Control signal generation device, control system, and control signal generation method

Abstract

It generates position command values ​​that correct for Abbe errors, allowing the point of application to follow the target trajectory even during acceleration, constant speed, and deceleration. [Solution] The control signal generation device for the linear motion guide device includes: a detection unit 25 that detects the position and orientation of the movable part 13; a deviation characteristic extraction unit that uses the position and orientation information of the movable part 13 detected by the detection unit 25 and the characteristics of the deviation between the position of the movable part 13 detected by the encoder 17 and a specified position; a calculation formula generation unit that generates a calculation formula for calculating the actual position of the movable part 13 based on the deviation characteristics; a movement target position setting unit that determines the movement target position of the movable part 13 to move the point of application Q to the target position, sets at least one of an acceleration section, a constant velocity section, and a deceleration section between the starting position and the ending position of the movable part 13, and generates trajectory information of the point of application Q during its movement for each section; and a control signal output unit that outputs a control signal to move the movable part to the movement target position along the trajectory.

Description

[Technical Field]

[0001] The present invention relates to a control signal generation device, a control system, and a control signal generation method. [Background technology]

[0002] A linear motion guide device having a slider that can move in one axis direction is known. An example of a device equipped with this linear motion guide device is the motor control device described in Patent Document 1. The motor control device in Patent Document 1 generates a position command value representing the desired position of the mechanical load at each moment when controlling a motor to move a mechanical load connected to the motor from a first position to a second position. Then, by inputting the distance traveled, travel time, and upper limit acceleration, it calculates the acceleration time, deceleration time, constant velocity time, and peak velocity to determine the acceleration profile, and generates a velocity profile and a position command value from this acceleration profile. It is stated that this motor control device can reduce the amount of power required for positioning control to move to the target position. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2013 / 129294 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the technology described in Reference 1 involves inputting the distance traveled, travel time, and upper limit acceleration into a command value generation circuit, calculating the acceleration time, deceleration time, constant velocity time, and peak velocity, and then integrating the resulting acceleration profile twice to generate the position command value. This double integration method, while minimizing the amount of power consumed, does not account for errors caused by mechanical strain (Abbe error), resulting in a problem where the point of application deviates from the target trajectory by the amount of the Abbe error.

[0005] For example, in a servo system with one degree of freedom in which a movable part moves in a linear direction, such as a "linear motor" or a "linear feed system using a servo motor and ball screw," when this movable part is actually moved in a linear direction, it appears to be moving in a straight line. However, when the position is precisely observed, there are absolute positioning errors, horizontal straightness errors, and vertical straightness errors, resulting in distorted motion in the translational direction of three degrees of freedom. Furthermore, when the posture is observed, there are roll errors, pitch errors, and yaw errors, resulting in rotational motion of three degrees of freedom. In other words, the movable part of a linear guide device moves in six degrees of freedom due to mechanical distortion, and if these six movements can be understood, the tip position (actual point of application) of the arm of the work device installed on the movable part can be geometrically calculated and Abbe errors can be corrected. However, there have been no conventional examples of addressing the problem of correcting such Abbe errors.

[0006] Therefore, the present invention aims to provide a control signal generation device, a control system, and a control signal generation method that can generate position command values ​​corrected for Abbe errors, and enable the point of application to follow a target moving trajectory even during acceleration, constant speed, and deceleration. [Means for solving the problem]

[0007] This invention consists of the following configuration. (1) A control signal generation device for a linear motion guide device comprising: a guide rail extending in a uniaxial direction; a movable part provided on the guide rail so as to be movable relative to the guide rail; a drive unit for moving the movable part along the guide rail; and an encoder for detecting the movement of the movable part, A detection unit for detecting the position and orientation of the movable part, After moving the movable part toward a designated position, the detection unit uses the position and orientation information of the movable part detected by the detection unit to determine the characteristics of the deviation between the position of the movable part detected by the encoder and the designated position, and a deviation characteristic extraction unit is provided, A calculation formula generation unit that generates a calculation formula for calculating the actual position of the movable part based on the characteristics of the displacement, A movement target position setting unit substitutes information about the target position relative to a specific point of application of the movable part, and distance information from the origin position of the movable part to the position of the point of application, into the generated calculation formula to determine the target position of the movable part to move the point of application to the target position, and sets at least one of the following between the starting position of the movement of the movable part and the ending position which is the target position: an acceleration section to accelerate the movable part, a constant velocity section to move at a constant velocity, and a deceleration section to decelerate the movable part, and generates trajectory information of the point of application during its movement for each set section. A control signal output unit outputs a control signal to move the movable part along the trajectory to the target position based on the generated trajectory information, A control signal generation device equipped with the following features. (2) A method for generating a control signal for a linear motion guide device comprising: a guide rail extending in a uniaxial direction; a movable part provided on the guide rail so as to be movable relative to the guide rail; a drive unit for moving the movable part along the guide rail; and an encoder for detecting the movement of the movable part, The position and orientation of the movable part are detected by the detection unit. After moving the movable part toward the designated position, the position and orientation information of the movable part detected by the detection unit is used to determine the characteristics of the deviation between the position of the movable part detected by the encoder and the designated position. Based on the characteristics of the displacement, a calculation formula is generated to calculate the actual position of the movable part. The generated calculation formula is used to determine the target position of the movable part for a specific point of application, and the distance information from the origin of the movable part to the position of the point of application, thereby determining the target position of the movable part to move the point of application to the target position. At the same time, between the starting position of the movement of the movable part and the ending position which is the target position, at least one of the following is set: an acceleration section to accelerate the movable part, a constant velocity section to move it at a constant velocity, and a deceleration section to decelerate it. For each set section, trajectory information of the point of application during its movement is generated. Based on the generated trajectory information, a control signal is output to move the movable part along the trajectory to the target position. A method for generating control signals for a linear motion guide device. [Effects of the Invention]

[0008] According to the present invention, a position command value corrected for Abbe error is generated, allowing the point of application to follow the target moving trajectory even during acceleration, constant speed, and deceleration. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an overall configuration diagram of a control system equipped with a linear motion guide device according to this example configuration. [Figure 2] Figure 2 is a functional block diagram of the control signal generation device. [Figure 3] Figure 3 is an explanatory diagram illustrating how errors occur in a linear motion guide device. [Figure 4] Figure 4 is an explanatory diagram schematically showing the absolute coordinate system, local coordinate system, and the errors that occur in a linear motion guide device. [Figure 5A] Figure 5A is a graph showing an example of roll error that occurs in the movable part when the movable part is moved in the X-axis direction. [Figure 5B] Figure 5B is a graph showing an example of the pitch error that occurs in the movable part when it is moved in the X-axis direction. [Figure 5C] Figure 5C is a graph showing an example of the yaw error that occurs in the movable part when it is moved in the X-axis direction. [Figure 6A] Figure 6A is a graph showing an example of the distribution characteristics of the horizontal error ey of straightness along the X-axis that occurs in the movable part. [Figure 6B] Figure 6B is a graph showing an example of the distribution characteristics of the vertical error ez of straightness along the X-axis that occurs in the movable part. [Figure 7] Figure 7 is an example of movement from a starting position to a target position, and is a schematic diagram illustrating the movement trajectory. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is an overall configuration diagram of a control system 200 equipped with a linear motion guide device 10 according to this example configuration. The configuration of the linear motion guide device 10 shown here is just one example and is not limited to this.

[0011] The control system 200 shown in Figure 1 comprises a linear motion guide device 10, a control unit 21 connected to the linear motion guide device 10, an input unit 23 connected to the control unit 21, and a detection unit 25. The control unit 21 includes a control signal generation device 100, but the control signal generation device 100 may be provided separately from the control unit 21.

[0012] The linear motion guide device 10 comprises a guide rail 11, a movable part 13, a drive unit 15, and an encoder 17. The guide rail 11 extends in the X-axis (uniaxial) direction, and the movable part 13 is mounted so as to be movable relative to the guide rail 11. The drive unit 15 is a drive source that moves the movable part 13 along the guide rail 11, and for example, a servo motor can be used. The encoder 17 may be, for example, a rotary encoder mounted on the motor shaft of the drive unit 15, or a linear encoder arranged along the guide rail 11. In either case, the encoder 17 detects the amount of movement of the movable part 13 along the guide rail 11.

[0013] The movable part 13 is equipped with devices according to the purpose of the work. Here, an example is shown in which a contact element 19 is mounted as the work device, but it is not limited to this, and may also be tools such as drills and end mills for performing various processes on materials not shown, or measuring instruments such as cameras and sensors for measuring the position of the object. In this configuration, the tip of the contact element 19 mounted on the movable part 13 is defined as the point of action Q.

[0014] The control unit 21 controls the operation of the drive unit 15 of the linear motion guide device 10. An input unit 23 is connected to the control unit 21, and various programs and data related to the contactor 19 are input from this input unit 23. An encoder 17 is connected to the control unit 21, and detection signals from the encoder 17 are input to the control unit 21.

[0015] Furthermore, a detection unit 25 is connected to the control unit 21. The detection unit 25 is a sensor, such as a camera, laser interferometer, or laser displacement meter, which detects the position and orientation of the movable part 13. The detection unit 25 is positioned near the linear motion guide device 10 when detecting the position and orientation of the movable part 13, but it may be removed, such as by moving it into a safe place, after detection is complete. In other words, the detection unit 25 only needs to be installed when generating a control signal by the control signal generation device 100, which will be described later. Furthermore, the detection unit 25 may be equipped with a temperature sensor to measure the ambient temperature of the linear motion guide device 10, etc.

[0016] Figure 2 is a functional block diagram of the control signal generation device 100. The control signal generation device 100 includes a deviation characteristic extraction unit 31, which will be described in detail later, a calculation formula generation unit 33, a moving target position setting unit 35, and a control signal output unit 37.

[0017] The displacement characteristic extraction unit 31 uses the position and orientation information of the movable part 13 detected by the detection unit 25 after the movable part 13 has been moved toward the specified position to determine the displacement characteristics between the position of the movable part 13 detected by the encoder 17 and the specified position P(x).

[0018] The calculation formula generation unit 33 generates a calculation formula (conversion equation) for calculating the actual position of the movable part 13 based on the characteristics of the deviation obtained.

[0019] The moving target position setting unit 35 substitutes information about the target position relative to a specific point of application Q of the movable part 13, and distance information from the origin position of the movable part 13 to the position of point of application Q, into the generated calculation formula to determine the target position of the movable part 13 to move the point of application Q to the target position. In addition, it sets at least one of the following between the starting position of the movement of the movable part 13 and the ending position which is the target position: an acceleration section to accelerate the movable part 13, a constant velocity section to move it at a constant velocity, and a deceleration section to decelerate it, and generates trajectory information for the movement in each set section.

[0020] The control signal output unit 37 generates a control signal to move the movable part 13 along the trajectory to the target position based on the generated trajectory information, and outputs it to the control unit 21.

[0021] Figure 3 is an explanatory diagram showing how errors occur in the linear motion guide device 10. Figure 4 is an explanatory diagram schematically showing the absolute coordinate system, local coordinate system, and the errors that occur in the linear motion guide device 10.

[0022] The linear motion guide device 10 shown in Figures 3 and 4 has a drive unit with one degree of freedom that allows the movable part 13 to move in the linear direction. For example, a servo motor such as a linear motor can be used as this drive unit. In such a configuration of the linear motion guide device 10, the movable part 13 can be moved in the X-axis (single axis) direction (x1 → x2), but if the position of the movable part 13 is precisely observed, It can be seen that there is a slight distortion in the straightness horizontal (Y-axis) direction and the straightness vertical (Z-axis) direction. In other words, the movable part 13 has a displacement in the straightness horizontal (Y-axis) direction (straightness horizontal error e y ) occurs, resulting in a deviation in the straightness vertical (Z-axis) direction (straightness vertical error e z Furthermore, the movable part 13 is displaced in the straightness extension (X-axis) direction due to the effects of temperature changes, etc. (straightness extension error e x ) may also occur.

[0023] Furthermore, observing the posture of the movable part 13 reveals that as the movable part 13 moves along the guide rail 11, it undergoes small rotations in the roll direction (rotation around the X axis), the pitch direction (rotation around the Y axis), and the yaw direction (rotation around the Z axis). In other words, the movable part 13 undergoes a roll error e due to rotation in the roll direction. roll This occurs, and the rotation in the pitch direction causes a pitch error e pitch This occurs, and furthermore, Yaw error e due to rotation in the yaw direction yaw This is happening.

[0024] Thus, when the movable part 13 moves on the guide rail 11, it moves with a total of six degrees of freedom including the translational directions (three degrees of freedom) of the X, Y, and Z axes and the rotational directions (three degrees of freedom) around the X, Y, and Z axes, and a positional error of deviation amount δ occurs between the target position and the action point Q (see FIG. 3). Therefore, if the positional error due to the six-degree-of-freedom movement of the movable part 13 in the linear motion guide device 10 can be grasped, the position of the action point Q at the tip of the contact 19, which is the working device installed on the movable part 13, can be positioned with high precision to the target position by correcting the generated positional error. That is, by obtaining the absolute position of the action point Q of the movable part 13, the positional deviation of this action point Q can be corrected, and the action point Q can be precisely positioned to the target position.

[0025] Next, the control of the control signal generation device 100, which is the correction method of the present invention, will be described. (Setting of coordinate system) As shown in FIG. 1, a detection unit 25 for detecting the position and orientation of the movable part 13 is installed. Further, the origin O ABS , Y ABS , Z ABS ) of the absolute coordinate system (X ABS is set. Furthermore, a relative coordinate system (X inc , Y inc , Z inc ) is set with a specific location of the movable part 13 as the origin O inc . It is preferable that the position of the origin O inc in the state where the movable part 13 is arranged at the starting point, which is one end side of the guide rail 11, is set as the origin O0 of the linear motion guide device 10. The X ABS , Y ABS , Z ABS axes of the absolute coordinate system (X ABS , Y ABS , Z ABS ) will hereinafter be simply referred to as the X-axis, Y-axis, and Z-axis, respectively. Further, for the sake of simplicity of explanation here, it is assumed that each axis of the X-axis, Y-axis, and Z-axis of the absolute coordinate system is parallel to the corresponding axis of the relative coordinate system.

[0026] Here, Equation (1) represents the origin O in the absolute coordinate system (X ABS , Y ABS , Z ABS )ABS Equation (2) shows the position vector from to the point of application Q, and the relative coordinate system (X inc ,Y inc ,Z inc ) Origin O inc This shows the position vector from the point of application Q.

[0027]

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[0028] Let x be the distance the movable part 13 moves in the X-axis direction from the origin O0 to the specified position P(x). This distance x is the distance detected by the encoder 17. However, the distance x is equal to the position command value x. ref Identical to (x=x ref In cases where this is the case, this distance x corresponds to the position command value.

[0029] (Detection of the position and rotation angle of the movable part 13) The movable part 13 is moved in the X-axis direction from the origin O0 toward a specified position P(x). At this time, the position and orientation of the movable part 13 during the entire stroke when moving the movable part 13 in the X-axis direction are detected by the detection unit 25, and the detection results are approximated by the least squares method using a higher-order function. The position and orientation of the movable part 13 can be obtained, for example, by placing the stroke end of the linear motor at the origin, pausing at an intermediate position from there to the full stroke, and measuring the displacements in the roll direction, pitch direction, and yaw direction using a laser interferometer. Then, to approximate the obtained displacement data with an n-th degree function, for example, if the higher-order function to be approximated along the X-axis direction is (3), then the acquired roll direction data r i The coefficient a is such that the evaluation function J in equation (4), which represents the difference between and f(x), is minimized. k We just need to find this. Here, m and N are constants.

[0030]

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[0031] The pitch and yaw directions can also be approximated by nth-degree polynomials in the same way as above. In this way, the position of the movable part 13 in the X-axis direction and the rotation angle θ of the movable part 13 around each of the XYZ axes are obtained. roll , θ pitch , θ yaw Let's find out the relationship between them.

[0032] Figure 5A shows the rotation angle θ around the X-axis when the movable part 13 is moved in the X-axis direction. roll This graph shows an example of variation (roll error). Figure 5B shows the rotation angle θ of the movable part 13 around the Y axis when the movable part 13 is moved in the X-axis direction. pitch This graph shows an example of variation (pitch error). Figure 5C shows the rotation angle θ of the movable part 13 around the Z axis when the movable part 13 is moved in the X-axis direction. yaw This graph shows an example of the variation (yaw error).

[0033] (Absolute position in the X-axis direction) Based on the value detected by the detection unit 25, the absolute position f in the X-axis direction of the movable part 13 after movement is determined. x Find (x). Equation (5) is given in absolute coordinate system (X ABS ,Y ABS ,Z ABS The absolute position of the movable part 13 in the X-axis direction f x This indicates (X).

[0034]

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[0035] The coefficients in equation (5) are as follows: x: Encoder detected value (= position command value) [m] e x (x): Mechanical strain error of the encoder at the reference temperature [m] T x (x): Current temperature of the encoder [°C] T x 0: Encoder reference temperature [°C] γ: Coefficient of thermal expansion of the encoder [m / °C] x0: Origin O of the absolute coordinate systemABS Distance in the X-axis direction from the origin O0 [m]

[0036] (Horizontal and vertical errors in straightness) The rotation angle θ around the Z axis detected by the detection unit 25 yaw and rotation angle θ around the Y axis pitch Therefore, the horizontal error of straightness, which is the absolute position error in the Y-axis direction, e y and the straightness vertical error e, which is the absolute position error in the Z-axis direction. z This calculates the detected rotation angle θ. yaw and rotation angle θ pitch By integrating each of these along the X-axis, the horizontal error of straightness e y and straightness and vertical error e z The position of the movable part 13 in the X-axis direction and the horizontal error of straightness e are calculated. y The relationship between the position f in the Y-axis direction and the position f y The relationship between (x) and the position of the movable part 13 in the X-axis direction and the vertical error of straightness e z The relationship between the position f in the Z-axis direction and the position f z The relationship with (x) is approximated by using the least squares method with higher-order functions.

[0037] Equation (6) represents the position f in the Y-axis direction. y This is the relationship between (x) and the position in the X-axis direction, and equation (7) is the position in the Z-axis direction f z This is the relationship between (x) and the position in the X-axis direction.

[0038]

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[0039] y0: Origin O of the absolute coordinate system ABS Distance in the Y-axis direction from the origin O0 [m] z0: Origin O of the absolute coordinate system ABS Distance in the Z-axis direction from the origin O0 [m]

[0040] Figure 6A shows the horizontal error of straightness along the X-axis e that occurs in the movable part 13. yThis graph shows an example of the distribution characteristics. Figure 6B shows the vertical error of straightness along the X axis e that occurs in the movable part 13. z This graph shows an example of the distribution characteristics.

[0041] (Position of movable part 13) In equation (8), the origin O of the movable part 13 inc The transformation matrix M used to determine the position is shown as a 4x4 homogeneous coordinate transformation matrix.

[0042]

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[0043] The transformation matrix M receives the position command X from the input unit 23. ref Enter this position command X ref This method determines the position of the movable part 13 when it is moved to the specified position P(x), and the straightness horizontal error e y and straightness and vertical error e z This has been taken into consideration.

[0044] (Position of movable part 13) Equations (9), (10), and (11) show the roll error e of the movable part 13. roll , pitch error e pitch , yaw error e yaw This is represented by a 4x4 homogeneous coordinate transformation matrix.

[0045]

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[0046] These errors e roll , e pitch , e yaw The input unit 23 receives the position command X ref Enter this position command X ref This is the error of the movable part 13 that occurs when the movable part 13 is moved to the specified position P(x), and it is an error corresponding to the roll error around the X axis, the pitch error around the Y axis, and the yaw error around the Z axis (rotational error in the three axes).

[0047] (Position and orientation of the movable part 13) Equation (12) represents the characteristic T(x) including each position and each error of the movable part 13 in a 4×4 matrix.

[0048] [Number]

[0049] This characteristic T(x) is obtained by inputting the position command X ref from the input unit 23, and represents the characteristics of the position and orientation of the movable part 13 when the movable part 13 is moved to the specified position P(x) by this position command X ref . That is, the characteristic T(x) represents the case where the straightness elongation error e x , the straightness horizontal error e y , and the straightness vertical error e z occur due to the movement, and further, the roll error e roll , the pitch error e pitch , and the yaw error e yaw occur as rotational errors around the X-axis, Y-axis, and Z-axis. This characteristic T(x) is obtained by the deviation characteristic extraction unit 31 of the control unit 21.

[0050] However, in Equation (12), as in Equation (13), when the rotation angles θ roll , θ pitch , θ yaw are small, the approximations of trigonometric functions sinθ≒θ and cosθ≒1 are used, and it is assumed that the roll error e roll , the pitch error e pitch , and the yaw error e yaw are also small.

[0051] [Number]

[0052] (Position of the action point Q) Equation (14) is in the absolute coordinate system (X ABS , Y ABS , Z ABS) The absolute position x of the point of action Q in the relative coordinate system (X inc , Y inc , Z inc ) is obtained from the characteristic T(x) of the movable part 13. The formula obtained by substituting Equation (14) into the absolute coordinate system (X ABS is as follows. Assuming that the position vector of the point of action Q as seen from the absolute coordinate system (X ABS , Y ABS , Z ABS ) is used, the position of the point of action Q in the absolute coordinate system can be expressed by Equation (15).

[0053]

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[0054] (Absolute position of the point of action Q in forward kinematics) In forward kinematics, when the detected value of the encoder 17 is x, the absolute position x of the point of action Q ABS can be expressed by Equation (16) based on Equation (15). Equation (16) is an arithmetic expression for calculating the absolute position of the point of action Q and is generated by the arithmetic expression generation unit 33 of the control unit 21.

[0055]

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[0056] In Equation (16), the meaning of each term is as follows. · Left side: Position of the point of action Q in the X-axis direction as seen from the absolute coordinate system · First term on the right side: Length in the X-axis direction from the origin O0 of the linear guide device 10 to the point of action Q · Second term on the right side: Product of the length in the Y-axis direction from the origin O0 of the linear guide device 10 to the point of action Q and the yaw error · Third term on the right side: Product of the length in the Z-axis direction from the origin O0 of the linear guide device 10 to the point of action Q and the pitch error · Fourth term on the right side: Sum of the detected value of the encoder 17, the strain error, and the thermal expansion error (absolute position in the X-axis direction)

[0057] (Absolute position of the point of action Q in inverse kinematics) d derived from forward kinematics xThe position obtained by substituting the encoder's detected value x into (x), and the absolute position X in the X-axis direction. ABS In other words, the desired position of the point of application should be the same as shown in equation (17), but in reality, errors occur. That is, when numerically calculating the encoder detection position x using equation (17), as shown in equation (18), x is a solution that is slightly deviated from the true solution x. i Substituting this value gives an error e i This equation (18) is also called the error equation.

[0058]

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[0059] x in equation (18) i to x i +δx i Substitute the error e i Set to 0. Furthermore, perform a Taylor expansion and δx i Since terms squared and above are infinitesimally small, we can ignore them and derive equation (19).

[0060]

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[0061] Substituting the error equation from equation (18) into equation (19) yields equation (20), and further, equation (20) δx i Expanding on this, we obtain equations (21) and (22).

[0062]

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[0063] Then, as in equation (23), the error e i The acceptable value is ε(e i δx until it is less than or equal to ε) i Add it.

[0064]

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[0065] In the addition process of equation (23), equations (24) and (25) were used, which utilize the equation for the x-component of forward kinematics and the differential equation.

[0066]

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[0067] (Derivation of the inverse kinematics equations) Absolute position x of point of application Q ABS Equation (26) is used to find the detected value x of encoder 17 when it reaches the target position, and the detected value x of encoder is used in the error equation (27) x i Substitute this into the error e i We will find the value of. Note that when deriving equation (26), e i If ≤ ε, we stop adding x and consider it a solution.

[0068]

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[0069] If the movable part 13 can be moved to the position x of equation (26) derived in this way, then the absolute position x of the point of application Q will be ABS This makes it possible to precisely position the object at the target location.

[0070] The above example shows a control method for moving to a target position, but here we will explain how to control the motion pattern until you reach the target position. Motion patterns include "acceleration," "constant velocity," and "deceleration," and these are combined arbitrarily to reach a predetermined target position. In other words, here we specify not only the coordinates of the destination but also the motion pattern along the movement trajectory. As an example, here we will explain a control method that moves from the starting position to the target position by setting an acceleration section, a constant velocity section, and a deceleration section in that order.

[0071] First, the absolute position command value is designed using the quintic function shown in equation (28). By using a quintic function, the coefficient 'a' in equation (29) can be calculated by making it an invertible matrix.

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[0072] The velocity of the absolute position command value obtained by the first derivative of equation (28) with respect to time (equation (29)) and the acceleration obtained by the second derivative of equation (28) (equation (30)) are calculated.

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[0073] By substituting the initial time t=0 and the final time t=T into equations (28) representing position, (29) representing velocity, and (30) representing acceleration, a total of six equations (31) are obtained.

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[0074] When equation (31) is expressed as a matrix and rearranged, we get equation (32). Solving for coefficients a0 to a5 from equation (33) gives us equation (33).

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[0075] Substitute equation (33) into equation (30) to obtain the absolute position command value X ABS We obtain the trajectory design equations (Equation (34)) for acceleration, constant velocity, and deceleration.

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[0076] Substituting equation (34) for the absolute position command value into equation (26), the position command value x(t) can be expressed by equation (35).

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[0077] Next, based on equation (35), position command values ​​are determined according to each motion pattern: acceleration, constant velocity, and deceleration. Figure 7 is a schematic diagram illustrating an example of movement from a starting point to a target position, showing the movement trajectory. The horizontal axis represents time, and the vertical axis represents distance traveled. The starting point of the movement is X. ABS (0) End point X after time T has elapsed ABS (T) + X ABS Between (0) and (0), there is an acceleration section SC1 with time Δa, a constant velocity section SC2, and a deceleration section SC3 with time Δd.

[0078] The position command value (t) is given by equation (36) in the initial acceleration section SC1 (0≦t≦Δa), by equation (37) in the constant velocity section SC2 (Δa≦t≦T-Δd), and by equation (38) in the deceleration section SC3 (T-Δd≦t≦T).

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[0079] The above equations (36) to (38) are given by equation (27) with error e i The calculation is repeated until the result falls within the acceptable value ε. In this way, by taking into account the positional deviation that actually occurs due to mechanical distortion, the control to the target position can be appropriately corrected for the resulting Abbe error. By determining the position command value in each of the acceleration, constant velocity, and deceleration sections set between the starting and ending points of movement, the movement trajectory can be accurately set to the desired trajectory. Therefore, even during acceleration, constant velocity, and deceleration, the point of application can be made to accurately follow the target trajectory, and moreover, highly efficient control is possible while suppressing the occurrence of overshoot, hunting, or excessive delay.

[0080] Furthermore, by arbitrarily combining acceleration, constant velocity, and deceleration motion patterns, the movement of the point of application from the starting position to the ending position can be freely set. As a result, by adjusting the motion pattern of the movable part moving along the guide rail, for example, in the case of a machine tool, tool and workpiece feeding and cutting operations can be achieved with accurate movements that correct for errors due to mechanical distortion. Moreover, when moving the point of application using multiple linear motion guide devices simultaneously, any arbitrary movement trajectory in two or three dimensions can be generated with greater accuracy.

[0081] As explained above, according to this configuration example, based on the position and orientation of the movable part 13 detected by the detection unit 25 shown in Figure 1, a target position for moving the point of application Q of the movable part 13 to the target position can be determined. In other words, by determining the target position before work and moving the movable part 13 based on this target position, feedback control that detects and corrects the position of the movable part 13 during work becomes unnecessary. Therefore, the installation of the detection unit 25 during work becomes unnecessary, and the space occupied around the device by the detection unit 25 can be eliminated. In addition, by inputting distance information of the point of application Q on the movable part 13, the amount of position correction can be easily and appropriately determined based on the generated calculation formula. Therefore, even if the position of the point of application Q on the movable part 13 changes by changing the contactor 19 (which may also be a tool), it is not necessary to detect the characteristics of the position and orientation of the movable part each time, and it can flexibly respond to various changes in conditions.

[0082] In other words, the origin O of the movable part 13 inc Since the distance information from the position of point A to the position of point Q is used as a variable term in the calculation, even if the position of point Q moves, the destination of this new position of point Q can be easily determined, and as a result, the position of point Q can be positioned with high precision.

[0083] Furthermore, since an approximation formula is generated by functionally approximating the amount of movement of the movable part 13 in the X-axis (uniaxial) direction and the position and orientation information of the movable part 13, positioning can be performed with high precision by considering the amount of movement of the movable part 13 in the X-axis (uniaxial) direction and the position and orientation information of the movable part 13.

[0084] Moreover, the absolute coordinate system of the movable part 13 (X ABS ,Y ABS ,Z ABS In the absolute coordinate system (X), errors are extracted from the errors in each axial direction of the movable part 13 and the rotation angles around each axis, and the calculation formula generation unit 33 generates a calculation formula to calculate the position of the point of action Q of the movable part 13 based on the errors obtained. ABS ,Y ABS ,Z ABS By considering the errors in each axial direction of the movable part 13 in the ) and the errors obtained from the rotation angle around each axis, the target position of movement can be determined and the point of application Q can be positioned with high precision.

[0085] Furthermore, by determining the characteristics of the displacement including the error in the X-axis (uniaxial) direction caused by temperature changes, it becomes possible to perform highly accurate positioning that takes into account the error caused by these temperature changes.

[0086] Furthermore, since the linear motion guide device 10 uses a servo motor as the drive source for the drive unit 15, high-precision positioning control becomes possible by controlling this drive source consisting of a servo motor.

[0087] The present invention is not limited to the embodiments described above. It is also intended and within the scope of protection to be provided for the combination of each configuration of the embodiments, as well as for modifications and applications by those skilled in the art based on the description in the specification and well-known art.

[0088] As described above, the following matters are disclosed in this specification: (1) A control signal generation device for a linear motion guide device comprising: a guide rail extending in a uniaxial direction; a movable part provided on the guide rail so as to be movable relative to the guide rail; a drive unit for moving the movable part along the guide rail; and an encoder for detecting the movement of the movable part, A detection unit for detecting the position and orientation of the movable part, After moving the movable part toward a designated position, the detection unit uses the position and orientation information of the movable part detected by the detection unit to determine the characteristics of the deviation between the position of the movable part detected by the encoder and the designated position, and a deviation characteristic extraction unit is provided, A calculation formula generation unit that generates a calculation formula for calculating the actual position of the movable part based on the characteristics of the displacement, A movement target position setting unit substitutes information about the target position relative to a specific point of application of the movable part, and distance information from the origin position of the movable part to the position of the point of application, into the generated calculation formula to determine the target position of the movable part to move the point of application to the target position, and sets at least one of the following between the starting position of the movement of the movable part and the ending position which is the target position: an acceleration section to accelerate the movable part, a constant velocity section to move at a constant velocity, and a deceleration section to decelerate the movable part, and generates trajectory information of the point of application during its movement for each set section. A control signal output unit outputs a control signal to move the movable part along the trajectory to the target position based on the generated trajectory information, A control signal generation device equipped with the following features. This control signal generation device can determine the target position for moving the point of action of the movable part to the target position based on the position and orientation of the movable part detected by the detection unit. Furthermore, by correcting for Abbe errors caused by mechanical distortion and determining position command values ​​in each of the acceleration section, constant velocity section, and deceleration section set between the starting and ending positions of the movement, the movement trajectory can be accurately set to the desired trajectory.

[0089] (2) The control signal generation device according to (1) or (2), wherein the displacement characteristic extraction unit generates an approximate formula that approximates the amount of movement of the movable part in the uniaxial direction and the position and orientation information of the movable part as a function. This control signal generation device allows for highly accurate positioning by considering the amount of movement of the movable part in one axis direction, as well as information on the position and orientation of the movable part.

[0090] (3) The displacement characteristic extraction unit extracts, in the absolute coordinate system of the movable part, linear motion errors in the three axes of the movable part, which consist of the one axis direction of the movable part and two axes that are orthogonal to the one axis direction and mutually orthogonal, and rotational errors in the direction of each of the three axes. The calculation formula generation unit generates a calculation formula for calculating the actual position of the point of application based on the linear motion error and the rotational error. A control signal generating device as described in (1) or (2). This control signal generation device allows for highly accurate positioning of the point of application by determining the target movement position, taking into account the errors in each axial direction of the movable part in the absolute coordinate system and the errors obtained from the rotation angle around each axis.

[0091] (4) The control signal generation device according to any one of (1) to (3), wherein the displacement characteristic extraction unit determines the displacement characteristics, including the uniaxial error caused by the temperature change. This control signal generator allows for highly accurate positioning, taking into account errors caused by temperature changes.

[0092] (5) A control signal generating device described in any one of (1) to (4), The linear motion guide device and, A control unit that drives the movable part of the linear motion guide device with a control signal output from the control signal generation device, A control system equipped with the following features. This control system determines the target position before operation and moves the movable part based on this target position, eliminating the need for feedback control that detects and corrects the position of the movable part during operation. Therefore, the installation of a detection unit during operation becomes unnecessary. This eliminates the need for the detection unit to occupy space around the device. Furthermore, by inputting distance information of the point of action in the movable part, the position correction amount can be easily and appropriately determined based on the generated calculation formula, allowing for flexible responses to various condition changes while minimizing the increase in man-hours.

[0093] (6) The drive unit is the control system described in (5), wherein the drive unit uses a servo motor as the drive source. This control system allows for highly accurate positioning control by controlling the drive source, which consists of a servo motor.

[0094] (7) A method for generating a control signal for a linear motion guide device comprising: a guide rail extending in one axial direction; a movable part provided on the guide rail so as to be movable relative to the guide rail; a drive unit for moving the movable part along the guide rail; and an encoder for detecting the movement of the movable part, The position and orientation of the movable part are detected by the detection unit. After moving the movable part toward the designated position, the position and orientation information of the movable part detected by the detection unit is used to determine the characteristics of the deviation between the position of the movable part detected by the encoder and the designated position. Based on the characteristics of the displacement, a calculation formula is generated to calculate the actual position of the movable part. The generated calculation formula is used to determine the target position of the movable part for a specific point of application, and the distance information from the origin of the movable part to the position of the point of application, thereby determining the target position of the movable part to move the point of application to the target position. At the same time, between the starting position of the movement of the movable part and the ending position which is the target position, at least one of the following is set: an acceleration section to accelerate the movable part, a constant velocity section to move it at a constant velocity, and a deceleration section to decelerate it. For each set section, trajectory information of the point of application during its movement is generated. Based on the generated trajectory information, a control signal is output to move the movable part along the trajectory to the target position. A method for generating control signals for a linear motion guide device. This control signal generation method allows for determining the target position for moving the point of action of the movable part to the target position, based on the position and orientation of the movable part detected by the detection unit. Furthermore, by correcting for Abbe errors caused by mechanical distortion and determining position command values ​​in each of the acceleration, constant velocity, and deceleration sections set between the starting and ending positions of the movement, the movement trajectory can be accurately set to the desired trajectory. [Explanation of Symbols]

[0095] 10 Linear motion guide device 11 Guide rail 13 Moving parts 15 Drive unit 17 Encoders 25 Detection unit 31. Shift characteristic extraction unit 33 Arithmetic expression generator 35. Moving target position setting unit 100 Control signal generator 200 Control Systems Q Point of action P(x) specified position

Claims

1. A control signal generation device for a linear motion guide system comprising: a guide rail extending in one axial direction; a movable part mounted on the guide rail so as to be movable relative to the guide rail; a drive unit for moving the movable part along the guide rail; and an encoder for detecting the movement of the movable part, A detection unit for detecting the position and orientation of the movable part, After moving the movable part toward a designated position, the detection unit uses the position and orientation information of the movable part detected by the detection unit to determine the characteristics of the deviation between the position of the movable part detected by the encoder and the designated position, and a deviation characteristic extraction unit is provided, A calculation formula generation unit that generates a calculation formula for calculating the actual position of the movable part based on the characteristics of the displacement, A movement target position setting unit substitutes information about the target position relative to a specific point of application of the movable part, and distance information from the origin position of the movable part to the position of the point of application, into the generated calculation formula to determine the target position of the movable part to move the point of application to the target position, and sets at least one of the following between the starting position of the movement of the movable part and the ending position which is the target position: an acceleration section to accelerate the movable part, a constant velocity section to move at a constant velocity, and a deceleration section to decelerate the movable part, and generates trajectory information of the point of application during its movement for each set section. A control signal output unit outputs a control signal to move the movable part along the trajectory to the target position based on the generated trajectory information, A control signal generation device equipped with the following features.

2. The displacement characteristic extraction unit generates an approximation formula that approximates the amount of movement of the movable part in the uniaxial direction and the position and orientation information of the movable part as a function. The control signal generation device according to claim 1.

3. The displacement characteristic extraction unit extracts, in the absolute coordinate system of the movable part, linear motion errors related to the three axes of the movable part, namely the one axis direction and two axes that are orthogonal to and mutually orthogonal to the one axis direction, and rotational errors related to the direction of each of the three axes. The calculation formula generation unit generates a calculation formula for calculating the actual position of the point of application based on the linear motion error and the rotational error. The control signal generation device according to claim 1.

4. The aforementioned displacement characteristic extraction unit determines the displacement characteristics, including the uniaxial error caused by temperature changes. The control signal generation device according to claim 1.

5. A control signal generation device according to any one of claims 1 to 4, The linear motion guide device and, A control unit that drives the movable part of the linear motion guide device by a control signal output from the control signal generation device, A control system equipped with the following features.

6. The aforementioned drive unit uses a servo motor as its drive source. The control system according to claim 5.

7. A method for generating a control signal for a linear motion guide device comprising: a guide rail extending in one axial direction; a movable part provided on the guide rail so as to be movable relative to the guide rail; a drive unit for moving the movable part along the guide rail; and an encoder for detecting the movement of the movable part, wherein The position and orientation of the movable part are detected by the detection unit. After moving the movable part toward the designated position, the position and orientation information of the movable part detected by the detection unit is used to determine the characteristics of the deviation between the position of the movable part detected by the encoder and the designated position. Based on the characteristics of the displacement, a calculation formula is generated to calculate the actual position of the movable part. The generated calculation formula is used to determine the target position of the movable part for a specific point of application, and the distance information from the origin of the movable part to the position of the point of application, thereby determining the target position of the movable part to move the point of application to the target position. At the same time, between the starting position of the movement of the movable part and the ending position which is the target position, at least one of the following is set: an acceleration section to accelerate the movable part, a constant velocity section to move it at a constant velocity, and a deceleration section to decelerate it. For each set section, trajectory information of the point of application during its movement is generated. Based on the generated trajectory information, a control signal is output to move the movable part along the trajectory to the target position. A method for generating control signals for a linear motion guide device.

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