Braking system based on back electromotive force and cooking robot

Abstract

The invention provides a braking system based on back electromotive force and a cooking robot, and the braking system comprises a motor which is used for driving a target object to move; the driver is connected with the motor and used for controlling the motor to generate counter electromotive force during power failure, the motor moves to generate mechanical energy, and the mechanical energy is converted into electric energy through electromagnetic induction; and the energy storage device forms a conduction loop with the motor and the driver during power failure, and is used for receiving and storing the electric energy and supplying power to the driver after power failure, so that the driver maintains and controls the motor to generate counter electromotive force after power failure, and a target object is braked.

Description

Technical Field

[0001] This invention relates to the field of robot control, and more specifically to a braking system based on back electromotive force and a cooking robot. Background Technology

[0002] With the increasing commercialization and household use of robots, the risk of robots colliding with people, obstacles, and other equipment due to improper operation or accumulated errors is also increasing. This requires not only that the actuators have the ability to stop immediately when powered on, but also that they can stop abruptly when the power is off. Furthermore, it is necessary for the robot to remain unlocked after stopping, so that it can be moved to a safe location to reduce the risk of further danger.

[0003] Traditional mechanical braking methods can no longer meet the requirements of robots moving from industrial to commercial and home scenarios. The braking safety of robots (such as multi-axis heterogeneous robotic arm robots) in commercial and home scenarios urgently needs to be solved. Summary of the Invention

[0004] In view of this, the present invention provides a braking system based on back electromotive force, comprising: An electric motor is used to drive the target object to move; a driver is connected to the electric motor and is used to control the electric motor to generate back electromotive force when the power is off, wherein the electric motor generates mechanical energy, and the mechanical energy is converted into electrical energy through electromagnetic induction; an energy storage device forms a conductive circuit with the electric motor and the driver when the power is off, and is used to receive and store the electrical energy, and to supply power to the driver after the power is off, so that the driver can maintain control of the electric motor to generate back electromotive force after the power is off, so as to brake the target object.

[0005] The braking system based on back electromotive force provided by the present invention uses a driver to control a motor to brake a target object using back electromotive force. In the event that the driver loses power, the motor first generates an instantaneous back electromotive force to charge the energy storage device at the moment of power failure, and then releases the electrical energy through the energy storage device, so that the driver maintains the back electromotive force output state of the motor, thereby effectively stopping the target object that is sliding due to inertia.

[0006] This invention enables emergency stopping in the event of a power outage, solving the key problem of traditional mechanical braking failing when power is cut off, and ensuring that braking can be performed immediately even when the power supply is unexpectedly cut off. This invention can maintain an unlocked state, and braking relies on electromagnetic force rather than mechanical engagement and locking, which allows the robot to be manually moved to a safe position after braking, providing convenience for subsequent processing.

[0007] This invention also features a fast emergency stop response, utilizing the electromagnetic characteristics of the motor itself for braking, resulting in a faster response speed compared to mechanical brakes.

[0008] This invention can also simplify the structure and reduce costs, potentially reducing or eliminating the need for dedicated mechanical braking devices, simplifying the system structure, reducing weight, and lowering hardware costs. This invention utilizes an electric motor to achieve braking, using the motor that drives the target object's movement as a braking actuator, thereby improving system integration.

[0009] Optionally, the energy storage device is connected to the motor via a controllable switch. When the power is off, the controllable switch puts the energy storage device in a closed circuit state, and when the power is on, it puts the energy storage device in a closed circuit state.

[0010] The above-mentioned optional solution uses a power failure signal as the trigger condition for the switch state change to realize the automatic connection and disconnection of the energy storage circuit without the need for additional complex control logic, thereby improving the reliability and robustness of the system. At the same time, it avoids power consumption when the power is on and disconnects the switch when the power is on, isolating the energy storage device from the main circuit and preventing the energy storage device from discharging through the driver or other paths during normal operation, thus wasting energy. Furthermore, it can also protect the energy storage device by isolating it to avoid the potential impact of voltage fluctuations or surges during normal operation on the energy storage device.

[0011] Optionally, the energy storage device includes at least one capacitor.

[0012] The aforementioned options feature fast charging and discharging, and high efficiency. Capacitors have very fast charging and discharging speeds, capable of instantly absorbing the back electromotive force energy generated by the motor and quickly releasing it when needed, making them ideal for short-duration, high-peak-power applications. Using capacitors as energy storage in the braking system extends service life and eliminates maintenance. Compared to rechargeable batteries, capacitors have a longer cycle life and require virtually no maintenance. Capacitors are also suitable for pulse power; their characteristics make them particularly adept at providing short-duration, high-current applications, meeting the power supply requirements of the driver during braking and the brief period after braking. Using capacitors reduces the cost of the braking system; in high-current pulse applications, the cost of capacitors achieving the same power handling capacity may be lower than that of battery solutions. The strong temperature adaptability of capacitors ensures power supply during power outages in high- or low-temperature environments.

[0013] Optionally, the driver controls the motor to generate back electromotive force in the following manner: all the upper bridge MOS of the driver are turned off and all the lower bridge MOS are turned on, thereby short-circuiting the three-phase coils of the motor, wherein the driver controls the short-circuiting of the three-phase coils based on the duty cycle D(k) of the lower bridge MOS.

[0014] The above-mentioned optional solution uses PWM control to provide the ability to continuously and accurately adjust the braking current; the high switching frequency of PWM enables the driver to respond quickly to state changes and adjust the braking torque in real time; by changing the duty cycle D(k), different braking curves can be flexibly realized to meet the needs of different application scenarios; on the basis of braking, it can convert part of the energy consumed by the short circuit into heat energy, and the remaining kinetic energy can be converted into electrical energy through back electromotive force and recovered by the energy storage device; this solution makes full use of the existing power switching devices of the motor driver, without the need to add additional high-power resistors or switching devices.

[0015] Optionally, the driver uses a pulse width modulation signal and changes the equivalent resistance of the short-circuit loop of the three-phase coil based on the duty cycle D(k) to adjust the magnitude of the braking current generated by the back electromotive force. The relationship between the duty cycle D(k) and the equivalent resistance is as follows: , in Let be the equivalent resistance at time k. Here is the estimated value of the motor coil resistance at time k. This is the estimated on-resistance value of the lower bridge MOS. Let $\frac{ ... This is the speed change rate compensation coefficient.

[0016] The above-mentioned alternatives consider the actual impact of coil resistance, MOSFET on-resistance, and the motor speed reduction rate n(k) on the equivalent resistance of the braking circuit. Introducing a speed change rate compensation coefficient λ can more accurately characterize the resistance change during dynamic braking; a more accurate equivalent resistance model is the basis for accurately calculating the required duty cycle D(k), and a key prerequisite for achieving precise braking torque control. This helps overcome interference caused by parameter fluctuations and dynamic processes; the model compensates for the non-ideal characteristics of the equivalent resistance caused by rapid speed changes during braking, enabling the system to maintain good braking performance under different speed ranges and dynamic changes.

[0017] Optionally, the driver is used to predict the braking torque at time k+1. And based on the estimated value of the motor coil resistance The estimated on-resistance of the lower bridge MOS. and braking torque prediction value Determine the conduction duty cycle D(k).

[0018] The above-mentioned alternative calculates the current control quantity D(k) based on the predicted future torque demand. This is a feedforward control strategy that can act in advance and reduce system response delay. Achieving the target braking torque: directly applying the desired braking torque... As a control objective, the duty cycle required to achieve the objective is calculated through the model, giving the braking process a clear target orientation; regardless of the initial speed and load inertia, the system strives to generate the expected braking torque trajectory, making the braking behavior more predictable and consistent.

[0019] Optionally, the driver determines the duty cycle D(k) in the following manner: , in, It is the motor torque constant. It is the back electromotive force constant of the motor. It is magnetic flux. It is the motor speed at time k. This is the predicted braking torque value at time k+1. It is the moment of inertia compensation coefficient. It is the change in the load's moment of inertia at time k.

[0020] The above-mentioned alternative schemes calculate D(k) through a model, achieving computational efficiency within the microcontroller of the driver; the change in load rotational inertia is introduced. The rotational inertia compensation coefficient μ can significantly compensate for the impact of changes in the robot's load on the braking process. When the load increases, the model automatically adjusts D(k) to maintain the expected braking effect; by compensating for this common disturbance of load change, the stability and performance consistency of the braking system under different operating conditions are greatly improved. The model integrates core motor parameters such as torque constant, back electromotive force constant, magnetic flux, and speed, establishing a direct physical relationship between braking torque and duty cycle.

[0021] Optionally, the driver is further configured to estimate the motor coil resistance at time k based on the motor's operating parameters at time k. and the estimated on-resistance of the lower bridge MOS .

[0022] The above-mentioned optional solutions can track the actual values ​​of these parameters in real time online estimation, overcome the impact of parameter drift on control accuracy, enable the system to adapt to changes in the state of the motor and drive itself, maintain high-precision braking performance over a long period of time, and eliminate the need for manual calibration; real-time monitoring of key parameters also helps to achieve fault diagnosis.

[0023] Optionally, the driver is also used to predict the motor speed at time k+1, n(k+1), and obtain the measured motor speed at time k+1. Then calculate the speed error. And utilize the speed error Correcting the estimated value of the motor coil resistance at time k+1 Estimated on-resistance at time k+1 Predicted braking torque at time k+2 .

[0024] The above-mentioned alternative solution introduces a crucial feedback loop, utilizing the error between the measured motor speed and the predicted motor speed. It achieves closed-loop predictive control; by continuously correcting key parameters and future control objectives in the predictive model using feedback errors, it can effectively suppress the influence of inaccurate models, unmodeled dynamics, and unknown external disturbances; through continuous correction, the system can dynamically optimize its predictive and control parameters throughout the braking process, achieving a smoother and more accurate braking effect.

[0025] The present invention also provides a cooking robot, comprising: a robotic arm, a linear actuator, and the aforementioned braking system; wherein the robotic arm is used to carry cooking utensils, the motor is used to drive the robotic arm to reciprocate on the linear actuator, and the braking system brakes the movement of the robotic arm when power is off.

[0026] The cooking robot provided by this invention adopts a back-EMF braking scheme, which is designed for commercial / home cooking robot scenarios. It solves the risk of loss of control due to power failure or emergency stop commands when the robotic arm moves at high speed, preventing it from colliding with people, equipment or heat sources, and protecting personal and property safety. It is especially important to keep it in an unlocked state after an emergency stop, so that the operator can manually remove the robotic arm / cookware to avoid burns or food spillage. The braking system can effectively cope with the reciprocating motion of the robotic arm on a linear track, as well as possible acceleration, deceleration and start-stop. It integrates all the advantages of the aforementioned braking systems and is particularly suitable for home and commercial kitchen environments with high requirements for safety, flexibility and ease of use. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a braking system based on back electromotive force in an embodiment of the present invention; Figure 2 This is a schematic diagram of another braking system based on back electromotive force in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the cooking robot in an embodiment of the present invention; Figure 4The displacement and velocity curves of the cooking robot in this embodiment of the invention when it comes to inertial braking. Figure 5 The graph shows the displacement and velocity curves of the cooking robot using the back EMF braking system in this embodiment of the invention. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] like Figure 1 As shown in the figure, this application provides a braking system based on back electromotive force, including a motor 1, a driver 2, and an energy storage device 3. The driver 2 is connected to the motor 1, and the energy storage device 3 is connected to both the motor 1 and the driver 2. The driver 2 can be an integrated module mounted on the motor 1 or a separate device.

[0033] Motor 1 is used to drive the target object to move. Under normal power supply conditions, motor 1 executes normal operation commands, driving the target object to perform corresponding actions, displacements, etc. The target object can be the base of a robotic arm, a moving platform, a conveyor belt, etc., which are displaced under the drive of motor 1.

[0034] The driver is used to control motor 1 to generate back electromotive force when power is off. Motor 1's motion generates mechanical energy, which is converted into electrical energy through electromagnetic induction. Motor 1 generates a braking current / induced current, which, under the influence of electromagnetic force in the magnetic field, produces an electromagnetic force opposite to the direction of motor 1's rotation, forming a braking torque. This reduces the rotational speed of motor 1, thereby achieving rapid braking. After power is off, motor 1 continues to rotate due to inertia. This rotational kinetic energy / mechanical energy can be converted into electrical energy in the closed loop constructed by the scheme of this application, serving as the subsequent energy source for the system.

[0035] In this scheme, a power outage refers to the loss of power supply to the actuator 2. Before the power outage, the motor 1 is in operation; at the instant of power outage, the system triggers power outage protection, controlling the motor 1 to generate back electromotive force within microseconds; at the instant of power outage and after power outage, the motor 1 continues to rotate due to inertia, and the rotational kinetic energy of the motor 1 is converted into electrical energy. At this time, the motor 1 is equivalent to a generator, changing from consuming electrical energy in normal operation to outputting electrical energy. However, due to the system power outage, the actuator 2 can only make the motor 1 generate an instantaneous back electromotive force. After the power outage, the actuator 2 loses its energy source, and its control over the motor 1 also stops. This application uses an energy storage device 3 as the energy source for the actuator 2 after a power outage, enabling the actuator 2 to continuously control the motor 1 and generate continuous braking torque.

[0036] When power is off, the energy storage device 3 forms a conductive circuit with the motor 1 and the driver 2 to receive and store electrical energy. After power is off, it supplies power to the driver 2, enabling the driver 2 to maintain control of the motor 1 to generate a back electromotive force to brake the target object. The energy storage device 3 completes charging within microseconds and then begins to supply power to the driver 2 as an energy source, keeping the windings short-circuited. This allows it to continuously generate a reverse electromagnetic force, effectively stopping the target object that continues to move due to inertia.

[0037] The braking system based on back electromotive force provided in this embodiment of the invention uses a driver 2 to control a motor 1 to brake a target object using back electromotive force. In the event that the driver 2 loses power, the motor 1 first generates an instantaneous back electromotive force to charge the energy storage device 3 at the moment of power failure. Then, the energy is released through the energy storage device 3, so that the driver 2 maintains the back electromotive force output state of the motor 1, thereby effectively stopping the target object that is sliding due to inertia.

[0038] Furthermore, the braking system provided in this embodiment is not limited to braking during power outages. When power is normal, if braking needs to be triggered, the system does not require the energy storage device 3 to participate in the braking process. The driver 2 can rely on the power supply to maintain the control motor 1 to generate back electromotive force, thereby braking the target object. The braking can be triggered by command, abnormal state, or other means. For example, braking can be triggered when the system experiences current over-limit, malfunction, or when the target object needs to stop moving.

[0039] like Figure 2 As shown, in one embodiment, the energy storage device 3 is connected to the motor 1 via a controllable switch. The controllable switch keeps the energy storage device 3 in a closed-circuit state when power is off and in a closed-circuit state when power is on. Specifically, a diode D1 can be used to achieve unidirectional conduction (closed-circuit when the system is normally powered on, and conducting when the system is powered off). When the system is normally powered on, diode D1 is in a reverse cutoff state, and the energy storage device 3 is in a closed-circuit state, avoiding interference with the operation of the motor 1 and preventing damage caused by prolonged charging of the energy storage device 3 during normal power supply. Furthermore, the short conduction time of diode D1 (nanosecond level) can meet the requirements for instantaneous braking response during power outages, further improving system reliability compared to other controllable switches (such as relays).

[0040] The energy storage device 3 in this embodiment includes at least one capacitor C, which may be composed of a single or multiple supercapacitors and / or aluminum electrolytic capacitors. The capacitor C can be charged in microseconds to meet the energy capture requirements during power outages, and its discharge rate is also relatively fast, meeting the requirements for instantaneous braking response during power outages. Furthermore, the capacitor C directly stores the electrical energy generated by the back electromotive force, avoiding energy waste through heat generated by resistors, thereby improving the efficiency of the braking system.

[0041] When the driver 2 controls the motor 1 to perform back EMF braking, it will face several problems, including time-varying parameters, lag in dynamic response, and poor load adaptability. These problems will affect the braking effect and ultimately affect the braking distance.

[0042] To more accurately control the braking distance, in one embodiment, the driver 2 controls the motor 1 to generate back electromotive force in the following manner: all the upper bridge MOS of the driver 2 are turned off and all the lower bridge MOS are turned on, thereby short-circuiting the three-phase coils of the motor 1, wherein the driver 2 controls the short-circuiting of the three-phase coils based on the conduction duty cycle D(k) of the lower bridge MOS.

[0043] Specifically, motor 1 includes three-phase coils, and driver 2 includes upper-bridge MOSFETs and lower-bridge MOSFETs. For example, the upper-bridge MOSFETs include three, corresponding to the upper arm of phase U, the upper arm of phase V, and the upper arm of phase W respectively; the lower-bridge MOSFETs also include three, corresponding to the lower arm of phase U, the lower arm of phase V, and the lower arm of phase W respectively. The drain of the upper arm of phase U is connected to the positive terminal of the power supply, and the source is connected to one end of the phase U winding; the drain of the upper arm of phase U is connected to the other end of the phase U winding, and the source is connected to the negative terminal of the power supply / ground; the connection logic of the upper arms of phase V and phase W is consistent with that of phase U, ultimately forming three independent paths: positive terminal of the power supply, upper-bridge MOSFET, winding, lower-bridge MOSFET, and negative terminal of the power supply.

[0044] Turning off all upper bridge MOS involves setting the gate drive signal of each of the U-phase upper bridge arm, V-phase upper bridge arm, and W-phase upper bridge arm to a low level to cut off the connection between the power supply and the three-phase coils. Turning on all lower bridge MOS involves setting the gate drive signal of each of the U-phase lower bridge arm, V-phase lower bridge arm, and W-phase lower bridge arm to a high level, and can conduct the connection between the three-phase coils and ground according to the set duty cycle D(k), thereby short-circuiting the three-phase coils and generating back electromotive force.

[0045] Furthermore, the driver 2 adjusts the magnitude of the braking current generated by the back electromotive force by changing the equivalent resistance of the short-circuit loop of the three-phase coil based on the duty cycle D(k) using a pulse width modulation signal. The short-circuit loop of the three-phase coil refers to the controlled conduction loop formed by the three-phase coil and the energy storage device 3 after short-circuiting.

[0046] The relationship between the duty cycle D(k) of the lower-bridge MOSFET and the equivalent resistance of the short-circuit loop of the three-phase coil is as follows: , in Let be the equivalent resistance of the short-circuit loop at time k. Here is the estimated value of the motor coil resistance at time k. This is the estimated on-resistance value of the lower bridge MOSFET. Let k be the rate of change of the rotational speed of motor 1. This is the speed change rate compensation coefficient.

[0047] In this embodiment, the equivalent resistance of the short-circuit loop of the three-phase coil is adjusted by adjusting the duty cycle D(k) of the lower bridge MOS, thereby achieving control of the braking distance.

[0048] In real-world scenarios, the system's environment and its own heat generation can cause changes in the resistance state of the circuit. The back EMF regulation capability of the system decreases by approximately 0.4% for every 1°C increase in temperature; for the integrated motor 1 module with driver 2 mounted on the motor 1 body, the estimated on-resistance of the lower bridge MOSFET is... The junction temperature significantly affects the control deviation. These changes in resistance can affect the magnitude of the braking current generated by the back electromotive force, resulting in different braking effects. The time-varying problem of the above parameters is particularly noticeable for cooking robots and their braking systems in the high-temperature environment of the kitchen.

[0049] To address the aforementioned issues, in one embodiment, the driver 2 estimates the motor coil resistance based on the value at time k. Estimated on-resistance of the lower-bridge MOSFET Determine the duty cycle D(k) at time k.

[0050] Sure and There are several ways to obtain this information, such as through real-time measurement or estimation using mathematical models or neural network models.

[0051] about A lightweight neural network can be pre-trained, taking the current, voltage, and temperature sequences of motor 1 during operation as input and outputting the resistance value. By training the network with a large amount of motor data, it can be run online with the latest sequence as input and directly output an estimated value.

[0052] Alternatively, based on the measured data such as voltage and current of motor 1, and combined with the mathematical model of motor 1, the recursive least squares method can be used to estimate... Specifically, during the operation of motor 1, the three-phase current, voltage, and winding temperature are collected synchronously; the collected data are input into the recursive least squares method module, and the estimated value is obtained based on the pre-established temperature-resistance linear relationship model, for example, the resistance increases by 4% for every 10°C increase in temperature.

[0053] about The junction temperature can be monitored in real time using a temperature sensor built into the MOSFET driver chip or an external infrared probe. Then, a compensation value is output by looking up a pre-stored on-resistance-temperature correspondence table. In this embodiment, a suitable duty cycle is determined based on the estimated motor coil resistance and the real-time state of the lower-bridge MOSFET's on-resistance, thereby dynamically estimating and compensating for these time-varying factors, ensuring braking current accuracy, solving the problem of time-varying parameters, avoiding sudden changes in braking current and motor 1 jitter caused by fixed resistance, and making braking smoother.

[0054] Furthermore, from the start of braking, the braking torque of motor 1 changes continuously. In order to accurately control the braking distance, the duty cycle D(k) should be calculated based on the braking torque of motor 1. However, if only the braking torque at the current moment is considered, it may lead to braking overshoot or response delay, i.e., dynamic response lag.

[0055] To address the aforementioned issues, in one embodiment, the driver 2 can also predict the braking torque at time k+1. And based on the estimated value of the motor coil resistance On-resistance estimate and braking torque prediction value Determine the conduction duty cycle D(k). Braking torque prediction value. It can be estimated using algorithms such as mathematical models and neural network models.

[0056] Specifically, the measured braking torque at time k can be obtained first. Then, based on the load moment of inertia and its change at time k, the inertia compensation value can be obtained. Finally, the measured braking torque at time k can be added to the inertia compensation value to obtain the predicted braking torque at time k+1. .

[0057] This embodiment will target braking torque The model predicts the duty cycle using the target torque of the next sampling period, setting it as the predicted value for the next sampling period. This enables proactive control, which is suitable for rapid braking scenarios of robots and solves the problem of dynamic response lag.

[0058] In this embodiment, the driver 2 determines the duty cycle D(k) as follows: , in, It is the motor torque constant. It is the back electromotive force constant of the motor. It is magnetic flux. It is the motor speed at time k. This is the predicted braking torque value at time k+1. It is the moment of inertia compensation coefficient. This is the change in the load's moment of inertia at time k. It should be noted that using the above mathematical model to calculate the duty cycle is not the only feasible method; alternatively, a neural network model can also be used for calculation.

[0059] Furthermore, to control the braking distance more precisely, in one embodiment, the driver 2 is also used to predict the predicted motor speed n(k+1) at time k+1 and obtain the measured motor speed at time k+1. Then calculate the speed error. And utilize the speed error Correcting the estimated value of the motor coil resistance at time k+1 Estimated on-resistance at time k+1 Predicted braking torque at time k+2 For example, the actual rotational speed n(k+1) at time k+1 can be collected, the rotational speed error can be calculated based on the predicted rotational speed data, and the above parameter correction can be achieved by updating the parameters online through recursive least squares method and iteratively optimizing the closed-loop logic of the prediction.

[0060] Specifically, in At a certain time, driver 2 outputs a duty cycle signal to the lower bridge MOSFET to control its conduction state, and also predicts... The predicted speed of motor 1 at time n(k+1); exist As can be seen from the above embodiment, at time k+1, the estimated value of the motor coil resistance can be obtained. and estimated on-resistance and braking torque prediction value ; In this embodiment, The system also continuously collects the actual speed data of motor 1 and calculates the speed error. Utilizing speed error Correction , and To carry out iterative optimization.

[0061] This embodiment utilizes model predictive control (MMCC) to estimate the speed at the next moment using the current state of motor 1, such as the current, voltage, and speed, along with the system model. This overcomes the lag inherent in traditional feedback control, allowing for advance planning of control strategies to address motor nonlinearity and time-varying characteristics, such as resistance changes caused by temperature, sudden load changes, and to compensate for deviations between the model and reality. Through speed error feedback, parameters such as speed, torque, and inertia in the predictive model are dynamically corrected, ensuring the accuracy of back-EMF regulation.

[0062] like Figure 3 As shown, this application provides a cooking robot, including: a robotic arm 31, a linear actuator 32, and a braking system as described in the above embodiment. The robotic arm 31 is used to carry cooking utensils, and the motor 1 in the braking system drives the robotic arm 31 to reciprocate on the linear actuator 32 and brakes the robotic arm 31 based on its back electromotive force.

[0063] For example, the base of the robotic arm 31 is mounted on the guide rail of the linear actuator 32, and the motor 1 directly drives the robotic arm 31 to move. The base of the robotic arm 31 serves as the target object, and the body of the robotic arm 31 is mounted on the base. The two can reciprocate synchronously along the guide rail direction. Alternatively, a slide is mounted on the guide rail of the linear actuator 32, and the motor 1 drives the slide to move. The robotic arm 31 is mounted on the slide, and the slide serves as the target object. Specifically, the robotic arm 31 can grasp cooking utensils such as pots, frying baskets, spoons, or spatulas and move along the linear actuator 32. In this embodiment, its direction of movement is defined as the X-axis direction, and the braking system is used for braking control in the X-axis direction.

[0064] Taking a specific cooking task as an example, the cooking robot performs the task of frying fast food: First, the robotic arm 31 is moved to one end of the linear actuator 32 and stopped. Then, through the joint movement of the robotic arm 31, the end gripper grabs the frying basket containing food. After grabbing the frying basket, the robotic arm 31 is moved to the position in the linear actuator 32 corresponding to a certain fryer and stops. Then, through the joint movement of the robotic arm 31, the gripper places the frying basket into the fryer. Afterwards, the robotic arm 31 can continue to grab other targets or wait in place until the frying time is reached. Then, it returns to the location of the fryer and stops moving. Through the joint movement of the robotic arm 31, the end gripper is used to remove the frying basket from the fryer. The robotic arm 31 is moved to the other end of the linear actuator 32 and stops, and the frying basket is placed at the serving position to complete the cooking task.

[0065] During the aforementioned tasks, the robotic arm 31 repeatedly transitions from movement to a stop. These normal braking actions can all be achieved using the back electromotive force of the motor 1. In the event of an abnormal power outage or a manual emergency power cut-off, the braking system of this embodiment can also perform emergency braking on the robotic arm 31.

[0066] Compared to existing mechanical brake solutions, this embodiment employs a back-EMF braking scheme, which significantly reduces costs, size, and ease of maintenance. Furthermore, after braking, a mechanical brake locks the linear motion of the mechanism, preventing the robotic arm from moving along the X-axis, hindering its movement or resetting and reducing its flexibility. In contrast, this solution eliminates the physical lock after braking, allowing a manual push of the robotic arm to the target position for subsequent operation or maintenance.

[0067] like Figure 4As shown, the motor motion data and motor speed curve without back EMF braking are displayed. The horizontal axis represents time, and the vertical axis represents the motor motion data (number of revolutions, r) and motor speed (number of revolutions / second, r / s), respectively. Starting from the maximum speed Vmax=50r / s, the motor decelerates and comes to a stop by inertia. Compared to the set soft limit of 34r, it coasts freely for 43.36r-34r=9.36r. Based on a lead of 0.04m / r, the coasting distance is calculated to be 9.36*0.04=0.374m.

[0068] like Figure 5 The diagram shows the motor motion data and motor speed curves of the back EMF braking system. The horizontal axis represents time, and the vertical axis represents the motor motion data (number of revolutions, r) and motor speed (revolutions / second, r / s), respectively. Decelerating from the maximum speed Vmax = 50 r / s, the robot stops by generating back EMF in motor 1. Compared to the set soft limit of 34 r, it slides 34.45 r – 34 r = 0.45 r. Based on a lead of 0.04 m / r, the calculated sliding distance is 0.45 * 0.04 = 0.018 m. Compared to free-slip braking, the stopping distance of the cooking robot using the back EMF braking scheme of this application is less than 5% of that of free-slip braking, demonstrating a significant braking and deceleration effect.

[0069] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0070] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0071] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0072] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0073] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A braking system based on back electromotive force, characterized in that, include: An electric motor is used to drive a target object to move. A driver, connected to the motor, is used to control the motor to generate a back electromotive force when the power is off, wherein the movement of the motor generates mechanical energy, and the mechanical energy is converted into electrical energy through electromagnetic induction; The energy storage device forms a conductive circuit with the motor and the driver when the power is off, and is used to receive and store the electrical energy. After the power is off, it supplies power to the driver so that the driver can maintain control of the motor to generate back electromotive force to brake the target object after the power is off.

2. The braking system according to claim 1, characterized in that, The energy storage device is connected to the motor via a controllable switch. When the power is off, the controllable switch puts the energy storage device in a closed circuit state, and when the power is on, it puts the energy storage device in a closed circuit state.

3. The braking system according to claim 1, characterized in that, The energy storage device includes at least one capacitor.

4. The braking system according to claim 1, characterized in that, The driver controls the motor to generate back electromotive force in the following manner: all the upper bridge MOS of the driver are turned off and all the lower bridge MOS are turned on, thereby short-circuiting the three-phase coils of the motor, wherein the driver controls the short-circuiting of the three-phase coils based on the conduction duty cycle D(k) of the lower bridge MOS.

5. The braking system according to claim 4, characterized in that, The driver uses a pulse width modulation signal and changes the equivalent resistance of the short-circuit loop of the three-phase coil based on the duty cycle D(k) to adjust the magnitude of the braking current generated by the back electromotive force. The relationship between the duty cycle D(k) and the equivalent resistance is as follows: , in Let be the equivalent resistance at time k. Here is the estimated value of the motor coil resistance at time k. This is the estimated on-resistance value of the lower bridge MOS. Let k be the rate of change of the motor's speed at time k. This is the speed change rate compensation coefficient.

6. The braking system according to claim 4, characterized in that, The driver is used to predict the braking torque at time k+1. And based on the estimated value of the motor coil resistance. The estimated on-resistance of the lower bridge MOS. and the predicted braking torque value Determine the conduction duty cycle D(k).

7. The braking system according to claim 6, characterized in that, The driver determines the duty cycle D(k) as follows: , in, It is the motor torque constant. It is the back electromotive force constant of the motor. It is magnetic flux. It is the motor speed at time k. It is the moment of inertia compensation coefficient. It is the change in the load's moment of inertia at time k.

8. The braking system according to claim 6, characterized in that, The driver is also used to estimate the motor coil resistance based on the motor's operating parameters at time k. and the estimated on-resistance of the lower bridge MOS .

9. The braking system according to claim 8, characterized in that, The driver is also used to predict the motor speed at time k+1, n̂(k+1), and to obtain the measured motor speed at time k+1. Then calculate the speed error. And utilize the speed error Correcting the estimated value of the motor coil resistance at time k+1 Estimated on-resistance at time k+1 Predicted braking torque at time k+2 .

10. A cooking robot, characterized in that, include: A robotic arm, a linear actuator, and a braking system according to any one of claims 1-9; wherein the robotic arm is used to carry a cooking appliance, the motor is used to drive the robotic arm to reciprocate on the linear actuator, and the braking system brakes the movement of the robotic arm when power is off.

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