A drive module applied to a robot joint

Abstract

The utility model relates to robot drive technical field, and disclose a kind of drive module applied to robot joint, including rectifier unit, DC bus unit, inverter unit and energy management unit, rectifier unit input end connects three-phase power supply, output end connects DC bus unit input end;DC bus unit output end connects inverter unit input end;Inverter unit output end connects robot each joint motor;Energy management unit input end is connected DC bus unit, inverter unit and rectifier unit respectively, and energy management unit output end is connected DC bus unit, rectifier unit and inverter unit respectively, the utility model is centralized by common rail framework local drive, different inverter unit design, three-level energy scheduling strategy, self-disturbance control and rolling time domain optimization scheduling, solve the existing independent servo drive scheme energy utilization rate low, power grid harmonic is serious, multi-shaft coupling interference is strong, dynamic stability is poor, integration is low, adaptability weak and so on.

Description

Technical Field

[0001] This utility model relates to the field of robot drive technology, specifically a drive module applied to robot joints. Background Technology

[0002] Industrial robot multi-joint drive systems enable precise and powerful rotation of each joint of the robotic arm, converting electrical energy into controllable joint motion. They often employ independent servo drive schemes, with each joint drive device set up separately, and are widely used in the field of CNC machine tools.

[0003] Although multi-joint drive systems for industrial robots have been widely used in existing technologies, they still have many technical shortcomings, namely: 1. Low equipment integration: rectifier, inverter, and energy management units are scattered, occupying a large space, complex assembly and debugging, poor adaptability, and difficulty in flexibly matching robot joints with different power specifications; 2. The regenerative energy of each axis can only be dissipated through the braking resistor, resulting in low energy utilization, and the parallel connection of multiple rectifier units can easily cause grid harmonic problems; 3. Severe coupling interference during multi-axis movement, traditional control strategies are difficult to achieve high-precision dynamic control, the dynamic working condition stability is weak, the joint trajectory tracking error is large, and it cannot meet the performance requirements of high-speed and high-dynamic operation of industrial robots.

[0004] To address the above issues, a drive module for robot joints is proposed. Utility Model Content

[0005] This invention provides a drive module for robot joints, which solves the problems mentioned in the background art, such as low integration, poor adaptability, prominent energy consumption and harmonic issues, large multi-axis coupling interference, and insufficient control accuracy and stability of existing multi-joint drive systems.

[0006] This utility model provides the following technical solution: a drive module applied to a robot joint, including a rectifier unit, a DC bus unit, an inverter unit, and an energy management unit; The input terminal of the rectifier unit is connected to a three-phase power frequency power supply, and the output terminal is connected to the input terminal of the DC bus unit; the output terminal of the DC bus unit is connected to the input terminal of the inverter unit; the output terminal of the inverter unit is connected to the motors of each joint of the robot; the input terminal of the energy management unit is connected to the DC bus unit, the inverter unit and the rectifier unit respectively, and the output terminal of the energy management unit is connected to the DC bus unit, the rectifier unit and the inverter unit respectively. The rectifier unit converts three-phase power frequency AC power into stable DC power and suppresses harmonics; The DC bus unit constructs a common rail energy sharing channel and stabilizes the bus voltage; The inverter unit converts direct current into alternating current adapted to different joints and drives the joint motors. The energy management unit monitors the system status in real time, optimizes the allocation of regenerated energy, and compensates for load disturbances.

[0007] Preferably, the rectifier unit is an active front-end rectifier unit, which adopts a three-phase full-bridge pulse width modulation rectifier topology and has a built-in grid voltage directional vector control module and predictive mode switching logic to realize power factor correction, harmonic suppression and advance switching of rectifier and inverter modes.

[0008] Preferably, the DC bus unit is a common rail energy sharing channel, and is equipped with a support capacitor, a low-inductance multilayer copper busbar and a high-frequency filter capacitor bank; The DC bus unit receives DC power output from the rectifier unit and regenerated power feedback from each inverter unit, and outputs DC power.

[0009] Preferably, the inverter unit is a differentiated power inverter unit, including an inverter sub-unit adapted to large inertia joints and an inverter sub-unit adapted to small inertia joints; and each inverter sub-unit adopts power devices and carrier frequencies that match the joint load.

[0010] Preferably, the energy management unit includes a high-precision sampling component, a supercapacitor energy storage module, and a bidirectional DC-DC converter unit; The energy management unit receives bus voltage, power of each shaft, and load disturbance signals, and outputs power allocation, bus voltage compensation, and supercapacitor energy storage module charging and discharging control signals. It also adopts a three-level scheduling strategy, equipped with a rolling time-domain optimization scheduling program and an active disturbance rejection control program, to estimate and compensate for load disturbances in real time and solve for the optimal power allocation scheme.

[0011] Preferably, the three-level scheduling strategy prioritizes the direct exchange of regenerative energy between joints through the DC bus unit; when there is excess energy, it is fed back to the grid by the rectifier unit; and when the bus voltage is abnormal, the supercapacitor energy storage module intervenes to regulate it.

[0012] This utility model has the following beneficial effects: 1. This application adopts a common rail architecture and three-level energy dispatch, which can efficiently recover and regenerate energy, reduce energy consumption, suppress grid harmonics, and improve power quality.

[0013] 2. This application adopts differentiated inverter to adapt to joint load, combined with active disturbance rejection control and rolling time domain optimization, to suppress multi-axis coupling interference, resulting in fast dynamic response and high trajectory tracking accuracy.

[0014] 3. This application adopts a centralized drive design to achieve high integration, which can flexibly adapt to joints with different power specifications, and solves the problems of weak adaptability and complicated debugging of traditional solutions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Example 1: Please refer to Figure 1 As shown, a drive module for robot joints includes a rectifier unit, a DC bus unit, an inverter unit, and an energy management unit.

[0018] The rectifier unit's input is connected to a three-phase power supply, and its output is connected to the DC bus unit's input. The DC bus unit's output is connected to the inverter unit's input. The inverter unit's output is connected to the motors of each joint of the robot. The energy management unit's input is connected to the DC bus unit, inverter unit, and rectifier unit, respectively, and its output is connected to the DC bus unit, rectifier unit, and inverter unit, respectively. The whole unit forms a two-layer structure of energy flow and signal flow, realizing centralized energy supply to the multi-joint drive system, as well as regenerative energy sharing and high-precision collaborative control.

[0019] The rectifier unit is an active front-end rectifier unit, which adopts a three-phase full-bridge pulse width modulation rectifier topology and serves as the only AC-DC conversion input for the entire drive system. The power devices are selected as 1200V / 400A silicon carbide metal oxide semiconductor field-effect transistors, and the switching frequency can be increased to 20kHz. It can control the total harmonic distortion rate of the input current to within 3% to meet the harmonic standards of the national public power grid.

[0020] The rectifier unit has a built-in vector control module based on grid voltage orientation. It controls active and reactive power separately through current components to achieve a power factor close to the unit value while stabilizing the output rated DC voltage. The inner current loop uses a proportional-integral controller, and the outer voltage loop also uses a proportional-integral controller. The inner and outer loops maintain a ten-fold bandwidth separation principle to avoid loop coupling that could lead to system instability.

[0021] The rectifier unit is equipped with predictive mode switching logic, which can trigger the switching from rectifier mode to inverter mode 5 milliseconds in advance under the condition of excess energy, so as to send the excess energy of the bus back to the grid, effectively avoid the bus voltage drop or overshoot during the switching process, and ensure the voltage safety margin of the inverter unit power devices.

[0022] The DC bus unit adopts a common rail energy-sharing architecture, serving as a common path for energy exchange between shafts, with a rated voltage of 540V. The bus is equipped with a thin-film capacitor as a supporting capacitor, with the capacitance selected based on the most severe braking conditions to ensure that the bus voltage fluctuation does not exceed 10% of the rated value. The bus conductor adopts a low-inductance multilayer copper busbar structure, with the positive and negative busbar spacing controlled within 3 mm, suppressing parasitic inductance to below 200 nanohenries, ensuring that the influence of bus impedance on voltage distribution is negligible under high-frequency switching conditions.

[0023] A high-frequency filter capacitor bank is connected in parallel at both ends of the bus to absorb the high-frequency ripple generated by the switching action of the inverter unit, prevent the ripple from being transmitted to other shafts through the bus, and ensure the signal purity of the current loop control of each shaft. The DC bus unit receives the DC power output from the rectifier unit and the regenerative power fed back by each inverter unit, forming a bidirectional energy flow channel, so that the power generated by the brake shaft can be directly supplied to the drive shaft without the need for brake resistor dissipation, which significantly improves the system energy utilization rate.

[0024] The inverter unit is a differentiated power inverter unit, which includes inverter sub-units adapted to large inertia joints and inverter sub-units adapted to small inertia joints. The electrical parameters are designed according to the rated power and peak torque requirements of each joint to avoid waste of components due to excessive margin design for small power shafts.

[0025] Taking a typical industrial robot structure as an example, the waist joint is the maximum power axis, and the corresponding inverter sub-unit uses a 650V / 100A insulated gate bipolar transistor with a carrier frequency set to 8kHz to meet the driving capability requirements of large inertia loads; the wrist joint is the minimum power axis, and the corresponding inverter sub-unit uses a 650V / 30A insulated gate bipolar transistor with a carrier frequency increased to 16kHz to reduce current ripple and improve the position control accuracy of small inertia joints.

[0026] The rated current margin of each inverter subunit is uniformly selected at 1.5 times the peak current to ensure that the device does not thermally break down under extreme conditions such as robot emergency stop; each inverter unit shares the bus voltage sampling signal, while the current sampling is independent, with a sampling resolution of 16 bits and a current control accuracy better than 0.5%, meeting the joint torque control accuracy requirements; the inverter unit converts DC bus power into AC power adapted to different joints to drive the permanent magnet synchronous motors of each joint.

[0027] The energy management unit integrates a high-precision sampling component, a supercapacitor energy storage module, and a bidirectional DC-DC converter unit. It monitors the bus voltage, power status of each shaft, and load disturbance signals in real time, coordinates the flow and distribution of regenerated energy among the modules, and outputs power distribution, bus voltage compensation, and supercapacitor energy storage module charging and discharging control signals.

[0028] The energy management unit adopts a three-level scheduling strategy, following the principle of prioritizing inter-axis exchange, followed by active front-end compensation, and with energy storage intervention as a backup. When the braking shaft generates regenerative energy, it first determines whether there are other shafts simultaneously in driving mode. If so, the inter-axis energy transfer is completed directly through the DC bus. If all shafts are in braking or no-load state, resulting in excess energy on the bus, the rectifier unit feedback mode is activated to send energy back to the grid. When the bus voltage fluctuation exceeds the preset threshold and the rectifier unit response speed is insufficient to suppress it in time, the supercapacitor energy storage module is put into operation as a third-level buffer to cope with the power pulse demand under extreme conditions such as high-speed commutation.

[0029] The energy management unit is equipped with an active disturbance rejection control program and a rolling time-domain optimization scheduling program. It estimates and compensates for multi-axis load power disturbances in real time through an extended state observer, decoupling the controller design from the load characteristics and making it inherently robust to changes in the load characteristics of each joint. At the same time, it uses the predicted power sequence of the next 5 milliseconds as input and the power distribution ratio of each axis as the decision variable to solve for the optimal allocation scheme that minimizes the bus voltage fluctuation. The optimization problem is solved quickly after convexity processing, meeting the timing requirements of real-time control.

[0030] The supercapacitor energy storage module adopts the 200F / 48V specification. After being boosted by a bidirectional DC-DC converter, it is connected in parallel to the bus. It can complete the large-capacity transient energy throughput in a short time, cover the power pulse demand under extreme commutation conditions, and ensure the stable operation of the system under harsh conditions such as simultaneous braking of multiple axes.

[0031] When this invention is in operation, the three-phase power frequency is converted into stable DC power by the rectifier unit and delivered to the DC bus unit; each inverter unit obtains power from the DC bus unit to drive the corresponding joint motor; when the joint is in braking state, the motor generates regenerative power and feeds it back to the DC bus unit; the energy management unit monitors the system status in real time and prioritizes the allocation of regenerative power to the joints in driving state to achieve efficient utilization of inter-axis energy; when there is excess energy, it is fed back to the grid by the rectifier unit; under extreme conditions, the supercapacitor energy storage module quickly absorbs and releases energy to stabilize the bus voltage.

[0032] This invention solves the problems of low energy utilization, severe grid harmonics, strong multi-axis coupling interference, poor dynamic stability, low integration, and weak adaptability of existing independent servo drive solutions by adopting a centralized drive with a common rail architecture, differentiated inverter unit design, three-level energy scheduling strategy, active disturbance rejection control, and rolling time-domain optimization scheduling. It achieves the technical effects of highly integrated drive unit, flexible adaptation to different joint specifications, efficient recovery of regenerative energy, stable bus voltage, fast multi-axis dynamic response, and high trajectory tracking accuracy.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0034] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A drive module for robot joints, characterized in that, It includes a rectifier unit, a DC bus unit, an inverter unit, and an energy management unit; The input terminal of the rectifier unit is connected to a three-phase power frequency power supply, and the output terminal is connected to the input terminal of the DC bus unit; the output terminal of the DC bus unit is connected to the input terminal of the inverter unit; the output terminal of the inverter unit is connected to the motors of each joint of the robot; the input terminal of the energy management unit is connected to the DC bus unit, the inverter unit and the rectifier unit respectively, and the output terminal of the energy management unit is connected to the DC bus unit, the rectifier unit and the inverter unit respectively. The rectifier unit converts three-phase power frequency AC power into stable DC power and suppresses harmonics; The DC bus unit constructs a common rail energy sharing channel and stabilizes the bus voltage; The inverter unit converts direct current into alternating current adapted to different joints and drives the joint motors. The energy management unit monitors the system status in real time, optimizes the allocation of regenerated energy, and compensates for load disturbances.

2. The drive module for a robot joint according to claim 1, characterized in that: The rectifier unit is an active front-end rectifier unit, which adopts a three-phase full-bridge pulse width modulation rectifier topology and has a built-in grid voltage directional vector control module and predictive mode switching logic to realize power factor correction, harmonic suppression and advance switching of rectifier and inverter modes.

3. A drive module for a robot joint according to claim 2, characterized in that: The DC bus unit is a common rail energy sharing channel, and is equipped with a support capacitor, a low-inductance multilayer copper busbar and a high-frequency filter capacitor bank. The DC bus unit receives DC power output from the rectifier unit and regenerated power feedback from each inverter unit, and outputs DC power.

4. A drive module for a robot joint according to claim 3, characterized in that: The inverter unit is a differentiated power inverter unit, including an inverter sub-unit adapted to large inertia joints and an inverter sub-unit adapted to small inertia joints; and each inverter sub-unit adopts power devices and carrier frequencies that match the joint load.

5. A drive module for a robot joint according to claim 4, characterized in that: The energy management unit includes a high-precision sampling component, a supercapacitor energy storage module, and a bidirectional DC-DC converter unit. The energy management unit receives bus voltage, power of each shaft, and load disturbance signals, and outputs power allocation, bus voltage compensation, and supercapacitor energy storage module charging and discharging control signals. It also adopts a three-level scheduling strategy, equipped with a rolling time-domain optimization scheduling program and an active disturbance rejection control program, to estimate and compensate for load disturbances in real time and solve for the optimal power allocation scheme.

6. A drive module for a robot joint according to claim 5, characterized in that: The three-level scheduling strategy prioritizes the direct exchange of regenerative energy between joints through the DC bus unit; when there is excess energy, it is fed back to the grid by the rectifier unit; and when the bus voltage is abnormal, the supercapacitor energy storage module intervenes to regulate it.

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