JPH05122971A - Speed estimation device - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the velocity estimation error even when the moving object is moving at a slow velocity. [Structure] A counter 4 that counts the output signal of a pulse encoder 2, a first adder 51 that receives the position detection value x _PE from the counter 4 as one input, and an estimated error x _e from the adder 51 is a constant. First and second gain multipliers 61 and 6 for multiplying
2, a third adder 53 for calculating the difference between the output signal of the gain multiplier 62 and the acceleration force or torque T of the object, and the output signal of the adder 53 are integrated to output the estimated speed value x ′ _A. A second integrator 72, and a second adder 52 that calculates the difference between the speed estimation value x ′ _A and the output signal of the gain multiplier 61,
A first integrator 71 which outputs a position estimate x _A output signal integration to the adder 52, the position estimate x _A and a quantizer 8 for quantization, from the quantizer 8 The position estimation value x _PEA is used as the other input of the first adder 51.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a velocity estimating device for estimating and detecting the moving velocity of an object having a mass.

[0002]

2. Description of the Related Art FIG. 4 is a functional block diagram of a conventional speed estimation device for estimating the rotation speed of an electric motor. In the figure, 1 is an electric motor, 2 is a pulse encoder as a position detector provided on the output side, 3 is a speed estimation device (observer), 4 is a counter in the speed estimation device 3, and 51 is a counter.
Is an adder into which a position detection value x _PE which is an output signal of the counter 4 and a position estimation value x _A which is an output signal of an integrator 71 which will be described later are inputted with the symbols shown in the figure, and 9 is an encoder from the pulse encoder 2. The adder 51 is turned on / off by a control signal.
A switch for transmitting the position estimation error x _e which is the output signal of the switch to the subsequent stage, 61, 62 and 63 are gain multipliers for multiplying the estimation errors x _e by gains K ₁ , K ₂ and K ₃ , respectively, and 73 is a gain multiplier 63. integrator output signal is applied via an adder 54, 53 is an output signal load force or the load torque of the integrator 73 (hereinafter, simply referred to as load torque) and the estimated value T _LA of the gain setting unit 62 An adder 72 to which an output signal and a force or torque (hereinafter, referred to as a drive torque) T for accelerating the electric motor 1 are added by the symbols shown in the drawing.
Is an integrator which receives the output signal of the adder 53 and serves as a model of the mass or inertia of the object, and 52 is the speed estimation value x ′ _A which is the output signal of the integrator 72 and the output signal of the gain setting unit 61. Reference numeral 71 is an adder, and 71 is an integrator to which the output signal of the adder 52 is input, and the output signal is added to the adder 51 as the position estimation value x _A as described above.

Reference numeral 50 denotes an adder provided on the input side of the electric motor 1, to which a drive torque T and a load torque T _L are added by the symbols shown in the figure, and the output signal thereof is inputted to the electric motor 1. . Here, as the driving torque T, not only the detected value is used, but a command value may be substituted for the detected value.

In this speed estimation device, an estimation error x _e , which is a difference between the position detection value x _PE from the counter 4 and the position estimation value x _A from the integrator 71, is passed through a switch 9 to gain multipliers 61 to 61. The switch 9 is closed for a certain period of time each time a pulse is output from the pulse encoder 2. Therefore, when the pulse is not output from the pulse encoder 2, the switch 9
Is open, at which time the estimation error x _e becomes zero.

[0005]

Since the output of the pulse encoder 2 is originally discrete, the pulse interval is widened and the information therebetween is lost when the electric motor 1 is at a very low speed. That is, conventionally, the switch 9 is closed to operate the speed estimation device 3 only while the pulse is being output from the pulse encoder 2, and the speed estimation device 3 operates simply as a simulator while the switch 9 is open. Therefore, even if the estimation error actually exists, it cannot be corrected. Therefore, as shown by the broken line in the lower part of FIG. 5, even though there is an actual estimation error between the position detection value x _PE and the position estimation value x _A , as shown by the solid line in the figure, the pulse output time t ₁ , T ₂ , ... Except for a certain period immediately after, the estimation error x _e becomes zero in other periods. Therefore, there is a problem that the speed error is gradually increased because the error correction operation is not performed promptly.

The present invention has been made to solve the above problems, and an object thereof is to correct the position estimation error even at a very slow speed to reduce the speed estimation error and enable accurate estimation. Another object of the present invention is to provide a speed estimation device according to the present invention.

[0007]

In order to achieve the above object, the first invention attempts to accelerate a pulse-shaped digital signal output from a position detector according to the moving distance of an object and the object. In a speed estimation device that receives a force or a torque and estimates the moving speed of the object based on these, a counter that counts the output signal of the position detector and a position detection value output from this counter And a first gain multiplier for multiplying the position estimation error output from the first adder by a constant, and an output signal of the second gain multiplier and the object. Third to calculate the difference between the force or torque to accelerate the vehicle
Of the third adder, a second integrator that integrates the output signals of the third adder and outputs a speed estimation value, the speed estimation value and the first
The second adder that calculates the difference from the output signal of the gain multiplier of, the first integrator that outputs the position estimation value by integrating the output signal of the second adder, and the position estimation value A quantizer for quantizing is provided, and the position estimation value output from this quantizer is used as the other input of the first adder.

A second invention is a pulse-shaped digital signal output from a position detector according to a moving distance of an object,
A force estimating device for inputting a force or torque for accelerating the object, and estimating a moving velocity of the object based on the force or torque, a first adder having an output signal of a position detector as one input, , A counter that counts the output signal of the first adder, first and second gain multipliers that respectively multiply the position estimation error output from this counter by a constant, and output signals of the second gain multiplier And a third adder for calculating the difference between the force or torque for accelerating the object, a second integrator for integrating the output signal of the third adder and outputting a speed estimation value, A second adder for computing the difference between the speed estimate and the output signal of the first gain multiplier;
A first integrator that integrates the output signal of the second adder to output a position estimation value, and a position detector model that outputs a pulse-shaped digital signal for each constant variation of the position estimation value are provided. , The output signal of this position detector model is the first
Is used as the other input of the adder.

[0009]

According to the first aspect of the invention, the quantizer operates as a model of the position detector and the counter, and if there is no position estimation error, the output signal of the counter and the output signal of the quantizer are completely matched. . If there is an estimation error, the difference in the number of output pulses of the counter and the quantizer or the phase difference between the pulses is always output as the estimation error. In the present invention, if the output signal of the quantizer changes due to the estimation error even during the period in which no pulse is output from the position detector, this will be immediately reflected in the estimation error, and the estimation error will be sequentially corrected. Therefore, the velocity estimation error is small even when the moving object is moving at a slight velocity.

According to the second invention, the difference between the output pulses of both the position detector and the position detector model is integrated by the counter. Therefore, if the counter is set to be capable of counting up to an appropriate finite value, the object Even when is moved over an infinite length and pulses are output from the position detector infinitely, overflow of the counter can be prevented and the speed can always be estimated with high accuracy.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram of a speed estimation device according to an embodiment of the first invention. The same components as those in FIG. 4 are designated by the same reference numerals and detailed description thereof will be omitted. explain. That is, in this embodiment, the switch 9 in FIG. 4 is removed, and the quantizer 8 is provided on the output side of the integrator 71, and the output signal thereof is used as one input of the adder 51 to estimate the speed. The device 3A is configured.

Here, in general, a quantizer divides the amplitude range of an input signal into a plurality of sections, and replaces a sample value belonging to each section with a representative value thereof, so that a continuous amplitude value of the input signal is finite. It is to be discretized into individual levels. In this embodiment, the quantizer 8 operates as a model of the pulse encoder 2 as a position detector and the counter 4,
If the estimation error x _e does not exist (x _e = 0), the position detection value x _PE from the counter 4 and the position estimation value x _PEA from the quantizer 8 completely match.

Next, the operation of this embodiment will be described with reference to FIG. 2. In this embodiment, the position estimated value x _A output from the integrator 71 is input to the quantizer 8.
The quantizer 8 quantizes the number of pulses of the pulse encoder 2. On the other hand, the output pulses of the pulse encoder 2 are counted by the counter 4, and the resulting position detection value x _PE is compared with the position estimation value x _PEA from the quantizer 8 by the adder 51. The output signal of the adder 51 is used as the position estimation error x _e and gain multipliers 61 and 6
2, 63 and adders 52, 53, 54 to form an integrator 7
1, 72, 73, thereby changing the output of the quantizer 8 and finally correcting the estimation error x _e .

FIG. 2 is a time chart showing the operation of this embodiment. In the figure, t ₁ and t ₂ are the pulse output points from the pulse encoder 2. If the position estimation value x _PEA from the quantizer 8 changes stepwise at time t ₁ ′, t ₂ ′, t ₃ ′, t ₄ ′ according to the position estimation value x _A as shown by the broken line, This operation immediately reflects this in the estimation error x _e, and the estimation error x _e also changes stepwise as shown by the solid line in the figure.

Comparing this FIG. 2 with FIG. 5 relating to the prior art, the pulse output time t ₁ from the pulse encoder 2
Other than t ₂ , the period during which the estimation error x _e becomes zero is small. In particular, at time t ₄ ′, the estimation error x _e also changes according to the change in the position estimation value x _PEA , even though no pulse is output, and it can be seen that the correction operation of the estimation error is performed. As described above, according to the present embodiment, the estimation error x _e can be corrected even during a period in which no pulse is output from the pulse encoder 2, so that the estimation error can be reduced even when the moving object is moving at a slow speed.
Therefore the error of which is the output speed estimation value x _'A of the integrator 72 can be reduced.

FIG. 3 shows an embodiment of the second invention.
This embodiment is designed to prevent the counter from overflowing when a moving object moves for an infinite length.
A pulse encoder model 10 as a position detector model is provided on the output side of 1, and the difference between the output signal of the pulse encoder model 10 and the output signal of the pulse encoder 2 is obtained by an adder 51, and the result is integrated by a counter 4 to obtain an estimated error x. It is designed to calculate _e . Here, the pulse encoder model 10 is configured to output a pulse-shaped digital signal for each constant change amount of the position estimation value x _A output from the integrator 71.

According to this embodiment, even if a moving object moves infinitely long and pulses are output infinitely from the pulse encoder 2, the counter 4 always outputs the pulse of the pulse encoder 2 and the pulse encoder model. Since the difference between the output pulse and the output pulse of 10 is counted and integrated, any counter that can count an appropriate finite value can be dealt with, and high precision is achieved even when the object moves infinitely without overflow. The advantage is that the speed can be estimated.

The components of the speed estimating devices 3A and 3B shown in the above embodiments can be realized by hardware including an analog circuit or a digital circuit or by software calculation. Further, although the load force or the load torque is also estimated in each of the embodiments, when the load force or the load torque is not applied, the gain multiplier 63, the adder 54 and the integrator 73 in each embodiment are used. Becomes unnecessary. Further, the present invention can be applied not only to the rotation speed of the electric motor as in the embodiment, but also to the estimation of other rotation speeds and speeds of linearly moving objects and the like.

[0019]

As described above, according to the first aspect of the invention, the estimation error is constantly corrected by obtaining the difference between the quantized output of the position estimation value and the counter output. The estimation error can be corrected even during a period in which no pulse is output from the position detector, and the velocity of the moving object can be accurately estimated by reducing the estimation error.

According to the second aspect of the invention, since the difference between the output pulses of the position detector and the position detector model is integrated by the counter to obtain the estimation error, the counter of the counter can be used even for an object moving infinitely long. Accurate velocity estimation is possible without overflow.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the first invention.

FIG. 2 is a time chart showing the operation of the embodiment of FIG.

FIG. 3 is a functional block diagram showing an embodiment of the second invention.

FIG. 4 is a functional block diagram showing a conventional technique.

FIG. 5 is a time chart showing the operation of FIG.

[Explanation of symbols]

 1 Motor 2 Pulse Encoder 3A Speed Estimator (Observer) 4 Counter 8 Quantizer 10 Pulse Encoder Model 50, 51, 52, 53, 54 Adder 61, 62, 63 Gain Multiplier 71, 72, 73 Integrator

Claims (2)

[Claims] 1. A pulse-shaped digital signal output from a position detector according to a moving distance of an object and a force or torque for accelerating the object are input, and based on these, a moving speed of the object. In a speed estimation device for estimating the following, a counter that counts the output signal of the position detector, a first adder that receives the position detection value output from this counter as one input, and an output that is output from the first adder And a third gain multiplier for multiplying the position estimation error by a constant, and a third gain multiplier for calculating the difference between the output signal of the second gain multiplier and the force or torque for accelerating the object. An adder; a second integrator that integrates the output signal of the third adder to output a speed estimated value; and a first integrator that calculates the difference between this speed estimated value and the output signal of the first gain multiplier. 2 adder and 2nd adder A first integrator that integrates the output signal of ## EQU1 ## and outputs a position estimation value; and a quantizer that quantizes this position estimation value. The position estimation value output from this quantizer is the first estimation value. Speed estimation device, which is used as the other input of the adder. 2. A pulse-shaped digital signal output from a position detector according to a moving distance of an object and a force or torque for accelerating the object are input, and based on these, a moving speed of the object. In a speed estimation device for estimating a position detector, a first adder having an output signal of a position detector as one input, a counter for counting an output signal of the first adder, and an estimation of a position output from the counter First and second gain multipliers that multiply the error by a constant, respectively, and a third adder that calculates the difference between the output signal of the second gain multiplier and the force or torque for accelerating the object, A second integrator that integrates the output signal of the third adder and outputs a speed estimation value, and a second adder that calculates the difference between this speed estimation value and the output signal of the first gain multiplier And the output signal of the second adder The output signal of the position detector model is provided with a first integrator that divides and outputs a position estimate value, and a position detector model that outputs a pulse-shaped digital signal for each constant change amount of the position estimate value. To the other input of the first adder.