JP2014136260A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device capable of compensating for an angular transmission error without the need to adjust each robot and without using an external sensor.SOLUTION: A speed-command generation unit 12 generates a speed command using a present position of a motor and a position command. A speed calculation unit 15 calculates a present speed of the motor. A current command generation unit 13 generates a current command using the present speed of the motor and the speed command. An adaptive estimation unit 16 generates an angular transmission error by adaptively estimating a frequency, an amplitude, and a phase of a periodic function indicating the angular transmission error of a reduction gear. An error compensation unit 18 generates a compensated current command that compensates for an angular transmission error component of the reduction gear from the current command. A torque command generation unit 14 generates a torque command using the present current and the compensated current command, and outputs the torque command to the motor. By so configuring, it is unnecessary to adjust an individual robot and to provide an external sensor when compensating for the angular transmission error.

Description

  The present invention relates to a control device that compensates for an angle transmission error of a reduction gear.

  When the tip of a manipulator such as an arc welding robot is moved linearly, periodic vibration may occur, which may adversely affect control accuracy. The vibration is considered to be caused by an angle transmission error of a speed reducer provided on each axis of the manipulator. As a method for compensating for such an angle transmission error, a method is known in which the angle transmission error is modeled by a mathematical expression and compensated. For example, Patent Document 1 describes a method in which an angle transmission error is modeled as a sine wave, and its amplitude and phase are identified from a torque command value to a motor, a motor angle command, and a hand position of the robot. Yes. Patent Document 2 describes a method of determining an angle transmission error correction amount in consideration of the rotation direction of a motor and the load weight of a robot. Patent Document 3 describes a control system design method in which an angle transmission error is modeled by three elements of a gear ratio variation of a reduction gear, a gear friction, and a gear output angle variation, and these are taken into consideration.

  In addition, as another method for compensating for the angle transmission error, a method of performing compensation using an actually measured value of the angle transmission error is also known. As the method, Patent Document 4 describes a method of compensating for errors by storing the power transmission characteristics of the speed reducer during deceleration and reflecting the information on the input torque to the motor.

JP 2011-212823 A JP 2010-149203 A JP-A-10-243676 Japanese Patent Laid-Open No. 1-210443

  The approach using the actual measurement values described in Patent Document 4 requires the actual measurement values of the power transmission characteristics for each robot or each speed reducer, so that there is a problem that the cost of data measurement is large and not practical. .

  On the other hand, with the modeling approaches described in Patent Documents 1 to 3, the cost for data measurement is less than that using measured values. However, there are problems that the mathematical formula model becomes too complicated and that parameter identification work for each individual takes time. Specifically, in Patent Document 1, the angle transmission error is modeled as a sine wave, but in order to identify the amplitude and phase, an external sensor for measuring the hand position of the robot is necessary. In addition, since it is necessary to perform measurement for each individual robot, there is a problem that the cost of parameter identification is high. Patent Document 2 describes a method of correcting a change in the undulation amplitude of an angle transmission error due to a change in the load weight of the robot and the motor rotation direction. In this method, since the map of the relationship between the load weight and the amplitude is created, it is necessary to operate the robot with a plurality of load weight patterns, and there is a problem that the cost of parameter identification is high. In Patent Document 3, the angle transmission error is divided into three elements, and each is modeled by a mathematical formula. However, identification is not easy because the model is complicated. Further, the model does not take into consideration that the amplitude of the swell changes, and there is a problem that a sufficient correction effect may not be obtained.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a control device that does not require adjustment for each robot and can compensate for an angle transmission error without using an external sensor. And

In order to achieve the above object, a control device according to the present invention is a control device that controls a manipulator having a plurality of arms connected by joints driven by a motor via a speed reducer, and a current position of the motor; A speed command generation unit that generates a speed command using the motor position command, a speed calculation unit that calculates the current speed of the motor from the current position of the motor, a current speed calculated by the speed calculation unit, and a speed command The current command generation unit that generates a current command using the current speed and the current speed calculated by the speed calculation unit are used to adaptively estimate the period, amplitude, and phase of a periodic function that indicates the angular transmission error of the reducer. By using the adaptive estimation unit that generates the angle transmission error and the angle transmission error generated by the adaptive estimation unit, a current command that compensates for the angular transmission error component of the reducer is generated from the current command. An error compensating unit, and the current current of the motor, generates a torque command by using the current command error compensation unit is generated, but with the torque command generator outputting a motor.
With this configuration, by modeling the angular transmission error of the speed reducer with a periodic function whose amplitude, frequency, and phase are unknown, the unknown parameters can be estimated adaptively using only the motor speed, and the angular transmission The error can be compensated. As a result, the angle transmission error can be compensated without requiring adjustment for each robot and without using an external sensor. In addition, it is possible to reduce the identification cost of parameters, which has been a problem with the conventional approach using a mathematical model.

In the control device according to the present invention, the periodic function may be a trigonometric function.
Such a configuration facilitates analysis of a periodic function.

In the control device according to the present invention, the adaptive estimation unit multiplies the first multiplier that multiplies the motor speed by the cosine value of the phase, the motor speed, and the negative value of the sine value of the phase. Amplitude and frequency are obtained by performing an operation according to a transfer function matrix corresponding to a transfer function related to a motor axis on a vector having each element of the multiplication result of the second multiplier and the first and second multipliers. A matrix multiplier for generating a vector having each element as an element, an integrator for calculating a phase obtained by integrating the frequency generated by the matrix multiplier, a cosine value of the phase calculated by the integrator, and a first multiplier The cosine calculator that is input to the negative value of the sine value of the phase calculated by the integrator, the sine calculator that is input to the second multiplier, the amplitude generated by the matrix multiplier, and the cosine calculator The angle transmission error is calculated by multiplying the calculated cosine value. A third multiplier for generating a may be provided.
With such a configuration, the unknown parameter can be adaptively estimated by using a matrix multiplier or the like.

The control apparatus according to the present invention further includes a changing unit that changes the angle transmission error by multiplying the angle transmission error generated by the adaptive estimation unit by a parameter that is greater than 0 and equal to or less than 1, and the error compensation unit includes a current A current command that compensates for the angle transmission error component after the change by the changing unit may be generated from the command.
With such a configuration, it is possible to effectively compensate for the angle transmission error by appropriately setting parameters used by the changing unit.

  According to the control device of the present invention, it is possible to compensate for the angle transmission error without requiring adjustment for each robot and without using an external sensor.

The block diagram which shows the structure of the industrial robot by Embodiment 1 of this invention. The block diagram which shows the structure of the adaptive estimation part by the embodiment The flowchart which shows operation | movement of the control apparatus by the embodiment

  Hereinafter, a control device according to the present invention will be described using embodiments. In the following embodiments, components and steps denoted by the same reference numerals are the same or equivalent, and repetitive description may be omitted.

(Embodiment 1)
A control apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. The control device according to the present embodiment compensates the angle transmission error by modeling the angle transmission error with a periodic function and adaptively estimating the amplitude, frequency, and phase of the function.

  FIG. 1 is a block diagram showing a configuration of an industrial robot 100 according to the present embodiment. The industrial robot 100 according to the present embodiment includes a control device 1 and a manipulator 2. The control device 1 controls a manipulator 2 having a plurality of arms connected by a joint driven by a motor. In the manipulator 2, each motor and the arm are connected via a speed reducer. A hand effector (end effector) may be provided at the tip of the arm connected in series. The manipulator 2 may be, for example, a manipulator of a vertical articulated robot or a manipulator of a horizontal articulated robot. The number of axes of the manipulator 2 is not limited. Moreover, the control apparatus 1 may control the manipulator 2 by a teaching playback system, or may control the manipulator 2 by an autonomous system. The industrial robot 100 according to the present embodiment may be, for example, a transfer robot, a welding robot, an assembly robot, a painting robot, or other uses. It may be a robot.

  As shown in FIG. 1, the control device 1 includes a position command generation unit 11, a speed command generation unit 12, a current command generation unit 13, a torque command generation unit 14, a speed calculation unit 15, and an adaptive estimation unit. 16, a change unit 17, and an error compensation unit 18.

  The position command generator 11 generates a motor position command and passes it to the speed command generator 12. The position command generation unit 11 may calculate the position of the motor by using, for example, teaching information and pass the position command indicating the position to the speed command generation unit 12. The position of the motor may be strictly the angle of the motor.

  The speed command generation unit 12 generates a speed command using the current position of the motor and the position command of the motor. The position command is generated by the position command generation unit 11 as described above. The speed command generation unit 12 may receive the current position from, for example, a motor position detector of the manipulator 2. The position detector may be an encoder, for example.

  The current command generation unit 13 generates a current command using the current speed of the motor calculated by the speed calculation unit 15 and the speed command generated by the speed command generation unit 12 for the motor. Strictly speaking, the motor speed may be the rotational speed of the motor, that is, the angular speed.

The torque command generator 14 generates a torque command using the current current of the motor and the current command generated by the error compensator 18 for the motor, and outputs the torque command to the motor. As a result, the motor operates to have a torque according to the torque command. For example, the torque command generator 14 may receive the current from a current detector that detects the current of the motor.
The feedback control process by the speed command generation unit 12, the current command generation unit 13, and the torque command generation unit 14 is already known as a servo controller process, and detailed description thereof is omitted. In the servo controller, for example, general PID control or the like is performed.

  The speed calculation unit 15 calculates the current speed of the motor from the current position of the motor. Specifically, the speed calculator 15 may calculate the current speed of the motor by differentiating the current position of the motor with respect to time. Since the current speed of the motor is used in the current command generation unit 13, the speed calculation unit 15 is equal to or shorter than the cycle in which the current command generation unit 13 generates the current command. Is preferably calculated.

  The adaptive estimation unit 16 uses the current speed calculated by the speed calculation unit 15 to adaptively estimate the period, amplitude, and phase of a periodic function indicating the angle transmission error of the speed reducer, thereby reducing the angle transmission error. Generate. That is, the angle transmission error is modeled by a periodic function, and the adaptive estimation unit 16 adaptively estimates the period, amplitude, and phase, which are unknown parameters of the function. The function may be a trigonometric function, a sawtooth wave, a triangular wave, a rectangular wave, or another periodic function. In the present embodiment, the case where this function is a trigonometric function, that is, the case where the angle transmission error is modeled by a trigonometric function will be mainly described. Since the angle transmission error estimated by the adaptive estimation unit 16 is used to compensate for the current command generated by the current command generation unit 13, the adaptive estimation unit 16 generates the current command by the current command generation unit 13. It is preferable to estimate the angle transmission error with the same period as the period to be performed or with a period shorter than that.

  FIG. 2 is a block diagram illustrating an example of a detailed configuration of the adaptive estimation unit 16. The adaptive estimator 16 includes a first multiplier 21, a second multiplier 22, a matrix multiplier 23, an integrator 24, a cosine calculator 25, a sine calculator 26, and a third multiplier. 27.

First multiplier 21 multiplies the speed omega _M of the motor is calculated by the cosine calculator 25, the cosine of the phase alpha and "cos (alpha)". The multiplication result y ₁ = ω _M × cos (α) is input to the matrix multiplier 23.
Second multiplier 22 multiplies the speed omega _M of the motor is calculated by a sine calculator 26, the negative value of the sine of the phase alpha and "-sin (alpha)". The multiplication result y ₂ = −ω _M × sin (α) is input to the matrix multiplier 23.

The matrix multiplier 23 corresponds to a vector (y ₁ y ₂ ) ^t having the multiplication results y ₁ and y ₂ of the first and second multipliers 22 as elements, and a transfer function P (s) related to the motor axis. The vector (θ ₁ θ ₂ ) ^t having the amplitude θ ₁ and the frequency θ ₂ in each element is generated by performing an operation according to the transfer function matrix C (s) to be performed. The amplitude θ ₁ is input to the third multiplier 27. The frequency θ ₂ is input to the integrator 24. The transfer function P (s) related to the motor shaft and the transfer function matrix C (s) corresponding thereto will be described later.

The integrator 24 integrates the frequency θ ₂ generated by the matrix multiplier 23. The integration result is the phase α. That is, the integrator 24 will calculate the phase α by integrating the frequency theta _2.

The cosine calculator 25 calculates the cosine value cos (α) of the phase α calculated by the integrator 24 and inputs it to the first multiplier 21. The cosine value “cos (α)” is also input to the third multiplier 27.
The sine calculator 26 calculates the negative value “−sin (α)” of the sine value of the phase α calculated by the integrator 24, and inputs it to the second multiplier 22.

The third multiplier 27 multiplies the amplitude θ ₁ generated by the matrix multiplier 23 and the cosine value cos (α) calculated by the cosine calculator 25 to thereby give an angle transmission error d _est = θ ₁ × cos ( α) is generated. This angle transmission error d _est is an angle transmission error that is finally adaptively estimated.

The changing unit 17 changes the angle transmission error by multiplying the angle transmission error d _est (t) generated by the adaptive estimation unit 16 by a parameter c that is greater than 0 and equal to or less than 1. The change of the angle transmission error is performed in order to adjust the degree of compensation of the angle transmission error. Therefore, it is preferable that the value c of this parameter can be changed so that the user can arbitrarily set it. The parameter c may be a parameter greater than 0 and less than 1, or a parameter greater than or equal to 0 and less than or equal to 1. When the parameter c includes 1, the change by the change unit 17 includes identity conversion. The angle transmission error after the change by the changing unit 17 is used as the feedforward compensation amount.

The error compensator 18 uses the angle transmission error c × d _est (t) generated by the adaptive estimator 16 and changed by the changing unit 17, and compensates for the angular transmission error component of the reduction gear from the current command. Is generated. Thereby, the angle transmission error can be compensated in a feed-forward manner. Here, the compensation of the angle transmission error component means that the motor is rotated by a torque command corresponding to the compensated current command, and the rotation is transmitted to the arm via the speed reducer having the angle transmission error. In other words, the angle transmission error of the speed reducer is canceled out. Therefore, by using the current command compensated for the angle transmission error component, the vibration of the tip of the manipulator 2 due to the angle transmission error is eliminated or reduced. The error compensator 18 may be, for example, an adder that adds the changed angle transmission error or a subtracter that subtracts the changed angle transmission error to the current designation generated by the current command generator 13. Good. In the present embodiment, the case where the error compensator 18 is an adder will be mainly described.

  1 shows a case where one torque command is output to the manipulator 2 and one current position or current is received from the manipulator 2, but this is for convenience of explanation, and the control device 1 The torque command may be output by the number of axes of the manipulator 2, that is, the number of motors, and the current position and current may be received by that number. That is, the process of the control device 1 may be performed for each motor.

Here, the adaptive estimation processing by the adaptive estimation unit 16 will be described.
Consider the following transfer function P (s) as a uniaxial model of a manipulator.
ω _M (s) = P (s) τ (s)
Here, ω _M (s) is the Laplace transform of the rotational angular velocity ω _M (t) of the motor, τ (s) is the Laplace transform of the input torque τ (t), and the transfer function P (s) is The following equation is obtained. This transfer function P (s) is already known as a transfer function of a uniaxial model of a manipulator.

In standard robot control, torque τ and angular velocity ω _M are acquirable quantities, and each parameter in the above formula is as follows.
J _L : Load inertia moment J _M : Load inertia moment of motor N: Reduction ratio D ₀ : Damping coefficient (damping ratio)
K ₀ : Spring constant

The above equation is a two-inertia model that takes into account the rigidity of the speed reducer, but does not consider the angle transmission error. When the angle transmission error is taken into consideration, the model to be controlled is as follows.
ω _M (s) = P (s) (τ (s) −d (s))
Here, d (s) is Laplace transform of the angle transmission error d (t). In the present embodiment, the angular transmission error d (t) is represented by a trigonometric function that is a periodic function. That is, it is assumed that the angle transmission error d (t) is expressed by the following equation.

Where θ _d is the amplitude of the trigonometric function, ω _d is the frequency, α _d (0) is the phase, and these are unknown parameters. The frequency is strictly an angular frequency. In addition, α _d (0) may be referred to as a phase, and α _d (t) = ω _d × t + α _d (0) may be referred to as a phase.

The following description of a method for compensating for the input torque tau (t) to cancel the vibrations appearing on the velocity omega _M under the influence of the angular transmission error d (t), will be described with reference to FIG. As can be seen from FIG. 2, the only external input required to adaptively estimate the angular transmission error d (t) is the angular velocity ω _M (t) of the motor. Therefore, the adaptive estimation unit 16 can estimate the angle transmission error without using an external sensor.

ここで、θ_１（ｔ）、θ_２（ｔ）、α（ｔ）は、それぞれ角度伝達誤差ｄ（ｔ）の振幅θ_ｄ、周波数ω_ｄ、位相α_ｄ（ｔ）＝ω_ｄ×ｔ＋α_ｄ（０）の推定値である。これらの推定値が真値に近づいていくことにより、角度伝達誤差の推定値ｄ_ｅｓｔ（ｔ）が、より正確な値となる。したがって、そのｄ_ｅｓｔ（ｔ）を用いて、入力トルクτ（ｔ）に対する角度伝達誤差の影響を打ち消すことによって、角度伝達誤差の補償を実現することができる。そのため、ロボットの個体ごと、または減速機ごとのパラメータ調整を行うことなく、適応推定処理のみによって、角度伝達誤差を補償することができるようになる。 In FIG. 2, the estimated value d _est (t) of the angle transmission error is represented by the following equation.

Here, θ ₁ (t), θ ₂ (t), and α (t) are the amplitude θ _d , frequency ω _d , and phase α _d (t) = ω _d × t + α _{d of the} angle transmission error d (t), respectively. This is an estimated value of (0). As these estimated values approach the true value, the estimated value d _est (t) of the angle transmission error becomes a more accurate value. Therefore, compensation of the angle transmission error can be realized by using d _dest (t) to cancel the influence of the angle transmission error on the input torque τ (t). Therefore, the angle transmission error can be compensated only by the adaptive estimation process without adjusting the parameters for each robot or each speed reducer.

The parameter update process in the adaptive estimation unit 16 shown in FIG. 2 is performed as follows. First, using the angular velocity ω _M (t) that is the output of the system, the first and second multipliers 21 and 22 generate internal signals y ₁ (t) and y ₂ (t) as follows: To do.
y ₁ (t) = ω _M (t) × cos (α (t))
y ₂ (t) = − ω _M (t) × sin (α (t))

Thereafter, in the matrix multiplier 23, a vector (y ₁ (t) y ₂ (t)) ^t having y ₁ (t) and y ₂ (t) as elements is set in accordance with the transfer function matrix C (s). By performing the calculation, a vector (θ ₁ (t) θ ₂ (t)) ^t having the amplitude θ ₁ and the frequency θ ₂ as elements is generated. That is, the following equation is obtained.
(Θ ₁ (t) θ ₂ (t)) ^t = C (s) × (y ₁ (t) y ₂ (t)) ^t

However, since C (s) is not Laplace-transformed but is Laplace transformed, for each element of (y ₁ (t) y ₂ (t)) ^t , the transfer function matrix C An operation according to (s), that is, an operation according to each element of the transfer function matrix C (s) is performed. The calculation may be, for example, integration, filtering, or other calculation. For example, when “1 / s” is included in an element of C (s), integration may be performed as an operation corresponding to the element. The transfer function matrix C (s) is expressed by the following equation.
C (s) = C ₁ (s) G ⁻¹ (θ ₂ )
Here, C ₁ (s) and G (θ ₂ ) are expressed as follows.

Note that g ₁ , g ₂ , a, and b are real design parameters larger than 0, respectively, and are preferably designed so that the poles of the closed-loop system including the adaptive estimation unit 16 are arranged at desired positions. . That is, it is preferable that these design parameters are designed so that the convergence of the adaptive estimation becomes faster. Also, P (s) is the transfer function of the above with respect to the axis of the motor, for _{P R (θ 2), P} I (θ 2) or the like, is as follows. In the following equation, Re [] and Im [] indicate the real part and imaginary part of the complex function, respectively. Also, _{P R} (θ _2), for use theta ₂ is at _{P I} (θ _2), and those using theta ₂ which are calculated at the previous one.
P _R (θ ₂ ) = Re [P (jθ ₂ )]
P _I (θ ₂ ) = Im [P (jθ ₂ )]

Here, a case has been described in which an operation that is equal to the multiplication of the vector (y ₁ (t) y ₂ (t)) ^t and the transfer function matrix C (s) is performed, but the result is the same. If present, y ₁ (t), y ₂ (t), θ ₁ (t), and θ ₂ (t) may not be treated as vector elements, and the transfer function matrix C (s) is treated as a matrix. It goes without saying that it is not necessary.

The estimated value α (t) of the phase is obtained by integrating θ ₂ (t) with the integrator 24. The cosine calculator 25 calculates a cosine value cos (α (t)) of the estimated value α (t) of the phase, and the sine calculator 26 calculates the sine value of the estimated value α (t) of the phase. A negative value −sin (α (t)) is calculated, and the internal signals y ₁ (t) and y ₂ (t) are updated using them. Finally, the third multiplier 27 multiplies the cosine value cos (α (t)) calculated by the cosine calculator 25 and the amplitude θ ₁ obtained by the matrix multiplier 23 to thereby obtain the angle. Estimated value of transmission error d _est (t) = θ ₁ × cos (α (t))
Is calculated and passed to the changing unit 17. In this way, the adaptive estimation unit 16 adaptively estimates the amplitude θ ₁ (t), the period θ ₂ (t), and the phase α (t) of the angle transmission error d (t) indicated by the trigonometric function. Will be.

Here, the details of the adaptive estimation process are described in, for example, the following document, so refer to such document.
Literature: M.M. Bodson, S.M. Douglas, "Adaptive Algorithms for the Rejection of Sinoidal Distillates with Unknown Frequency", Automatica, vol. 33, no. 12, p. 2213-2221, 1997

Note that the initial values of the parameter estimated values θ ₁ (t), θ ₂ (t), and α (t) are determined by using information on mechanical constants such as the number of input gear teeth and performing an identification experiment. May be. Strictly speaking, there are individual differences for each reducer and robot, but since it can be compensated by adaptive estimation, it is not necessary to perform an identification experiment for each individual.

  Next, operation | movement of the control apparatus 1 is demonstrated using the flowchart of FIG. In this flowchart, only operations of the current command generation unit 13, the speed calculation unit 15, the adaptive estimation unit 16, the change unit 17, and the error compensation unit 18 will be described.

  (Step S101) The current command generator 13 determines whether to generate a current command. If a current command is generated, the process proceeds to step S102. If not, the process of step S101 is repeated until it is determined that a current command is generated. The current command generation unit 13 may determine to generate a current command, for example, at predetermined time intervals.

  (Step S102) The speed calculation unit 15 calculates the current speed of the motor using the current position of the motor.

  (Step S <b> 103) The current command generation unit 13 generates a current command using the current motor speed calculated by the speed calculation unit 15 and the speed command generated by the speed command generation unit 12.

(Step S104) The adaptive estimation unit 16 estimates the angle transmission error d _est (t) using the current speed of the motor calculated by the speed calculation unit 15.

(Step S105) The changing unit 17 changes the angle transmission error by multiplying the parameter value c set in advance by the estimated angle transmission error d _est (t).

  (Step S106) The error compensator 18 generates a current command in which the angle transmission error component is compensated using the current command generated by the current command generator 13 and the angle transmission error changed by the changing unit 17. Then, the process returns to step S101.

  In the flowchart of FIG. 3, the process ends when the power is turned off or the process is terminated. In the flowchart of FIG. 3, only the process of generating the current command and compensating for the angle transmission error with respect to the current command is shown, but other processes such as the generation of the speed command and the generation of the torque command are performed by the servo. Since it is already known as processing of the controller and the like, detailed description thereof is omitted.

  As described above, according to the control device 1 according to the present embodiment, the angle transmission error can be compensated by adaptively estimating the angle transmission error by the adaptive estimation unit 16 and using the estimation result. As a result, it is possible to suppress periodic vibration that may occur when the tip of the manipulator 2 is linearly operated, and to perform more accurate trajectory control. In addition, since the adaptive estimation does not require actual measurement for each robot or each speed reducer, there is an advantage that the data measurement cost can be reduced. Further, since the adaptive estimation unit 16 estimates the angle transmission error using only the angular velocity of the motor, there is an advantage that it is not necessary to use an external sensor. Further, since a complicated model is not used, it is easy to estimate the angle transmission error.

  In the present embodiment, the configuration shown in FIG. 2 is shown as an example of the configuration of the adaptive estimation unit 16, but the adaptive estimation unit 16 is not limited thereto. Other configurations may be used as long as the angular transmission error can be adaptively estimated using the angular velocity of the motor.

  Moreover, although this Embodiment demonstrated the case where the control apparatus 1 was provided with the change part 17, it may not be so. The control device 1 may not include the changing unit 17. In that case, the error compensator 18 uses the angle transmission error itself estimated by the adaptive estimator 16 to generate a current command that compensates for the angular transmission error component of the reduction gear from the current command generated by the current command generator 13. It may be generated.

  In the above embodiment, each process or each function may be realized by centralized processing by a single device or a single system, or may be distributedly processed by a plurality of devices or a plurality of systems. It may be realized by doing.

  In the above embodiment, the information exchange between the components is performed by one component when, for example, the two components that exchange the information are physically different from each other. It may be performed by outputting information and receiving information by the other component, or when two components that exchange information are physically the same, one component May be performed by moving from the phase of the process corresponding to to the phase of the process corresponding to the other component.

  In the above embodiment, information related to processing executed by each component, for example, information received, acquired, selected, generated, transmitted, or received by each component In addition, information such as threshold values, mathematical formulas, addresses, setting values, parameters, and the like used by each component in processing may be temporarily or over a long period of time on a recording medium (not shown) even if not specified in the above description. It may be held. Further, the storage of information in the recording medium (not shown) may be performed by each component or a storage unit (not shown). Further, reading of information from the recording medium (not shown) may be performed by each component or a reading unit (not shown).

  Further, in the above embodiment, information used by each component, for example, information such as threshold values and addresses used by each component in processing, various setting values, parameters, etc. may be changed by the user However, even if it is not specified in the above description, the user may be able to change the information as appropriate, or it may not be. If the information can be changed by the user, the change is realized by, for example, a not-shown receiving unit that receives a change instruction from the user and a changing unit (not shown) that changes the information in accordance with the change instruction. May be. The change instruction received by the receiving unit (not shown) may be received from an input device, information received via a communication line, or information read from a predetermined recording medium, for example. .

  Moreover, in the said embodiment, when two or more components contained in the control apparatus 1 have a communication device, an input device, etc., two or more components may have a physically single device. Alternatively, it may have a separate device.

  In the above embodiment, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. At the time of execution, the program execution unit may execute the program while accessing the storage unit or the recording medium. The program may be executed by being downloaded from a server or the like, or may be executed by reading a program recorded on a predetermined recording medium. The program may be used as a program constituting a program product. Further, the computer that executes the program may be singular or plural. That is, centralized processing may be performed, or distributed processing may be performed.

  Further, the present invention is not limited to the above-described embodiment, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, the control device according to the present invention does not require adjustment for each robot, can compensate for the angle transmission error without using an external sensor, and is useful as a manipulator control device.

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Manipulator 11 Position command generation part 12 Speed command generation part 13 Current command generation part 14 Torque command generation part 15 Speed calculation part 16 Adaptive estimation part 17 Change part 18 Error compensation part 21 1st multiplier 22 2nd multiplier Multiplier 23 Matrix multiplier 24 Integrator 25 Cosine calculator 26 Sine calculator 27 Third multiplier

Claims (4)

A control device for controlling a manipulator having a plurality of arms connected by a joint driven by a motor via a speed reducer,
A speed command generation unit that generates a speed command using the current position of the motor and the position command of the motor;
A speed calculator that calculates the current speed of the motor from the current position of the motor;
A current command generation unit that generates a current command using the current speed calculated by the speed calculation unit and the speed command;
Adaptive estimation that generates the angular transmission error by adaptively estimating the period, amplitude, and phase of a periodic function indicating the angular transmission error of the speed reducer using the current speed calculated by the speed calculation unit And
An error compensation unit that generates a current command that compensates an angle transmission error component of the reduction gear from the current command using the angle transmission error generated by the adaptive estimation unit;
A control device comprising: a torque command generation unit that generates a torque command using the current current of the motor and the current command generated by the error compensation unit and outputs the torque command to the motor. The control device according to claim 1, wherein the periodic function is a trigonometric function. The adaptive estimation unit includes:
A first multiplier for multiplying the speed of the motor by the cosine value of the phase;
A second multiplier that multiplies the speed of the motor by the negative value of the sine value of the phase;
By performing an operation according to a transfer function matrix corresponding to a transfer function relating to the motor axis, on the vector having the multiplication results of the first and second multipliers in each element, the amplitude and the frequency are changed to each element. A matrix multiplier for generating a vector having
An integrator for calculating a phase obtained by integrating the frequency generated by the matrix multiplier;
A cosine calculator for calculating a cosine value of the phase calculated by the integrator and inputting the cosine value to the first multiplier;
A sine calculator that calculates a negative value of the sine value of the phase calculated by the integrator and inputs the second value to the second multiplier;
The control device according to claim 2, further comprising: a third multiplier that generates an angle transmission error by multiplying the amplitude generated by the matrix multiplier and the cosine value calculated by the cosine calculator. A change unit that changes the angle transmission error by multiplying the angle transmission error generated by the adaptive estimation unit by a parameter that is greater than 0 and less than or equal to 1;
4. The control device according to claim 1, wherein the error compensator generates a current command in which an angle transmission error component after the change by the changing unit is compensated from the current command. 5.

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