Robot control method, device, system and electronic equipment

Abstract

The present disclosure provides a robot control method and device, system and electronic equipment. The method comprises: receiving a trigger signal sent by a collision prediction module; wherein the trigger signal at least includes a collision time when the robot collides; switching the inverter to an active short circuit mode or a dynamic braking mode before the collision time, so that the motor winding current flows through the switch tube channel; wherein the inverter is connected with the motor winding, and the inverter comprises a plurality of switch tubes. The present disclosure solves the technical problem that the existing scheme for processing motor regenerative energy does not solve the uncontrollable freewheeling problem from the perspective of inverter switch state switching.

Description

Technical Field

[0001] This disclosure relates to the field of robotics, and more specifically, to a robot control method, apparatus, system, and electronic device. Background Technology

[0002] Existing technologies for processing regenerative energy from motors mainly include the following solutions: Option 1: Braking resistor (bleeder circuit). A braking resistor and a switching transistor are connected in parallel at the DC bus terminal. When the bus voltage exceeds the threshold, the braking resistor is activated to dissipate energy.

[0003] Option 2: Active Front End (AFE) rectifier. A controllable rectifier replaces the diode rectifier bridge, feeding regenerative energy back to the grid.

[0004] Option 3: Increase the DC bus capacitance. Increasing the bus capacitance will reduce the rate of increase in bus voltage.

[0005] Option 4: Software overcurrent protection delay. Overcurrent protection is temporarily disabled or delayed during a collision, allowing for a short-term overcurrent exceedance.

[0006] Option 5: Mechanical buffer / clutch structure. A flexible coupling or overrunning clutch is added between the motor and the load to reduce shock transmission.

[0007] None of the above solutions can solve the problem of uncontrolled freewheeling current in the body diode of the inverter switching transistor, which leads to conduction losses, electromagnetic interference, and the risk of damage to functional power devices. Summary of the Invention

[0008] This disclosure provides a robot control method, device, system, and electronic device to solve the technical problem that existing solutions for handling regenerative energy from motors cannot address the uncontrollable freewheeling current issue in the body diode of the inverter switching transistor, leading to conduction losses, electromagnetic interference, and the risk of damage to functional power devices.

[0009] According to one aspect of the present disclosure, a robot control method is provided, the method comprising: receiving a trigger signal from a collision prediction module; wherein the trigger signal includes at least the collision time at which the robot collides; and switching an inverter to an active short-circuit mode or a dynamic braking mode before the collision time to allow motor winding current to flow through the switching transistor channel; wherein the inverter is connected to the motor winding and includes a plurality of switching transistors.

[0010] Optionally, the inverter can be switched to active short-circuit mode, including one of the following: controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; or controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; wherein, the equivalent resistance of the low-impedance short-circuit loop is determined based on the phase resistance of the motor windings, the on-resistance of the switching transistors, and the parasitic resistance of the connecting lines.

[0011] Optionally, the above method further includes inserting a dead time during the process of controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, or controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off.

[0012] Optionally, switching the inverter to dynamic braking mode includes: controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; or, controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; controlling the connection state of at least one resistor connected in series in the low-impedance short-circuit loop so that the equivalent resistance of the low-impedance short-circuit loop is adjustable.

[0013] Optionally, when a resistor is connected in series in the low-impedance short-circuit loop, controlling the connection state of the resistor connected in series in the low-impedance short-circuit loop includes: controlling the duty cycle of the switching transistor through pulse width modulation to adjust the connection state of the resistor; wherein the switching transistor and the resistor are connected in parallel.

[0014] Optionally, the above method further includes: determining the target braking current based on the expected maximum allowable torque and torque constant; determining the error between the target braking current and the measured value of the current sensor; and using a PI controller to calculate the duty cycle based on the error.

[0015] Optionally, the above method further includes: determining the target braking current based on the desired maximum allowable torque and torque constant; and using a hysteresis controller to determine the duty cycle based on the target braking current and the measured value of the current sensor.

[0016] Optionally, when multiple resistors are connected in series in the low-impedance short-circuit loop, controlling the connection state of the resistors connected in series in the low-impedance short-circuit loop includes: adjusting the connection state of the multiple resistors by controlling the on or off state of the switching transistor; wherein, each of the multiple resistors is connected in parallel with a switching transistor.

[0017] Optionally, the above method further includes: when the bus voltage exceeds a preset voltage threshold, storing the regenerative energy generated by the collision into an energy storage unit through a bidirectional DC-DC converter, and releasing the regenerative energy after the collision ends.

[0018] Optionally, the trigger signal is issued by the collision prediction module at least a target time before a collision occurs; wherein the target time is determined based on at least one of the following: the collision time, the inverter switching state switching time, and the stabilization time of the motor current transitioning from normal mode to active short-circuit mode or dynamic braking mode.

[0019] Optionally, the collision time is determined based on the current observation time, the distance between the robot's end effector and the collision surface at the current observation time, and the velocity component of the robot's end effector in the normal direction of the collision surface at the current observation time.

[0020] Optionally, the above method further includes: dividing overcurrent protection into three levels: hardware instantaneous peak protection, firmware short-term instantaneous peak protection, and application long-term overcurrent protection; and dynamically adjusting the protection thresholds of hardware instantaneous peak protection and firmware short-term instantaneous peak protection, and the criteria for application long-term overcurrent protection within the collision prediction window; wherein, the collision prediction window is determined based on the collision time, the target time, and the integral window time of application long-term overcurrent protection.

[0021] Optionally, the above method further includes: determining the peak current after the collision; verifying whether the peak current exhibits an exponential decay characteristic; and if the peak current does not exhibit an exponential decay characteristic, determining that the motor winding has failed.

[0022] According to another aspect of the present disclosure, a robot control device is provided, the device comprising: a receiving module for receiving a trigger signal from a collision prediction module; wherein the trigger signal includes at least the collision time at which the robot collides; and a control module for switching an inverter to an active short-circuit mode or a dynamic braking mode before the collision time, so that motor winding current flows through the switching transistor channel; wherein the inverter is connected to the motor winding and includes a plurality of switching transistors.

[0023] According to another aspect of the present disclosure, a robot control system is provided, comprising: a collision prediction module for predicting the collision time of the robot before a collision occurs and outputting a trigger signal; wherein the trigger signal includes at least the collision time; an inverter connected to a motor winding and a DC bus, including multiple switching transistors; an energy buffer module connected to the DC bus, including a bidirectional DC-DC converter and an energy storage unit; a mechanical compliance isolation module disposed between the motor output shaft and the load, including a one-way overrunning clutch or an adjustable damping flexible coupling, for mechanically reducing the magnitude of speed change transmitted to the motor winding; and a controller connected to the collision prediction module, the inverter, and the energy buffer module, for implementing the above method.

[0024] According to another aspect of the present disclosure, an electronic device is provided, comprising: a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the above-described method.

[0025] According to another aspect of the present disclosure, a computer-readable storage medium is provided that stores a computer program thereon, which, when executed by a processor, implements the above-described method.

[0026] According to another aspect of the present disclosure, a computer program product is provided, including a computer program that, when executed by a processor, implements the above-described method.

[0027] The beneficial effects of the technical solutions provided in this disclosure are: The technical solution proposed in this disclosure, through predictive active short circuit, switches the current path from an uncontrollable body diode to a fully controllable switching transistor channel, eliminating the root cause of uncontrollable freewheeling at the physical mechanism. By replacing uncontrollable freewheeling with a controlled current path, the electrical and thermal stresses on power devices are significantly reduced, extending the service life of inverters and motors. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments of this disclosure will be briefly introduced below.

[0029] Figure 1 A flowchart illustrating a robot control method provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of the structure of a robot control device provided in an embodiment of the present disclosure; Figure 3 A schematic diagram of the structure of a robot control system provided in an embodiment of this disclosure; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present disclosure. Detailed Implementation

[0030] The embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this disclosure, and do not constitute a limitation on the technical solutions of the embodiments of this disclosure.

[0031] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the terms “comprising” and “including” as used in embodiments of this disclosure mean that the corresponding feature can be implemented as the presented feature, information, data, step, operation, element, and / or component, but do not exclude implementation as other features, information, data, step, operation, element, component, and / or combinations thereof supported by the art. It should be understood that when we say that an element is “connected” or “coupled” to another element, the one element can be directly connected or coupled to the other element, or it can mean that the one element and the other element are connected through an intermediate element. Furthermore, “connected” or “coupled” as used herein can include wireless connection or wireless coupling. The term “and / or” as used herein indicates at least one of the items defined by the term, for example, “A and / or B” or “A, B” indicates implementation as “A,” or implementation as “B,” or implementation as “A and B.”

[0032] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0033] First, the technical terms used in this disclosure will be introduced and explained: Regenerative energy in motors is often referred to in engineering as the energy generated by "regenerative braking" or "kinetic energy recovery." Simply put, it refers to the electrical energy generated when a motor transforms from a "motor" into a "generator" during deceleration, braking, or lowering of heavy objects.

[0034] A body diode, also called a parasitic diode, is not an independent component that is soldered onto a circuit board. Rather, it is a physical structure that is naturally formed during the semiconductor manufacturing process of a power MOSFET or an insulated gate bipolar transistor (IGBT).

[0035] The body diode freewheeling is the process in which the parasitic diode inside the switching transistor is forced to conduct when the switching transistor is turned off, providing a freewheeling path for the inductor current to protect the circuit from being broken down by high voltage.

[0036] When an external force drives the motor to generate high speed, the back electromotive force exceeds the maximum output voltage that the bus voltage can support, that is:

[0037] in, This is the back electromotive force of the motor. Let be the back electromotive force constant of the motor. The mechanical angular velocity of the motor. This is the maximum phase voltage amplitude that the inverter can output. This is the DC bus voltage.

[0038] At this point, the body diode of the inverter switch is forced to conduct, and the current path is no longer controlled by the Space Vector Pulse Width Modulation (SVPWM) switching signal. The amplitude of this freewheeling current is... , The expression is as follows:

[0039] in, This represents the amplitude of the freewheeling current of the body diode. Let be the back electromotive force constant of the motor. The mechanical angular velocity of the motor. This is the DC bus voltage. The phase resistance of the motor stator winding. The dynamic on-resistance of the body diode.

[0040] because and They are all very small (milliohms to ohms), and the freewheeling current can reach tens of amperes or even higher, far exceeding the current limit set by the driver. Moreover, the current loop controller cannot stop the freewheeling current from flowing, regardless of the duty cycle it outputs.

[0041] Existing technologies for processing regenerative energy from motors mainly include: Option 1: Braking resistor (bleeder circuit). A braking resistor and a switching transistor are connected in parallel at the DC bus terminal. When the bus voltage exceeds the threshold, the braking resistor is activated to dissipate energy.

[0042] Option 2: Active Front End (AFE) rectifier. A controllable rectifier replaces the diode rectifier bridge, feeding regenerative energy back to the grid.

[0043] Option 3: Increase the DC bus capacitance. Increasing the bus capacitance will reduce the rate of increase in bus voltage.

[0044] Option 4: Software overcurrent protection delay. Overcurrent protection is temporarily disabled or delayed during a collision, allowing for a short-term overcurrent exceedance.

[0045] Option 5: Mechanical buffer / clutch structure. A flexible coupling or overrunning clutch is added between the motor and the load to reduce shock transmission.

[0046] The shortcomings of the existing solutions mainly include the following aspects: Option 1 has a large response delay (from a few milliseconds to tens of milliseconds), and can only consume the energy that has already flowed into the bus, but cannot prevent the body diode from continuing to flow.

[0047] Option 2 is costly and complex to control, and it also fails to solve the problem of freewheeling current in the motor-side diodes.

[0048] Option 3 can only delay the triggering of overvoltage protection, but cannot limit the amplitude of the freewheeling current.

[0049] Option 4 carries the risk of damage to power devices and cannot fundamentally solve the problem of excessive current.

[0050] Option 5 would affect the collision dynamics and may weaken the collision effect.

[0051] None of the above solutions address the uncontrollable freewheeling problem from the perspective of inverter switching state, resulting in conduction losses, electromagnetic interference, and the risk of damage to functional power devices; nor do they achieve coordination between upper-level collision prediction and lower-level drive control.

[0052] The robot control methods, devices, systems, and electronic devices disclosed herein are intended to solve at least one of the above-mentioned technical problems in the prior art.

[0053] The following description of several exemplary embodiments illustrates the technical solutions of this disclosure and the technical effects produced by these solutions. It should be noted that the following embodiments can be referenced, learned from, or combined with each other. Identical terms, similar features, and similar implementation steps in different embodiments will not be repeated.

[0054] This disclosure provides a robot control method, such as... Figure 1 As shown, the method includes the following steps: Step S101: Receive a trigger signal from the collision prediction module; wherein the trigger signal includes at least the collision time when the robot collides.

[0055] In some embodiments, a collision prediction module predicts the collision time before a collision occurs and outputs a trigger signal. The collision prediction module integrates signals from multiple sensors (e.g., force sensors, accelerometers, proximity sensors, microphones) and motion planning information to output a predicted collision time. and confidence level .

[0056] Step S102: Before the collision, the inverter is switched to active short-circuit mode or dynamic braking mode so that the motor winding current flows through the switching transistor channel; wherein, the inverter is connected to the motor winding and includes multiple switching transistors.

[0057] In some embodiments, after receiving the trigger signal from the collision prediction module, the control unit switches the three-phase inverter from normal torque control mode to active short-circuit mode or dynamic braking mode before the collision time.

[0058] According to some optional embodiments of this disclosure, the three-phase inverter connects the motor windings to the DC bus and includes six switching transistors (three in the upper bridge arm and three in the lower bridge arm), each transistor having a body diode. During normal operation, it is used to output SVPWM modulated voltage; in collision mode, it is used to construct an active short-circuit or dynamic braking circuit.

[0059] By employing the aforementioned technical solution, predictive active short-circuiting switches the current path from the uncontrollable body diode to a fully controllable switching transistor channel, thus eliminating the root cause of uncontrollable freewheeling at the physical mechanism level. Replacing uncontrollable freewheeling with a controlled current path significantly reduces the electrical and thermal stress on power devices, extending the lifespan of inverters and motors.

[0060] According to some optional embodiments of this disclosure, step S102, which switches the inverter to active short-circuit mode, includes one of the following: controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; or controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; wherein the equivalent resistance of the low-impedance short-circuit loop is determined based on the phase resistance of the motor windings, the on-resistance of the switching transistors, and the parasitic resistance of the connecting lines.

[0061] The core physical principle of active short-circuit mode is as follows: The current path impedance when the body diode is conducting is , The expression is as follows:

[0062] in, This is the current path impedance when the body diode is conducting. The phase resistance of the motor stator winding. The dynamic on-resistance of the body diode. It is the imaginary unit. It is the electrical angular velocity of the motor. It is a stator inductor. It is the inductive reactance of the motor winding.

[0063] The current path impedance during an active short circuit (when the switching transistor is turned on) is: , The expression is as follows:

[0064] in, The current path impedance during an active short circuit. The phase resistance of the motor stator winding. This is the on-resistance of the MOSFET. It is the imaginary unit. It is the electrical angular velocity of the motor. It is a stator inductor. It is the inductive reactance of the motor winding.

[0065] The typical value is on the order of 1-10mΩ, which is much smaller than the equivalent on-resistance of the body diode (which typically includes the equivalent resistance corresponding to a forward voltage drop of 0.7-1.5V). Therefore, active short-circuiting can significantly reduce conduction losses and improve system efficiency; it can also greatly reduce heat generation and simplify heat dissipation design.

[0066] In some embodiments, during active short-circuit mode, the control unit outputs the following switching signals to the three-phase inverter: , That is, all three upper bridge arm switches are turned off, and all three lower bridge arm switches are turned on (lower bridge arm short circuit).

[0067] In some embodiments, during active short-circuit mode, the control unit may also output the following switching signals to the three-phase inverter: , That is, all three upper bridge arm switches are turned on, and all three lower bridge arm switches are turned off (upper bridge arm short circuit).

[0068] The short-circuit current in active short-circuit mode is , The expression is as follows:

[0069] in, This refers to the short-circuit current in active short-circuit mode. Let be the back electromotive force constant of the motor. The mechanical angular velocity of the motor. The phase resistance of the motor stator winding. This is the on-resistance of the switching transistor. This refers to the parasitic resistance of PCB copper foil traces and connecting copper busbars.

[0070] The generated braking torque is , The expression is as follows:

[0071] in, This refers to the braking torque generated under active short-circuit mode. The torque constant is This refers to the short-circuit current in active short-circuit mode. Let be the back electromotive force constant of the motor. The mechanical angular velocity of the motor. The phase resistance of the motor stator winding. This is the on-resistance of the MOSFET. This refers to the parasitic resistance of PCB copper foil traces and connecting copper busbars.

[0072] The braking torque is proportional to the rotational speed, exhibiting damping characteristics. The damping coefficient is... , The expression is as follows:

[0073] in, The damping coefficient is... The torque constant is Let be the back electromotive force constant of the motor. The phase resistance of the motor stator winding. This is the on-resistance of the switching transistor. This refers to the parasitic resistance of PCB copper foil traces and connecting copper busbars.

[0074] The solution proposed in this disclosure uses predictive active short circuits to dissipate collision energy through a low-impedance controlled path, avoiding current spikes caused by uncontrolled freewheeling current in the body diode. The readback current is limited to a preset safety threshold, allowing the robot to continuously perform collision operations without stopping.

[0075] The key advantages of active short-circuit mode include the following: 1. Controllable current path: The channel current of the switching transistor is completely controlled by the gate drive signal. The current can be interrupted at any time by turning off the switching transistor, unlike the body diode which is not turn-off.

[0076] 2. Low voltage stress: Switching transistor channel on-state voltage drop This is far lower than the 0.7-1.5V forward voltage drop of the body diode. This significantly reduces the instantaneous power dissipation of power devices.

[0077] 3. No reverse recovery problem: The body diode has reverse recovery charge during high-speed switching, which leads to additional switching losses and electromagnetic interference (EMI). However, in active short-circuit mode, the current always flows through the channel and is not involved in the switching process of the diode.

[0078] This disclosure provides a possible implementation method in which dead time is inserted during the process of controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, or controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off.

[0079] To prevent shoot-through of switches on the same bridge arm, a dead time must be inserted during the switching process. The typical value is 1-2 μs.

[0080] In a half-bridge or full-bridge circuit, the two switching transistors (such as MOSFETs or IGBTs) on the same bridge arm cannot be turned on simultaneously. If they are turned on at the same time, the DC bus will be directly short-circuited to ground, generating a huge short-circuit current and instantly burning out the devices (i.e., bridge arm shoot-through). In actual engineering, after the controller sends a signal to turn off one transistor, it will force a very short wait time (i.e., dead time) to confirm that the transistor is completely turned off before allowing the other transistor to be turned on.

[0081] By inserting a dead time, the problem of instantaneous device burnout due to bridge arm straightness can be avoided.

[0082] According to some optional embodiments of this disclosure, step S102 switches the inverter to dynamic braking mode, including: controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; or, controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; controlling the connection state of at least one resistor connected in series in the low-impedance short-circuit loop so that the equivalent resistance of the low-impedance short-circuit loop is adjustable.

[0083] In this embodiment, the control unit first controls all three upper-arm switches of the three-phase inverter to turn off and all three lower-arm switches to turn on (lower arm short circuit), or controls all three upper-arm switches of the three-phase inverter to turn on and all three lower-arm switches to turn off (upper arm short circuit). Then, one or more braking resistors are connected in series in the short-circuit circuit. By controlling the connection state of the series resistors, the equivalent resistance in the low-impedance short-circuit circuit can be adjusted.

[0084] This disclosure provides a possible implementation method for controlling the connection state of the resistor connected in series in the low-impedance short-circuit loop when a resistor is connected in series in the low-impedance short-circuit loop, including: controlling the duty cycle of the switching transistor through pulse width modulation to adjust the connection state of the resistor; wherein the switching transistor and the resistor are connected in parallel.

[0085] In this embodiment, a braking resistor is connected in series in the low-impedance short-circuit circuit. A switching transistor is connected in parallel across the resistor. Controlled by PWM The duty cycle of the conduction Equivalent adjustment loop resistance, resistance of low impedance short-circuit loop The expression is as follows:

[0086] in, The resistor is for a low-impedance short-circuit loop. Based on the short-circuit resistor, The phase resistance of the motor stator winding. This is the on-resistance of the MOSFET. The parasitic resistance of PCB copper foil traces and connecting copper busbars. The duty cycle of the switching transistor. It is a braking resistor connected in series in a low-impedance short-circuit circuit.

[0087] when hour, Fully conductive, When short-circuited, the equivalent circuit degenerates into a pure active short-circuit (ASC) mode; when hour, When completely shut off, the braking resistor is fully connected, and the equivalent resistance is at its maximum.

[0088] The braking current of the low-impedance short-circuit circuit is , The expression is as follows:

[0089] in, For the braking current of the low-impedance short-circuit circuit, Let be the back electromotive force constant of the motor. The mechanical angular velocity of the motor. Based on the short-circuit resistor, The phase resistance of the motor stator winding. This is the on-resistance of the MOSFET. The parasitic resistance of PCB copper foil traces and connecting copper busbars. The duty cycle of the switching transistor. It is a braking resistor connected in series in a low-impedance short-circuit circuit.

[0090] Adjust the duty cycle via closed loop This allows the braking current to remain at a preset value. nearby.

[0091] In some embodiments, the target braking current is determined based on the desired maximum permissible torque and torque constant; the error between the target braking current and the measured value of the current sensor is determined; and a PI controller is used to calculate the duty cycle based on the error.

[0092] In some embodiments, the braking current control in dynamic braking mode adopts the following closed-loop structure: 1. Reference value generation Based on the expected maximum allowable torque and torque constant The target braking current is calculated using the following expression. , The expression is as follows:

[0093] in, For the target braking current, For the maximum permissible torque, is the torque constant.

[0094] 2. Error Calculation

[0095] in, For the target braking current, This is the measured value from the current sensor. The error between the target braking current and the measured value of the current sensor.

[0096] 3. Controller Output: The duty cycle is calculated using a PI controller. .

[0097] The PI controller is in the following form:

[0098] in, It is proportional gain. It is the integral gain.

[0099] In some embodiments, the target braking current is determined based on the desired maximum permissible torque and torque constant; the duty cycle is determined using a hysteresis controller based on the target braking current and the measured value from the current sensor.

[0100] In some embodiments, the braking current control in dynamic braking mode can also adopt the following closed-loop structure: 1. Reference value generation Based on the expected maximum allowable torque and torque constant The target braking current is calculated using the following expression. , The expression is as follows:

[0101] in, For the target braking current, For the maximum permissible torque, is the torque constant.

[0102] 2. Controller output: The duty cycle is calculated using a hysteresis controller. .

[0103] Hysteresis controller types: when < - / 2 o'clock, = 1 (fully conductive); in, This is the measured value from the current sensor. For the target braking current, For hysteresis bandwidth, Typical values ​​are taken 5-10%; when > + / 2 o'clock, = 0 (All off); in, This is the measured value from the current sensor. For the target braking current, Hysteresis bandwidth; Typical values ​​are taken 5-10%; In other cases, the previous value is retained (hysteresis control).

[0104] According to some optional embodiments of this disclosure, when multiple resistors are connected in series in a low-impedance short-circuit loop, controlling the connection state of the resistors connected in series in the low-impedance short-circuit loop includes: adjusting the connection state of the multiple resistors by controlling the on or off state of a switching transistor; wherein, each of the multiple resistors is connected in parallel with a switching transistor.

[0105] In some embodiments, a multi-stage braking resistor is provided in the short-circuit circuit. Each is a switching transistor Controls the connection or bypass of braking resistors at each stage. Discrete equivalent resistance values ​​are achieved through different switch combinations:

[0106] in, The resistor is for a low-impedance short-circuit loop. Based on the short-circuit resistor, The phase resistance of the motor stator winding. This is the on-resistance of the MOSFET. The parasitic resistance of PCB copper foil traces and connecting copper busbars. This refers to the serial number of the braking resistor or switching transistor. This refers to the total number of braking resistors or switching transistors. For braking resistor, For switching transistors, This indicates that the braking resistor is in bypass mode. This indicates that the braking resistor is in the connected state. This method has a fast response speed, but the adjustable resolution of the equivalent resistance is limited by the number of resistors.

[0107] By using the above technical solution, by connecting an adjustable impedance element (braking resistor and PWM switch, or multi-stage resistor network) in series in the active short-circuit loop, and by precisely adjusting the equivalent loop resistance through closed-loop control, the braking current is precisely limited to any set value during the collision process.

[0108] According to some optional embodiments of this disclosure, when the bus voltage exceeds a preset voltage threshold, the regenerative energy generated by the collision is stored in the energy storage unit through a bidirectional DC-DC converter, and the regenerative energy is released after the collision ends.

[0109] In embodiments of this disclosure, when the bus voltage Exceeding the first threshold When the voltage is 110% of the rated bus voltage, the synchronous Buck-Boost bidirectional converter is switched to Buck mode (from the bus side to the energy storage side) to transfer excess energy from the bus to the energy storage unit and maintain the stability of the bus voltage.

[0110] The control objective is:

[0111] in, This is the DC bus voltage. The upper limit of the bus voltage is usually taken as 80-85% of the rated withstand voltage of the power device.

[0112] The synchronous Buck-Boost bidirectional converter is a non-isolated DC-DC power electronic converter. Its core capability is to enable bidirectional energy flow between two DC ports and automatically perform voltage boost or buck conversion. The topology includes two switching transistors. and An inductor and a storage capacitor .

[0113] In some embodiments, the selection of the supercapacitor bank capacity must meet the energy buffering requirements of a single collision:

[0114] in, For energy storage capacitors, The maximum regenerative energy generated in a single collision. For DC-DC converter efficiency, and These are the maximum and minimum operating voltages of the supercapacitor bank, respectively.

[0115] For typical robot joint collision scenarios Typically, in the 10-100J range, a supercapacitor bank with a capacity of 1-10F is sufficient to meet the requirements.

[0116] The above technical solution uses a bidirectional DC-DC converter to store the regenerative energy generated by the collision into a supercapacitor or battery, which not only prevents overvoltage on the bus but also allows energy to be fed back in subsequent operations, thereby improving the overall energy efficiency of the system.

[0117] According to some optional embodiments of this disclosure, the trigger signal is issued by the collision prediction module at least a target time before a collision occurs; wherein the target time is determined based on at least one of the following: the collision time, the inverter switching state switching time, and the stabilization time of the motor current transitioning from normal mode to active short-circuit mode or dynamic braking mode.

[0118] In some embodiments, the prediction module needs to predict the collision beforehand. Time sends a trigger signal, in which, The expression is as follows:

[0119] In the formula, The inverter switching state switching time (typically half to one cycle of the PWM cycle, i.e., 25-100μs). The settling time for the motor current to transition from normal mode to active short-circuit / dynamic braking mode (typically 3-5 times the electrical time constant). For safety margin, a value of 0.5-2 ms is typically used; electrical time constant Typical value: 0.5-2ms For stator inductance, This is the stator resistance.

[0120] therefore, The typical value range is 1-5ms.

[0121] The above technical solution utilizes multi-sensor fusion (force sensor, accelerometer, proximity sensor, encoder) and motion planning information to achieve advance... Time-triggered drive mode switching ensures that the system is fully braked when a collision occurs.

[0122] In some of the disclosed optional embodiments, the collision time is determined based on the current observation time, the distance between the robot's end effector and the collision surface at the current observation time, and the velocity component of the robot's end effector in the direction normal to the collision surface at the current observation time.

[0123] In the embodiments of this disclosure, the algorithm for predicting the collision time is as follows:

[0124] in, The predicted collision time; This is the current observation time; In order to be in At any given moment, the relative distance between the robot's end effector and the collision surface; In order to be in At time t, the velocity component of the robot's end effector in the direction normal to the collision surface.

[0125] This disclosure provides a possible implementation method that divides overcurrent protection into three levels: hardware instantaneous peak protection, firmware short-term instantaneous peak protection, and application long-term overcurrent protection. Within the collision prediction window, the protection thresholds of hardware instantaneous peak protection and firmware short-term instantaneous peak protection, as well as the criteria for application long-term overcurrent protection, are dynamically adjusted. The collision prediction window is determined based on the collision time, the target time, and the integral window time of application long-term overcurrent protection.

[0126] The hierarchical overcurrent protection strategy provided in this disclosure divides overcurrent protection into three levels: 1. Instantaneous peak protection (hardware level): Implemented by a hardware comparator, with a response time of <1μs. In collision mode, this threshold is increased from 2-3 times the rated current to 5-8 times the rated current.

[0127] 2. Short-time overcurrent protection (firmware level): Implemented by firmware in the current loop interrupt, with a response time of one current loop cycle (50-200μs). In collision mode, it allows the current to exceed the rated value by 3-5 times for a duration of 1-5ms.

[0128] 3. Long-term overcurrent protection (application level): Monitored by upper-layer application software, using integral overcurrent criterion:

[0129] in, This is the thermal accumulation value, representing the additional thermal stress accumulated by the motor during the current time period due to exceeding the rated current. For the integration window, in collision mode, The time has been reduced from the normal 100-500ms to 10-50ms; This represents the actual effective current flowing through the motor windings at the current moment. Rated continuous current represents the maximum continuous current that the motor can safely withstand over a long period of time without triggering thermal limits. This represents the maximum amount of excess heat energy that the motor is allowed to consume within a specific time window. If Exceeding this limit means that the motor's heat capacity has reached its limit, and intervention measures must be taken to prevent the insulation layer from burning out or the magnets from demagnetizing.

[0130] In some embodiments, during the collision prediction window The above collision protection strategy is implemented internally. For the predicted collision time, The time before a trigger signal is issued before a collision occurs. This is the integration window.

[0131] This disclosure provides a possible implementation method to determine the peak current after a collision; verify whether the peak current exhibits an exponential decay characteristic; if the peak current does not exhibit an exponential decay characteristic, determine that the motor winding has failed.

[0132] In embodiments of this disclosure, the readback current signal is processed as follows in collision mode: Record the peak current after the collision And verify whether it exhibits typical exponential decay characteristics:

[0133] in, At any time after the collision The actual current value, The current peak after the collision. For the predicted collision time, This is the mechanical time constant. If the actual current waveform deviates from this characteristic (e.g., it continues to not decay or continues to increase), it is determined to be a real fault.

[0134] In some embodiments, only continuous Protection is triggered only if overcurrent conditions are detected for more than one PWM cycle (or other values).

[0135] By using the above technical solution, overcurrent protection is divided into three levels: hardware instantaneous, firmware short-term, and application long-term. The protection threshold and criteria are dynamically adjusted within the collision prediction window to distinguish between instantaneous inrush current and continuous overcurrent, thus avoiding false triggering of shutdown.

[0136] The solution proposed in this disclosure is further illustrated below with reference to a specific embodiment: State S0: Normal operation mode: The inverter executes normal SVPWM control, and the overcurrent protection threshold uses the normal value.

[0137] State S1: Collision Preparation Mode (Entry condition: Collision prediction module sends a trigger signal): Maintain normal operation control, but switch the overcurrent protection threshold to the collision mode value, and the energy buffer module enters standby mode.

[0138] State S2: Active Short Circuit / Dynamic Braking Mode (Entry Condition: Arrival) Timing: Immediately stop SVPWM output, switch inverter switching state to active short-circuit ASC or dynamic braking mode, and start braking current closed-loop controller.

[0139] State S3: Brake recovery mode (Entry condition: detected) and ): Gradually release the braking state and restore SVPWM control; among which, The mechanical angular velocity of the motor. The recovery speed threshold for the mechanical angular velocity of the motor. For the braking current of the low-impedance short-circuit circuit, This is the safe current threshold.

[0140] Status S4: Normal recovery complete: All normal parameters are restored, and status S0 is returned.

[0141] In some embodiments, the following timing sequence must be strictly followed when switching from state S1 to state S2: Timing: Stop SVPWM output, turn off all switching transistors, and insert dead time. ; Timing: Turn on the lower arm switch (ASC mode) or the switch in the braking circuit (dynamic braking mode). Timing: The switching transistor is fully turned on, and the ASC or dynamic braking circuit is established; This is the gate drive response time of the switching transistor; At this moment: the braking current control circuit is stable, and the system has full braking capability. This refers to the settling time for the motor current to transition from normal mode to active short-circuit / dynamic braking mode.

[0142] To ensure the system is fully braked in the event of a collision, the following must be met:

[0143] in, Dead time, The gate drive response time of the switching transistor. The settling time for the motor current to transition from normal mode to active short-circuit / dynamic braking mode. Hardware-level safety margin refers to the fault tolerance space at the hardware control level. It acknowledges the imperfections of physical components and ensures that, by forcibly extending the safety lead time, the motor drive system can calmly and reliably take over the current path in the event of a collision, achieving absolutely safe flexible braking.

[0144] The technical solution proposed in this disclosure tightly integrates upper-level collision prediction (based on sensor fusion and motion planning) with lower-level power electronic control (inverter switching state switching, braking current regulation), achieving end-to-end closed-loop management from the task level to the device level. It is applicable to any robot scenario involving intentional collisions or impact interactions, including drumming, hammering, striking, stamping, riveting, and impact detection.

[0145] This disclosure provides a robot control device, such as... Figure 2 As shown, the device 20 may include: The receiving module 201 is used to receive the trigger signal sent by the collision prediction module; wherein the trigger signal includes at least the collision time when the robot collides.

[0146] The control module 202 is used to switch the inverter to active short-circuit mode or dynamic braking mode before the collision time so that the motor winding current flows through the switching transistor channel; wherein, the inverter is connected to the motor winding and includes multiple switching transistors.

[0147] The apparatus of this disclosure embodiment can execute the method provided in this disclosure embodiment, and its implementation principle is similar, and it has corresponding technical effects. The actions performed by each module in the apparatus of each embodiment of this disclosure correspond to the steps in the method of each embodiment of this disclosure. For a detailed functional description of each module of the apparatus, please refer to the description in the corresponding method shown above, and it will not be repeated here.

[0148] This disclosure provides a control system for a robot, such as... Figure 3 As shown, the system 30 includes: The collision prediction module 301 is used to predict the collision time of the robot before the collision occurs and output a trigger signal; wherein the trigger signal includes at least the collision time.

[0149] In some embodiments, the collision prediction module 301 predicts the collision time before a collision occurs and outputs a trigger signal. The collision prediction module integrates multiple sensor signals (e.g., force sensor, accelerometer, proximity sensor, microphone) and motion planning information to output a predicted collision time. and confidence level .

[0150] In some embodiments, the proximity sensor is mounted on the end effector of the robotic arm or on the collision surface to measure the relative distance between the robot end effector and the collision surface, with a sampling rate ≥1kHz and a measurement range covering the range of 0-200mm before the collision.

[0151] In some embodiments, the accelerometer is mounted on the end effector of the robotic arm or on a joint link to measure acceleration, with a range ≥50g and a bandwidth ≥500Hz.

[0152] In some embodiments, a force sensor or tactile sensor is installed at the collision contact point to detect changes in initial contact force, with a response time of <1ms.

[0153] In some embodiments, the joint encoder is used to provide joint angle and angular velocity signals for calculating the predicted collision moment.

[0154] Inverter 302 is connected to the motor windings and the DC bus respectively, and includes multiple switching transistors.

[0155] In some embodiments, the inverter 302 connects the motor windings to the DC bus and includes six switching transistors (three on the upper bridge arm and three on the lower bridge arm), each with a body diode. During normal operation, it is used to output SVPWM modulated voltage; in collision mode, it is used to construct an active short-circuit or dynamic braking circuit.

[0156] The energy buffer module 303 is connected to the DC bus and includes a bidirectional DC-DC converter and an energy storage unit.

[0157] In some embodiments, the energy buffer module 303 is connected to the DC bus and includes a bidirectional DC-DC converter and an energy storage unit (supercapacitor bank or battery bank) to absorb regenerative energy during a collision and clamp the bus voltage within a safe range.

[0158] The mechanical compliance isolation module 304 is located between the motor output shaft and the load, including a one-way overrunning clutch or an adjustable damping flexible coupling, to reduce the magnitude of speed change transmitted to the motor windings from a mechanical perspective.

[0159] The controller 305 is connected to the collision prediction module 301, the inverter 302 and the energy buffer module 303 respectively, and is used to implement the method in any of the above embodiments.

[0160] This disclosure provides an electronic device including a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of the method provided in any optional embodiment of this disclosure. Compared with the prior art, it achieves the following: by predictively and actively short-circuiting, the current path is switched from an "uncontrollable body diode" to a "fully controllable switching channel," thus eliminating the root cause of uncontrollable freewheeling at the physical mechanism. By replacing uncontrollable freewheeling with a controlled current path, the electrical and thermal stresses of power devices are significantly reduced, extending the service life of inverters and motors.

[0161] In one alternative embodiment, an electronic device is provided, such as Figure 4 As shown, Figure 4 The illustrated electronic device 4000 includes a processor 4001 and a memory 4003. The processor 4001 and the memory 4003 are connected, for example, via a bus 4002. Optionally, the electronic device 4000 may further include a transceiver 4004, which can be used for data interaction between the electronic device and other electronic devices, such as sending and / or receiving data. It should be noted that in practical applications, the transceiver 4004 is not limited to one type, and the structure of the electronic device 4000 does not constitute a limitation on the embodiments of this disclosure.

[0162] Processor 4001 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure herein. Processor 4001 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0163] Bus 4002 may include a pathway for transmitting information between the aforementioned components. Bus 4002 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 4002 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 4The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0164] The memory 4003 may be ROM (Read Only Memory) or other types of static storage devices capable of storing static information and instructions, RAM (Random Access Memory) or other types of dynamic storage devices capable of storing information and instructions, or EEPROM (Electrically Erasable Programmable Read Only Memory), CD-ROM (Compact Disc Read Only Memory) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, other magnetic storage devices, or any other medium capable of carrying or storing computer programs and capable of being read by a computer, without limitation herein.

[0165] The memory 4003 is used to store computer programs that execute embodiments of the present disclosure, and is controlled by the processor 4001 to execute them. The processor 4001 is used to execute the computer programs stored in the memory 4003 to implement the steps shown in the foregoing method embodiments.

[0166] Electronic devices include, but are not limited to: computer equipment and robot control systems.

[0167] This disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the steps and corresponding content of the aforementioned method embodiments.

[0168] This disclosure also provides a computer program product, including a computer program that, when executed by a processor, can implement the steps and corresponding content of the aforementioned method embodiments.

[0169] It should be understood that although arrows indicate various operation steps in the flowcharts of the embodiments of this disclosure, the order in which these steps are implemented is not limited to the order indicated by the arrows. Unless explicitly stated herein, in some implementation scenarios of the embodiments of this disclosure, the implementation steps in each flowchart can be executed in other orders as required. Furthermore, some or all of the steps in each flowchart may include multiple sub-steps or multiple stages based on the actual implementation scenario. Some or all of these sub-steps or stages can be executed at the same time, and each sub-step or stage can also be executed at different times. In scenarios where execution times differ, the execution order of these sub-steps or stages can be flexibly configured as required, and the embodiments of this disclosure do not limit this.

[0170] The above description is only an optional implementation method for some implementation scenarios of this disclosure. It should be noted that for those skilled in the art, other similar implementation methods based on the technical concept of this disclosure without departing from the technical concept of this disclosure also fall within the protection scope of the embodiments of this disclosure.

Claims

1. A method for controlling a robot, characterized in that, include: Receive a trigger signal from the collision prediction module; wherein the trigger signal includes at least the moment of collision in which the robot collides; Before the collision, the inverter is switched to active short-circuit mode or dynamic braking mode to allow the motor winding current to flow through the switching transistor channel; wherein, the inverter is connected to the motor winding and includes multiple switching transistors; Switching the inverter to active short-circuit mode includes one of the following: controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; or controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors. Switching the inverter to dynamic braking mode includes: controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; or, controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; controlling the connection state of at least one resistor connected in series in the low-impedance short-circuit loop, so that the equivalent resistance of the low-impedance short-circuit loop is adjustable.

2. The method according to claim 1, characterized in that, The method further includes: Dead time is inserted during the process of controlling all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, or controlling all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off.

3. The method according to claim 1, characterized in that, When a resistor is connected in series in the low-impedance short-circuit loop, controlling the connection state of the resistor connected in series in the low-impedance short-circuit loop includes: The duty cycle of the switching transistor is controlled by pulse width modulation to adjust the connection state of the resistor; wherein the switching transistor and the resistor are connected in parallel.

4. The method according to claim 3, characterized in that, The method further includes: Determine the target braking current based on the expected maximum allowable torque and torque constant; Determine the error between the target braking current and the measured value of the current sensor; The duty cycle is calculated based on the error using a PI controller.

5. The method according to claim 3, characterized in that, The method further includes: Determine the target braking current based on the expected maximum allowable torque and torque constant; The duty cycle is determined using a hysteresis controller based on the target braking current and the measured value from the current sensor.

6. The method according to claim 1, characterized in that, When multiple resistors are connected in series in the low-impedance short-circuit loop, controlling the connection state of the resistors connected in series in the low-impedance short-circuit loop includes: The connection state of the plurality of resistors is adjusted by controlling the on or off state of the switching transistor; wherein, each of the plurality of resistors is connected in parallel with one of the switching transistors.

7. The method according to any one of claims 1 to 6, characterized in that, The method further includes: When the bus voltage exceeds a preset voltage threshold, the regenerative energy generated by the collision is stored in the energy storage unit through a bidirectional DC-DC converter, and the regenerative energy is released after the collision ends.

8. The method according to any one of claims 1 to 6, characterized in that, The trigger signal is issued by the collision prediction module at least a target time before a collision occurs; wherein the target time is determined based on at least one of the following: the collision time, the switching state switching time of the inverter, and the stabilization time of the motor current transitioning from normal mode to active short-circuit mode or dynamic braking mode.

9. The method according to claim 1, characterized in that, The collision time is determined based on the current observation time, the distance between the robot's end effector and the collision surface at the current observation time, and the velocity component of the robot's end effector in the normal direction of the collision surface at the current observation time.

10. The method according to claim 8, characterized in that, The method further includes: Overcurrent protection is divided into three levels: hardware instantaneous peak protection, firmware short-term instantaneous peak protection, and application long-term overcurrent protection. Within the collision prediction window, the protection thresholds of the hardware instantaneous peak protection and the firmware short-term instantaneous peak protection, as well as the criteria for application long-term overcurrent protection, are dynamically adjusted. The collision prediction window is determined based on the collision time, the target time, and the integral window time of the long-term overcurrent protection.

11. The method according to any one of claims 1 to 6, characterized in that, The method further includes: Determine the peak current after the collision; Verify whether the peak current exhibits an exponential decay characteristic; If the peak current does not exhibit an exponential decay characteristic, it is determined that the motor winding has a fault.

12. A control device for a robot, characterized in that, include: A receiving module is used to receive a trigger signal sent by the collision prediction module; wherein the trigger signal includes at least the collision time when the robot collides; A control module is configured to switch the inverter to an active short-circuit mode or a dynamic braking mode before the collision time, so that the motor winding current flows through the switching transistor channel; wherein the inverter is connected to the motor winding and includes multiple switching transistors; The control module is also configured to perform one of the following: control all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; control all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors. The control module is also used to control all upper bridge arms of the inverter to be turned off and all lower bridge arms to be turned on, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; or, to control all upper bridge arms of the inverter to be turned on and all lower bridge arms to be turned off, so that the motor windings form a low-impedance short-circuit loop through the switching transistors; and to control the connection state of at least one resistor connected in series in the low-impedance short-circuit loop, so that the equivalent resistance of the low-impedance short-circuit loop is adjustable.

13. A control system for a robot, characterized in that, include: A collision prediction module is used to predict the collision time of the robot before a collision occurs and output a trigger signal; wherein the trigger signal includes at least the collision time. The inverter is connected to the motor windings and the DC bus, and includes multiple switching transistors. An energy buffer module, connected to the DC bus, includes a bidirectional DC-DC converter and an energy storage unit; A mechanically compliant isolation module, located between the motor output shaft and the load, including a one-way overrunning clutch or an adjustable damping flexible coupling, is used to mechanically reduce the magnitude of speed change transmitted to the motor windings. The controller is connected to the collision prediction module, the inverter, and the energy buffer module, respectively, and is used to implement the method of any one of claims 1 to 11.

14. An electronic device, comprising: A memory, a processor, and a computer program stored on the memory, characterized in that the processor executes the computer program to implement the method of any one of claims 1 to 11.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 11.

16. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 11.

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