JPH0556527B2 - - Google Patents

Abstract

PURPOSE:To execute exactly a position control by bringing a motor to a driving control so as to compensate a variation of a frictional force, in accordance with the variation of the frictional force of a power transfer path. CONSTITUTION:A controller 51 derives a power transfer loss (h) for showing a frictional force in a power transfer path 2, from sensor detected values (f), (g), and also, a friction compensating controller 10 calculates and outputs a compensating command (i) for briging a motor 1 to a driving control so as to compensate the power transfer loss (h). Accordingly, a driving command (d) and a compensating command (i) are inputted and the motor 1 is driven to rotate. In this case, when the frictional force in the power transfer path is varied, a value of the compensating command (i) is varied in accordance with it, therefore, even if the frictional force is varies, the motor 1 is brought to a driving control so as to compensate it, and to a driving object 3, an optimum driving force required for moving it exactly to a target position is always transmitted. In this way, a position control is executed exactly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position control method with added friction compensation that can precisely control the position of a servo device having a power transmission path using a wire.

[Conventional technology]

In a work robot, the power of a motor is transmitted to a driven object via a power transmission path using a wire to operate the driven object. In this case, since the wire comes into contact with a pulley or the like and frictional force is generated in the power transmission path, position control is performed to compensate for the influence of the frictional force to ensure accurate positioning of the driven object.

Such a conventional position control method will be explained with reference to FIG. As shown in the figure, the power of the motor 1 is transmitted to a driven object 3 via a power transmission path 2 using a wire, and the driven object 3 operates. The operating position of the driven object 3 is detected by a position sensor 4. On the other hand, the controller 5 calculates the deviation c between the detected position signal a detected by the position sensor 4 and the target position signal b indicating the target position of the driven object 3. The position control gain adjuster 6 calculates and outputs a drive command d for driving and controlling the motor 1 so that the deviation c becomes zero. Further, the friction compensation command unit 7 outputs a compensation command e for driving and controlling the motor 1 so as to compensate for the friction force A generated in the power transmission path. Therefore, the motor 1 is driven to rotate upon receiving the drive command d and the compensation command e. As a result, the driving force required to accurately move the driven object 3 to the target position is reduced to B
Then, the motor 1 outputs a motor power of A+B, and even if the frictional force A occurs, the necessary driving force B is input to the driven object 3. In this way, the position of the driven object 3 can be controlled by compensating for the influence of frictional force.

[Problem that the invention seeks to solve]

By the way, in the conventional control method described above, the frictional force in the power transmission path 2 is assumed to be constant, and a constant value of the compensation command e is set in advance. However, when the driven object 3 moves, the path of the wire in the power transmission path 2 and the contact state between the wire and the pulley change, and the frictional force generated in the power transmission path 2 actually changes. Despite this, the value of the compensation command e is constant, so when the frictional force increases, the driving force input to the driven object 3 decreases, and conversely, when the frictional force decreases, the driving force input to the driven object 3 decreases. increase. As a result, the conventional technology cannot cope with fluctuations in frictional force, and the position control accuracy of the driven object 3 is low.

In view of the above-mentioned prior art, the present invention provides a position control method with added friction compensation that can perform friction compensation in response to fluctuations in frictional force occurring in the power transmission path, thereby enabling highly accurate positioning control. The purpose is to

[Means for solving problems]

The gist of the present invention to achieve the above object is to control the position of a servo device that transmits the power of a motor to a driven target via a power transmission path using a wire to operate the driven target. In a position control method that drives and controls the motor so that the deviation from the target position is zero, the power on the inlet and outlet sides of the power transmission path is detected, and the power transmission loss in the power transmission path is determined from both detected values. The purpose of this invention is to further control the drive of the motor to compensate for this power transmission loss.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings. Note that the same parts as in the prior art are given the same numbers to simplify the explanation.

FIG. 1 shows a first embodiment of the invention. The driven object 3 receives power from the motor 1 via the power transmission path 2 and operates. The position control gain adjuster 6 of the controller 51 calculates and outputs a drive command d that makes the deviation c determined from the detected position signal a of the position sensor 4 indicating the position of the driven object 3 and the target position signal b to zero. .

Furthermore, in this embodiment, force sensors 8 and 9 are provided on the input side and the output side of the power transmission path 2, respectively. As the force sensors 8 and 9, a type that measures the tension of the wire in the power transmission path 2 using a strain gauge, or a type that measures the tension of the wire using the displacement of a cantilever may be used. Then, the sensor detection value f indicating the power on the input side and the sensor detection value g indicating the power on the output side are input to the controller 51.

The controller 51 determines a power transmission loss h indicating the frictional force in the power transmission path 2 from the sensor detected values f and g. Further, the friction compensation controller 10 calculates and outputs a compensation command i for driving and controlling the motor 1 so as to compensate for the power transmission loss h. Therefore, the motor 1 is rotated by receiving the drive command d and the compensation command i. In this case, when the frictional force in the power transmission path fluctuates, the compensation command i
As the value of changes, the drive of motor 1 is controlled to compensate for variations in frictional force, and the drive target 3 always receives the optimal driving force necessary to accurately move it to the target position. Reportedly. Accurate position control is thus achieved.

FIG. 2 shows a second embodiment of the invention. In this embodiment, the friction compensation controller 1 of the controller 52
1 is a gain adjustment signal j that adjusts the gain of the position control gain adjuster 6 according to the value of the power transmission loss h.
Output. In other words, if the gain of the position control gain adjuster 6 is Kp (1 + α × Loss) Kp: initial value of position control gain α: friction compensation coefficient Loss: amount of power transmission loss, the above Loss is controlled by the gain adjustment signal j. . Therefore, according to the drive command k output from the position control gain adjuster 6, the motor 1 can be drive-controlled so as to make the deviation c zero and compensate for the power transmission loss. Note that other parts are the same as in the first embodiment. In this way, accurate position control is also possible in this embodiment.

It goes without saying that the present invention is applicable not only to work robots but also to other servo devices having power transmission paths using wires.

〔Effect of the invention〕

As specifically explained above in conjunction with the embodiments, according to the present invention, the drive of the motor is controlled to compensate for variations in the frictional force in the power transmission path, so accurate position control is achieved. can do.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the invention, FIG. 2 is a block diagram showing a second embodiment of the invention, and FIG. 3 is a block diagram showing a prior art. In the drawing, 1 is a motor, 2 is a power transmission path, 3 is a driven object, 4 is a position sensor, 5, 51, 52 are controllers, 6 is a position control gain adjuster, 7 is a friction compensation command device, 8, 9 are Force sensor, 10, 11 are friction compensation controllers, a is a detected position signal, b is a target position signal, c is a deviation, d is a drive command, e is a compensation command, f, g are sensor detection values, h is power transmission loss,
i is a compensation command, j is a gain adjustment signal, and k is a drive command.

Claims (1)

[Claims] 1. In order to control the position of a servo device that has a motor as a power source, a power transmission path that transmits the power of the motor using a wire, and a drive target that operates by the transmitted power, A drive system that detects the operating position of the motor using a position sensor, calculates the deviation between the detected position signal detected by the position sensor and the target position signal that indicates the target position of the driven object, and controls the motor so that this deviation becomes zero. In a position control method that calculates a command and inputs the drive command to the motor, force sensors are provided on the input side and output side of the power transmission path, respectively, and the power transmission in the power transmission path is determined based on the detected values of both force sensors. Position control with friction compensation, characterized in that a loss is determined, a compensation command is calculated to drive and control the motor to compensate for this power transmission loss, and this compensation command is input to the motor in addition to the drive command. method. 2. In order to control the position of a servo device that has a power transmission path that transmits the power of the motor using a motor as a power source and a wire, and a driven object that operates by the transmitted power, a position sensor is used to measure the operating position of the driven object. At the same time, the deviation between the detected position signal detected by the position sensor and the target position signal indicating the target position of the driven object is calculated, and a drive command to drive the motor is calculated so that this deviation becomes zero. In a position control method in which a drive command is input to the motor, force sensors are provided on the input side and output side of the power transmission path, and the power transmission loss in the power transmission path is determined from the detected values of both force sensors, and further detected. It is characterized by adjusting the gain to compensate for power transmission loss when calculating the drive command from the deviation between the position signal and the target position signal, and inputting the drive command obtained by adjusting the gain to the motor. Position control method with added friction compensation.