JPS60169912A - Method and apparatus for controlling travelling of moving body - Google Patents

Abstract

PURPOSE:To attain stable travelling control by detecting and calculating a load to be applied to a moving body and correcting a travelling control signal on the basis of the load. CONSTITUTION:While picking up road surface indication marks on a travelling road by an image pickup processor 13 to recognize the travelling state, the moving body continues to travel. The travelling command is applied from a computer 23 and a control part drives motors 6 for driving wheels. The speed of the motors 6 is detected by detectors 12 and said control part 100 executes the operation or the like of a travelling control signal. In this case, an arithmetic unit 30 calcurates and estimates the load state of the moving body of the basis of speed detecting signals Va, Vb from the detectors 12, calculates a gain control signal G for controlling the speed controlling system at its optimum gain and supplies the calculated result to a servo amplifier 28. On the basis of the correction, the control system can control travelling under stable status.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method and apparatus for controlling the running of a moving body such as a transport vehicle.

[Background of the invention]

Various types of moving objects are known that run on the ground, and can be roughly divided into those that run on tracks and those that run on tracks without tracks. Cranes, railway vehicles, etc. are typical examples of things that run on tracks. Examples of things that run on trackless roads include transport vehicles, rubber tire cranes, and traveling robots.

Among these moving objects, moving objects that run unmanned are equipped with a drive unit (for example, a motor) for driving the moving body to travel, and are also provided with a control unit that provides a travel control signal to the drive unit. There is. This control section includes, for example, a speed control system that controls the speed of the motor. Therefore, the moving object is automatically controlled to travel at a predetermined speed. Now, when it comes to moving objects that are loaded with cargo and run,
The response of the speed control system changes greatly depending on whether there is a load or not, and it may take too much time to control the speed to a predetermined speed, or the speed may fluctuate significantly, making stable travel control impossible. This phenomenon also occurs depending on the size of the cargo.

[Purpose of the invention]

An object of the present invention is to provide a traveling control method and apparatus for a moving body that can realize stable traveling of a moving body.

[Summary of the invention]

The present invention focuses on the fact that the factor that hinders the stable running of a moving object is the fluctuation in the weight (load) of the cargo loaded on the moving object, and detects or calculates the load applied to the moving object, and calculates the load applied to the moving object. The present invention is characterized in that the travel control signal supplied to the drive unit is corrected based on this.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on specific examples.

The configuration of an automatic guided vehicle, which is a typical moving object to which the present invention is applied, will be explained with reference to FIG. The automatic guided vehicle shown in Fig. 1 uses an imaging device to image road markings 2 provided on a running route 1, recognizes the running state based on this captured image, and avoids deviations from the planned running route. (In this figure, 4
Reference numerals a and 4b denote imaging devices for inputting images of the road markings 2-, which are attached to the front and rear of the transport vehicle. 5 is a vehicle body, and cargo is loaded onto the central recess. 6a and 6b are driving motors. 7a and 7b are motors 6a and 6b
These are the running wheels that are driven respectively by the wheels, and are particularly referred to as driving wheels below. 8a and 85 are reduction gears. 9a and 9b are running wheels provided at the front and rear of the vehicle body 5. Reference numeral 10 denotes a control panel, which includes a control section to be described later. Motors 6a and 6b are controlled by travel control signals from the control section.

Reference numeral 11 is a battery device, which supplies necessary power to the control panel. 12a and 12b are speed detectors that detect the speeds of the motors 6a and 6b, and these detection signals are supplied to the control section. The image taken by the imaging device F114m shown in FIG. 1 is supplied to an image processing device, and a running portion is calculated. This image processing! FIG. 2 shows a schematic configuration of 1Fj13. That is, the image captured by the imaging device U4a (1(li
The wound signal is converted to 2 by an analog-to-digital converter 19.
It is converted into a digitized digital signal and is sequentially stored in the image memory 2.
Stored within 0. '/lI arithmetic glue η calculates the trajectory deviation amount,
Calculates and outputs running conditions such as attitude angle. This information is
Used for steering control of moving objects.

Next, an embodiment of the present invention for controlling the automatic guided vehicle shown in FIGS. 1 and 2 will be described. FIG. 3 is a diagram showing an embodiment of the present invention. In this figure, numeral 23 is a combination rotor that gives a movement command (target angle U information) to the moving body. 100 is a control unit, which is housed in the control panel 10 of the moving body. Part or all of this control section 100 can also be implemented by a conbeater. 6a,
6b is a motor for moving the left and right drive wheels once;
2a.

12b is a speed detector that detects the speed of the motor. The control unit 100 is composed of various devices as shown in the figure, and calculates travel control signals and outputs them to the drive unit.
is the image processing device described above, and outputs the running state 13I (trajectory deviation amount y, attitude angle ψ).

Reference numeral 24 is a target paddle position r setting register, in which data corresponding to the station to which the mobile object should move is registered.

5 is a subtraction circuit which calculates the difference ΔL between the target position fl Lo and the actual distance traveled. 26 is a one-time pattern generator, and the speed setting value V corresponds to ΔL.

Output. 27 a' and 27 b are speed setting values V
This is a speed setting register for setting o. 29a and 29b
is an adder. The adder 29a inputs the speed setting value Vo, the speed setting correction value ΔV, and the detected speed value ■, and calculates the speed deviation Δ■8. The adder 29b is the speed setting value V. , speed setting correction value △V, and speed detection value vb
is input, and the speed deviation Δvb is calculated.

28a and 28b are servo amplifiers incorporating a rotary servo mechanism for adjusting control gain, and output a control signal (travel control signal) for eliminating speed deviation.

This control signal controls the speeds of the motors 6a, 6b to the driver's set value. Although not shown in the figure, a thyristor Leonard or the like is used as this speed control system. 3
0 is an arithmetic device, and specifically, a micro-combiner or the like is used. The third component is a correction device and a calculation device W! 30
The left and right motors (ia,
This is for correcting and outputting the speed setting correction values Δv, . . . Δvb of 6b.

Although the correction circuit 31 may be a function of the arithmetic device 30, it is provided separately here. In this example,
Steering is controlled by the speed difference between the left and right drive wheels, that is, by the left and right motors 6a.
, 6b, and therefore the speed settings of the left and right motors are corrected using the steering signal ΔV. In a conveyance vehicle equipped with a steering mechanism, steering control can be performed by supplying a steering signal ΔV to its drive motor. Characteristic parts of this embodiment are the arithmetic unit FR30 and servo amplifiers 28a and 28b, which perform control to eliminate instability in noise control based on load fluctuations. Among them, the arithmetic unit 30 is the central one. The arithmetic device 30 in this embodiment has the following
■Implement the function.

■ The output of the speed detectors 12a and 12b, Vb
Input these values and integrate them to calculate 1lILa for driving.

Based on Lb, the average running WIL is calculated and outputted to the subtraction circuit 25. (This function is a travel distance detection function in the position control system.) ■ Inputs the output of the image processing device [13] and also inputs the speed detection signal VR1Vb so that the moving object travels on the planned travel path. The steering signal △V is calculated and output to the correction circuit. (This function is a steering fi calculation function in steering control.) ■ Input the speed detection signal Va + Vb, calculate the time from when the moving object starts traveling until it reaches the planned speed, and calculate this time. The load state (ie, load) of the moving body is estimated from the above, and a gain control signal G for controlling the speed control system to the optimum gain is calculated and supplied to the servo amplifiers 28a and 28b.

(This function is a function to control the control system in a stable state.) Among these functions, the function (2) according to the present invention will be described in detail below. This function can of course be implemented without measuring the time until the speed reaches the expected value.In other words, to measure the load, a load detector such as a load cell can be attached to the vehicle body 5, and this The detection value can be used to control the control gain to an optimum level.Furthermore, the motor 6a for driving.

Detect the dynamic current of 6b, estimate the load from this current,
Similar gain control can be performed. However, in this embodiment, a method of controlling by measuring the time taken to accelerate to the scheduled speed was adopted.

The basis for estimating the load by measuring the time taken to accelerate to the planned speed is as follows. That is, the equation of motion for the moving direction of the moving body is approximated by equation (1).

M・α== F1+ F2 ・・・・・・・・・・・・
...(1) However, M: the sum of the load of the moving body and the cargo load loaded on the moving body (total weight) α: the acceleration of the moving body Fl, F,; the driving force F of the left and right traveling motors, = F2
= F, then from equation (1) -M・α=F...
(2), and since this driving force F is proportional to the current i, substituting this relationship into equation (21) yields the following equation.

Engineering M, α==,・l ・・・・・・・・・・・・・・・
・(3) However, the voltage equation of ky + proportional constant running wheel is approximated by (4 formula).

Ri+kv・V=e・・・・・・・・・・・・・・・
(4) where, R: resistance i of the motor; current kv of the motor; constant of proportionality ■; speed e of the motor; voltage applied to the motor (31, +41 When i is deleted from the equation, the following equation is obtained.

When Equation (5) is Laplace-transformed by setting e=B (voltage-x), Equation (6) is obtained.

(When Equation 61 is inversely transformed into the domain of time t, it becomes as follows.As is clear from Equation (7), the time t for reaching the same speed becomes longer in proportion to the load M.

That is, when the load M increases by N times, the time t required to reach the same speed ■ also increases by N times. Therefore, the load M can be calculated by calculating the speed response time.

Since a first-order linear relationship as shown in FIG. 5 is established between load NM and response time, if this relationship is stored in advance as a table, the arithmetic unit can be easily used. ! 30, the load M can be estimated by simply finding the response time and referring to the table.

Next, we will explain how to modify the parameters of the control system based on these results. 29a * 2 in Figure 3
8a * 6 a +] 2a or 29b, 28
Parts b, 6b, and 12b are the speed control system, and the characteristics of each element of this speed control system are shown in FIG.

In this figure, 4' corresponds to 29a or 29b, 28' corresponds to 28a or 28b, and 6' corresponds to 6.
corresponds to a or 6b, and 2' is 12g or 12b
Applies to. K is the gain of the servo amplifier 28, and kvf is the velocity feedback gain. The transfer function G(2) of this control system is expressed by the following equation.

In two cases, if K >> 1, then K-kvf+kv:
K-kvf, and equation (8) can be approximated as equation (91).

In this equation (9), M/K should be kept constant in order to prevent variations in the load M from affecting the responsiveness of the moving body. In other words, the gain K may be adjusted in proportion to the variation in the load M. Such adjustment can be realized by changing the rotation angle of a servo motor directly connected to the variable resistor using a voltage proportional to the load M. The servo amplifier 288.degree. 28b has a ridge portion for adjusting the gain K, and is adjusted by the gain control signal G calculated and outputted by the calculation device 30.

In this way, in the embodiment of FIG.
outputs a control signal to adjust the gain of the control system to an appropriate value according to the load M, and outputs a control signal for each servo amplifier 2B+.
1.28b adjusts the gain according to this control signal.

This makes it possible to control the vehicle in a stable state of the control system. Note that at the start of running, the servo amplifier 28a,
The gain of 28b is set to a known small value. This is because if the gain K is increased and the vehicle starts traveling, rapid acceleration will occur if the vehicle is not loaded with cargo.

In the embodiment described above, the moving object is actually run,
We learned the load situation based on the time it took to reach a predetermined speed (response time) and adjusted the gain to an appropriate level.
If it is done properly, the intended purpose will be achieved. Since one view of the moving object itself is known, the gain of the control system can be adjusted by measuring only the weight of the cargo. Therefore, a detector (for example, a load null) that detects the weight of the cargo can be attached to the moving object. By supplying this detection signal to the control section, a gain control signal can be set. Furthermore, since the moving body travels to each stage to load cargo, this can also be achieved by receiving data regarding the weight of the cargo at the time of loading the cargo. The same can be achieved by supplying data regarding the load from the combination Hatake-Yu. In devices that directly detect the load or receive load data, the gain of the control system can be adjusted to an appropriate value before the moving object starts moving, so the entire process from the time the moving object starts moving until it stops at the target position can be adjusted. Stable travel control can be achieved over a period of time.

〔Effect of the invention〕

As described above in detail, according to the present invention, the gain of the control system is adjusted to an appropriate value according to the load applied to the moving body, so stable travel control can be realized.

[Brief explanation of the drawing]

Fig. fjS1 is a diagram showing the configuration of the automatic guided vehicle, Fig. 2 is a diagram showing the schematic configuration of the image processing NJ device, Fig. 3 is a diagram showing an embodiment of the present invention, and Fig. 4 is the characteristic of the speed control system. FIG. 5 is a diagram showing the relationship between load and response time. 4a, 4b...imaging device, 5...vehicle body, 6a. 6b...Motor, 7a, 7b...Running wheel, 8m. 8b... Reduction gear, 9a, 9b... Traveling wheel, 10... Control panel, 11... Battery device, 12a, 12b...・Speed detector,
13...Image processing device,...Computer,...Target position setting register, 25...
...Subtraction circuit, ... Speed pattern generator, 27a, 27b... Speed setting register, 2
8, 28b... Servo amplifier, 29a +2
9b... Adder, ■... Arithmetic device, Figure 2, Figure 4, Figure 1,5

Claims (1)

[Claims] 1. A traveling control method for a moving body that supplies a traveling control signal to a drive unit of the moving body, wherein a load applied to the moving body is detected or calculated, and the traveling control is performed based on the load. A traveling control method for a mobile object, the method comprising determining a signal. 2. A travel control device for a mobile body comprising a drive unit for the mobile body and a speed control unit that supplies a travel control signal to the drive unit, including means for applying a load to the mobile body; 1. A travel control device for a moving body, comprising: means for adjusting a gain of a control section based on the load.