Control device and control method

Abstract

A control device and control method control a motor so that, when an angle instruction signal instructs maintaining a constant rotation angle of an output shaft, the motor resists a load without degrading responsiveness. A driving controller performs a first determination process, based on the angle instruction signal, to determine whether maintaining the constant rotation angle is instructed, and a second determination process, based on load correlation information, to determine whether a load is applied. When maintaining is instructed and a load is detected, the motor is controlled to a lock state; when maintaining is instructed and no load is detected, the motor is controlled to a free state. The load correlation information may be an angle detection signal from an angle detection part that detects the output-shaft rotation angle. In an H-bridge driving circuit, the lock state may be implemented by setting one switch pair to a conductive state.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2025-050464 filed on Mar. 25, 2025, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to a control device for controlling a motor and a method therefor; and, more particularly, to a motor control technology for a case where an instruction to stop a motor at a constant rotation angle is provided.BACKGROUND

[0003] For example, a control system for remotely controlling a controlled object such as a model automobile, a model aircraft, and various robotic devices is known, and a servo motor used in such a remote control system is also known. For example, Japanese Laid-open Patent Publication No. 2002-127993 discloses a servo motor for driving a swash plate in a model helicopter.SUMMARY

[0004] Here, in conventional servo motor control, there is employed a method in which an absolute value of an error between a value of an instruction signal indicating a rotation angle of an output shaft of a motor and a value of a detection signal obtained by an angle detection part that detects the rotation angle of the output shaft of the motor is used as a reference, and when the absolute value of the error is within a predetermined dead zone, the motor is set to a free state, and when the absolute value of the error is not within the dead zone, the motor is driven in response to the instruction signal.

[0005] However, according to the conventional method, for example, when an instruction to stop the motor at a constant rotation angle is provided, such as when the value of the instruction signal is maintained at zero, if a load is applied to the motor, the motor in a free state is easily rotated, which makes it impossible to maintain the rotation angle indicated by the instruction signal. For clarity, the load used here refers to an external force that attempts to rotate the motor.

[0006] In order to prevent the motor rotation angle from easily changing from the instructed rotation angle due to the load, it is conceivable to control the motor to a lock state. However, in that case, when the rotation of the motor from the constant rotation angle is instructed by the instruction signal, the start-up of the motor is delayed, which may result in deterioration of responsiveness.

[0007] The present disclosure has been made in view of the above circumstances, and aims to prevent a motor from being easily rotated by a load when the motor is stopped, while suppressing deterioration of the responsiveness of the motor.

[0008] A control device according to the present disclosure is a control device for controlling a motor, and includes a driving controller configured to perform: (i) a first determination process of determining, based on an angle instruction signal that instructs a rotation angle of an output shaft of the motor, whether the angle instruction signal instructs maintaining a constant rotation angle; and (ii) a second determination process of determining, based on load correlation information correlated with a load applied to the motor, whether the load is applied to the motor; and, when it is determined that maintaining the constant rotation angle is instructed by the angle instruction signal, control the motor to a lock state when it is determined that the load is applied to the motor, and control the motor to a free state when it is determined that no load is applied to the motor.

[0009] According to the above configuration, in a state where an instruction to stop the motor at a constant rotation angle is provided, when it is determined that a load is applied to the motor, the motor is controlled to a lock state, and when it is determined that no load is applied to the motor, the motor is controlled to a free state. When the motor is controlled to a lock state, it is possible to prevent the motor from being easily rotated by the load, and when the motor is controlled to a free state, it is possible to prevent the start-up of the motor from being delayed when the rotation of the motor from the constant rotation angle is instructed by the angle instruction signal.

[0010] A control method according to the present disclosure is a control method in a control device that controls a motor, the control method comprising: performing a first determination process of determining, based on an angle instruction signal that instructs a rotation angle of an output shaft of the motor, whether the angle instruction signal instructs maintaining a constant rotation angle; and performing a second determination process of determining, based on load correlation information correlated with a load applied to the motor, whether the load is applied to the motor; and, when it is determined that maintaining the constant rotation angle is instructed by the angle instruction signal, controlling the motor to a lock state when it is determined that the load is applied to the motor, and controlling the motor to a free state when it is determined that no load is applied to the motor.

[0011] Such a control method can also obtain the same effects as those of the control device according to the present disclosure.

[0012] According to the present disclosure, it is possible to prevent the motor from being easily rotated by a load when the motor is stopped, while suppressing deterioration of the responsiveness of the motor.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a diagram illustrating a configuration example of a control system according to an embodiment of the present disclosure.

[0014] FIG. 2 is a diagram illustrating an electrical schematic configuration example of a controlled object in an embodiment.

[0015] FIG. 3 is a block diagram illustrating an internal configuration example of a control device according to an embodiment.

[0016] FIGS. 4A and 4B are diagrams for explaining a configuration example of a driving circuit of a motor.

[0017] FIG. 5 is a functional block diagram for explaining functions of a processor part of the control device according to an embodiment.

[0018] FIG. 6 is an explanatory diagram of a control example in which the motor is set to a lock state.

[0019] FIG. 7 is an explanatory diagram of a control example in which the motor is set to a free state.

[0020] FIG. 8 is a flowchart illustrating an example of a specific processing procedure to be executed in order to implement a control method according to an embodiment.

[0021] FIG. 9 is an explanatory diagram of a control device according to a modified example.DETAILED DESCRIPTION

[0022] Hereinafter, embodiments according to the present disclosure will be described in the following order:

[0023] <1. Overview of configuration of control system>

[0024] <2. Configuration of controlled object>

[0025] <3. Configuration of control device>

[0026] <4. Control method as embodiment>

[0027] <5. Processing procedure>

[0028] <6. Modified examples>

[0029] <7. Summary of embodiments>1. Overview of Configuration of Control System

[0030] FIG. 1 is a diagram illustrating an example of a configuration of a control system 100 according to an embodiment.

[0031] As illustrated, the control system 100 includes a controlled object 101 and a transmitter 102 that functions as a controller for wirelessly controlling the controlled object 101.

[0032] In the present embodiment, the controlled object 101 may be, e.g., model automobiles, model aircrafts, and various robot devices for hobby use or industrial use. Here, the model aircrafts may be in the form of airplanes, helicopters, or multicopters.

[0033] For example, it is assumed that the controlled object 101 of this example is configured as a model helicopter. Although it is not illustrated in detail, the controlled object 101 as a model helicopter includes, as mechanical components for flight, a main rotor as a main wing, a swash plate for adjusting an inclination angle of blades of the main rotor, and a tail rotor, and further includes electronic devices such as servo motors for driving the mechanical components, and communication devices such as a receiver for communicating with the transmitter 102, specifically for receiving at least control signals from the transmitter 102.

[0034] The transmitter 102 includes various manipulation elements for controlling the controlled object 101, a processor for generating control signals according to the manipulation of the manipulation elements, and a communication device for transmitting the control signals to the controlled object 101. Specifically, when the controlled object 101 is a model helicopter as in this example, the transmitter 102 includes a manipulation element for instructing the rotational speed of the main rotor of the controlled object 101, and a manipulation element for instructing angles in pitch, roll, and yaw directions and collective pitch. The processor generates control signals including operation instruction information for the rotational speed of the main rotor, and each of the pitch, the roll, the yaw, and the collective pitch according to the manipulation of the manipulation elements.

[0035] Japanese Laid-open Patent Publication No. 2002-127993 described above will be referred to regarding the adjustment of the pitch, the roll, and the collective pitch in the model helicopter. In the controlled object 101 of this example, the yaw angle is adjusted by adjusting the rotor pitch angle of the tail rotor.2. Configuration of Controlled Object

[0036] FIG. 2 is a block diagram illustrating an electrical schematic configuration example of the controlled object 101.

[0037] As illustrated, the controlled object 101 includes a receiver 111, a gyro device 112, a throttle servo motor 113, and various servo motors 1 for adjusting pitch, roll, and collective pitch. Hereinafter, in order to distinguish the pitch servo motor, the roll servo motor, and the collective pitch servo motor, they are respectively referred to as “servo motor 1_1” (for pitch), “servo motor 1_2” (for roll), and “servo motor 1_3” (for collective pitch).

[0038] The controlled object 101 of this example also includes a motor for adjusting the yaw angle, i.e., a motor for driving the tail rotor. However, illustration thereof is omitted because it has little relevance to a control method as an embodiment to be described later.

[0039] Here, in this example, for simplicity of description, it is assumed that the swash mixing method disclosed in Japanese Laid-open Patent Publication No. 2002-127993 is not employed for the adjustment of the pitch, the roll, and the collective pitch using a swash plate. In other words, a driving mechanism for roll angle adjustment, a driving mechanism for pitch angle adjustment, and a driving mechanism for collective pitch adjustment are provided as independent mechanisms as the driving mechanism of the swash plate. This is merely an example for explanation, and a swash mixing method may be employed.

[0040] In the controlled object 101 of this example, the main rotor is driven using an engine (not illustrated) as a driving source. The throttle servo motor 113 is provided as a servo motor for adjusting a carburetor of the engine that drives the main rotor.

[0041] The receiver 111 has an antenna 111a and performs wireless data communication with the transmitter 102 according to a predetermined wireless communication method.

[0042] The receiver 111 receives control signals from the transmitter 102. As described above, the control signals of this example include operation instruction information for the rotational speed of the main rotor and each of the pitch, the roll, the yaw, and the collective pitch. Hereinafter, the description of the yaw angle control will be omitted.

[0043] Specifically, the control signals of this example include, as information related to the instruction of the rotational speed of the main rotor, information on the instruction of the rotation angle of the throttle servo motor 113, as well as information indicating the rotation angle of the pitch adjustment servo motor 1_1, information indicating the rotation angle of the roll adjustment servo motor 1_2, and information indicating the rotation angle of the collective pitch adjustment servo motor 1_3.

[0044] The receiver 111 outputs, to the throttle servo motor 113, information included in the received control signal that instructs the rotation angle of the throttle servo motor 113. Accordingly, the main rotor is rotated at a rotational speed corresponding to the operator's manipulation of the transmitter 102.

[0045] Further, the receiver 111 outputs, to the gyro device 112, information included in the received control signal indicating the respective rotation angles of the servo motors 1_1 to 1_3.

[0046] Hereinafter, a signal that transmits the information indicating the rotation angle of the servo motor will be referred to as “angle instruction signal” meaning a signal that instructs a rotation angle.

[0047] The gyro device 112 includes an angular velocity sensor, and performs attitude stabilization control of the controlled object 101 based on detection information of the angular velocity sensor. Specifically, the gyro device 112 performs attitude stabilization control by adjusting at least one of the angle instruction signals for the servo motors 1_1 to 1_3 based on the detection information of the angular velocity sensor. In this example, in the attitude stabilization control, the adjustment is performed for all the angle instruction signals for the servo motors 1_1 to 1_3, for example.

[0048] The gyro device 112 outputs the adjusted angle instruction signals to the corresponding servo motors 1.

[0049] In each servo motor 1, a built-in motor (a motor 2 to be described later) is driven based on the inputted angle instruction signal. Accordingly, the operation of the controlled object 101 corresponding to the operator's manipulation of the transmitter 102 is realized for each of the pitch angle, the roll angle, and the collective pitch. Further, the attitude stabilization control of the controlled object 101 is realized.

[0050] Here, the processing performed by each servo motor 1 based on the angle instruction signal in the present embodiment will be described in detail later.

[0051] In the controlled object 101 configured as a model helicopter, the main rotor may also be driven using a motor as a driving source. In that case, it is conceivable to provide a motor serving as the driving source for the rotor instead of the throttle servo motor 113, and to provide an electric speed controller (ESC) for controlling the motor.

[0052] The case in which the swash mixing method can be employed has been described. When the swash mixing method is employed, a mixed angle instruction signal is inputted to each servo motor 1.3. Configuration of Control Device

[0053] FIG. 3 is a block diagram illustrating an internal configuration example of the servo motor 1, which is an embodiment of a control device according to the present disclosure.

[0054] As illustrated, the servo motor 1 includes a motor 2, and further includes a processor part 3, a driving circuit 4, an angle detection part 5, and an analog to digital (A / D) converter 6. In addition, the servo motor 1 includes, as mechanical components, a gear gr and an output shaft os.

[0055] The motor 2 functions as a driving source for the driving mechanism by transmitting the rotational power to the driving mechanism of the swash plate. Although detailed illustration is omitted, in the servo motor 1, the rotation of the rotor of the motor 2 is transmitted to the output shaft os via the gear gr. The rotational power of the output shaft os is transmitted to the driving mechanism of the swash plate.

[0056] The driving circuit 4 is configured as a circuit for supplying a driving current to a driving coil 2a of the motor 2. Specifically, the driving circuit 4 has a function of adjusting a current value of the current flowing through the driving coil 2a, and a function of switching polarity.

[0057] FIGS. 4A and 4B are diagrams for explaining a configuration example of the driving circuit 4.

[0058] FIGS. 4A and 4B illustrate the configuration example for supplying a current to the driving coil 2a of the driving circuit 4. FIG. 4A illustrates a state in which the motor 2 is rotated in a forward direction, and FIG. 4B illustrates a state in which the motor 2 is rotated in a reverse direction.

[0059] The driving circuit 4 of this example includes a current supply part 4a as a configuration for adjusting the current value of the current flowing through the driving coil 2a, and includes a supply control part 4b as a configuration for adjusting the polarity of the current flowing through the driving coil 2a.

[0060] The current supply part 4a is configured as a variable current output circuit configured to adjust the current value of the current outputted to the supply control part 4b to a value corresponding to an instruction from the processor part 3 shown in FIG. 3.

[0061] In this example, an H-bridge circuit is employed as the supply control part 4b. As illustrated, in the supply control part 4b that is the H-bridge circuit, switches SW1 and SW2 are provided as a pair of switches on the positive side (the current supply part 4a side) when viewed from the driving coil 2a, and switches SW3 and SW4 are provided as a pair of switches on the negative side (the ground GND side) when viewed from the driving coil 2a.

[0062] As illustrated, the driving coil 2a is inserted between the connection point between the switches SW1 and SW3 and the connection point between the switches SW2 and SW4.

[0063] As shown in FIG. 4A, in the case of rotating the motor 2 in the forward direction, in the supply control part 4b that is the H-bridge circuit, among the switches SW1, SW2, SW3, and SW4, only the switches SW1 and SW4 are turned ON, and the switches SW2 and SW3 are turned OFF. In this case, the driving current flows to the ground GND via the switch SW1→the driving coil 2a→the switch SW4.

[0064] On the contrary, in the case of rotating the motor 2 in the reverse direction, in the supply control part 4b that is the H-bridge circuit, among the switches SW1, SW2, SW3, and SW4, only the switches SW2 and SW3 are turned ON, and the switches SW1 and SW4 are turned OFF. In this case, the driving current flows to the ground GND via the switch SW2→the driving coil 2a→the switch SW3, and a driving current in a direction opposite to that during forward rotation flows through the driving coil 2a.

[0065] In FIG. 3, the processor part 3 is configured as, e.g., a microcomputer including a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM). The CPU executes processing according to the program stored in the ROM to realize various operations of the servo motor 1, such as reception of an angle instruction signal from an external device (the gyro device 112 in this example) and control of the motor 2 based on the angle instruction signal.

[0066] The processor part 3 controls the operation of the motor 2 by controlling the operation of the driving circuit 4 based on the value of the angle instruction signal. Specifically, in this example, the processor part 3 controls the operation of the motor 2 by controlling the output current value of the current supply part 4a and controlling the switches SW1 to SW4 in the supply control part 4b based on the value of the angle instruction signal.

[0067] In the servo motor 1, the rotation control of the motor 2 is performed based on information on the rotation angle of the motor 2 detected by the angle detection part 5. Here, the angle detection part 5 detects the rotation angle of the motor 2, specifically, the rotation angle of the output shaft os described above. In this example, a potentiometer is used.

[0068] As illustrated, the detection signal of the angle detection part 5 is digitally sampled by the A / D converter 6 and inputted to the processor part 3.

[0069] Hereinafter, the detection signal from the angle detection part 5 will be referred to as “angle detection signal.” In addition, a sampled value outputted from the A / D converter 6 will be referred to as “angle detection value.” The output signal of the A / D converter 6 can also be referred to as an angle detection signal in the form of a digital signal.

[0070] The processor part 3 controls the rotation angle of the motor 2 by feedback loop control using the angle detection value inputted from the A / D converter 6 as feedback input. Specifically, the processor part 3 calculates an error e between the rotation angle value indicated by the angle instruction signal inputted from the gyro device 112 (hereinafter referred to as “angle instruction value”) and the angle detection value inputted from the A / D converter 6, and performs controls of the output current value of the driving circuit 4 such that the error e becomes zero, i.e., performs control of the driving current value flowing through the driving coil 2a and control of the polarity of the driving current.

[0071] Here, as understood from the above description, the rotation angle control of the motor 2 of this example is performed not based on the rotation angle of the rotor of the motor 2, but based on the rotation angle of the output shaft os. Accordingly, in this example, the angle instruction signal is not a signal that instructs the rotation angle of the rotor of the motor 2, but is a signal that instructs the rotation angle of the output shaft os.

[0072] As described above, the dead zone was conventionally provided in the rotation angle control of the motor 2 based on the error e. Specifically, when the absolute value of the error e (hereinafter referred to as “error value E”) is within a predetermined value that defines the dead zone, the processor part 3 does not perform the rotation control of the motor by feedback loop control based on the error e.

[0073] Further, the processor part 3 of the present embodiment performs control corresponding to a state in which the motor 2 is stopped, i.e., a state in which it is instructed to maintain the rotation angle at a constant angle by the angle instruction signal, as will be described later.4. Control Method as Embodiment

[0074] Here, as described above, the method in which the motor 2 is set to a free state when the absolute value of the error e (error value E) is within a predetermined dead zone was employed in the conventional case. Therefore, when an instruction to stop the motor 2 at a constant rotation angle is provided, if a load is applied to the motor 2, the motor 2 is easily rotated, which makes it impossible to maintain the rotation angle instructed by the angle instruction signal.

[0075] In order to prevent the motor rotation angle from easily changing from the instructed rotation angle due to the load, it is conceivable to control the motor 2 to a lock state. However, in that case, when the rotation of the motor 2 from the constant rotation angle is instructed by the angle instruction signal, the start-up of the motor 2 is delayed, which may result in deterioration of responsiveness.

[0076] Here, for clarity, a lock state of the motor 2 refers to a state in which the motor 2 is held in a rotation stop state. Holding the motor in a rotation stop state does not require that the rotation-stopped state is maintained against loads of any magnitude, and requires that an electromagnetic resisting force that suppresses the rotation of the motor 2 against a load is generated.

[0077] A free state of the motor 2 refers to a state in which the motor 2 is in a non-energized state and the above-described electromagnetic resisting force is not generated.

[0078] In view of the above circumstances, the present embodiment aims to prevent the motor 2 from being easily rotated by a load when the motor 2 is stopped, while suppressing deterioration of the responsiveness of the motor 2.

[0079] FIG. 5 is a functional block diagram for explaining functions of the processor part 3 of the servo motor 1 according to an embodiment in order to achieve the above object.

[0080] As illustrated, the processor part 3 has a function of a driving controller F1.

[0081] The driving controller F1 performs a first determination process of determining, based on the angle instruction signal, whether or not it is instructed to maintain a constant rotation angle by the angle instruction signal, and a second determination process of determining, based on load correlation information correlated with a load applied to the motor 2, whether or not a load is applied to the motor 2. Further, the driving controller F1 controls the motor 2 to a lock state when it is determined by the first determination process that it is instructed to maintain the constant rotation angle by the angle instruction signal and it is determined by the second determination process that the load is applied to the motor 2, and controls the motor 2 to a free state when it is determined by the first determination process that it is instructed to maintain the constant rotation angle by the angle instruction signal and it is determined by the second determination process that no load is applied to the motor 2.

[0082] In this example, the first determination process described above, i.e., the process of determining whether or not it is instructed to maintain a constant rotation angle by the angle instruction signal, is performed as follows. In other words, on the assumption that the angle instruction value at time t is “At” and the angle instruction value at one time step before time t is “At−1,” the absolute value (|At−At−1|) of the difference between “At” and “At−1” is calculated as an instruction value difference ΔAt, and whether or not the instruction value difference ΔAt is zero (ΔAt=0) is determined.

[0083] Further, in this example, in the second determination process, an angle detection signal, which is the detection signal of the angle detection part 5, is used as the above-described load correlation information. Specifically, in the second determination process of this example, on the assumption that an angle detection value at time t is “Pt” and an angle detection value at one time step before time t is “Pt−1,” the absolute value (|Pt−Pt−1|) of the difference between “Pt” and “Pt−1” is calculated as a detection value difference ΔPt, and whether or not the detection value difference ΔPt is a value other than zero (ΔPt≠0) is determined.

[0084] According to the control method of the embodiment in which the motor 2 is controlled to a lock state or a free state as described above based on the results of the first and second determination processes, when an instruction to stop the motor 2 at a constant rotation angle is issued, if it is determined that a load is applied to the motor 2, the motor 2 is controlled to a lock state, and if it is determined that no load is applied to the motor 2, the motor 2 is controlled to a free state.

[0085] When the motor 2 is controlled to a lock state, it is possible to prevent the motor 2 from being easily rotated by the load, and when the motor 2 is controlled to a free state, it is possible to prevent the start-up of the motor 2 from being delayed when the rotation from the constant rotation angle is instructed by the angle instruction signal.

[0086] Accordingly, the motor 2 can be prevented from being easily rotated by the load when the rotation of the motor 2 is stopped while suppressing deterioration in responsiveness of the motor 2.

[0087] FIG. 6 is an explanatory diagram illustrating a control example in which the motor 2 is set to a lock state.

[0088] As illustrated, in order to set the motor 2 to a lock state, among the switches SW1, SW2, SW3, and SW4 of the supply control part 4b that is an H-bridge circuit, only the switches SW3 and SW4 are turned ON, and the switches SW1 and SW2 are turned OFF. Accordingly, it is possible to generate an electromagnetic holding force that resists the load on the motor 2, thereby setting the motor 2 to a lock state.

[0089] Here, the control in which only the switches SW3 and SW4 are turned ON as described above can also be referred to as the control in which only a pair of switches on the negative electrode side between a pair of switches on the positive electrode side and a pair of switches on the negative electrode side of the H-bridge circuit are set to a conductive state.

[0090] The control for setting the motor 2 to a lock state is not limited to the control in which only the pair of switches on the negative electrode side of the H-bridge circuit are set to a conductive state as described above. For example, the motor 2 can also be set to a lock state by setting only the pair of switches on the positive electrode side (the switches SW1 and SW2) of the H-bridge circuit to a conductive state.

[0091] Here, in a stepping motor as a motor that operates based on the angle instruction signal, it is required to supply a current to the driving coil of the motor in order to generate a holding force. On the contrary, by adopting the method in which only one pair of switches of the H-bridge circuit are set to a conductive state as described above, it is possible to generate a holding force without supplying a current to the driving coil 2a.

[0092] Accordingly, it is possible to reduce power consumption when preventing the motor 2 from being easily rotated by a load when the rotation of the motor 2 is stopped.

[0093] FIG. 7 is an explanatory diagram illustrating a control example in which the motor 2 is set to a free state.

[0094] In this example in which an H-bridge circuit is employed, the control for setting the motor 2 to a free state is the control in which all the switches SW1, SW2, SW3, and SW4 are turned OFF, as illustrated.

[0095] Here, the driving controller F1 of this example performs a third determination process for determining whether or not the error value E (the absolute value of the error between the value of the angle instruction signal and the value of the angle detection signal) is within a predetermined value DB. Here, the predetermined value DB is a threshold that defines the above-described dead zone.

[0096] When it is determined in the third determination process that the error value E is not within the predetermined value DB, the driving controller F1 performs control such that the rotation angle of the motor 2 becomes the rotation angle indicated by the angle instruction value. In other words, the control is performed to reduce the above-described error e to zero by feedback loop control.

[0097] Accordingly, even when the motor 2 is set to a lock state in response to an instruction to stop the motor 2 at a constant rotation angle, if the error between the angle instruction signal and the angle detection signal increases to a certain extent due to a load, the motor 2 is driven to be returned to the constant rotation angle.

[0098] Hence, even if a load of a magnitude greater than the holding force due to a lock state is applied to the motor 2 in a lock state, it is possible to prevent the rotation angle of the motor 2 from continuing to deviate from the instructed rotation angle, thereby realizing appropriate motor control.5. Processing Procedure

[0099] A specific example of the processing procedure executed by the processor part 3 to implement the control method as the above-described embodiment will be described with reference to the flowchart of FIG. 8.

[0100] The processing illustrated in FIG. 8 is executed by the CPU in the processor part 3 based on the program stored in the ROM in the processor part 3. However, in the following description, for simplicity of description, the processing is executed by the processor part 3.

[0101] First, in step S101, the processor part 3 inputs an angle instruction value At and an angle detection value Pt.

[0102] In step S102 subsequent to step S101, the processor part 3 calculates an error value Et. Here, the error value Et is the error value E at time t, and the processor part 3 calculates the error value Et as |Pt−At|.

[0103] In step S103 subsequent to step S102, the processor part 3 calculates an instruction value difference ΔAt and a detection value difference ΔPt. (The instruction value difference ΔAt=|At−At−1|, and the detection value difference ΔPt=|Pt−Pt−1|.)

[0104] In step S104 subsequent to step S103, the processor part 3 determines whether or not the error value Et is less than or equal to the predetermined value DB. This corresponds to a process of determining whether or not the error value Et is within the dead zone, and corresponds to the above-described third determination process.

[0105] When it is determined in step S104 that the error value Et is less than or equal to the predetermined value DB (i.e., within the dead zone), the processor part 3 proceeds to step S105 and determines whether or not the instruction value difference ΔAt is zero. This corresponds to the above-described first determination process for determining whether or not it is instructed to maintain a constant rotation angle by the angle instruction signal.

[0106] When it is determined in step S105 that the instruction value difference ΔAt is zero (i.e., it is instructed to maintain a constant rotation angle), the processor part 3 proceeds to step S107 and determines whether or not the detection value difference ΔPt is a value other than zero. This corresponds to the above-described second determination process for determining whether or not a load is applied to the motor 2.

[0107] When it is determined in step S107 that the detection value difference ΔPt is not a value other than zero (i.e., no load is applied to the motor 2), the processor part 3 proceeds to step S108 and controls the motor 2 to a free state.

[0108] On the other hand, when it is determined in step S107 that the detection value difference ΔPt is a value other than zero (i.e., a load is applied to the motor 2), the processor part 3 proceeds to step S109 and controls the motor 2 to a lock state.

[0109] Further, when it is determined in step S104 that the error value Et is not less than or equal to the predetermined value DB, the processor part 3 proceeds to step S106 and controls the motor 2 to a driving state according to the instruction value. Specifically, the motor 2 is driven by feedback loop control based on the above-described error e.

[0110] Due to the processing of steps S104→S106, the dead zone is realized for the driving control of the motor 2 by the feedback loop control based on the error e. Further, due to the processing of steps S104→S106, it is possible to prevent the rotation angle of the motor 2 (the rotation angle of the output shaft os) from continuing to deviate from the instructed rotation angle when a load of a magnitude greater than the holding force due to a lock state is applied.

[0111] Further, when it is determined in the above-described step S105 that the instruction value difference ΔAt is not zero (i.e., it is not instructed to maintain a constant rotation angle), the processor part 3 proceeds to the above-described step S108 and controls the motor 2 to a free state.

[0112] In other words, when the error value Et is within the dead zone and it is not instructed to maintain a constant rotation angle by the angle instruction signal (i.e., the rotation of the motor 2 is instructed), the motor 2 is controlled to a free state.

[0113] Upon execution of any one of the processes of steps S106, S108, and S109, the processor part 3 proceeds to step S110.

[0114] In step S110, the processor part 3 determines whether or not the processing has been terminated, i.e., whether or not predetermined processing termination conditions have been satisfied, such as whether or not the power supply has been interrupted.

[0115] When it is determined in step S110 that the processing has not been terminated, the processor part 3 returns to step S101. As a result, the processing proceeds to processing at next processing time.

[0116] When it is determined in step S110 that the processing has been terminated, the processor part 3 ends the series of processes illustrated in FIG. 8.6. Modified Examples

[0117] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the specific examples described above, and various modified examples can be adopted.

[0118] For example, in the above description, an example in which the processor part that executes processing as the driving controller F1 is provided in the same device as the device including the motor 2 (the servo motor 1), and the control method of the present embodiment is completed in a single device has been provided. However, the processor part that executes processing as the driving controller F1 is not necessarily provided in the device including the motor 2.

[0119] FIG. 9 is an explanatory diagram of a control device 10 as a modified example in which the processor part that executes processing as the driving controller F1 is provided in a device separate from the device including the motor 2.

[0120] In FIG. 9, the servo motor 11 has the same hardware configuration as that of the servo motor 1, but the processor part 3 does not serve as the driving controller F1.

[0121] The control device 10 includes a processor part serving as the driving controller F1.

[0122] In this case, the driving controller F1 executes the above-described first and second determination processes based on the angle detection value outputted from the A / D converter 6 provided in the servo motor 11 and the angle instruction value inputted from an external source, and executes processing for controlling the motor 2 in the servo motor 11 to a lock state or a free state based on the results of the first and second determination processes. Specifically, the instruction to set the motor 2 to a lock state or a free state is issued to the processor part 3 in the servo motor 11 based on the results of the first and second determination processes.

[0123] Further, in the above description, an example in which the control method of the present disclosure is applied to the servo motors 1 for adjusting the pitch, the roll, and the collective pitch in a model helicopter has been provided. However, the control method of the present disclosure can be suitably applied to various motors, such as servo motors for steering or throttle control in model automobiles, servo motors for controlling ailerons, rudders, and the like in model aircraft, and servo motors for driving joints of hobby or industrial robots.

[0124] Further, in the above description, an example in which the value of the angle detection signal detected by the angle detection part 5 is used as the load correlation information has been provided. However, various types of load correlation information may be used.

[0125] For example, when a torque sensor is provided for the motor 2, the detection information from the torque sensor may be used as the load correlation information. In this case, if torque is generated in a state where it is instructed to maintain a constant rotation angle by the angle instruction value, it can be estimated that a load is applied.

[0126] Alternatively, for example, in a case where application of a motor for driving wheels of a model automobile is assumed, the estimation information of the inclination angle of the road surface may be used as the load correlation information.7. Summary of Embodiments

[0127] As described above, the control device (the servo motor 1, and the control device 10) according to the embodiment is a control device for controlling the motor (the motor 2), and includes the driving controller F1 that performs the first determination process for determining, based on the angle instruction signal that instructs the rotation angle of the output shaft of the motor, whether or not it is instructed to maintain a constant rotation angle by the angle instruction signal, and the second determination process for determining whether or not a load is applied to the motor based on the load correlation information correlated with the load applied to the motor. When it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that the load is applied to the motor, the driving controller controls the motor to a lock state. When it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that no load is applied to the motor, the driving controller controls the motor to a free state.

[0128] According to the above configuration, in a state where an instruction to stop the motor at a constant rotation angle is issued, if it is determined that a load is applied to the motor, the motor is controlled to a lock state, and if it is determined that no load is applied to the motor, the motor is controlled to a free state. When the motor is controlled to a lock state, it is possible to prevent the motor from being easily rotated by the load, and when the motor is controlled to a free state, it is possible to prevent the start-up of the motor from being delayed when the rotation from the constant rotation angle is instructed by the angle instruction signal.

[0129] Accordingly, with the above configuration, it is possible to prevent the motor from being easily rotated by a load when the rotation of the motor is stopped, while suppressing deterioration in responsiveness of the motor.

[0130] Further, in the control device according to the embodiment, the driving controller performs the third determination process in which the absolute value of the error between the value of the angle instruction signal and the value of the angle detection signal, which is the detection signal of the angle detection part 5 that detects the rotation angle of the output shaft of the motor, is calculated, and it is determined whether or not the absolute value of the error is within a predetermined value. When it is determined by the third determination process that the absolute value of the error is not within the predetermined value, the control is performed such that the rotation angle of the output shaft of the motor becomes the rotation angle indicated by the angle instruction value.

[0131] Accordingly, even when the motor is set to a lock state in response to the instruction to stop the motor at a constant rotation angle, if the error between the angle instruction signal and the angle detection signal increases to a certain extent due to the load, the motor is driven to be returned to the constant rotation angle.

[0132] Hence, even if a load of a magnitude greater than the holding force due to the lock state is applied to the motor, it is possible to prevent the rotation angle of the motor from continuing to deviate from the instructed rotation angle, thereby realizing appropriate motor control.

[0133] Further, the control device according to the embodiment (the servo motor 1) is configured as a servo motor device including a motor and an angle detection part that detects a rotation angle of an output shaft of the motor, and the driving controller uses, as the load correlation information, the angle detection signal that is the detection signal of the angle detection part.

[0134] Accordingly, the operation for setting the motor to a lock state or a free state based on the determination results of the first and second determination processes are completed in a single device as the servo motor device.

[0135] For example, when the motor and the angle detection part are provided in a device separate from a device including the driving controller and the operations thereof are realized by multiple devices, wiring between devices is required for communication of control signals for controlling the motor to a lock state or a free state or angle detection signals. Since, however, the operations are completed in a single device as described above, the wiring between devices is not required. Hence, the wiring work for assembling the controlled object can be simplified, and the workload associated with the assembly of the controlled object can be reduced.

[0136] Further, in the control device according to the embodiment, the control for setting the motor to a lock state is the control for setting only one pair of switches, among the pair of switches on the positive electrode side and the pair of switches on the negative electrode side of the H-bridge circuit of the motor driving circuit to a conductive state.

[0137] In the stepping motor as a motor that operates based on the angle instruction signal, it is required to supply a current to the driving coil of the motor in order to generate a holding force. On the contrary, by adopting a method in which only one switch pair of the H-bridge circuit is set to a conductive state as described above, it is possible to generate a holding force without supplying a current to the driving coil of the motor.

[0138] Accordingly, it is possible to reduce power consumption while preventing the motor from being easily rotated by a load when the rotation of the motor is stopped.

[0139] The control method according to the embodiment is a control method for a control device that controls a motor. The control method includes: performing the first determination process for determining, based on the angle instruction signal that instructs the rotation angle of the output shaft of the motor, whether or not it is instructed to maintain a constant rotation angle by the angle instruction signal; and performing the second determination process for determining whether or not a load is applied to the motor based on the load correlation information correlated with the load applied to the motor. When it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that the load is applied to the motor, the motor is controlled to a lock state. When it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that no load is applied to the motor, the motor is controlled to a free state.

[0140] Such a control method can also obtain the same effects as those of the control device according to the above-described embodiment.

Claims

1. A control device that controls a motor, comprising:a driving controller configured to perform a first determination process that determines, based on an angle instruction signal that is a signal instructing a rotation angle of an output shaft of the motor, whether or not it is instructed to maintain a constant rotation angle by the angle instruction signal, and a second determination process that determines, based on load correlation information that is information correlated with a load applied to the motor, whether or not the load is applied to the motor,wherein when it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that the load is applied to the motor, the motor is controlled to a lock state, andwhen it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that no load is applied to the motor, the motor is controlled to a free state.

2. The control device of claim 1, wherein the driving controller performs a third determination process in which an absolute value of an error between a value of the angle instruction signal and a value of an angle detection signal that is a detection signal of an angle detection part that detects a rotation angle of an output shaft of the motor is calculated and whether or not the absolute value of the error is within a predetermined value is determined, andwhen it is determined by the third determination process that the absolute value of the error is not within the predetermined value, the driving controller performs control such that the rotation angle of the output shaft of the motor becomes the rotation angle indicated by the angle instruction value.

3. The control device of claim 1, wherein the control device is configured as a servo motor device including the motor and an angle detection part that detects the rotation angle of the output shaft of the motor, andthe driving controller uses, as the load correlation information, an angle detection signal that is a detection signal of the angle detection part.

4. The control device of claim 1, the control for setting the motor to a lock state comprises setting only one pair of switches, among a pair of switches on a positive electrode side and a pair of switches on a negative electrode side of an H-bridge circuit provided in a driving circuit of the motor, to a conductive state.

5. The control device of claim 2, the control for setting the motor to a lock state comprises setting only one pair of switches, among a pair of switches on a positive electrode side and a pair of switches on a negative electrode side of an H-bridge circuit provided in a driving circuit of the motor, to a conductive state.

6. The control device of claim 3, the control for setting the motor to a lock state comprises setting only one pair of switches, among a pair of switches on a positive electrode side and a pair of switches on a negative electrode side of an H-bridge circuit provided in a driving circuit of the motor, to a conductive state.

7. A control method for a control device that controls a motor, the control method comprising:performing a first determination process that determines, based on an angle instruction signal that is a signal instructing a rotation angle of an output shaft of a motor, whether or not it is instructed to maintain a constant rotation angle by the angle instruction signal and a second determination process that determines, based on load correlation information that is information correlated with a load applied to the motor, whether or not the load is applied to the motor;controlling the motor to a lock state when it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that the load is applied to the motor, andcontrolling the motor to a free state when it is determined by the first determination process that it is instructed to maintain a constant rotation angle by the angle instruction signal and it is determined by the second determination process that no load is applied to the motor.

Images