JP5264308B2 - Control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a controller for calculating correct temperatures with a simple structure and also controlling a robot based on the calculated correct temperatures. <P>SOLUTION: In a robot controller for controlling each mechanism X comprising a motor and an encoder and also acting as a robot based on an encoder temperature measured by a temperature sensor sx in the encoder Ex of the mechanism X, temperatures T1-T5 at virtually specified locations in the mechanism X are calculated using a thermal circuit model of the mechanism X defined based on a heat conductivity and a shape of a component constituting the mechanism X and the encoder temperature, and the mechanism X is controlled based on the calculated temperatures T1-T5. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a control device that controls the operation of a robot.

  Industrial robots generate heat by, for example, the operation of a motor that drives an arm, and various temperature changes occur at various locations within the arm during actual operation. When a temperature change occurs in the arm, the operating characteristics of the motor, reducer, etc. in the arm change according to the temperature change. For this reason, unless the temperature in the robot is accurately detected and operation control of the motor or the like according to the detected temperature change is not performed, the robot cannot be accurately operated.

  For example, in the industrial robot control device described in Patent Document 1, the temperature sensor is attached to the robot control device, the robot mechanism unit, and each axis of the servo motor. The acceleration and speed of the motor are controlled based on the temperature measured by each temperature sensor.

JP-A-7-136961

  However, an encoder communication line, a motor power line, and the like need to be installed for each axis of the arm, so that the number of wires increases in a robot with a large number of axes (number of arms). For this reason, when a large number of temperature sensors are installed and wired in the motors and robot mechanism portions of the respective axes as in the conventional technique, there is a problem that the workability of the arm is lowered. In addition, depending on the shape of the arm and the number of axes, the installation space and wiring space of the temperature sensor are limited, so it is difficult to install a large number of temperature sensors.

  In addition, since a large number of temperature sensors are installed in the robot, there is a problem that costs such as temperature sensors, wiring, and input / output interfaces are increased. Furthermore, when temperature measurement is performed using only the temperature sensor, since the temperature sensor can only measure temperature information of the place where the temperature sensor is installed, there is a difference between the temperature at the location where measurement is actually desired and the temperature measured by the temperature sensor. There was a problem.

  The present invention has been made in view of the above, and an object thereof is to obtain a control device that calculates an accurate temperature with a simple configuration and controls a robot based on the calculated accurate temperature.

In order to solve the above-described problems and achieve the object, the present invention measures each operation mechanism unit that includes a motor and an encoder and that operates as a robot within the encoder of each operation mechanism unit. In the control device that controls the encoder based on the encoder temperature of the encoder, the thermal circuit model set in the operation mechanism unit and the encoder temperature are used, at a position virtually set in the operation mechanism unit. A temperature calculation unit that calculates a virtual position temperature; and a control unit that controls the operation mechanism unit based on the virtual position temperature calculated by the temperature calculation unit, wherein the temperature calculation unit includes: The virtual position temperature at a predetermined position is calculated using a first thermal circuit model which is a thermal circuit model set using information on thermal conductivity, and the dynamic The virtual position temperature at the predetermined position is calculated using a second thermal circuit model that is a thermal circuit model set using information on energy loss generated in the mechanism unit, and the control unit calculates the temperature The operation mechanism unit is controlled based on two virtual position temperatures calculated by the unit .

  According to the present invention, since the operation mechanism unit is controlled based on the temperature in the operation mechanism unit calculated using the thermal circuit model set in the operation mechanism unit and the encoder temperature, an accurate temperature is calculated with a simple configuration. In addition, the robot can be controlled based on the calculated accurate temperature.

  Hereinafter, embodiments of a control device according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a robot according to Embodiment 1 of the present invention. The robot includes a robot control device 100 and a mechanism unit (operation mechanism unit) X. The robot control device 100 includes a position / speed command device 20 and a motor control device 10.

  In FIG. 1, the configuration in the case where the robot control apparatus 100 controls the mechanism unit X will be described. However, since the robot includes the mechanism units 1 to 4 as described later, the mechanism unit X includes the mechanism units 1 to 1. Corresponding to 4. In other words, the robot control device 100 controls the mechanism units 1 to 4. Therefore, the robot control device 100 is connected to each of the mechanism units 1 to 4.

  The position speed command device 20 includes a control unit 21 and a storage unit 22. The storage unit 22 is a memory that stores a control program for operating the mechanism unit X and the like. The control unit 21 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the position and speed of the mechanism unit X. Based on the control program in the storage unit 22 and the temperature of the encoder Ex (temperature sensor value S described later) T2 sent from the mechanism unit X via the motor control device 10, the control unit 21 stores in the mechanism unit X. The temperatures at a plurality of locations set in are respectively calculated. The control unit 21 generates information (hereinafter referred to as position / speed instruction information) for controlling the position and speed of the mechanism unit X based on the calculated temperature in the mechanism unit X. The control unit 21 transmits the generated position speed instruction information to the motor control device 10.

  The motor control device 10 includes a control unit 11 and a motor driver unit 12. The control unit 11 includes a CPU, a ROM, a RAM, and the like, and controls the power and torque of the motor Mx of the mechanism unit X. The control unit 11 instructs the motor driver unit 12 on the electric power (current) to be applied to the mechanism unit X based on the position / speed instruction information sent from the position / speed command device 20. Further, the control unit 11 sends the temperature sensor value (encoder temperature) S (° C.) sent from the mechanism unit X to the position speed command device 20. The motor driver unit 12 sends electric power (U, V, W) to the mechanism unit X based on an instruction from the control unit 11.

  The mechanism part X operates based on an instruction from the motor control device 10. The mechanism part X is, for example, a robot arm or base, and an encoder Ex, a motor Mx, and a speed reducer Dx are arranged in the arm. In the mechanism part X, the temperature sensor sx is disposed in the encoder Ex physically connected to the servo motor, and the temperature sensor sx measures the temperature in the encoder Ex. The temperature measured by the temperature sensor sx is sent as a temperature sensor value S to the position / speed command device 20 via the motor control device 10.

  The motor Mx drives an arm or the like with electric power supplied from the motor driver unit 12. The encoder Ex detects the number of rotations of the motor Mx and sends the detection result (number of rotations N) to the motor control device 10. The reducer Dx has a function as a brake that decelerates the operation of the arm.

  The robot control device 100 may output an alarm when the temperature sensor value S becomes a predetermined value or more, or may stop the operation of the mechanism unit X. Based on the temperature sensor value S, the robot control apparatus 100 according to the present embodiment calculates the temperature of each location in the mechanism unit X. Then, the robot control apparatus 100 controls (feedback control) the mechanism unit X based on the calculated temperature while correcting an operation error of the mechanism unit X caused by the temperature.

  The robot control apparatus 100 uses information such as the thermal conductivity and shape of the mechanism part X, the temperature T1 (° C.) of the motor Mx, the ambient temperature T3 (° C.) of the motor Mx, and the temperature T5 (° C.) of the speed reducer Dx. Then, the mechanism temperature (ambient temperature of the motor Mx) T4 (° C.), which is the temperature of the housing of the mechanism X, is calculated. Since the robot here has four mechanism parts 1 to 4, the robot control device 100 calculates T1, T3, T5, and T4 for each mechanism part.

  Next, a detailed configuration of the position / speed command device 20 will be described. FIG. 2 is a functional block diagram showing the configuration of the position / speed command device. The position speed command device 20 includes a control unit 21 and a storage unit 22.

  The control unit 21 includes an input unit 23, an output unit 24, a temperature calculation unit 25, and a position / velocity calculation unit 26. The storage unit 22 includes a thermal circuit model storage unit 27, an operation characteristic storage unit 28, and a control program storage unit 29. have. The input unit 23 inputs the temperature sensor value S sent from the temperature sensor sx of each mechanism unit 1 to 4 and sends it to the temperature calculation unit 25.

  The thermal circuit model storage unit 27 stores a model (thermal circuit model) related to a thermal circuit for each mechanism unit. The thermal circuit model is a thermal resistance model related to a thermal circuit set at a plurality of locations (positions) in each of the mechanical units 1 to 4 and is information for calculating the temperature at each set position. The thermal circuit model is set based on the thermal conductivity, shape, and the like of the parts that constitute each of the mechanism units 1 to 4. Examples of the thermal circuit model include a model for calculating the temperature T1 of the motor Mx, a model for calculating the ambient temperature T3 of the motor Mx, a model for calculating the temperature T5 of the speed reducer Dx, and a mechanism temperature T4 ( A model for calculating (C) is set.

  The operation characteristic storage unit 28 stores the operation characteristic (efficiency characteristic) of the motor Mx with respect to the temperature T1, the operation characteristic of the speed reducer Dx with respect to the temperature T5, and the operation characteristic of the mechanism unit X with respect to the temperature T4. The control program storage unit 29 stores a control program for operating the mechanism unit X.

  The temperature calculation unit 25 calculates the temperature at each position in the mechanism units 1 to 4 based on the thermal circuit model in the thermal circuit model storage unit 27 and the temperature sensor value S sent from the input unit 23. To do. The temperature calculation unit 25 sends the calculated temperature at each position in the mechanism units 1 to 4 to the position speed calculation unit 26 as temperature information.

  The position speed calculation unit 26 is based on the temperature information sent from the temperature calculation unit 25, the control program stored in the control program storage unit 29, and the efficiency characteristics of the mechanism units 1 to 4 described later. Generate instruction information. The output unit 24 outputs the position speed instruction information generated by the position speed calculation unit 26 to the motor control device 10. Note that the position / velocity calculation unit 26 and the like in the present embodiment correspond to the control unit described in the claims.

  Next, the configuration of the mechanism units 1 to 4 that are the operation parts of the robot will be described. FIG. 3 is a diagram illustrating an example of a configuration of an operation part of the robot. The operation part of the robot is configured to include mechanism units 1 to 4 and is controlled by the motor control device 10.

  The mechanism unit 1 includes a motor M1 and an encoder E1, and the mechanism unit 2 includes a motor M2 and an encoder E2. The mechanism unit 3 includes a motor M3 and an encoder E3, and the mechanism unit 4 includes a motor M4 and an encoder E4.

  The mechanism parts 1-4 are a chassis etc., for example. The mechanism part 1 is a substantially columnar base, and the mechanism parts 2 to 4 are arms. The mechanism unit 1 rotates the mechanism unit 2 by rotating the motor M1, and the mechanism unit 2 rotates the mechanism unit 3 by rotating the motor M2. Moreover, the mechanism part 3 rotates the mechanism part 4 by rotating the motor M3, and the mechanism part 4 rotates the front-end | tip part of the mechanism part 4 by rotating the motor M4.

  The encoders E1 to E4 and the motors M1 to M4 are connected to the motor control device 10 by wires. Further, in the present embodiment, temperature sensors (not shown in FIG. 3) installed in the encoders E1 to E4 are connected to the motor control device 10 by wires. In FIG. 3, wirings connected to the motor control device 10 are collectively shown as wiring A.

  Here, the thermal circuit model stored in the thermal circuit model storage unit 27 will be described. FIG. 4 is a diagram for explaining a thermal circuit model of the mechanism unit. In addition, since the same thermal circuit model is respectively set to the mechanism parts 1-4, the thermal circuit model of the mechanism part 3 is demonstrated as an example of a thermal circuit model below.

  In the mechanism part 3, the temperature sensor value S in the encoder E3 is measured by the temperature sensor s3. In the present embodiment, the temperature sensor value S is used to calculate the temperature T1 of the motor M3, the ambient temperatures T3 and T4 of the motor M3, and the temperature T5 of the reduction gear D3. The temperatures T1 to T4 are calculated based on the thermal conductivity, the shape, and the like of components arranged in the mechanism unit 3, not the actually measured temperatures. Accordingly, only the temperature sensor value S (temperature S = T2) is the actual measured temperature, and the temperatures T1, T3, to T5 are calculated temperatures (virtual position temperatures) at virtually set positions.

For example, the temperature T1 of the motor M3 is calculated using the thermal resistance R11 from the measurement point of the temperature sensor s3 to the measurement point corresponding to the temperature T1 (hereinafter referred to as between the measurement points). The thickness of the component arranged between the measurement points is L (mm), the thermal conductivity of the material of the component arranged between the measurement points is k (W / (m · k)), and is arranged between the measurement points. If the area of the component is A (cm ² ), the thermal resistance R11 can be calculated by R11 = L (k × A). Furthermore, if the heat flow between the measurement points is Q1 (W), the temperature T1 can be calculated by T1 = S− (Q1 × R11).

  Further, the ambient temperature T3, T4 of the motor M3 and the temperature T5 of the reduction gear D3 are also similar to the temperature T1 of the motor M3, the thermal resistance R12 from the measurement point of the temperature sensor s3 to the measurement points of the temperatures T3, T5, T4, Calculated using R13 and R14.

  Next, a detailed configuration of the mechanism unit 3 will be described. FIG. 5 is a diagram showing a detailed configuration of the mechanism unit. The mechanism unit 3 stores an encoder E3, a motor M3, a speed reducer D3, and the like in a hermetically sealed housing 5 made of a material such as aluminum.

  The encoder E3 has a rotating plate 31 that rotates in accordance with the rotation of the motor M3, and detects the rotational speed N (rpm) of the motor M3 by detecting the rotational speed of the rotating plate 31. The motor M3 includes a magnet 37, a frame 36, a coil 35, a bearing 32, and the like. The motor M3 is joined to the reduction gear D3 via the iron core 34. The reduction gear D3 has a bearing 33 or the like soaked with lubricating oil.

  Thus, the mechanism part 3 is comprised by various components. And the component which comprises the mechanism part 3 has a various shape and a various heat conductive characteristic for every component. Therefore, the position / velocity command device 20 may calculate temperatures at various positions in the mechanism unit 3 using not only the thermal circuit model shown in FIG. 3 but also various thermal circuit models. For example, by setting the thermal circuit model shown in FIG. 6, the position / speed command device 20 can calculate the temperature at each position using the thermal circuit model shown in FIG. When calculating the temperature using the thermal circuit model shown in FIG. 6, the temperature of each measurement point is calculated using the temperature of an adjacent measurement point or the like. For example, a measurement point to be calculated is a measurement point b1 (not shown), a temperature at a measurement point b2 (not shown) adjacent to the measurement point b1 is Ty, and the measurement point b1 is between the measurement point b2 and the measurement point b2. When the thermal resistance is the thermal resistance Ry, the temperature at the measurement point b1 can be calculated using the temperature Ty and the thermal resistance Ry. Thus, by calculating the temperature using the thermal circuit model, flexible temperature detection is possible in addition to temperature detection at a fixed position.

  Next, the operation procedure of the robot will be described. When the robot starts operation, the position / velocity calculation unit 26 of the position / speed command device 20 reads the control program from the control program storage unit 29 and generates position / speed instruction information. The position speed instruction information is sent from the position speed calculation unit 26 to the motor control device 10 via the output unit 24.

  The motor control device 10 operates each mechanism unit X based on the position / speed instruction information from the position / speed command device 20. The mechanism part X measures the temperature by the temperature sensor sx, and sends the measured temperature as the temperature sensor value S to the position / speed command device 20 via the motor control device 10.

  The position / speed command device 20 inputs the temperature sensor value S from the temperature sensor sx from the input unit 23. This temperature sensor value S is sent to the temperature calculation unit 25. The temperature calculation unit 25 uses the thermal circuit model (for example, the thermal circuit model shown in FIG. 3) and the temperature sensor value S stored in the thermal circuit model storage unit 27, and the temperature T1 of the motor Mx and the surroundings of the motor Mx. Temperature T3, T4, temperature T5 of reduction gear Dx, etc. are calculated.

  The temperature calculation unit 25 transmits the calculated temperatures T1 to T5 to the position speed calculation unit 26. The position / velocity calculation unit 26 receives the temperatures T <b> 1 to T <b> 5 from the temperature calculation unit 25. Then, the position / velocity calculation unit 26 reads out the operation characteristics of the motor Mx, the reduction gear Dx, and the mechanism unit X from the operation characteristic storage unit 28.

  7 to 9 are diagrams illustrating examples of efficiency characteristics of the motor, the speed reducer, and the mechanism unit, respectively. In FIG. 7, as the operation characteristics of the motor M3, the operation efficiency characteristics (operation efficiency with respect to the supplied power) corresponding to the temperature T1 of the motor M3 are shown.

  As shown in FIG. 7, the efficiency characteristics of the motor M3 are deteriorated in the order in the case where the rotational speed N of the motor M3 is 2000 rpm, 1000 rpm, and 500 rpm. Further, as the temperature T1 of the motor M3 increases, the efficiency characteristics of the motor M3 improve. The position speed calculation unit 26 calculates the operating efficiency of the motor M3 in operation based on the efficiency characteristics of the motor M3 shown in FIG. 7, the rotational speed N of the motor M3, and the calculated temperature T1 of the motor M3. To do.

  Moreover, in FIG. 8, the efficiency characteristic according to temperature T5 of the reduction gear D3 is shown as an operation characteristic of the reduction gear D3. As shown in FIG. 8, the efficiency characteristics of the speed reducer D3 are deteriorated in the order in which the speed N of the speed reducer D3 is 2000 rpm, 1000 rpm, and 500 rpm. Further, as the temperature T5 of the speed reducer D3 increases, the efficiency characteristics of the speed reducer D3 improve. Based on the efficiency characteristics of the speed reducer D3 shown in FIG. 8, the rotational speed N of the speed reducer D3, and the calculated temperature T5 of the speed reducer D3, the position speed calculation unit 26 calculates the speed of the speed reducer D3 in operation. Calculate operating efficiency.

  FIG. 9 shows the efficiency characteristic according to the temperature T3 of the mechanism part 3 (the ambient temperature T3 of the motor M3) as the operation characteristic of the mechanism part 3. As shown in FIG. 9, the efficiency characteristics of the mechanism unit 3 (arm) deteriorate in the order in which the operation condition of the mechanism unit 3 is the operation a3, the operation a2, and the operation a1. Further, as the temperature T3 of the mechanism unit 3 increases, the efficiency characteristics of the mechanism unit 3 are improved. The position speed calculation unit 26 operates the mechanism unit 3 during operation based on the efficiency characteristics of the mechanism unit 3 illustrated in FIG. 9, the operation conditions of the mechanism unit 3, and the calculated temperature T3 of the mechanism unit 3. Calculate efficiency.

  The position speed calculation unit 26 generates position speed instruction information based on the calculated operation efficiency of the motor M3, the operation efficiency of the speed reducer D3, and the operation efficiency of the mechanism unit 3. For example, when the operation efficiency of the motor M3 is 70%, the motor M3 is operating only for 70% of the supplied power. In this case, the position / velocity calculation unit 26 generates position / velocity instruction information that can compensate for the insufficient 30% of the operation. The position speed instruction information generated by the position speed calculation unit 26 is sent to the motor control device 10 via the output unit 24. In the motor control device 10, electric power is supplied to the mechanism unit 3 based on the position / speed instruction information from the position / speed command device 20 to operate the mechanism unit 3.

  During the operation of the robot, the temperature in the mechanism unit 3 changes according to the operation of the mechanism unit 3 (rotation of the motor M3, etc.) and the surrounding environment, and the temperature detected by the temperature sensor sx also changes. As a result, the temperatures T1, T3 and the like calculated by the position / velocity calculation unit 26 also change according to the operation of the mechanism unit 3 and the surrounding environment, and the position / velocity instruction information generated by the position / velocity calculation unit 26 also changes. The motor control device 10 controls the operation of the mechanism unit 3 in accordance with the position / speed instruction information that changes during the operation of the mechanism unit 3.

  In other words, the robot uses the temperature data in the encoder E3 and the control data of the motor M3 to dynamically correct the temperature characteristic parameters of the motor M3 and the speed reducer D3 to control the operation of the mechanism unit 3. Yes.

  The position / speed instruction information that changes during the operation of the mechanism unit 3 is position / speed instruction information that changes according to the temperature change of the mechanism unit 3, and the mechanism unit 3 is controlled based on the position / speed instruction information. Then, appropriate operation control according to the temperature change of the mechanism part 3 will be performed.

  In the present embodiment, a case has been described in which the robot operation portion is the mechanism units 1 to 4 shown in FIG. 3, but the robot operation portion may have other configurations. For example, the number of mechanism units may be three or less, or five or more.

  As described above, according to the first embodiment, the temperatures at various positions in the mechanism units 1 to 4 are calculated based on the temperature sensor value S and the thermal circuit model. It becomes possible to calculate the exact temperature at various positions within 4. Moreover, since the mechanism parts 1-4 are controlled based on the calculated exact temperature, it becomes possible to operate a robot correctly.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the temperature is calculated for each position (measurement target point) of the mechanism unit X using energy loss generated in the mechanism unit X. In the present embodiment as well, the operation portion of the robot will be described using the mechanism unit 3 as an example of the mechanism unit X as in the case of the first embodiment.

  FIG. 10 is a diagram for explaining energy loss in the mechanism. The mechanism unit 3 stores the encoder E3, the motor M3, and the like in the sealed casing 5A, and stores the speed reducer D3 and the like in the sealed casing 5B.

When the current I (ampere) is sent from the motor control device 10 to the motor M3, the input power P _I (W) is supplied to the motor M3. Thereby, the motor M3 rotates and the mechanism part 3 operates. When the mechanism unit 3 operates, the load loss W _C (W: Watt) and iron loss W _I (W) resulting from the operation of the motor M3, and the mechanical loss W _M (W _M1) resulting from the operation of the bearing 32 and the reduction gear D3. , W _M2 , W _M3 ) (W) are generated.

The load loss W _C is a Joule loss caused by a current flowing through an electric conductor having an electric resistance, and the iron loss W _I is a hysteresis loss or an overcurrent loss. The mechanical loss W _M here is the friction loss W _M1 of the bearing 32, the friction loss W _{M2 of} the reduction gear D3, and the wind loss W _M3 of the reduction gear D3.

Output power P _O of the motor M3 is the torque and T _O (newton meters), rotational speed of the motor M3 (rotation speed) when the N (rpm), is calculated by _{P O = (2πN / 60)} × T O It becomes possible. Here, T _O can be calculated by T _O = K _T × I using the torque constant K _T and the current I. Therefore, the output power P _O of the motor M3 is P _O = (2πN / 60) × K _T × I.

Further, when the total loss in the mechanism unit 3 is W _T , W _T = W _C + W _I + W _M. Since W _T of total loss is W _T = P _I −P _O , W _T = P _I − ((2πN / 60) × K _T × I). If the resistance constant between the lines (constant having temperature dependence) is R (ohms), the load loss W _C of the motor M3 is W _C = (3/2) × I ² R. Further, W _I and W _M can be obtained based on the structure of the motor M3 and the speed reducer D3.

  The temperature calculation unit 25 of the present embodiment uses the amount of heat generated by the motor M3, the value of the temperature sensor value S measured by the temperature sensor s3, and the thermal circuit model related to the heat generation of the motor M3, in the mechanism unit 3. The temperature at each position is calculated.

  Here, the thermal circuit model in the present embodiment will be described. FIG. 11 is a diagram for explaining a thermal circuit model used by the robot according to the second embodiment. In the mechanism part 3, the temperature sensor value S in the encoder E3 is measured by the temperature sensor s3. In the present embodiment, the temperature T1 of the motor M3, the ambient temperature T3 of the motor M3, and the like are calculated using the temperature sensor value S, the value of energy loss at a predetermined position, the thermal resistance between measurement points, and the like.

For example, the temperatures T1 and T3 are the amount of heat generation (W _C + W _I ), which is energy loss at the center position (temperature T0) of the motor M3 in the mechanism unit 3, and from the surface of the motor M3 to the center position of the motor M3. It is calculated using the thermal resistance R1 between the measurement points (between measurement points) and the thermal resistance R3 between the surface portion of the motor M3 and the peripheral portion of the motor M3.

Here, a temperature calculation method using the thermal circuit model shown in FIG. 12 will be described as an example of a temperature calculation method in the mechanism part X by the temperature calculation unit 25 of the position / speed command device 20. In the thermal circuit model of FIG. 12, the center position of the motor M3 is defined as a position p0 (temperature T0), and the temperature at each position is calculated with reference to this position p0. The thermal circuit model of FIG. 12 shows a case where the area of the motor M3 in the rotation axis direction is A1 (m ² ) and the area of the motor M3 in the direction perpendicular to the rotation axis is A2 (m ² ). When the motor M3 has a cylindrical shape with the rotation axis direction as the column axis direction, the side area of the columnar shape is A1, and the area of the top surface or the bottom surface is A2.

  Further, the thickness of the motor M3 in the rotation axis direction (distance from the position p0 to the upper surface) is L3 (m), and the thickness in the direction perpendicular to the rotation axis of the motor M3 (distance from the position p0 to the side surface). Is a case where L is L1 (m). When the motor M3 has a cylindrical shape with the rotation axis direction as the column axis direction, the height of the cylinder is 2 × L3, and the radius of the upper surface or the lower surface is L1.

  In the thermal circuit model of FIG. 12, the calculation target of the temperature is a position p1 that is a surface portion of the motor M3 and positions p3 and p4 that are peripheral portions of the motor M3. Hereinafter, a method of calculating the temperature T1 at the position p1, the temperature T3 at the position p3, and the temperature T4 at the position p4 will be described.

Here, as shown in Expression (1), the case where the temperature T2 measured by the temperature sensor sx inside the encoder E3 is the temperature sensor value S (° C.) will be described.
T2 = S (1)

Further, as shown in Expression (2), it is assumed that the heat flow Q0 (W) generated from the motor M3 is the total value of the load loss W _C and the iron loss W _I.
Q0 = W _C + W _I (2)

Further, as shown in the equation (3), the heat flow Q0 at the position p0 includes the heat flow Q1 (W) from the position p0 to the position p1, and the heat flow Q2 (W) from the position p0 to the position p2 (temperature sensor sx). Is the total value of
Q0 = Q1 + Q2 (3)

The thermal resistance R1 (K / W) between the measurement points between the position p0 and the position p1 and the thermal resistance R2 (K / W) between the measurement points between the position p0 and the position p2 are respectively expressed by the formula ( 4) As shown in Equation (5), the calculation is performed using the shape (L1, L3, A1, A2) of the motor M3 and the thermal conductivity k (W / (m · K)) of the motor M3. For example, when the motor M3 is made of iron, k = 67 (W / (m · K)).
R1 = L1 / (k · A1) (4)
R2 = L2 / (k · A2) (5)

Further, the thermal resistance R3 (K / W) between the measurement points between the position p1 and the position p3 and the thermal resistance R4 (K / W) between the measurement points between the position p2 and the position p4 are respectively As shown in the equations (6) and (7), the calculation is performed using the surface area (A1, A2) of the motor M3 and the convective heat transfer coefficient h (W / (m ² · K)). The convective heat transfer coefficient h is a convective heat transfer coefficient in the space between the motor M3 and the sealed casing 5, and for example, in the case of natural convection (air), h = 5 to 10 (W / (m ² · K) ).
R3 = 1 / (h · A1) (6)
R4 = 1 / (h · A2) (7)

The relationship between T0, T3, and Q1 is expressed by equation (8) using the heat capacity C (J / K), and the relationship between T0, T4, and Q2 is expressed by equation (9) using the heat capacity C (J / K). Represented by
T0-T3 = Q1. (R1 + R3 (1-e- ^{t (R3.C)} ) (8)
T0−T4 = Q2 · (R2 + R4 (1−e ^{−t (R4 · C)} ) (9)

The heat capacity C is C = G · Cp when the weight of the motor M3 is G (kg) and the ratio of the motor M3 is Cp (J / (kg · K)). Moreover, R3 * C and R4 * C in Formula (8) and Formula (9) are thermal time constants, and t is time (sec). From Expression (8) and Expression (9), Expression (10) and Expression (11) can be derived.
T3 = T0−Q1 · (R1 + R3 (1−e ^{−t (R3 · C)} ) (10)
T4 = T0−Q2 · (R2 + R4 (1−e ^{−t (R4 · C)} ) (11)

Assuming that the ambient temperature of the motor M3 is constant and the relationship between the temperature T3 at the position p3 and the temperature T4 at the position p4 is T3≈T4, the expressions (10) and (11) to (12) Can be derived.
T0-Q1 * (R1 + R3 (1-e- ^{t (R3 * C)} ) = T0-Q2 * (R2 + R4 (1-e- ^{t (R4 * C)} )) (12)

The equation (12) is transformed into the equation (13), the equation (13) is transformed into the equation (14), and the equation (14) can be expressed by the equation (15) using the equation (16).
Q1 · (R1 + R3 (1−e ^{−t (R3 · C)} ) = Q2 · (R2 + R4 (1−e ^{−t (R4 · C)} ) (13)
Q1 = Q2 · ((R2 + R4 (1-e− ^{t (R4 · C)} )) / ((R1 + R3 (1−e− ^{t (R3 · C)} ))) (14)
Q1 = n · Q2 (15)
n = ((R2 + R4 (1-e- ^{t (R4.C)} )) / ((R1 + R3 (1-e- ^{t (R3.C)} ))) (16)

Thus, assuming that the ambient temperature of the motor M3 is substantially constant, the ratio of the heat flows Q1 and Q2 can be expressed by a constant n that is uniquely determined by the shape and material of the motor M3 using a heat equivalent circuit equation. . If equation (15) is transformed using equation (3), equation (17) is obtained, and if equation (17) is transformed, equation (18) is obtained. Further, when equation (18) is transformed, equation (19) is obtained, and when equation (19) is transformed, equation (20) is obtained.
Q1 = n · (Q0−Q1) (17)
Q1 = n · Q0−n · Q1 (18)
(1 + n) Q1 = n · Q0 (19)
Q1 = (n · Q0) / (1 + n) (20)

Further, when Expression (20) is transformed using Expression (2), Expression (21) is obtained. Further, when Expression (3) is modified, Expression (22) is obtained, and when Expression (22) is modified using Expression (2) and Expression (21), Expression (23) is obtained.
Q1 = (n · (W _C + W _I )) / (1 + n) (21)
Q2 = Q0-Q1 (22)
Q2 = W _C + W _I − (n · (W _C + W _I )) / (1 + n) (23)

Moreover, the relationship of Formula (24) is established between T0 and T2 as a formula of a thermal equivalent circuit. If equation (24) is modified using equations (1), (5), and (23), equation (25) is obtained, and if equation (25) is modified, equation (26) is obtained.
T0−T2 = Q2 · R2 (24)
T0−S = (W _C + W _I − (n · (W _C + W _I )) / (1 + n)) × (L2 / (k · A2)) (25)
T0 = S + (W _C + W _I − (n · (W _C + W _I )) / (1 + n)) × (L2 / (k · A2)) (26)

Moreover, the relationship of Formula (27) is established between T0 and T1 as a formula of a thermal equivalent circuit. When Expression (27) is modified, Expression (28) is obtained, and when Expression (28) is modified using Expression (1), Expression (4), and Expression (21), Expression (29) is obtained.
T0−T1 = Q1 · R1 (27)
T1 = T0−Q1 · R1 (28)
T1 = S + (W _C + W _I − (n · (W _C + W _I )) / (1 + n)) × (L2 / (k · A2) − ((n · (W _C + W _I )) / (1 + n))・ (L1 / (k • A1)) (29)

Further, the relationship of Equation (30) is established between T2 and T4 (T3) as a thermal equivalent circuit equation. When Expression (30) is transformed, Expression (31) is obtained, and when Expression (31) is transformed using Expression (1), Expression (7), and Expression (23), Expression (32) is obtained.
T2-T4 = Q2 * R4 (1-e- ^{t (R4.C)} ) (30)
T4 = T2-Q2 * R4 (1-e- ^{t (R4.C)} ) (31)
T4 = S− (W _C + W _I − (n · (W _C + W _I )) / (1 + n)) × (1 / (h · A2)) (32)

As described above, if the temperature sensor value S (T2) by the temperature sensor s3 of the encoder E3 and the heat generation amount Q0 (W _C + W _I ) of the motor M3 corresponding to the electric power supplied to the motor M3 are known, the above-mentioned It is possible to calculate the surface temperature T1 of the motor M3 and the ambient temperatures T3 and T4 of the motor M3 by the equations (29) and (32).

  In the conventional robot, the temperature in the mechanism unit is measured by a temperature sensor, and the use of the mechanism unit is restricted using the measurement result. For example, a use limit temperature is set for a motor or an encoder, and when the temperature sensor detects a temperature exceeding the use limit temperature range, the operation of the robot is stopped or an alarm is output. Specifically, a use limit temperature such as 0 to 125 ° C. is set for the surface temperature of the motor, a use limit temperature such as 0 to 90 ° C. is set for the temperature in the encoder, and the ambient temperature of the motor is 0 to 40 ° C. The use limit temperature such as was set. As a result, the conventional robot guarantees the temperature during operation.

  On the other hand, since the robot according to the present embodiment can accurately calculate the temperature at an arbitrary position (point) at which the heat equivalent circuit can be configured, it is possible to perform fine operation control when operating the robot. Further, it is possible to perform data processing relating to maintenance of the mechanism part X such as calculation of the outflow limit temperature of the lubricating oil flowing out from the mechanism part (mainly the bearing 33) using the calculated temperature in the mechanism part. .

  In this embodiment, the temperatures T1, T5, T3, and T4 are calculated when the temperature T3 and the temperature T4 are the same. However, when the temperature T3 and the temperature T4 are different, the heat shown in FIG. A thermal circuit model different from the circuit model is used. For example, when the apparatus size of the motor M3 is very large, the ambient temperature of the motor M3 may differ depending on the position p3 and the position p4. Thus, when a difference arises in the ambient temperature, the ambient temperature of the motor M3 is calculated using, for example, a thermal circuit model shown in FIG.

  FIG. 13 is a diagram for explaining a thermal circuit model in which a reference point of the thermal circuit is set. In setting the thermal circuit model, a predetermined reference point F (° C.) is set, and the thermal resistance between the measurement points from the reference point F to the position to be measured is set. Here, since it is necessary to calculate the temperatures of the positions p3 and p4 when a difference occurs in the ambient temperature of the motor M3, the thermal resistance R33 between the measurement points from the reference point F to the position p3 and the position from the reference point F are determined. The thermal resistance R34 between the measurement points up to p4 is set in advance. The reference point F may be the room temperature (one place) where the motor M3 and the robot are installed as long as an equivalent circuit model can be formed between the measurement points. The reference point F is measured by, for example, a room temperature measuring device 60 arranged outside the operating part.

  In FIG. 13, only one thermal resistance to the mechanism units 1, 2, and 4 is shown, but the mechanism units 1, 2, and 4 are also subject to temperature calculation targets similar to the mechanism unit 3. Set the thermal resistance between measurement points.

  In the present embodiment, the case where the temperatures at the position p1, the position p3, and the position p4 in the mechanism unit 3 are calculated using the thermal circuit model shown in FIG. 12 has been described. The temperature in the mechanism unit 3 may be calculated using the thermal circuit model of FIG.

  As described above, according to the second embodiment, the temperatures at various positions in the mechanism units 1 to 4 are calculated based on the temperature sensor value S and the heat generation amount Q0 of the motor M3. It becomes possible to calculate accurate temperatures at various positions in the mechanism units 1 to 4.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIG. In the third embodiment, by using the temperature inside the mechanism portion X, obtained by the method described in the first embodiment, both the total loss W _T obtained by the method described in the second embodiment, mechanism Recalculate the temperature in X. In the present embodiment, as in the case of the first and second embodiments, the operation portion of the robot will be described using the mechanism unit 3 as an example of the mechanism unit X.

FIG. 14 is a diagram illustrating the relationship between the total loss in the mechanism and the temperature in the mechanism. In the mechanism unit 3, energy loss occurs due to heat dissipation or the like. The total loss W _T in the mechanism unit 3 can be calculated by a predetermined calculation formula as described in the second embodiment. For example, as shown in FIG. 14 (a), the total loss value gradually increases with the passage of time since the start of the rotation of the motor M3. It becomes constant. At this time, the temperatures T1, T3, and T5 also increase in temperature as time elapses after the rotation of the motor M3 is started, and the temperature increase rate decreases after a predetermined time.

In FIG. 14, (a) shows the characteristics of the total loss W _T and temperatures T1, T3, and T5 in the sealed casing environment, and (b) shows the total loss W _T in the open environment. And the characteristics of temperatures T1, T3, and T5. Here, the open environment refers to, for example, a case where the motor M3 is forcibly cooled or a case where the mechanism unit 3M is housed is a large case having a large volume. Moreover, under a sealed casing environment is, for example, a case where the casing that stores the mechanism unit 3M is a small casing having a small volume.

As shown in FIGS. 14 (a) and 14 (b), when the motor M3 is in an open environment, the total loss W _T is smaller and the temperature T1, T3, T5 increases than in a sealed housing environment. The rate is also low. Thus, since the characteristics of the total loss W _T and the temperatures T1, T3, and T5 differ depending on the environment in which the motor M3 is disposed, in the present embodiment, the motor M3 is disposed based on the calculated total loss W _T. Guess the environment. Then, the temperatures T1, T3, and T5 calculated using the thermal circuit model are corrected using characteristic data corresponding to the environment where the motor M3 is disposed.

  In the storage unit 22 (for example, the thermal circuit model storage unit 27) of the position / speed command device 20, information related to the characteristic data shown in FIGS. 14A and 14B is stored in advance. The information on the characteristic data stored in the storage unit 22 may be a data table indicating the relationship between the characteristic data shown in (a) and (b), or the characteristic data shown in (a) and (b). It may be a calculation formula that can be derived.

Here, the case where the motor M3 operates continuously has been described. However, when the motor M3 operates intermittently, the total loss W _T and the temperatures T1, T3, and T5 are as shown in FIG. To change. That is, the values of the total loss W _T and the temperatures T1, T3, and T5 increase while the motor M3 is rotating, and decrease while the rotation of the motor M3 is stopped. Therefore, when the motor M3 operates intermittently, the temperatures T1, T3, and T5 are calculated using the information related to the characteristic data shown in (c).

When the operation of the motor M3 is started, the temperature calculation unit 25 calculates the total loss W _T in the mechanism unit 3 by the method described in the second embodiment. The temperature calculation unit 25 extracts the characteristic data of the motor M3 corresponding to the total loss W _T from the storage unit 22. For example, when the motor M3 is used in a sealed environment, the temperature calculation unit 25 selects the characteristic data (a) based on the total loss W _T. When used in an environment with a constant ambient temperature, the temperature calculation unit 25 selects the characteristic data (b) based on the total loss W _T. Furthermore, the temperature calculation unit 25 extracts temperatures T1, T3, and T5 corresponding to the total loss W _T based on the selected characteristic data. The temperatures T1, T3, T5 are sent from the temperature calculation unit 25 to the position speed calculation unit 26.

  Moreover, the temperature calculation part 25 calculates temperature T1, T3, T5 using the thermal circuit model by the method demonstrated in Embodiment 1. FIG. The temperatures T1, T3, T5 are sent from the temperature calculation unit 25 to the position speed calculation unit 26.

The position speed calculation unit 26 uses the temperatures T1, T3, T5 corresponding to the total loss W _T and the temperatures T1, T3, T5 calculated by the method described in the first embodiment to obtain new temperatures T1, T3. T3 and T5 are calculated. In other words, the position / velocity calculation unit 26 corrects the temperatures T1, T3, T5 calculated by the method described in the first embodiment using the temperatures T1, T3, T5 corresponding to the total loss W _T. For example, the position / velocity calculation unit 26 calculates an average value of the temperatures T1, T3, T5 corresponding to the total loss W _T and the temperatures T1, T3, T5 calculated by the method described in the first embodiment as the new temperature. Let T1, T3, T5.

  Thereafter, the position / velocity calculation unit 26 determines the calculated new temperatures T1, T3, T5, the efficiency characteristics of the motor M3, the efficiency characteristics of the speed reducer D3, and the efficiency characteristics of the mechanism section 3 described with reference to FIGS. Based on this, position speed instruction information is generated. In the motor control device 10, electric power is supplied to the mechanism unit 3 based on the position / speed instruction information from the position / speed command device 20 to operate the mechanism unit 3.

As described above, according to the third embodiment, the temperature in the mechanism unit is recalculated based on the temperature in the mechanism unit calculated using the thermal circuit model and the temperature in the mechanism unit corresponding to the calculated total loss W _T. Therefore, it is possible to calculate accurate temperatures at various positions in the mechanism units 1 to 4 with a simple configuration.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the fourth embodiment, the positional deviation of the robot operating part is corrected using the temperature in the mechanism unit obtained by any of the methods described in the first to third embodiments and the thermal expansion coefficient of the mechanism unit.

  FIG. 15 is a diagram for explaining the thermal expansion of the operating part of the robot, and shows the cross-sectional configuration of each mechanism unit. In FIG. 15, the central axis direction (longitudinal direction) of the mechanism unit 1 and the mechanism unit 2 is the z-axis direction, the mechanism unit 3 rotates by an angle θ3 from the x-axis direction, and the mechanism unit 4 rotates from the z-axis direction by an angle θ4. Only the case of rotating is shown.

  The mechanism units 1 to 4 are thermally expanded due to heat generated by the mechanism units 1 to 4. For this reason, a position error occurs in the operation of the arm or the like (trajectory accuracy or position repeatability) by a distance corresponding to the thermally expanded size. For example, in a robot, it is necessary to accurately control the position of the tip of the mechanism unit 4. If the mechanism part 3 or the mechanism part 4 is thermally expanded in the state shown in FIG. 15, the position of the tip part of the mechanism part 4 is shifted from a desired position.

  For example, when the lengths in the longitudinal direction (axial direction) of the mechanism units 3 and 4 are L3 and L4, respectively, and the thermal expansion coefficients of the mechanism units 3 and 4 are α3 and α4, the temperature of the mechanism units 3 and 4 increases. Is ΔT3, ΔT4, the distance ΔL3 in which the mechanical unit 3 expands and contracts in the longitudinal direction due to thermal expansion is ΔL3 = α3 × L3 × ΔT3. Further, the distance ΔL4 in which the mechanical unit 4 expands and contracts in the longitudinal direction due to thermal expansion is ΔL4 = α4 × L4 × ΔT3. In this case, the positional deviation amount Δx in the x-axis direction of the tip portion of the mechanism unit 4 is Δx = cos θ3 × (ΔL3) + sin θ4 × (ΔL4).

  Further, the amount of positional deviation in the y-axis direction (the direction from the top to the bottom of the drawing) of the tip of the mechanism unit 4 and the amount of positional deviation in the z-axis direction of the tip of the mechanism unit 4 are also the same as those of the tip of the mechanism unit 4. It can be calculated by the same method as the positional deviation amount in the x-axis direction.

  In the present embodiment, the length information in the longitudinal direction, the length in the short direction, the thickness, etc. of each mechanism unit 1 to 4 such as the length in the short direction, the thickness information of each mechanism unit 1 to 4 in advance. The thermal expansion coefficients α1 to α4 and the like are stored in the storage unit 22 of the position / speed command device 20.

  The temperature calculation unit 25 calculates the temperature of each mechanism unit 1 to 4 by any of the methods of the first to third embodiments, and the temperature change amount (change amount from the initial value) of each mechanism unit 1 to 4. A certain ΔT is calculated. The position speed calculation unit 26 is based on ΔT calculated by the temperature calculation unit 25, dimensional information of each mechanism unit 1 to 4 stored in the storage unit 22, and thermal expansion coefficients α1 to α4 of each mechanism unit 1 to 4. Thus, the positional deviation amount of the tip portion of the mechanism unit 4 is calculated. The position / velocity calculation unit 26 calculates the positional deviation amount in the x-axis direction, the positional deviation amount in the y-axis direction, and the positional deviation amount in the z-axis direction as the positional deviation amount of the tip portion of the mechanism unit 4.

  The position / velocity calculation unit 26 corrects the position / speed instruction information so as to eliminate the positional deviation amount of the distal end portion of the mechanism unit 4 based on the calculated positional deviation amount of the distal end portion of the mechanism unit 4. In the motor control device 10, the mechanism unit 3 is operated by supplying power to the mechanism unit 3 based on the corrected position speed instruction information.

  Here, the case where the position / velocity calculation unit 26 calculates the amount of positional deviation of the tip of the mechanism unit 4 has been described. However, the position / velocity calculation unit 26 includes the mechanism units 1 to 4 for each mechanism unit 1 to 4. A positional deviation amount may be calculated.

  Next, a description will be given of the correction processing procedure for the positional deviation amount (error of the movement target position) due to the thermal expansion of the mechanism units 1 to 4. FIG. 16 is a flowchart illustrating a correction processing procedure for the positional deviation amount of the operation caused by the thermal expansion of the mechanism unit. Here, the operation of the robot will be described with the mechanism units 1 to 4 as the mechanism unit X. When the robot starts operation, the control unit 11 of the motor control device 10 requests the temperature sensor value S measured by the temperature sensor sx from the encoder Ex of each mechanism unit X (step S110). The temperature sensor sx of each encoder Ex responds the temperature sensor value S to the control unit 11 (step S120).

  This temperature sensor value S is sent from the motor control device 10 to the position speed command device 20. The position speed command device 20 inputs the temperature sensor value S from the motor control device 10 from the input unit 23. This temperature sensor value S is sent to the temperature calculation unit 25.

  The temperature calculation unit 25 checks whether or not the change amount (temperature change) of the temperature sensor value S has changed by 1 ° C. or more from the initial value. If the difference between the temperature change and the initial value is less than 1 ° C. (step S130, No), the robot position speed command device 20 returns to the process of step S110.

  On the other hand, when the temperature change is larger by 1 ° C. or more than the initial value (step S130, Yes), the temperature calculation unit 25 calculates the temperatures T1 to T5 in the mechanism unit X using the temperature sensor value S and the thermal circuit model. (Step S140). At this time, the temperature calculation unit 25 performs a temperature calculation process by any of the methods described in the first to third embodiments. Furthermore, the temperature calculation unit 25 calculates ΔT1 to ΔT5 as temperature change amounts from the initial temperature of the mechanism unit X.

  The temperature calculation unit 25 determines whether or not it is necessary to correct the position error of the operation due to the thermal expansion of the mechanism unit X (step S150). The temperature calculation unit 25 determines whether or not to correct the operation of the mechanism unit X based on whether or not each of the calculated temperatures ΔT1 to ΔT5 is greater than a predetermined threshold value. Specifically, the temperature calculation unit 25 compares the threshold value A (° C.) with respect to the temperature ΔT1 and the temperature ΔT1, and determines whether or not the temperature ΔT1 is greater than the threshold value A. Further, the temperature calculation unit 25 compares the threshold values B (° C.) for the temperatures ΔT3 and ΔT4 with the temperatures ΔT3 and ΔT4, and determines whether or not the temperatures ΔT3 and ΔT4 are larger than the threshold value B. Furthermore, the temperature calculation unit 25 compares the threshold value C (° C.) with respect to the temperature ΔT5 and the temperature ΔT5, and determines whether or not the temperature ΔT5 is greater than the threshold value C.

  When all of the temperatures ΔT1 to ΔT5 are smaller than the threshold value (No at Step S150), the robot position / speed command device 20 returns to the process at Step S110. If any one of the temperatures ΔT1 to ΔT5 is larger than the threshold value (step S150, Yes), the temperature calculation unit 25 determines to correct the operation of the mechanism unit X. Then, the temperature calculation unit 25 sends the calculated temperatures ΔT1 to ΔT5 to the position speed calculation unit 26.

  The position speed calculator 26 calculates the position of the mechanism X based on ΔT1 to ΔT5 calculated by the temperature calculator 25, the dimensional information of the mechanism X stored in the storage unit 22, and the thermal expansion coefficient of the mechanism X. A deviation amount (thermal expansion error) is calculated (step S160).

  The position speed calculation unit 26 generates position speed instruction information based on the temperatures T1 to T5 and the control program stored in the control program storage unit 29 until the thermal expansion error of the mechanism part X is calculated. (Step S210).

  When the position / velocity calculation unit 26 calculates the thermal expansion error of the mechanism unit X, the position / velocity calculation unit 26 corrects the position error caused by the thermal expansion of the mechanism unit X. Specifically, the position / speed calculator 26 corrects the position / speed instruction information using the temperatures ΔT <b> 1 to ΔT <b> 5 sent from the temperature calculator 25. At this time, the position / velocity calculation unit 26 corrects the position / speed instruction information so as to eliminate the positional deviation amount of the operation of the mechanism unit X (step S220).

  The control unit 11 of the motor control device 10 calculates the power to be supplied to the mechanism unit 3 based on the corrected position / speed instruction information (step S230). Then, the motor driver unit 12 of the motor control device 10 sends the power (U, V, W) calculated by the control unit 11 to the mechanism unit X.

  In the robot, the processes in steps S110 to S160 and the processes in steps S210 to S240 are performed on all the mechanical units 1 to 4. The robot operates by repeating the processes in steps S110 to S160 and the processes in steps S210 to S240.

  As described above, according to the fourth embodiment, since the positional deviation of the operation part of the robot is corrected based on the temperature and the thermal expansion coefficient of the mechanism units 1 to 4, the robot can be accurately operated with a simple configuration. It becomes possible.

  As described above, the control device according to the present invention is suitable for controlling a robot.

It is a figure which shows the structure of the robot which concerns on Embodiment 1 of this invention. It is a functional block diagram which shows the structure of a position speed command apparatus. It is a figure which shows an example of a structure of the operation | movement part of a robot. It is a figure for demonstrating the thermal circuit model of a mechanism part. It is a figure which shows the detailed structure of a mechanism part. It is a figure which shows the other example of a thermal circuit model. It is a figure which shows an example of the efficiency characteristic of a motor. It is a figure which shows an example of the efficiency characteristic of a reduction gear. It is a figure which shows an example of the efficiency characteristic of a mechanism part. It is a figure for demonstrating the energy loss in a mechanism part. It is a figure for demonstrating the thermal circuit model which the robot of Embodiment 2 uses. It is a figure which shows the thermal circuit model used for temperature calculation. It is a figure for demonstrating the thermal circuit model which set the reference point of the thermal circuit. It is a figure which shows the relationship between the total loss in a mechanism part, and the temperature in a mechanism part. It is a figure for demonstrating the thermal expansion of the operation | movement part of a robot. It is a flowchart which shows the correction | amendment processing procedure of the position shift amount of the operation | movement resulting from the thermal expansion of a mechanism part.

Explanation of symbols

1-4, X Mechanism part 5, 5A, 5B Sealed housing 10 Motor control device 11, 21 Control part 12 Motor driver part 20 Position speed command device 22 Storage part 23 Input part 24 Output part 25 Temperature calculation part 26 Position speed calculation Unit 27 thermal circuit model storage unit 28 operation characteristic storage unit 29 control program storage unit 100 robot control device D3, Dx reduction gear E1-E4, Ex encoder sx temperature sensor M1-M4, Mx motor

Claims (5)

In a control device configured to include a motor and an encoder and to control each operation mechanism unit that operates as a robot based on the encoder temperature of the encoder measured in the encoder of each operation mechanism unit,
A temperature calculation unit that calculates a virtual position temperature at a position virtually set in the operation mechanism unit using the thermal circuit model set in the operation mechanism unit and the encoder temperature;
A control unit that controls the operation mechanism unit based on the virtual position temperature calculated by the temperature calculation unit;
Equipped with a,
The temperature calculation unit calculates the virtual position temperature at a predetermined position using a first thermal circuit model which is a thermal circuit model set using information on the thermal conductivity of the operation mechanism unit, and Calculating the virtual position temperature at the predetermined position using a second thermal circuit model which is a thermal circuit model set using information on energy loss generated in the operation mechanism unit;
The control unit controls the operation mechanism unit based on two virtual position temperatures calculated by the temperature calculation unit .   A storage unit that stores a temperature change characteristic of a virtual position temperature corresponding to the second thermal circuit model for each arrangement environment of the operation mechanism unit;
  The temperature calculation unit extracts a temperature change characteristic corresponding to the virtual position temperature calculated using the second thermal circuit model from the storage unit, and uses the extracted temperature change characteristic to convert the first thermal circuit model. The control apparatus according to claim 1, wherein the virtual position temperature calculated using the correction is corrected. The control unit calculates the operation efficiency of the operation mechanism unit corresponding to the virtual position temperature based on the information on the operation efficiency characteristics of the operation mechanism unit and the virtual position temperature calculated by the temperature calculation unit, control device according to claim 1 or 2, wherein the controller controls the operation mechanism on the basis of the calculated operating efficiency. The control unit is configured to eliminate an error in a movement target position of the operation mechanism unit due to thermal expansion of the operation mechanism unit based on the virtual position temperature and a thermal expansion coefficient of the operation mechanism unit. control device according to claim 1 or 2, characterized in that for controlling the parts. The temperature calculation unit calculates the virtual position temperature using information in which the energy loss and the virtual position temperature are associated with each other when calculating the virtual position temperature using the second thermal circuit model. The control device according to claim 1 , wherein:

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