JPH08123537A - Predictive controller - Google Patents

Abstract

PURPOSE: To enable a high-speed positioning operation without generating delay for M steps by shifting the contents of a memory storing a target command to the past for one sampling at the next sampling time and storing the target command preceding for M steps in the memory. CONSTITUTION: Corresponding to a target command switching signal, a command generator 21 generates future target command increments Δr(i+M), ..., Δr(i) at the first sampling time to perform predictive control and generates only the future target command increment Δr(i+M) at the next sampling time. Corresponding to the target command switching signal, a memory 22 with shift operation stores the target command increments from the current time preceding for the M steps in the memory at the first sampling time to perform predictive control and newly stores the future target command increment Δr(i+M) at the next sampling time after the contents of the memory are shifted to the past just for one sampling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for robots, machine tools and the like.

[0002]

2. Description of the Related Art For example, Japanese Patent Application No. 5-197956 discloses a preview control device for making an output of a controlled object follow a target command.
There is a device proposed by the applicant of the present invention. In this device, based on the transfer function of the controlled object, a future target command increment value, a past control input increment value, an output increment value of the controlled object, a deviation of the controlled object, and a predetermined preview control parameter are set. It is possible to obtain a preview controller that optimally follows the target command by using simple arithmetic operations.

[0003]

However, in the above-mentioned conventional example, when the command generator for generating the target command and the preview control device are combined, the target command at the current time is generated from the command generator in each sampling. If this is M
Since the preview control calculation is performed by considering the target command of the step destination, there is a problem that the operation is delayed by M samplings. Therefore, an object of the present invention is to provide a preview control device that can solve this problem.

[0004]

In order to solve the above problems, the present invention provides a preview control apparatus that uses a future target command so that the output of a control target follows the target command.
At the first sampling time when the preview control is performed, a target command from the current time to M steps ahead is generated, and
A command generator that creates a target command that generates only a target command M steps ahead from the next sampling time, a memory that stores the target command, and a first sampling time that performs the preview control have M steps from the current time. Contents of the memory that stores the target command up to the previous, performs prediction calculation using the target command stored in the memory, and stores the target command from the next sampling time. Shift one sampling past,
Means for storing a target command of M steps ahead in the memory and performing a preview control calculation using the target command stored in the memory.

[0005]

By the above means, it is possible to provide a preview control device capable of high-speed positioning operation without causing a delay of M steps, which is a problem when realizing preview control in combination with a command generator.

[0006]

EXAMPLES The present invention will be specifically described below based on examples. FIG. 1 is a block diagram when performing motor control using the present invention. In the figure, 11 is a preview control device,
It has a command generator inside, and the target command switching signal and the output increment value of the motor before K sampling (K ≧ 0) Δ
y (iK) is input and the control input v (i) is input to the motor controller 12
Output to. The motor controller 12 controls the motor 13, 14 is a detector for detecting the output y (iK) of the motor, and 15 is an output increment value from the output y (iK) of the motor. △ y (i
-K) is a differentiator. In addition, Δ represents the increment value between each sampling time. Next, a block diagram of the preview control device 11 is shown in FIG. The present invention can be applied to all preview control devices that use future target commands, but here, the device proposed by the present applicant in Japanese Patent Application No. 5-197956 will be described. Reference numeral 21 in the figure denotes a command generator, and at the first sampling time for performing preview control by the target command switching signal, future target command increment value Δr (i + M), ..., Δr
(i) is generated, and only the future target command increment value Δr (i + M) is generated from the next sampling time. Reference numeral 22 is a memory with a shift operation, and at the first sampling time at which the preview control is performed by the target command switching signal, M is read from the current time.
The target command increment value up to the step destination is stored in the memory, and after the next sampling time, the content of the memory is shifted by one sampling past, and then the future target command increment value Δr is newly added.
Remember (i + M). 23 is a preview control parameter v _{-K + 1} ,
..., v _M , p ₀ , ..., p _Na-1 , E, g ₁ , ..., g _{Nb + K-1} (N
_a , N _b are natural numbers), 24 is a memory for storing output increment values Δy (iK), ..., Δy (iKN _a +1), 2
Reference numeral 5 is a memory for storing past control inputs v (i-1), ..., V (iKN _b +1). 26 is a difference Δ between the target command increment value Δr (iK) and the output increment value Δy (iK) stored in the memory 22.
A subtracter for obtaining e (iK), and 27 is an integrator for obtaining e (iK) from Δe (iK). 28 is a computing unit,

[0007]

[Equation 1]

The control input v (i) is calculated by the following calculation. The calculated v (i) is stored in the memory 25 and is output to the motor controller 12 as an output of the preview control device 11. In this embodiment, the case where the command generator is provided inside the preview control device has been described, but when the command generator is provided outside, the target command switching signal is input to both the command generator and the preview control device, and the present embodiment The procedure may be similar to the example.

[0009]

As described above, according to the present invention, a high-speed positioning operation can be performed without causing a delay of M steps, which is a problem when realizing preview control in combination with a command generator. A possible preview control device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram when the present invention is applied to motor control.

FIG. 2 is a block diagram of a preview control device.

[Explanation of Codes] 11 Preview control device 12 Motor controller 13 Motor 14 Detector 15 Difference device 21 Command generator 22 Future target command increment value Δr (i + M),…, Δr (i) Memory with shift operation for storing 23 Prediction control parameters v _{-K + 1} , ..., V _M , p ₀ , ...,
Memory for storing p _Na-1 , E, g ₁ , ..., g _{Nb + K-1} 24 Memory for storing output increment value Δy (iK), ..., Δy (iKN _a +1) 25 Past control A memory that stores the inputs v (i-1), ..., V (iKN _b +1) 26 subtractor 27 integrator 28 arithmetic unit

Claims (1)

[Claims] 1. In a preview control device using a future target command so that the output of a controlled object follows the target command, a target command from the current time to M steps ahead is generated at the first sampling time when the preview control is performed. Along with
A command generator that creates a target command that only generates a target command that is M steps ahead from the next sampling time, a memory that stores the target command, and the first sampling time when the preview control is performed are M steps from the current time. Contents of the memory that stores the target command up to the previous, performs prediction calculation using the target command stored in the memory, and stores the target command from the next sampling time. Is shifted one sampling past, a target command M steps ahead is stored in the memory, and a preview control calculation is performed using the target command stored in the memory. Preview control device.