γ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ + γ) / [ (H / 2 + δ + γ) L−εT / 2}]
It is characterized by improving straightness and convergence when going straight.
However, H is wheel base, T is the tread, [delta] is the sensor mounting length is longitudinal distance from the steering wheel of the front with respect to the traveling direction until the inductive sensor of the vehicle body front and delta epsilon predetermined value, F Is a constant and the maximum value is H / 2 .
[0008]
The guided traveling method of the omnidirectional automatic guided vehicle according to claim 2 of the present invention for solving the above-described problems is to detect the distances from the guiding lines at the front part and the rear part of the vehicle body as the guidance deviations ε ₁ and ε ₂ , respectively. For an omnidirectional automated guided vehicle having sensors and front and rear steering wheels, as a precondition, a target point P ₁ ′ that is a distance L ahead from the guide line sensor at the front of the vehicle body is set. Based on the distance L and the induced deviations ε ₁ and ε ₂ detected by the guidance sensor, the steering angle ψ _{1 of the} steered wheel on the front side with respect to the traveling direction and the steering on the rear side with respect to the traveling direction In the control of guiding the omnidirectional automatic guided vehicle by calculating the wheel steering angle ψ ₂ by calculation ,
When | ε ₁ −ε ₂ | ≦ Δε holds for the induced deviations ε ₁ and ε ₂ , the steering angles ψ ₁ and ψ ₂ are obtained according to the following equation (where ε = ε ₁ ) ,
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L−εT / 2}]
When | ε ₁ −ε ₂ |> Δε holds for the induced deviations ε ₁ and ε ₂ , F ′ (ε ₁ −ε ₂ ) is added to the denominator term on the right side as shown in the following equation , and the steering angles ψ ₁ and ψ By correcting ₂
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + F ′ (ε ₁ −ε ₂ ) + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + F ′ (ε ₁ −ε ₂ ) −εT / 2}]
It is characterized by improving straightness and convergence when going straight.
However, H is wheel base, T is the tread, [delta] is the sensor mounting length is longitudinal distance from the steering wheel of the front with respect to the traveling direction until the inductive sensor of the vehicle body front and delta epsilon predetermined value, F ' Is a constant and the maximum value is H / 2.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
[Example 1]
In this embodiment, as a precondition, the target point P ₁ ′ is set in front to improve the turning performance. However, since the problem shown in the above-described prior art occurs if the state is left as it is, when the turning radius R is obtained from the guidance deviation in the traveling direction, the turning center is determined by the center offset amount γ determined by the deviation amounts ε ₁ and ε ₂ of the front and rear guidance deviations. By shifting the point P ₀ , straightness and convergence are improved when traveling straight. The deviation amount ε ₁ is a value detected by the induction sensor 21 attached to the front part of the vehicle body, and is a distance from the induction sensor center point P _{1 of} the induction sensor 21 to the induction line. The deviation amount ε ₂ is a value detected by the guidance sensor 22 attached to the rear part of the vehicle body, and is a distance from the guidance sensor center point of the guidance sensor 22 to the guidance line.
[0010]
First, when the equation (6) is established for the front and rear induced deviations ε ₁ and ε ₂ , the turning radius obtained from the equation (1) is used.
| Ε ₁ −ε ₂ | ≦ Δε (6)
| Ε ₁ −ε ₂ |> Δε (7)
However, Δε is a predetermined value determined as a dead zone of deviation.
That is, when (6) holds, the steering angles ψ ₁ and ψ ₂ are obtained according to the following equations by substituting the turning radius R obtained from the equation (1) into the equations (2) and (3) (provided that ε = ε ₁ ).
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L−εT / 2}]
On the other hand, when the formula (7) is established, as shown in the formula (8), the turning radius R is obtained by adding the center offset amount γ to the formula in the numerator of the formula (1).
R = (H / 2 + δ + γ) L / ε (8)
Here, ε is an induced deviation ε ₁ indicating the traveling direction.
[0011]
As shown in FIG. 1, the center offset amount γ is an amount by which the turning center point P ₀ is shifted, and is obtained by the equation (9).
γ = F (ε ₁ −ε ₂ ) / ε ₁ (9)
However, F is a constant and the maximum value is H / 2.
Further, the steering angle and the traveling speed are obtained by setting the obtained turning radius R and P in the expressions (2) to (5) as P = H / 2 + δ + γ. The steering angle ψ ₁ is for the steering wheel 11 disposed on the front side with respect to the traveling direction of the vehicle body, and the steering angle ψ ₂ is for the steering wheel 12 disposed on the rear side with respect to the traveling direction of the vehicle body. , and the finding as follows.
ψ ₁ = tan ⁻¹ { ( H / 2 + δ + γ) / (R + T / 2)} (2) ′
ψ ₂ = tan ⁻¹ { ( H / 2 + δ + γ) / (RT−2)} (3) ′
In other words, when equation (7) holds , by substituting the turning radius R obtained from equations (8) and (9) into equation (2) ' (3) ' , the numerator and denominator on the right side as shown in the following equation: The steering angle ψ ₁ , ψ ₂ is corrected by adding the center offset amount γ to the term (where ε = ε ₁ ).
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ + γ) / [ (H / 2 + δ + γ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ + γ) / [ (H / 2 + δ + γ) L−εT / 2}]
[0012]
As described above, in this embodiment, by adding the center offset γ to the expression in the numerator of the expression (1), the turning radius R is obtained as shown in the expression (8). Based on the turning radius R, the steering angle and the traveling speed are obtained with P in the equations (2) to (5) as P = H / 2 + δ + γ.
Here, the turning center point P ₀ and the two drive wheels 11 when the guidance deviation ε ₁ of the guidance sensor 21 in the traveling direction is the same amount and the magnitude of the guidance deviation ε ₂ of the guidance sensor 22 opposite to the traveling direction is different. , the steering angle [psi ₁ of 12, showing the [psi ₂ in relation to Figure 1.
As shown in FIG. 1, by shifting the turning center point P ₀ by the center offset amount γ, the turning center point moves from O to O ′ by the center offset amount γ, so that the steering angles ψ ₁ and ψ ₂ are reduced. , Straightness and convergence are improved.
[0013]
[Example 2]
In this embodiment, as a precondition, the target point P ₁ ′ is set in front to improve the turning performance. However, since the problem shown in the above-mentioned prior art occurs, the ΔR is obtained from the state of the input values of the front and rear guidance sensors with respect to the equation (1) for obtaining the turning radius from the guidance deviation in the traveling direction. By adding ΔR as a correction value to the equation (1) to obtain the turning radius R, the straightness and convergence during straight traveling are improved.
First, when the expression (10) is established for the front and rear induction deviations ε ₁ and ε ₂ , the turning radius obtained from the expression (1) is used.
| Ε ₁ −ε ₂ | ≦ Δε (10)
| Ε ₁ −ε ₂ |> Δε (11)
However, Δε is a predetermined value determined as a dead zone of deviation.
[0014]
On the other hand, the turning radius when equation (11) holds is the value obtained by adding ΔR to the right side of equation (1). That is, the turning radius R is obtained from the equation (12).
R = (H / 2 + δ) L / ε + ΔR (12)
Here, ε is an induced deviation ε ₁ indicating the traveling direction.
ΔR = F ′ (ε ₁ −ε ₂ ) / ε ₁ (13)
However, F ′ is a constant, and the maximum value is H / 2.
Further, from the obtained R, the steering angle and the traveling speed are obtained from the equations (2) to (5).
That is, when the equation (10) is established for the induced deviations ε ₁ and ε ₂ , the steering angle ψ ₁ ,, according to the following equation is substituted by substituting the turning radius R obtained from the equation (1) into the equations (2) and (3) . ψ ₂ is obtained (where ε = ε ₁ ).
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L−εT / 2}]
Further, when the equation (11) holds for the induced deviations ε ₁ and ε ₂ , the right side as shown in the following equation is obtained by substituting the turning radius R obtained from the equations (12) and (13) into the equations (2) and (3). The steering angles ψ ₁ and ψ ₂ are corrected by adding F ′ (ε ₁ −ε ₂ ) to the denominator term .
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + F ′ (ε ₁ −ε ₂ ) + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + F ′ (ε ₁ −ε ₂ ) −εT / 2}]
[0015]
Here, the turning radii R ₁ and R ₂ and the two drives when the guidance deviation ε ₁ of the guidance sensor 21 in the traveling direction is the same amount and the magnitude of the guidance deviation ε ₂ of the guidance sensor 22 opposite to the traveling direction is different. FIG. 2 shows the relationship between the steering angles ψ ₁ and ψ ₂ of the wheels 11 and 12.
As shown in FIG. 2, since the two turning radii have a relationship of R ₁ > R ₂ , the steering angle ψ _{2 in} the case of the turning radius R ₁ is smaller than the steering angle ψ _{2 in} the case of the turning radius R _2. Thus, the improvement in straightness and convergence is improved.
[0016]
As described above, in the _first embodiment, the turning center point P ₀ and the turning center point O (→ O ′) are shifted by the center offset amount γ with respect to the front and rear induced deviations ε ₁ and ε ₂ . On the other hand, in the second embodiment, the turning radius is corrected, and in any method, the improvement in straightness and convergence is improved.
[0017]
【The invention's effect】
As described above in detail, according to the present invention, the turning radius is corrected or the turning center point is offset, thereby improving the turning performance and improving the straightness and convergence during straight running. be able to.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a relationship between front and rear guidance deviations and a turning center offset amount.
FIG. 2 is an explanatory diagram showing front and rear guidance deviations and turning radii.
FIG. 3 is an explanatory diagram of guided traveling of an omnidirectional automatic guided vehicle.
FIG. 4 is a control block diagram.
FIG. 5 is an explanatory diagram when the turning radius is small.
FIG. 6 is an explanatory diagram when the turning radius is large.
[Explanation of symbols]
11, 12 Drive wheels 21, 22, 23, 24 Guidance sensors 31, 32 Free casters 40 Guidance control units 51, 52 Drive wheel control units 61, 62 Steering motors 71, 72 Drive motor 80 Automated guided vehicle

Claims (2)

As a precondition for an omnidirectional automatic guided vehicle that has induction sensors that detect the distance from the guide line as induction deviations ε ₁ and ε _{2 at} the front and rear parts of the vehicle body and that respectively has steering wheels at the front and rear of the vehicle body A target point P ₁ ′ set apart from the guide line sensor at the front of the vehicle body by a distance L is set, and the progression proceeds based on the distance L and the guide deviations ε ₁ and ε ₂ detected by the guide sensor. In the control for guiding the omnidirectional automatic guided vehicle by calculating the steering angle ψ _{1 of the} steering wheel on the front side with respect to the direction and the steering angle ψ ₂ of the steering wheel on the rear side with respect to the traveling direction by calculation ,
When | ε ₁ −ε ₂ | ≦ Δε holds for the induced deviations ε ₁ and ε ₂ , the steering angles ψ ₁ and ψ ₂ are obtained according to the following equation (where ε = ε ₁ ) ,
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L−εT / 2}]
When | ε ₁ −ε ₂ |> Δε holds for the induced deviations ε ₁ and ε ₂ , the center offset amount γ = F (ε ₁ −ε ₂ ) / ε _{1 is} added to the numerator term and denominator term on the right side as shown in the following equation. To correct the steering angles ψ ₁ and ψ ₂ ,
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ + γ) / [ (H / 2 + δ + γ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ + γ) / [ (H / 2 + δ + γ) L−εT / 2}]
A guided traveling method for an omnidirectional automatic guided vehicle characterized by improving straightness and convergence when traveling straight.
However, H is wheel base, T is the tread, [delta] is the sensor mounting length is longitudinal distance from the steering wheel of the front with respect to the traveling direction until the inductive sensor of the vehicle body front and delta epsilon predetermined value, F Is a constant and the maximum value is H / 2 . As a precondition for an omnidirectional automatic guided vehicle that has induction sensors that detect the distance from the guide line as induction deviations ε ₁ and ε _{2 at} the front and rear parts of the vehicle body and that respectively has steering wheels at the front and rear of the vehicle body A target point P ₁ ′ set apart from the guide line sensor at the front of the vehicle body by a distance L is set, and the progression proceeds based on the distance L and the guide deviations ε ₁ and ε ₂ detected by the guide sensor. In the control for guiding the omnidirectional automatic guided vehicle by calculating the steering angle ψ _{1 of the} steering wheel on the front side with respect to the direction and the steering angle ψ ₂ of the steering wheel on the rear side with respect to the traveling direction by calculation ,
When | ε ₁ −ε ₂ | ≦ Δε holds for the induced deviations ε ₁ and ε ₂ , the steering angles ψ ₁ and ψ ₂ are obtained according to the following equation (where ε = ε ₁ ) ,
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L−εT / 2}]
When | ε ₁ −ε ₂ |> Δε holds for the induced deviations ε ₁ and ε ₂ , F ′ (ε ₁ −ε ₂ ) is added to the denominator term on the right side as shown in the following equation , and the steering angles ψ ₁ and ψ By correcting ₂
ψ ₁ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + F ′ (ε ₁ −ε ₂ ) + εT / 2}]
ψ ₂ = tan ⁻¹ [ε (H / 2 + δ) / [ (H / 2 + δ) L + F ′ (ε ₁ −ε ₂ ) −εT / 2}]
A guided traveling method for an omnidirectional automatic guided vehicle characterized by improving straightness and convergence when traveling straight.
However, H is wheel base, T is the tread, [delta] is the sensor mounting length is longitudinal distance from the steering wheel of the front with respect to the traveling direction until the inductive sensor of the vehicle body front and delta epsilon predetermined value, F ' Is a constant and the maximum value is H / 2.

Images