JP2001105358A - Joint drive control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contribute to a diversity of operations by ensuring high-precision joint drive control. SOLUTION: A torque command and the rotational speed of a drive motor 12 are determinative of the drive, either forward or reverse, of the drive motor 12. A forward drive friction estimation part 201 or reverse drive friction estimation part 202 of a friction estimating instrument 20 is selected accordingly to estimate the friction torque. The estimated friction torque and the torque command provide a motor torque command, by which the drive motor 12 is drive-controlled to control a joint 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot system mounted on, for example, a spacecraft to construct various structures in outer space, and more particularly, to a joint for rotatably connecting the robot arms and the like. The present invention relates to a joint drive control device used for drive control with an output torque of the joint.

[0002]

2. Description of the Related Art In the field of space development, a plan is underway to construct a space station in which humans can reside in outer space and to use this space station as a space base for maintenance and inspection of other spacecraft. I have. For such a space station construction concept, a robot system that carries out transportation and assembly work of building materials by remotely operating a work robot instead of a human being is effective.

Since the working robot arm in this robot system has a work environment of a space environment, the control stability of the joint drive system greatly affects the inertia of a work object which becomes a load during work. By receiving it, high responsiveness is required.

[0004] However, in the above-mentioned working robot arm, there are static friction, Coulomb friction, viscous friction, and rotational resistance proportional to the torque at the joint, and the friction applied according to the forward drive or reverse drive state. Due to the difference in torque, its responsiveness and robot characteristics such as followability are degraded.For example, a work object having various load inertia or an object having unknown inertia is grasped with high accuracy. Is difficult to perform.

The problem is that the environment of use is an extreme environment of a space environment, and it is highly likely that a single working robot can perform highly accurate work on various work objects having different load inertia. Being requested is an important issue.

[0006]

As described above, in the conventional joint drive system of the working robot arm, the friction torque applied according to the forward drive or reverse drive state is different, so that the load inertia is reduced. When a different work target is configured as a work target, there is a problem that robot characteristics such as grip performance are reduced.

The present invention has been made in view of the above circumstances, and has a simple configuration, realizes highly accurate joint drive control, and can contribute to diversification of work contents. The purpose is to provide.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a joint whose rotational force is transmitted via a speed reduction mechanism to control the driving of a drive motor, a rotational angle detecting means for detecting a rotational angle of the drive motor, A rotation speed command of the drive motor is generated based on the angle information and the detected rotation angle information of the rotation angle detection unit, and a rotation speed command based on the rotation command speed and the motor rotation speed based on the detected rotation angle information of the rotation angle detection unit. A torque generating means for generating a torque command, and a forward drive friction estimator and a reverse drive friction estimator having different friction parameters for estimating friction torque at the time of forward drive and reverse drive of the drive motor. From the rotation speed information based on the detected rotation angle information of the means and the torque command generated by the torque generating means,
Friction estimating means for judging the rotational state of the drive motor and selecting the forward drive friction estimating section and the reverse drive friction estimating section to estimate the friction torque; the friction torque estimated by the friction estimating means and the torque generation; Means for generating a motor torque command based on the torque command generated by the means and controlling the drive of the drive motor to control the joint.

According to the above construction, the friction estimating means determines the rotational state of the drive motor as either forward drive or reverse drive based on the torque command and the rotational speed of the drive motor. A driving friction estimating unit is selected, the friction torque is estimated, a motor torque command is obtained based on the estimated friction torque and torque command, and the drive motor is drive-controlled to control the joint. In this way, forward drive and reverse drive are determined, the friction torque in the forward drive or reverse drive is estimated, and a motor torque command is generated based on the estimated friction torque and torque command to drive the drive motor. And controlling the joints,
It is possible to increase the accuracy of robot characteristics such as responsiveness and followability, and even when the work target is large in load inertia, high-precision operation control is possible in almost the same way as those with small load inertia Becomes

[0010] Therefore, even when the load inertia is unknown, it is possible to secure stable follow-up control and quick responsiveness, and to perform a safe, highly reliable and highly accurate robot operation. It is possible to contribute.

Further, the present invention provides a joint whose driving force is transmitted via a speed reduction mechanism to control the driving of a driving motor, a rotation angle detecting means for detecting a rotation angle of the driving motor, and an output shaft of the joint. Torque detecting means for detecting the torque of
A rotation speed command of the drive motor is generated based on the target angle information and the detected rotation angle information of the rotation angle detection unit, and the rotation command speed and the motor rotation speed based on the detected rotation angle information of the rotation angle detection unit are calculated. A torque generating unit for generating a torque command; a forward drive friction estimating unit and a reverse drive friction estimating unit for estimating friction torque during forward drive and reverse drive of the drive motor; From the rotation speed information based on the rotation angle information and the torque command generated by the torque generation unit, the rotation state of the drive motor is determined, and the forward drive friction estimation unit and the reverse drive friction estimation unit are selected to perform forward drive. A friction estimating means for estimating a friction torque at the time of reverse driving, a torque detected by the torque detection sensor, a motor rotation speed based on detected rotation angle information of the rotation angle detection means, and the torque. Friction parameter setting means for identifying joint friction based on the torque command generated by the generation means and setting friction parameters of the forward drive friction estimation section and the reverse drive friction estimation section of the friction estimation means; and Means for generating a motor torque command based on the estimated friction torque and the torque command generated by the torque generating means and controlling the drive motor to drive the joint to control the joint. .

According to the above configuration, the friction parameter setting means determines the joint friction based on the detected torque of the torque detection sensor, the motor rotation speed based on the detected rotation angle information of the rotation angle detection means, and the torque command generated by the torque generation means. And sets the friction parameters of the forward drive friction estimator and the reverse drive friction estimator of the friction estimator. Then, the friction estimating means determines the rotational state of the drive motor as either forward drive or reverse drive based on the torque command and the rotational speed of the drive motor, and selects a forward drive friction estimator or a reverse drive friction estimator. Then, a friction torque is estimated based on the friction parameter, a motor torque command is obtained based on the estimated friction torque and torque command, and the drive motor is drive-controlled to control the joint. In this manner, the forward drive and the reverse drive are determined, the friction torque in the forward drive or the reverse drive is estimated based on the friction parameter, and a motor torque command is generated based on the estimated friction torque and the torque command to drive the motor. By controlling the motor to control the joints, it is possible to improve the accuracy of the robot characteristics such as its responsiveness and follow-up performance. Operation control with high accuracy can be performed in substantially the same manner as that with low inertia.

Therefore, even if the load inertia is unknown as a work object, it is possible to secure stable follow-up control and quick responsiveness, and to perform a safe, highly reliable and highly accurate robot work. It is possible to contribute.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a joint drive control apparatus according to an embodiment of the present invention.
At one of the input terminals, a target angle θR
Is input to the other input terminal.
Output terminals are connected. This rotation angle detection sensor 11
As shown in FIG. 2, it is assembled to a drive motor 12 of the joint 9, and the drive shaft of the drive motor 12 is connected to a joint output shaft 14 via a speed reduction mechanism 13.

The output terminal of the first subtractor 10 is connected to a speed profile generator 15, and the first subtracter 10 subtracts the motor rotation angle θm from the rotation angle detection sensor 11 and the target angle θR to perform a speed profile generation. 15 is output. The output terminal of the speed profile generator 15 is connected to one input terminal of the second subtractor 16, and generates a rotational speed command ωR based on the output information of the first subtractor 10 to perform the second subtraction. Table 16
Output to

The output terminal of the differentiator 17 is connected to the other input terminal of the second subtracter 16. The differentiator 17 is
The motor rotation angle θm from the rotation angle detection sensor 11 is differentiated to calculate a rotation speed ωm, which is output to the second subtractor 16.

The output terminal of the second subtracter 16 is connected to an integrator 18, which subtracts the input rotational speed command ωR and the rotational speed ωm generated by the differentiator 17 and outputs the result to the integrator 18. The output terminal of the integrator 18 is connected to one input terminal of an adder 19, and the output of the second subtractor 16 is multiplied by the gain KV to generate a torque command τR.
Output to

The adder 19 has the other input terminal connected to the output terminals of the forward drive friction estimator 201 and the reverse drive friction estimator 202 of the friction estimator 20. The forward driving friction estimating unit 201 and the reverse driving friction estimating unit 202 have their friction parameters set to different characteristics depending on the forward driving and the reverse driving, and the forward driving friction estimating unit 201 and the reverse driving friction estimating unit 202 The friction torque is estimated based on the torque command τR and the rotation speed ωm and output to the adder 19. The adder 19 calculates the friction torque information and the torque command τR.
Is added to calculate the motor torque command τmR to drive and control the drive motor 12 of the joint 9. The drive motor 12 drives (see FIG. 2) the joint output shaft 14 via a speed reduction mechanism 13 that forms the joint 9 in conjunction with the rotation of the drive motor 12 to control the operation of a robot arm (not shown).

In the friction estimator 20, fixed contacts a and b of a switch 203 are connected to input ends of a forward drive friction estimator 201 and a reverse drive friction estimator 202, and a movable contact c of the switch 203 has The output terminal of the rotation state determination unit 204 is connected. The rotation state determination unit 204 has one input terminal connected to the output terminal of the differentiator 17 and the other input terminal connected to the output terminal of the integrator 18. The rotation state determination unit 204 drives the drive motor 12 forward (the rotation direction of the drive motor is in the same direction as the torque) or reverse drive based on the rotation speed information from the differentiator 17 and the torque command τR from the integrator 18. (The rotational direction of the drive motor is opposite to the torque) is determined, and the movable contact c of the switch 203 is switched to the fixed contacts a and b.

The forward drive friction estimation section 201 and the reverse drive friction estimation section 202 estimate forward drive friction and reverse drive friction based on the rotation speed information and the torque command τR from the integrator, and add the friction torque. Output to the container 19.

In the above configuration, when the target angle θR is input to the first subtractor 10, the first subtractor 10
The motor rotation angle θm from the rotation angle detection sensor 11 is subtracted from the target angle θR, and a processing signal is output to the speed profile generation unit 15. The speed profile generation unit 15 generates a rotation speed command ωR based on the input processing information and outputs the rotation speed command ωR to the second subtractor 16. The second subtractor 16 subtracts the rotation speed ωm calculated by the differentiator 17 from the rotation speed command ωR and outputs the result to the integrator 18. The integrator 18 integrates the gain KV with the input speed command, calculates a torque command τR, and outputs the torque command τR to the adder 19.

At the same time, the friction estimator 20 receives the rotation speed ωm from the differentiator 17 and the torque command τR from the integrator 18 in the rotation state determination unit 204, and based on the rotation speed ωm and the torque command τR. The switch 204 controls the movable contact c of the switch 204 by determining the forward drive or the reverse drive to generate a switch switching signal. Here, the forward drive friction estimation unit 201 or the reverse drive friction estimation unit 202
Generates a friction torque based on the rotation speed ωm and the torque command τR, and outputs friction torque information to the adder 19.

The adder 19 receives friction torque information from the forward drive friction estimator 201 or the reverse drive friction estimator 202 of the friction estimator 20 and converts the friction torque information into a torque command τR from the integrator 18. The motor torque command τmR is calculated by the addition to drive and control the drive motor 12 of the joint 9.

The drive of the drive motor 12 of the joint 9 is controlled based on the input motor torque command τmR, and the torque of the drive motor 12 is transmitted to the joint output shaft 14 via the speed reduction mechanism 13. The output torque of the joint output shaft 14 is set to a predetermined value.

As described above, the rotational speed ωm of the drive motor 12
The forward drive friction estimator 201 or the reverse drive friction estimator 202 of the friction estimator 20 estimates the friction torque in the forward drive or the reverse drive based on the torque command τR and compensates the friction torque in the forward drive or the reverse drive. By controlling the driving of the drive motor 12, the joint output shaft follows the load with a predetermined torque even in the case where the work object has a large load inertia, almost in the same manner as the one with a small load inertia. Can be controlled.

That is, the friction estimator 20 estimates the friction torque in the forward drive or the reverse drive to compensate for the friction torque, so that the so-called damping proportional to the static friction, Coulomb friction, viscous friction, and load torque of the joint 9 is performed. The drive control of the joint 9 in consideration of the elements is executed.

As described above, the joint drive control device determines whether the drive motor 12 is to be driven forward or backward based on the torque command and the rotation speed of the drive motor 12, and determines the forward drive friction of the friction estimator 20. The estimating unit 201 or the reverse drive friction estimating unit 202 is selected, the friction torque is estimated, a motor torque command is obtained based on the estimated friction torque and torque command, and the drive motor 12 is driven to control the joint 9. It was configured to be.

According to this, the generation of a highly accurate motor torque command according to the forward drive and reverse drive states is realized, thereby improving the robot characteristics such as responsiveness and followability. Therefore, even when the work target has a large load inertia, highly accurate operation control can be realized in substantially the same manner as that with a small load inertia. As a result, even if the load inertia is unknown as a work target, stable follow-up control and quick response can be ensured, and a safe, highly reliable and highly accurate robot work is realized. be able to.

The present invention is not limited to the above embodiment, and may be configured as shown in FIG.
However, in FIG. 3, the same portions as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the detailed description thereof will be omitted for convenience.

That is, the friction estimator 20 is provided with a forward drive friction estimator 205 and a reverse drive friction estimator 206 whose friction parameters can be variably adjusted.
The output terminal of the friction parameter adjusting unit 21 is connected to the signal input terminal of the reverse drive friction estimating unit 206 and the signal input terminal of the reverse drive friction estimating unit 206. The output end of the joint friction identification calculation unit 22 is connected to the friction parameter adjustment unit 21.

The output terminals of the integrator 18 and the differentiator 17 and the output terminal of the torque detection sensor 23 are connected to the joint friction identification calculating unit 22. The torque detection sensor 23 is attached to the joint output shaft 14, for example, and detects a load torque of the joint output shaft 14 and outputs the torque to the joint friction identification calculation unit 22. The joint friction identification calculation unit 22
A friction identification signal is generated based on the torque command τR from the integrator 18, the rotation speed ωm from the differentiator 17 and the load torque τP of the torque detection sensor 23 and output to the friction parameter adjustment unit 21.

The friction parameter adjusting section 21 generates a parameter setting signal based on the input friction identification signal and generates the forward driving friction estimating section 205 and the reverse driving friction estimating section 206.
And sets the friction parameters of the forward drive friction estimator 205 and the reverse drive friction estimator 206. At this time, the forward drive friction estimation section 205 and the reverse drive friction estimation section 206 are switched and set according to the forward drive or reverse drive state via the rotation state determination section 204 and the switch 203, and one of them is selected, and the friction is determined. The parameter, that is, the friction torque is estimated, and the estimated friction torque is output to the adder 19. As a result, it is possible to estimate the friction torque with higher accuracy, and it is possible to achieve higher accuracy of the robot characteristics such as responsiveness and followability. In the above embodiment, the joint output shaft 14 is used as the joint structure. Although the description has been given of the case where it is configured to be directly connected to the speed reduction mechanism 13, the present invention is not limited to this, and is also applicable to a joint structure in which a spring mechanism is interposed between a joint output shaft and a speed reduction mechanism, for example. A substantially similar effect can be expected.

Therefore, the present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0035]

As described in detail above, according to the present invention, a highly accurate joint drive control can be realized with a simple configuration.
A joint drive control device that can contribute to diversification of work content can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a joint drive control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a joint in FIG. 1;

FIG. 3 is a block diagram showing a joint drive control device according to another embodiment of the present invention.

[Explanation of symbols]

 9 ... joints. 10 1st subtracter. 11 A rotation angle detection sensor. 12 ... drive motor. 13 ... reduction gear mechanism. 14 Joint output shaft. 15 Speed profile generator. 16 Second subtractor. 17 ... Differentiator. 18 ... Integrator. 19 ... Adder. 20 ... friction estimator. 201: forward drive friction estimation unit. 202 ... reverse drive friction estimation unit. 203 ... switch. 204: rotation state determination unit. 205 ... forward drive friction estimation unit. 206: reverse drive friction estimation unit. 21 ... friction parameter adjustment unit. 22 ... joint friction identification calculation unit. 23 ... torque detection sensor.

Claims (3)

[Claims] 1. A joint whose driving force is transmitted via a speed reduction mechanism to control the driving force of a driving motor, rotation angle detecting means for detecting a rotation angle of the driving motor, target angle information and the rotation angle detecting means. A rotation speed command for the drive motor based on the detected rotation angle information, and a torque generation for generating a torque command based on the rotation command speed and the motor rotation speed based on the detected rotation angle information of the rotation angle detection means. Means, a forward drive friction estimator and a reverse drive friction estimator having different friction parameters for estimating the friction torque at the time of forward drive and reverse drive of the drive motor, and based on the detected rotation angle information of the rotation angle detection means. From the rotational speed information and the torque command generated by the torque generating means, the rotational state of the drive motor is determined, and the forward drive friction estimator and the reverse drive friction estimator are selected to determine the friction. Friction estimating means for estimating a torque, a motor torque command is generated based on the friction torque estimated by the friction estimating means and a torque command generated by the torque generating means, and drive control of the drive motor is performed to control the joint. Control means for controlling the joint drive. 2. A joint whose driving force is transmitted through a speed reduction mechanism to control the driving force of the driving motor, a rotation angle detecting means for detecting a rotation angle of the driving motor, and a torque of an output shaft of the joint. A rotation speed command of the drive motor based on the target angle information and the detected rotation angle information of the rotation angle detection unit, and the rotation command speed and the detected rotation angle information of the rotation angle detection unit. And a torque generating means for generating a torque command from the motor rotation speed based on: a forward drive friction estimator and a reverse drive friction estimator for estimating the friction torque at the time of forward drive and reverse drive of the drive motor,
The rotation state of the drive motor is determined from rotation speed information based on rotation angle information detected by the rotation angle detection unit and a torque command generated by the torque generation unit, and the forward drive friction estimation unit and the reverse drive friction estimation are performed. A friction estimating means for selecting a portion to estimate a friction torque at the time of forward drive and reverse drive; a detected torque of the torque detection sensor, a motor rotation speed based on detected rotation angle information of the rotation angle detection means, and the torque generation means. Frictional parameter setting means for identifying the joint friction based on the torque command generated in step 1 and setting the friction parameters of the forward driving friction estimating section and the reverse driving friction estimating section of the friction estimating means, and the friction estimating means. A motor torque command is generated based on a friction torque and a torque command generated by the torque generating means, and drive control of the drive motor is performed to generate the motor torque command. Joint driving control device being characterized in that and means for controlling. 3. The joint drive control device according to claim 1, wherein an output shaft of the joint is elastically deformable connected to the speed reduction mechanism via a spring mechanism.