Controller for robot motor and method thereof, robot and drive unit thereof

Abstract

A controller for a robot motor (50) comprises a power drive stage (40) and a sub-controller (100); the power drive stage comprises power electronics (41-46) for driving the motor, and the sub-controller is adapted to generate drive signals for driving the power electronics (41-46), wherein the sub-controller (100) can cut off the drive signals based on a stop request to stop driving the motor (50); meanwhile, the sub-controller (100) can also switch part of the power electronics (41-46) based on a brake request to implement short-circuit braking on the motor (50). The application also provides a drive unit comprising the controller, a robot comprising the drive unit, and a method for controlling a robot motor by using the controller.

Description

Technical Field

[0001] The present invention relates to a controller for a robot motor (“robot motor”), a robot drive unit including the controller, a robot including the drive unit, and a method for controlling the robot motor using the controller. Background Technology

[0002] EN60204-1 and EN61800-5-2 relate to the so-called safe torque shutdown function in robot control, in which the robot needs to be stopped as quickly as possible in the event of an emergency.

[0003] This can be achieved by cutting off the power supplied to the motor in the controller circuit to avoid providing the motor with the power that could generate driving force.

[0004] To enable the robot to stop more quickly, three-phase short-circuit braking of the motor is achieved by short-circuiting the three phases of the motor. When braking is required, the motor controller short-circuits the three-phase power supply circuit of the motor, causing the motor to generate braking torque, thereby achieving the braking effect.

[0005] Such short-circuit braking typically employs a circuit independent of the safe torque shutdown circuit, which short-circuits the motor's power terminals via resistors, relays, and diodes.

[0006] Using two completely independent circuits to implement safe torque shutdown and short-circuit braking would increase workload and cost. Furthermore, the use of relays would occupy board space. Additionally, the existing safe torque shutdown function cuts off all power to the power electronics, thus preventing control of low-side components and making short-circuit braking impossible. Summary of the Invention

[0007] The purpose of this invention is to improve the control of robots, especially one or more robot motors, preferably the power-off and braking of the motors, and preferably to reduce or avoid one or more of the aforementioned problems. In particular, the objective or design concept of this invention is to simultaneously satisfy the functional safety requirements of the safe torque shutdown circuit and the implementation requirements of the motor short-circuit braking function in a single circuit. Alternatively, the objective or design concept of this invention may be to trigger the short-circuit braking function in a controlled manner after the safe torque shutdown function is triggered, thereby achieving rapid motor shutdown. Alternatively, the objective or design concept of this invention may be that the short-circuit braking can only be triggered after the safe torque shutdown is available.

[0008] The aforementioned objectives, preferably one or more of the aforementioned goals, are achieved, particularly by the controller for robot motors of the present invention. The present invention also relates to a drive unit including the controller described herein, a robot including the drive unit, and a method for controlling robot motors using the controller described herein. The present invention also provides preferred embodiments of the above solutions.

[0009] According to some embodiments of the present invention, a controller for a robot motor, particularly a controller for a robot (including a drive unit for the motor), and / or a controller for controlling the motor, comprises: A power drive stage, comprising, preferably at least six, power electronic devices, which are at least temporarily used to drive the motor, or individually used for or suitable for this purpose; and Sub-controller, in some embodiments, a sub-controller structure that at least temporarily generates drive signals for driving power electronics (to drive a motor), or is used for or adapted for this purpose.

[0010] According to some embodiments of the present invention, the motor is a multiphase motor, preferably a three-phase motor, which includes a plurality of electromagnets powered by or potentially powered by power electronic devices to drive the motor (rotor) (electromagnetically).

[0011] According to some embodiments of the present invention, the robot includes a manipulator arm and / or a mobile base, wherein the motor is preferably used to drive the joints of the manipulator arm or the wheels of the mobile base, etc.

[0012] This invention offers significant advantages based on the working conditions of such motors and robots, but is not limited to such motors or robots.

[0013] According to some embodiments of the invention, the sub-controller, preferably one or more electronic components, more preferably electronic components with at least two safety chains, at least temporarily, especially based on, preferably in response to a stop request, cuts off the drive signal to stop the drive motor, or is used or adapted for this purpose.

[0014] According to some embodiments of the invention, this can achieve a so-called "safe torque off" (STO), preferably as defined in EN60204-1. According to some embodiments, stopping the drive motor includes, preferably, preventing the supply of electrical power that could generate driving force and accelerate the motor to the motor, and more preferably, preventing the supply of electrical power that could generate driving force to the motor.

[0015] According to some embodiments of the invention, the sub-controller switches some power electronics, preferably only a (actual) subset of power electronics, such as half and / or three, at least temporarily, especially in response to a braking request, to apply short-circuit braking to the motor, or is used or adapted for this purpose.

[0016] According to some embodiments of the present invention, this can achieve so-called "short-circuit braking" (SCB). According to some embodiments, the motor short-circuit braking includes short-circuiting the motor's power supply circuit, preferably a three-phase power supply circuit, to generate braking torque in the motor, thereby achieving a braking effect.

[0017] According to some embodiments of the present invention, the sub-controller applies short-circuit braking to the motor by switching some power electronics. The advantage is that the STO and SCB can be implemented through the same sub-controller. Therefore, according to some embodiments, it is not necessary to set up two separate circuits for the STO and SCB. Thus, according to some embodiments, costs can be reduced. According to some embodiments, the SCB does not need to use relays that occupy board space. According to some embodiments of the present invention, the STO and SCB are integrated through power electronics.

[0018] According to some embodiments of the present invention, the braking request is triggered by a stop request and / or by a drive signal cutting off an established indication, preferably by at least one drive signal cutting off an established feedback signal.

[0019] Therefore, according to some embodiments, the SCB and STO (function) are interlocked, preferably by hardware interlock, and this interlock is preferably independent of firmware functions. In other words, according to some embodiments, the SCB (function) will not function when the STO function is not triggered, a design that can advantageously improve reliability.

[0020] According to some embodiments of the invention, there is a configurable, preferably parameterized, delay before the braking request is triggered by an indication of a stop request and / or a cut-off drive signal, respectively. According to some embodiments, this design optimizes the behavior of the robot (motor) because the drive force is cut off first, and short-circuit braking with a configurable delay is initiated.

[0021] According to some embodiments of the invention, the sub-controller switches these power electronic devices to supply power to a portion of the power electronic devices by closing a switch, thereby implementing short-circuit braking of the motor, or is used for or adapted to this purpose. In particular, the sub-controller may include the switch.

[0022] Alternatively, according to some embodiments, short-circuit braking of the motor is achieved by switching power electronics, particularly by closing the aforementioned switch, with at least one resistor electrically connected, preferably electrically connected to the aforementioned (switched) power electronics.

[0023] By employing one or both of the above two features, high-performance motor short-circuit braking can be achieved.

[0024] According to some embodiments of the present invention, the driving signal is a PWM ("pulse width modulation") signal.

[0025] Alternatively, according to some embodiments, the power electronics include high-side power electronics and low-side power electronics.

[0026] According to some embodiments of the present invention, the sub-controller switches low-side power electronics based on a braking request to apply short-circuit braking to the motor, while the high-side power electronics remain in the off state. In other words, according to some embodiments, the "partial power electronics" switched by the sub-controller based on a braking request to apply short-circuit braking to the motor are the low-side power electronics of the power drive stage.

[0027] Alternatively, according to some embodiments, the high-side power electronics and low-side power electronics include, preferably, IGBTs (“Insulated Gate Bipolar Transistors”).

[0028] By employing one or more of the above features, high-performance STO and / or SCB can be achieved.

[0029] According to some embodiments of the present invention, the sub-controller includes at least two safety signal chains, wherein at least one safety signal chain switches some power electronics to apply short-circuit braking to the motor based on, and preferably in response to, a braking request, or is used for or adapted for this purpose. The aforementioned one or more safety signal chains may each include a SoC (“System-on-Chip”).

[0030] According to some embodiments of the present invention, this design can further enhance security.

[0031] According to some embodiments of the present invention, the sub-controller includes at least one electronic component that cuts off the drive signals of some power electronic devices based on a shutdown request; preferably, one or more safety signal chains each include at least one electronic component that cuts off the drive signals of some power electronic devices based on a shutdown request. According to some embodiments, one safety signal chain includes at least one electronic component, in some embodiments a PWM buffer, etc., that cuts off the drive signals of high-side power electronic devices; another safety signal chain includes at least one electronic component, in some embodiments another PWM buffer, etc., that cuts off the drive signals of low-side power electronic devices, or are respectively used for or adapted to this purpose.

[0032] By employing one or more of the above features, high-performance STO and / or SCB can be achieved.

[0033] According to some embodiments of the present invention, an electrical isolation device, in some embodiments including a PWM isolator, is disposed between a power drive stage and a sub-controller, particularly for cutting off drive signals of power electronic devices (one or more) electronic components.

[0034] Some components of the sub-controller, especially the aforementioned electronic components used to cut off the drive signals of power electronic devices, can also be placed after the isolation device, but this will require more isolation channels for control signals and feedback signals, thereby increasing costs.

[0035] According to some embodiments of the present invention, the shutdown request is based on at least two signals, wherein preferably at least one signal is triggered by an emergency stop command, and / or at least the other signal is a monitoring signal, which may originate from a power circuit or another circuit that may experience a dangerous fault. Preferably, the at least two signals are coupled using a logical AND operation (with AND logic coupling) such that the shutdown request is triggered only when all signals are either in a valid state or issuing an indication.

[0036] The controller in this invention can be implemented in hardware and / or software, or may include hardware and / or software, particularly one or more programs or program modules, and / or one or more preferably digital processing units and / or electronic components, especially buffers, switches, microprocessor units, graphics processors, etc.; the above components are preferably connected to a storage system and / or a bus system via data or signals. The controller is adapted to execute program instructions implemented and stored in the storage system to receive input signals from the data bus and / or output signals to the data bus. The storage system may include one or more storage media, preferably different types of digital storage media, particularly optical storage media, magnetic storage media, solid-state storage media and / or other non-volatile storage media. The program is designed or implemented in a way that enables it to embody or execute the methods described in this specification, thereby enabling the controller to perform the steps of the method and achieve precise control of the motor.

[0037] In one embodiment of the invention, one or more steps of the method, specifically all steps, may be executed fully or partially automatically, particularly by the controller.

[0038] Further advantages and technical features of the present invention can be derived from the dependent claims and specific embodiments. Attached Figure Description

[0039] The above and / or additional aspects and advantages of this disclosure will be apparent and readily understood in conjunction with the accompanying drawings: Figure 1 Figure 1 shows a drive unit according to an embodiment of the present invention, including a robot motor and a controller for the motor; Figure 2 A method for controlling the motor according to an embodiment of the present invention is shown.

[0040] List of reference numerals 10 SoC (System-on-a-Chip) 11PWM buffer 20 SoC 21PWM buffer 29 SCB Module 30 PWM Isolator 31 Electrical isolation device 40 power drive stage 41-43 High-side power electronic devices 44-46 Low-side power electronic devices 50 motors 100 Sub-controllers 101 and 102 monitors pwm_h high-side PWM pulse signal pwm_l low-side PWM pulse signal PWM_h High-side PWM drive signal PWM_l Low-side PWM drive signal R resistor S1-S3 switches SCB_CTRL Braking Request STOA, STOB Stop Request STOA_FB, STOB_FB feedback signals STO_A, STO_B Emergency Stop V_STO, V_PU electrical energy Detailed Implementation Figure 1 A drive unit according to an embodiment of the present invention is shown, the drive unit including a robot motor 50 (the robot body is not shown in detail) and a controller for the motor.

[0041] The controller includes a power drive stage 40 with three sets of high-side power electronics 41-43 and three sets of low-side power electronics 44-46, such as insulated-gate bipolar transistors (IGBTs) or other power electronics, for driving the motor 50. The aforementioned IGBTs can also be implemented in an IPM (“intelligent power module”) integrating these IGBTs.

[0042] The controller also includes a sub-controller 100 configured with two safety signal chains.

[0043] One of the safety signal chains mainly includes the System-on-Chip (SoC) 10, the switch S1, and the PWM buffer 11.

[0044] Another safety signal chain mainly includes (another) System-on-Chip (SoC) 20, (another) Switch S2, and (another) PWM Buffer 21.

[0045] SoC 20 generates PWM pulse signals pwm_h and pwm_l. The PWM pulse signal pwm_h is processed by PWM buffer 11 into PWM signal PWM_h for driving high-side power electronic devices 41-43. The PWM pulse signal pwm_l is processed by PWM buffer 21 into PWM signal PWM_l for driving low-side power electronic devices 44-46, and is used to drive motor 50 (see...). Figure 2 Step S10).

[0046] When an emergency stop command is triggered, such as in the event of a serious internal fault or exceeding a critical limit, the on-chip systems 10 and 20 will issue STO signals STO_A and STO_B, respectively.

[0047] There are also other monitoring signals from monitors 101 and 102, which are logically ANDed with the STO signals STO_A and STO_B, respectively. These monitoring signals may come from, for example, power supply circuits or other circuits that may cause dangerous malfunctions.

[0048] The obtained shutdown request signals STOA and STOB trigger power supply switches S1 and S2 respectively.

[0049] The output of the power supply switch S1 controlled by STOA is used as the feedback signal of STOA in the safety signal chain where the high-side PWM buffer 11 is located.

[0050] The output of the power supply switch S2 controlled by STOB is used as the feedback signal of STOB in the safety signal chain where the low-side PWM buffer 21 is located.

[0051] The aforementioned PWM buffers 11 and 21 act as PWM signal switches for the sub-controller, cutting off the drive signal based on stop requests STOA and STOB, thereby stopping the drive motor 50: by cutting off the power supply to buffers 11 and 21, the PWM signals from SoCs 10 and 20 are cut off. Figure 2 (Step S20). Any electronic component can be used in this step as long as it can achieve the purpose of cutting off the PWM signal when STOA and STOB cut off the power supply to the components.

[0052] STOA_FB and STOB_FB are feedback signals used as diagnostic signals. These two feedback signals will be verified by SoC10 and SoC20 respectively to ensure that the STO control signal is issued correctly.

[0053] Once STOA and STOB are both activated and the correct STO feedback is received, the safety-side sub-controller will send a signal indicating that STO is activated and the SCB trigger driver is ready.

[0054] exist Figure 1 In the illustrated embodiment, the SCB module 29 implemented within the SoC 20 issues a braking request (signal) SCB_CTRL after a configurable delay to turn on switch S3, causing the low-side pulse width modulation (PWM) signal to be pulled up by V_PU through resistor R. This operation switches all three sets of low-side insulated-gate bipolar transistors (IGBTs) 44-46 to the on state, thereby implementing short-circuit braking on the motor 50, because the three power terminals of the motor 50 are shorted to the neutral line N through the low-side IGBTs 44-46. Figure 1 The dashed arrow in the middle (shown as) Figure 2 (Step S30). At the same time, under the control of the STO signal, all three sets of high-side insulated-gate bipolar transistors 41-43 remain in the off state.

[0055] Because the low-side pulse width modulation (PWM) signal is pulled up by V_PU through resistor R when the stop request STO_B is not triggered, the SCB function will not be effective. This interlocks the SCB and STO functions. SCB is triggered only after STO is enabled; otherwise, it will cause a short circuit fault between the IGBT high and low sides. Figure 1 In the circuit shown, if STO is not triggered, the SCB function will not work because the low-side control of the IGBT driver is controlled by the SoC, which has a higher priority than the SCB circuit.

[0056] As described above, the braking request (signal) SCB_CTRL is triggered by the feedback signal STOB_FB, which is an indication to cut off the drive signal. According to some embodiments, the braking request (signal) SCB_CTRL may also be triggered by the feedback signal STOA_FB and / or an external signal received by the SCB module 29 for implementing short-circuit braking.

[0057] Figure 1 The illustrated embodiment shows that the sub-controller supplies power to the low-side power electronics 44-46 via V_PU by closing switch S3 to switch the power electronics, thereby applying short-circuit braking to the motor 50; and shows that the motor 50 is applied short-circuit braking by electrically connecting the resistor R through the aforementioned power electronics.

[0058] Figure 1 The illustrated embodiment also shows a PWM drive signal.

[0059] Figure 1 The illustrated embodiment further shows a sub-controller that switches low-side power electronics 44-46 to implement SCB on motor 50 based on a braking request (signal) SCB_CTRL, while high-side power electronics 41-43 remain in the off state.

[0060] Figure 1 The illustrated embodiment also shows a sub-controller comprising two safety signal chains, wherein the safety signal chain having a SoC 20 for the low side and a PWM buffer 21 responds to a braking request (signal) SCB_CTRL by switching low-side power electronics 44-46 to apply short-circuit braking to the motor 50.

[0061] Figure 1The illustrated embodiment also shows two safety signal chains of the sub-controller, each of which includes an electronic component, in this embodiment in the form of PWM buffers 11 and 21, used to cut off the drive signals of the power electronics based on a shutdown request.

[0062] Figure 1 The illustrated embodiment also schematically shows electrical isolation 31, wherein a PWM isolator 30 is disposed between the power drive stage 40 and the sub-controller.

[0063] Figure 1 The illustrated embodiment also schematically shows a stop request signal based on a logical AND operation of three signals.

[0064] In this disclosure, the expression "comprising one X" is generally not exclusive and is equivalent to "comprising at least one X," while also covering the case of "comprising two or more Xs." Although the foregoing has described exemplary embodiments, it should be noted that the present invention can be modified in various ways.

[0065] Furthermore, it should be noted that the exemplary embodiments are merely examples and are not intended to limit the scope of protection, application scenarios, or structure of the present invention in any way. Rather, the foregoing description aims to provide guidance to those skilled in the art in implementing at least one exemplary embodiment. Those skilled in the art can make various modifications to the function and arrangement of the components or features, and such modifications will not exceed the scope of protection defined by the claims and their equivalents.

Claims

1. A controller for a robot motor, characterized in that, The controller includes: A power drive stage including power electronics for driving the motor, the power electronics including high-side power electronics and low-side power electronics; and A sub-controller adapted to generate drive signals to drive the power electronic devices; The sub-controller is adapted to cut off the drive signal based on a stop request in order to stop driving the motor; When the shutdown request is activated and a shutdown request feedback signal is received, the sub-controller sends a signal that shutdown has been activated and brake trigger drive is ready. The sub-controller is adapted to switch all the low-side power electronic devices to the on state based on a braking request after a configurable delay to implement short-circuit braking on the motor, while the high-side power electronic devices remain in the off state. The braking request is triggered by at least one of the stop request and the indication to cut off the drive signal; If the shutdown is not triggered, the braking function will not be effective; braking will only be triggered after the shutdown is restarted.

2. The controller according to claim 1, characterized in that, At least one of the following conditions must be met: The sub-controller is adapted to supply power to some of the power electronics by closing a switch, thereby switching the power electronics to apply short-circuit braking to the motor; By switching the power electronics to apply short-circuit braking to the motor, at least one resistor is electrically connected.

3. The controller according to claim 1, characterized in that, At least the following conditions must be met: The driving signal is a PWM signal.

4. The controller according to claim 1, characterized in that, The sub-controller includes at least two safety signal chains, at least one of which is adapted to switch the low-side power electronics in response to the braking request to apply short-circuit braking to the motor.

5. The controller according to claim 1, characterized in that, The sub-controller includes at least one electronic component adapted to cut off the drive signal of the low-side power electronics based on a shutdown request.

6. The controller according to claim 1, characterized in that, The controller also includes an electrical isolation device disposed between the power drive stage and the sub-controller.

7. The controller according to claim 1, characterized in that, The shutdown request is based on at least two signals.

8. A robot drive unit, characterized in that, Includes a motor and a controller for a robot motor according to any one of claims 1-7.

9. A robot, characterized in that, It includes at least one drive unit for driving the robot as described in claim 8.

10. A method for controlling a robot motor, characterized in that, Controlling the robot motor using the controller according to any one of claims 1-7 includes the following steps: generating a drive signal to drive the power electronics of the power drive stage, thereby driving the motor; cutting off the drive signal based on a stop request to stop driving the motor; and switching the low-side power electronics based on a braking request to apply short-circuit braking to the motor.

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