JPH06266439A - Speed control method for moving body - Google Patents

Abstract

PURPOSE:To execute smooth speed control, and to raise a cycle time by setting acceleration/deceleration to a multistage. CONSTITUTION:A microcomputer waits for a moving start command. When the moving start command is received, whether a load exists at present or not is confirmed, and when the load exists, parameters alpha1-alpha7, beta1-beta7, Vmax, and ta1-ta7, tb1-tb7... of acceleration/deceleration, the maximum speed, etc., at the time when the load exists, and a parameter at the time of no-load are fetched, when the load exists, and when the load does not exist, respectively. Subsequently, a moving distance L is calculated, and an acceleration distance 1e is derived. From this acceleration distance 1e, a pattern of acceleration is generated, but in the case in which the acceleration distance 1e is long, ta4 is calculated so as not to exceed Vmax, an actual acceleration distance 1e' and an acceleration variation point are derived, and a speed pattern of acceleration is generated. In the case in which the acceleration distance is short and ta4 becomes minus and cannot be calculated, ta4 is calculated by varying the number of acceleration stages from 7 to 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving body which recognizes a current position by counting pulses of an encoder or the like and performs position control.

[0002]

2. Description of the Related Art In the prior art, the acceleration / deceleration is usually controlled to be constant. Further, in the acceleration control method for the traveling crane for loading and unloading disclosed in Japanese Patent Laid-Open No. 63-11095, a motor is used.
And an S-shaped speed pattern is proposed based on the torque characteristics of the inverter, but no mention is made of deceleration.
Also, it does not describe the case of a short travel distance that does not reach the maximum speed.

[0003]

In the prior art, since the acceleration / deceleration is controlled to be constant, when the acceleration changes to the constant speed, when the constant speed changes to the deceleration, or when the deceleration changes to the creep. It is necessary to consider the shock at the change point of the acceleration / deceleration of the vehicle, the collapse of the load when transporting the load, and the shaking of the mobile vehicle when the vehicle is tall. Even if there was a margin, I had to lower the overall acceleration / deceleration. When the acceleration / deceleration is constant, the control system (especially the followability of the inverter)
The delay must be absorbed by increasing the creep distance from the delay of 1, or the delay can be reduced by decreasing the overall acceleration / deceleration. Therefore, it was difficult to improve the cycle time.

An object of the present invention is to minimize shock at a change point of acceleration / deceleration, perform smooth speed control, and increase cycle time.

[0005]

In order to achieve the above object, the present invention has a multistage acceleration / deceleration to minimize the shock at the change point of the acceleration / deceleration. When carrying a load, the motor and inverter capacities are selected with the load loaded (rated load). The cycle time can be increased by increasing the acceleration / deceleration and maximum speed.

[0006]

[Function] By controlling the acceleration / deceleration in multiple stages, shockless and smooth speed control is possible. In addition, by changing the acceleration / deceleration and the maximum speed during loading and unloading, it is possible to use the capacity of the inverter and the motor without waste and increase the cycle time.

[0007]

1 is a control block diagram of the present invention, FIG. 2 is a control flow chart in a microcomputer, and FIG. 3 is a speed pattern diagram. As shown in FIG. 1, the control structure is such that the speed pattern is calculated from the moving distance before the movement, and the microcomputer 1 which outputs the command according to the speed pattern and the motor 4 according to the command are output.
An inverter 3 for controlling the motor 4, a brake 5 for stopping the motor 4 and an encoder for outputting a pulse signal synchronized with the rotation of the motor 4 to the microcomputer 1 for position information of the moving body.
It consists of da. Next, the control content of the microcomputer 1 will be described below with reference to FIGS.

First, the microcomputer 1 waits for a movement start command (for example, a command from a host computer) (F1). When the movement start command is received, it is confirmed whether or not there is a load at present, and if there is a load, parameters (α1 to α7, β1 to β7, Vma) such as acceleration / deceleration and maximum speed when loading
x, ta1 to ta7, tb1 to tb7 --- where ta
Since 4 and tb4 are variable values calculated, they do not exist as parameters. ) Is not loaded, the parameters (same as above) when unloading are taken out (F2, F3a, F
3b). Next, the moving distance L (target position-current position) is calculated (F4), and the acceleration distance le ((moving distance-creep distance) / 2) is calculated (F5). The acceleration / deceleration pattern is created from this acceleration distance le. When the acceleration distance le is long, ta4 is calculated so as not to exceed Vmax as shown in FIG. 3a, and the actual acceleration distance le ′ and the acceleration change are calculated. Create a speed pattern for acceleration based on the points (F6, F
7, F8). When the acceleration distance le is short and ta4 is negative and calculation is not possible, the number of acceleration stages is changed from 7 to 5 as shown in FIG. To calculate. This is also ta4
If becomes negative and calculation is not possible, increase the number of acceleration stages from 3 to 1
And ta4 is calculated (F6, F7). Similar to the above, from ta4 to actual acceleration distance le ', maximum speed Vma
An acceleration velocity pattern is created based on x'and the acceleration change point (F8). The speed pattern of deceleration is the actual maximum speed Vmax '(or Vmax) obtained by acceleration.
Then, from the target position, td4 is calculated in the same manner as during acceleration, the deceleration change point is calculated, and the deceleration pattern is created (F
9, F10, F11).

The brake is released, and a control signal (forward or backward) and a minimum speed command (command output at startup) are output to the inverter. The current position is recognized by counting the pulse signals from the encoder, and the speed command is output to the inverter according to the found speed pattern (F
12).

[0010]

EFFECTS OF THE INVENTION By making the acceleration / deceleration multistage, shockless and smooth speed control can be performed. Also, by changing the acceleration / deceleration and maximum speed between loading and empty
The abilities of the inverter and the motor are used without waste, and the cycle time can be increased.

[Brief description of drawings]

FIG. 1 is a control block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of an embodiment of the present invention.

FIG. 3 is a velocity pattern diagram.

[Explanation of symbols]

1 ... Microcomputer, 2 ... Encoder, 3 ... Inverter, 4 ...
Motor, 5 ... Brake, α1 to α7 ... Acceleration, β1 to
β7 ... deceleration, ta1 to ta7 ... acceleration time, tb1 to t
b7 ... deceleration time, Vmax ... maximum speed (parameter),
V'max ... Maximum speed (maximum speed when the travel distance is short and Vmax is not reached).

Claims (3)

[Claims] 1. A motor for driving a moving body, an inverter for controlling the motor, an encoder mounted on a wheel shaft or the like to generate a pulse during movement, and an encoder.
In a method of controlling a position-moving body, which comprises a controller for inputting a pulse from a controller and counting the pulse to recognize the current position and outputting a speed command to the inverter based on the position information , A method of controlling a moving body, characterized in that the moving body is moved in a shockless manner by setting acceleration / deceleration in multiple stages. 2. A method of controlling a moving body according to claim 1, wherein the number of stages of acceleration / deceleration and the maximum speed are changed according to the moving distance. 3. A method of controlling a moving body according to claim 1, wherein, when a load is conveyed, the acceleration / deceleration and the maximum speed are changed depending on the presence or absence of the load.