Robot direct drive carrier power line communication system

Abstract

The application provides a robot direct-drive carrier power line communication system, and relates to the technical field of robots.The application multiplexes a power line to supply power to multiple joint communication nodes, and transmits communication signals between a central controller and the joint communication nodes, without the need of additionally laying communication cables, which is beneficial to reducing the number of cables and connectors, and reducing the weight of a wire harness and wiring complexity.The motor noise spectrum is used to determine a target communication frequency band, so as to reduce motor noise interference;orthogonal communication resources are allocated to the joint communication nodes, so as to avoid data collision, random backoff and retransmission caused by competition access, thereby improving the reliability and real-time performance of internal communication of the robot.

Description

Technical Field

[0001] This application relates to the field of robotics technology, and more particularly to a robot direct-drive carrier power line communication system. Background Technology

[0002] As robots evolve towards multi-joint, high-degree-of-freedom designs, they typically incorporate a central controller, multiple joint actuators, and corresponding communication nodes for each joint. The central controller periodically sends control data to each joint communication node, while the nodes periodically transmit data such as position, speed, current, temperature, torque, and fault status back to the central controller. To ensure coordinated movement of the robot's joints, the communication between the central controller and the joint communication nodes requires high reliability and low transmission latency.

[0003] Existing robots typically use communication buses such as CAN, CAN-FD, RS-485, or EtherCAT. Using these communication methods requires additional communication cables to be laid outside the power lines. As the number of joint communication nodes increases, the number of communication cables and connectors also increases, potentially leading to increased internal wiring weight, wiring complexity, and rotational inertia, and possibly reducing connection reliability during long-term operation. This is especially true in space-constrained areas of humanoid robots, such as arms, legs, and fingers, where the increased number of cables and connectors significantly increases the difficulty of mechanical design.

[0004] To reduce communication cables, power line communication (PLC) technology can be used, allowing the power line to transmit both power and communication signals simultaneously. However, robot power lines typically contain noise generated by motor PWM control, inverter switching, motor start-stop, and load changes. The communication frequency band used by traditional PLCs may overlap with the energy frequency band of the aforementioned motor noise, causing interference to the communication signal and affecting the reliable transmission of control and status data.

[0005] Furthermore, existing power line communication systems typically employ a contention-based access method. When multiple joint communication nodes communicate through the same power line, each node must contend for the communication channel through processes such as carrier sensing and contention backoff, which can easily lead to data collisions, random backoff, and retransmissions, making communication latency and jitter unpredictable. For legged robots, robotic arms, and other devices requiring coordinated control of multiple joints, the uncertainty of communication latency may cause control data or status data from each joint to be transmitted out of sequence, thereby affecting the robot's coordinated movement and control stability.

[0006] Therefore, how to reduce the interference of motor noise on communication signals and avoid the time delay uncertainty caused by multiple joint communication nodes competing for communication channels while utilizing robot power lines to achieve both power supply and communication simultaneously has become an urgent problem to be solved. Summary of the Invention

[0007] The technical problem solved by this application is to provide a robot direct-drive carrier power line communication system to overcome the defects of traditional power line communication, which is easily affected by motor noise interference, and communication delay and jitter uncertainty caused by multiple joint communication nodes competing for access, resulting in insufficient communication reliability and real-time performance.

[0008] In a first aspect, this application proposes a robot direct-drive carrier power line communication system, the system comprising: a central controller, a power line, and multiple joint communication nodes; The power line is used to supply power to the plurality of joint communication nodes and to form a communication channel between the central controller and the plurality of joint communication nodes; The central controller is used to allocate mutually orthogonal communication resources to the plurality of joint communication nodes, and to map the first data to be sent to each of the joint communication nodes to the corresponding communication resources, so as to generate a downlink carrier communication signal located in the target communication frequency band in the digital domain and couple it to the power line; wherein, the target communication frequency band is determined based on the motor noise spectrum in the power line; Each of the joint communication nodes is configured to extract the downlink carrier communication signal from the power line, demodulate the communication resources corresponding to the joint communication node to obtain the corresponding first data; and map the second data to be sent to the central controller to the corresponding communication resources to generate an uplink carrier communication signal in the digital domain located in the target communication frequency band and couple it to the power line, so that the central controller can obtain the second data from the uplink carrier communication signal.

[0009] In one embodiment, the central controller includes: The resource scheduling module is used to allocate mutually orthogonal communication resources to the multiple joint communication nodes and generate the resource allocation relationship between each joint communication node and the corresponding communication resource. The downlink direct-drive carrier transmission module is used to map the first data to be transmitted to each of the joint communication nodes to the corresponding communication resources according to the resource allocation relationship, so as to generate a downlink carrier communication signal located in the target communication frequency band in the digital domain; The first signal coupling module is used to couple the downlink carrier communication signal to the power line and extract the uplink carrier communication signal sent by each of the joint communication nodes from the power line; The uplink signal receiving module is used to demodulate the communication resources corresponding to each of the joint communication nodes in the uplink carrier communication signal according to the resource allocation relationship, so as to obtain the second data sent by each of the joint communication nodes.

[0010] In one embodiment, the downlink direct-drive carrier transmission module includes: A digital baseband unit is used to perform digital baseband processing on the first data to obtain modulation symbols, and to map the modulation symbols to corresponding communication resources according to the resource allocation relationship. An orthogonal frequency division multiplexing modulation unit is used to generate orthogonal frequency division multiplexing signals based on modulation symbols mapped to each of the communication resources; A digital frequency shift unit is used to shift the orthogonal frequency division multiplexed signal to the target communication frequency band; A digital-to-analog converter is used to perform digital-to-analog conversion on orthogonal frequency division multiplexing signals moved to the target communication frequency band, so as to output the downlink carrier communication signal located in the target communication frequency band.

[0011] In one embodiment, the digital baseband unit performs digital baseband processing on the first data to obtain modulation symbols, including: The digital baseband unit generates a bit stream based on the first data, performs at least one of scrambling, forward error correction coding and interleaving on the bit stream, and performs constellation mapping on the processed bit stream to obtain the modulation symbol.

[0012] In one embodiment, the central controller further includes: The frequency band selection module is used to obtain the prohibited frequency bands corresponding to the protected wireless services, and to scan the motor noise spectrum in the power line during robot startup, calibration or operation, determine the frequency bands in the motor noise spectrum whose noise power spectral density is greater than a preset noise threshold, and select the target communication frequency band from outside the prohibited frequency bands and the determined frequency bands.

[0013] In one embodiment, the frequency band selection module is further configured to detect the communication quality of each frequency point within the target communication frequency band during communication, identify frequency points whose communication quality does not meet preset communication conditions as interference frequency points, perform at least one of subcarrier deactivation, transmission power reduction, and communication resource migration on the interference frequency points, and adjust the communication bandwidth according to the amount of available spectrum after performing the operation.

[0014] In one embodiment, the resource scheduling module includes: A superframe generation unit is used to divide communication time into periodic superframes; The resource allocation unit is used to divide the target communication frequency band into multiple mutually orthogonal subcarrier sets, determine multiple communication time windows in the periodic superframe, and allocate corresponding subcarrier sets and communication time windows to each joint communication node according to the node identifier of each joint communication node, so as to use the allocated subcarrier sets and communication time windows as the communication resources of the corresponding joint communication node.

[0015] In one embodiment, the uplink signal receiving module includes: The channel estimation unit is used to determine the channel estimation result and noise statistics result of each communication resource based on the pilot signal corresponding to each of the joint communication nodes, determine the signal-to-noise ratio of each communication resource based on the channel estimation result and the noise statistics result, and determine the communication quality of each communication resource based on the signal-to-noise ratio. The data demodulation unit is used to perform equalization, demodulation, and decoding on the corresponding communication resources in the uplink carrier communication signal based on the channel estimation results of each of the communication resources, so as to obtain the second data sent by each of the joint communication nodes.

[0016] In one embodiment, the uplink signal receiving module further includes: A sampling unit is used to sample the uplink carrier communication signal to obtain a time-domain sampled signal; The impulse noise processing unit is used to perform time-domain limiting or time-domain blanking on the time-domain sampled signal when impulse noise is detected in the uplink carrier communication signal, or to perform frequency-domain erasure on the subcarrier affected by the impulse noise.

[0017] In one embodiment, the central controller further includes: An adaptive modulation and coding module is used to determine the modulation and coding methods for the corresponding joint communication nodes based on the communication quality of each of the communication resources. The resource scheduling module is further configured to adjust the communication resources allocated to each of the joint communication nodes based on the service priority of each of the joint communication nodes and the communication quality of each of the communication resources. The adaptive modulation and coding module is further configured to update at least one of the corresponding modulation and coding methods based on the communication quality corresponding to the adjusted communication resources.

[0018] In one embodiment, each of the joint communication nodes includes: The second signal coupling module is used to extract the downlink carrier communication signal from the power line and couple the uplink carrier communication signal to the power line; The downlink signal receiving module is used to demodulate the communication resources corresponding to the communication node of the joint to obtain the corresponding first data; The uplink direct-drive carrier transmission module is used to map the second data to the communication resources corresponding to the communication node of the joint, so as to generate the uplink carrier communication signal in the digital domain.

[0019] In one embodiment, the resource scheduling module is further configured to periodically allocate communication resources for transmitting pilot signals and training sequences to each of the joint communication nodes; Each of the uplink direct-drive carrier transmission modules is further configured to insert the pilot signal and the training sequence into the corresponding uplink carrier communication signal according to the configuration of the resource scheduling module; The channel estimation unit is further configured to update the channel estimation results and noise statistics results of each communication resource based on the periodically received pilot signals and the training sequence, and update the communication quality of each communication resource based on the updated channel estimation results and noise statistics results.

[0020] In one embodiment, both the first signal coupling module and the second signal coupling module include a passive high-pass coupling network; The passive high-pass coupling network is used to couple the downlink carrier communication signal and the uplink carrier communication signal within the target communication frequency band, and to isolate the power supply component, motor PWM signal and its low-frequency harmonics in the power line.

[0021] In one embodiment, the central controller further includes an uplink synchronization module, and each of the joint communication nodes further includes a timing control module; The uplink synchronization module is used to determine the uplink arrival time deviation of each joint communication node based on the training sequence, pilot signal or measurement signal sent by each joint communication node, and generate a corresponding transmission advance based on the uplink arrival time deviation. The timing control module is used to adjust the transmission time of the uplink carrier communication signal according to the corresponding transmission advance, so that the uplink carrier communication signals transmitted by each joint communication node are time-aligned at the central controller.

[0022] In one embodiment, the central controller further includes: The attitude-aware electromagnetic compatibility control module is used to acquire the robot's attitude information and cable layout information, determine the electromagnetic radiation risk of the robot at the corresponding frequency of each of the communication resources based on the attitude information and the cable layout information, and control the resource scheduling module to adjust at least one of the usage status and transmission power of the corresponding communication resources based on the electromagnetic radiation risk.

[0023] In one embodiment, the attitude-aware electromagnetic compatibility control module includes: An equivalent length determination module is used to determine the equivalent radiation length of a robot limb or power line loop based on the posture information and the cable layout information. The risk assessment module is used to determine the target communication resources with radiation enhancement risk based on the equivalent radiation length and the frequency corresponding to each of the communication resources. The radiation suppression module is used to perform at least one of the following operations on the target communication resource: stop using it, reduce transmission power, relocate the communication resource, or adjust the modulation and coding scheme.

[0024] In one embodiment, the central controller further includes: The safety degradation and fault protection module is used to perform emergency operations when preset conditions are met; The preset condition is determined to be met when at least one of the following occurs: the communication link quality is lower than a preset quality threshold, uplink synchronization fails, the number of consecutive packet losses of the joint communication node reaches a preset number, and the communication bandwidth corresponding to the available communication resources is less than a preset bandwidth. The emergency operations include at least one of the following: reducing the modulation order, increasing coding redundancy, shortening the scheduling cycle of critical communication nodes, suspending non-critical data transmission, switching to a backup communication frequency band, and activating an emergency communication mode.

[0025] The above-mentioned robot direct-drive carrier power line communication system has at least the following advantages: This application utilizes a multiplexed power line to power multiple joint communication nodes and transmits communication signals between the central controller and these nodes. This eliminates the need for separate communication cables, reducing the number of cables and connectors within the robot, lowering wiring weight and complexity. By determining the target communication frequency band based on the motor noise spectrum in the power line, the carrier communication signal avoids the energy frequency band corresponding to motor noise, reducing interference from motor noise and improving data transmission reliability. Furthermore, by allocating mutually orthogonal communication resources to multiple joint communication nodes and mapping the data of each node to its corresponding resource, multiple nodes can communicate via the same power line without contention for access. This helps avoid data collisions, random backoff, and contention-based retransmissions, reducing communication latency and jitter, and improving the real-time performance of internal robot communication. Attached Figure Description

[0026] Figure 1 This is a block diagram of a robot direct-drive carrier power line communication system in one embodiment; Figure 2 This is a block diagram of the central controller in one embodiment; Figure 3 Here is a block diagram of the central controller in another embodiment; Figure 4 This is a structural block diagram of a joint communication node in one embodiment. Detailed Implementation

[0027] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0028] Some exemplary embodiments of this application have been described for illustrative purposes. It should be understood that this application may be implemented in other ways not specifically shown in the accompanying drawings.

[0029] Please see Figure 1 In one exemplary embodiment, this application provides a robot direct-drive carrier power line communication system suitable for robots with multiple joint actuators. The system includes: a central controller, power lines, and multiple joint communication nodes.

[0030] The power line is used to supply power to multiple joint communication nodes and to form a communication channel between the central controller and multiple joint communication nodes.

[0031] The central controller is used to allocate mutually orthogonal communication resources to multiple joint communication nodes, and to map the first data to be sent to each joint communication node to the corresponding communication resources, so as to generate downlink carrier communication signals in the digital domain within the target communication frequency band and couple them to the power line; wherein, the target communication frequency band is determined based on the motor noise spectrum in the power line.

[0032] Each joint communication node is used to extract downlink carrier communication signals from the power line, demodulate the communication resources corresponding to the joint communication node to obtain the corresponding first data; and map the second data to be sent to the central controller to the corresponding communication resources to generate uplink carrier communication signals in the target communication frequency band in the digital domain and couple them to the power line so that the central controller can obtain the second data from the uplink carrier communication signals.

[0033] Specifically, the central controller is used for unified communication scheduling of multiple joint communication nodes and for data interaction with these nodes. Joint communication nodes can be located in the robot's joint actuators, motor drivers, sensors, or end effectors. One joint communication node can correspond to one robot component or multiple interconnected robot components.

[0034] The power line connects the central controller and multiple joint communication nodes, transmitting power to the joint communication nodes and serving as the physical medium for transmitting communication signals between the central controller and the joint communication nodes, thus eliminating the need to install separate communication cables for each joint communication node outside the power line.

[0035] Communication resources refer to the time-domain resources, frequency-domain resources, or time-frequency resources in a carrier communication signal used to carry data of corresponding joint communication nodes. For example, communication resources include one or more subcarriers, one or more communication time windows, or a combination of subcarriers and communication time windows.

[0036] Mutually orthogonal communication resources can be different subcarriers or sets of subcarriers with mutually orthogonal frequencies, or resources set in different communication time windows. By allocating mutually orthogonal communication resources to different joint communication nodes, the data of different joint communication nodes can remain distinguishable when transmitted on the same power line, reducing signal interference or communication conflicts between different joint communication nodes.

[0037] In this embodiment, the first data refers to the data sent from the central controller to the joint communication node, including at least one of joint control commands, motion parameters, synchronization information, resource allocation information, and configuration data. The central controller will carry the bits, modulation symbols, or data symbols corresponding to the first data on the corresponding subcarrier, subcarrier set, or communication time window, thereby mapping the first data to the communication resources of the corresponding joint communication node.

[0038] The central controller performs at least one of the following processes on the first data mapped to each communication resource: data encoding, modulation, orthogonal frequency division multiplexing, and frequency shifting, so that the generated digital signal corresponds to the target communication frequency band. This digital signal can be directly converted into an analog carrier communication signal located within the target communication frequency band without the need for analog up-conversion through an analog mixer and local oscillator, thus forming a direct-drive carrier communication mode.

[0039] The target communication frequency band refers to the frequency range used to transmit carrier communication signals. By detecting the motor noise spectrum in the power line during robot startup, calibration, or operation, and based on the energy distribution of the motor noise at different frequencies, the target communication frequency band is determined from the relatively low-noise frequency bands. For example, the noise power spectral density of each frequency or band in the power line is detected, frequency bands with a noise power spectral density greater than a preset noise threshold are excluded, and the target communication frequency band is selected from the remaining frequency bands. Using this method, the downlink and uplink carrier communication signals can avoid frequency bands where noise energy is concentrated, such as motor PWM, inverter switching, and their low-frequency harmonics.

[0040] Furthermore, the central controller couples the generated downlink carrier communication signal to the power line. For example, the central controller superimposes the downlink carrier communication signal onto the power line via capacitive coupling, inductive coupling, differential-mode coupling, common-mode coupling, or a combination of the above coupling methods, and the signal propagates along the power line to multiple joint communication nodes.

[0041] Furthermore, the downlink carrier communication signal transmitted by the power line simultaneously carries the first data to be sent to multiple joint communication nodes. Each joint communication node, according to its allocated communication resources, demodulates only the corresponding communication resources in the downlink carrier communication signal to obtain the first data to be sent to its respective joint communication node.

[0042] Furthermore, after obtaining the first data, a joint communication node controls the corresponding robot component based on the first data. For example, when the first data includes joint control instructions, the joint communication node controls the motor driver according to the joint control instructions to make the corresponding joint move according to the target position, target speed, or target torque; when the first data includes configuration data, the joint communication node adjusts the operating parameters of the corresponding robot component according to the configuration data.

[0043] In this embodiment, the second data refers to the data sent from each joint communication node to the central controller, including at least one of joint position, movement speed, motor current, temperature, torque, sensor measurement results, operating status, and fault status. Each joint communication node maps the second data to the communication resources allocated to it, and generates an uplink carrier communication signal in the digital domain within the target communication frequency band based on the mapped second data.

[0044] Furthermore, each joint communication node couples its uplink carrier communication signal to the power line to transmit the second data to the central controller via the power line. Different joint communication nodes utilize mutually orthogonal communication resources to transmit uplink carrier communication signals simultaneously or in a predetermined communication sequence, thereby eliminating the need to contend for the power line through competitive access processes such as carrier sensing and random backoff.

[0045] Furthermore, the central controller extracts the uplink carrier communication signals sent by each joint communication node from the power line, and demodulates the corresponding communication resources in the uplink carrier communication signals according to the correspondence between each joint communication node and the communication resources, so as to obtain the second data sent by each joint communication node. Then, the operating status of each robot component is determined according to the second data, and subsequent control data is generated accordingly to realize closed-loop control of multiple joints of the robot.

[0046] By adopting the above scheme, power supply and communication are completed simultaneously through the power line. The impact of motor noise on communication signals is reduced by determining the target communication frequency band based on the motor noise spectrum. Furthermore, by allocating mutually orthogonal communication resources to multiple joint communication nodes, collisions, back-offs, and retransmissions caused by multiple joint communication nodes competing for access are reduced, thereby improving the reliability and real-time performance of internal robot communication.

[0047] Please see Figure 2 Optionally, the central controller includes: a resource scheduling module, a downlink direct-drive carrier transmission module, a first signal coupling module, and an uplink signal receiving module.

[0048] The resource scheduling module is used to allocate mutually orthogonal communication resources to multiple joint communication nodes and generate the resource allocation relationship between each joint communication node and its corresponding communication resources. The resource allocation relationship characterizes the correspondence between each joint communication node and the communication resources allocated to that node.

[0049] The downlink direct-drive carrier transmission module is used to map the first data to be transmitted to each joint communication node to the corresponding communication resource according to the resource allocation relationship, so as to generate a downlink carrier communication signal located in the target communication frequency band in the digital domain.

[0050] The first signal coupling module is used to couple downlink carrier communication signals to the power line and extract uplink carrier communication signals sent by each joint communication node from the power line.

[0051] The uplink signal receiving module is used to demodulate the communication resources corresponding to each joint communication node in the uplink carrier communication signal according to the resource allocation relationship, so as to obtain the second data sent by each joint communication node.

[0052] Please see Figure 3 Optionally, the downlink direct-drive carrier transmission module includes: a digital baseband unit, an orthogonal frequency division multiplexing modulation unit, a digital frequency shift unit, and a digital-to-analog converter.

[0053] The digital baseband unit is used to perform digital baseband processing on the first data to obtain modulation symbols, and to map the modulation symbols to the corresponding communication resources according to the resource allocation relationship.

[0054] Optionally, the digital baseband unit performs digital baseband processing on the first data to obtain modulation symbols, including: The digital baseband unit generates a bitstream based on the first data, performs at least one of the following processes on the bitstream: scrambling, forward error correction coding, and interleaving, and performs constellation mapping on the processed bitstream to obtain modulation symbols. The modulation scheme used for constellation mapping can be configured according to actual communication requirements.

[0055] An orthogonal frequency division multiplexing modulation unit is used to generate orthogonal frequency division multiplexing signals based on modulation symbols mapped to each communication resource.

[0056] Specifically, the orthogonal frequency division multiplexing modulation unit can perform inverse fast Fourier transform on the modulation symbols mapped to different orthogonal subcarriers, convert the frequency domain modulation symbols into time domain orthogonal frequency division multiplexing symbols, and add a cyclic prefix or guard interval to the orthogonal frequency division multiplexing symbols to obtain orthogonal frequency division multiplexing signals.

[0057] Digital frequency shift unit is used to shift orthogonal frequency division multiplexed signals to the target communication frequency band.

[0058] Specifically, the digital frequency shifting unit performs frequency shifting on the orthogonal frequency division multiplexing signal in the digital domain, so that the frequency-shifted orthogonal frequency division multiplexing signal is located within the target communication frequency band, and the center frequency of the output signal of the digital-to-analog converter is located within the target communication frequency band.

[0059] A digital-to-analog converter is used to perform digital-to-analog conversion on orthogonal frequency division multiplexing signals moved to the target communication frequency band, so as to output downlink carrier communication signals located in the target communication frequency band.

[0060] For example, the digital-to-analog converter is employed and outputs the downlink carrier communication signal within the target communication frequency band in any of the following ways: First, a sampling rate that meets the Nyquist sampling requirements can be used to perform digital-to-analog conversion on the digitally frequency-shifted orthogonal frequency division multiplexing signal, directly outputting a real-valued bandpass signal within the target communication frequency band.

[0061] Secondly, the complex digital baseband signal can be up-converted in the digital domain to generate a corresponding real-valued digital signal, which can then be converted into an analog signal within the target communication frequency band by a high-speed digital-to-analog converter.

[0062] Finally, the mirror spectrum generated during the digital-to-analog conversion process by the high-speed digital-to-analog converter can be utilized, and a bandpass filter can be used to select the signal located in the target communication frequency band from the mirror spectrum.

[0063] For example, when the target communication frequency band is 30 MHz to 50 MHz, the sampling rate of the high-speed digital-to-analog converter can be set to 120 MS / s, 160 MS / s, 200 MS / s, or higher, thereby directly outputting the downlink carrier communication signal within the 30 MHz to 50 MHz frequency band. When the target communication frequency band is higher, a digital-to-analog converter with a higher sampling rate can be used, or bandpass sampling or mirror spectrum selection can be used to output the downlink carrier communication signal within the target communication frequency band.

[0064] Furthermore, the downlink carrier communication signal output by the digital-to-analog converter can be reconstructed and filtered to suppress spectral components outside the target communication frequency band. The transmission link can also perform power limiting, amplitude limiting protection, and impedance matching on the downlink carrier communication signal as needed to control the output power spectral density and make the downlink carrier communication signal suitable for coupling to the power line through the first signal coupling module.

[0065] The above scheme allows for the digital domain to complete the encoding, modulation, communication resource mapping, orthogonal frequency division multiplexing modulation, and frequency shifting of the first data. A high-speed digital-to-analog converter (DAC) directly outputs the downlink carrier communication signal within the target communication frequency band, eliminating the need for analog mixers, local oscillators, and traditional RF transceiver chips, thus simplifying the carrier transmission link. Furthermore, the high-speed DAC employs various methods depending on the target communication frequency band, facilitating adaptation to different target communication frequency bands and sampling rate conditions. By adjusting the digital frequency shift parameters and the DAC's output method, the downlink carrier communication signal can be configured to operate in a low-noise frequency band that meets operational requirements, improving the flexibility of frequency band configuration and the anti-interference capability of downlink data transmission.

[0066] Please see Figure 2 Optionally, the central controller may also include a frequency band selection module.

[0067] The frequency band selection module is used to obtain the prohibited frequency bands corresponding to the protected wireless services, and to scan the motor noise spectrum in the power line during robot startup, calibration or operation, determine the frequency bands in the motor noise spectrum whose noise power spectral density is greater than the preset noise threshold, and select the target communication frequency band from outside the prohibited frequency bands and the determined frequency bands.

[0068] Specifically, protected wireless services include FM broadcasting, aviation communications, emergency communications, positioning and navigation, or other wireless services that need to be avoided according to the radio management regulations of different countries and regions. Prohibited frequency bands refer to the frequency ranges that are prohibited from use to avoid interference from robot carrier communication signals to protected wireless services. These prohibited frequency bands can be pre-stored in the central controller or configured according to the robot's country, region, or application scenario. For example, 88 MHz to 108 MHz corresponding to FM broadcasting can be set as a prohibited frequency band, preventing the frequency selection module from selecting the target communication frequency band from this range.

[0069] Furthermore, the frequency band selection module performs a spectrum scan on the power line during robot startup, calibration, or operation to obtain the noise power spectral density at each frequency point in the power line, forming a motor noise spectrum. This motor noise spectrum is used to characterize the noise energy distribution generated at different frequencies by motor PWM control, inverter switching, motor start-stop, and load changes.

[0070] In this embodiment, frequency bands with noise power spectral density greater than a preset noise threshold are identified as frequency bands with strong noise interference and marked as low-priority frequency bands or unusable frequency bands. The preset noise threshold is determined based on the target signal-to-noise ratio of the carrier communication signal, the allowable bit error rate, the receiver sensitivity, or the reliability requirements of the robot control data.

[0071] Furthermore, in this embodiment, frequency bands other than the prohibited frequency bands and those with strong noise interference are marked as candidate communication frequency bands, and the target communication frequency band is selected from the candidate communication frequency bands. When selecting, the target data rate, the frequency response of the power line coupled network, and the electromagnetic compatibility requirements of the whole machine should be taken into account, and a frequency band with low noise and high coupling efficiency should be selected from the candidate frequency bands that meet the corresponding conditions.

[0072] Optionally, the frequency band selection module is also used to detect the communication quality of each frequency point in the target communication frequency band during the communication process, identify the frequency points whose communication quality does not meet the preset communication conditions as interference frequency points, perform at least one of the following operations on the interference frequency points: subcarrier deactivation, transmission power reduction and communication resource migration, and adjust the communication bandwidth according to the amount of available spectrum after the operation is performed.

[0073] Specifically, the frequency band selection module also continuously or periodically detects the communication quality of each frequency point within the target communication frequency band. A frequency point can correspond to a single subcarrier or a frequency range consisting of multiple adjacent subcarriers. Communication quality is determined based on at least one of the following: signal-to-noise ratio, bit error rate, number of retransmissions, pilot measurement results, and motor operating status.

[0074] When the signal-to-noise ratio of a certain frequency point is lower than the preset signal-to-noise ratio threshold, the bit error rate is higher than the preset bit error rate threshold, the number of retransmissions reaches the preset number of retransmissions, or the pilot measurement results do not meet the preset requirements, it is determined that the communication quality of that frequency point does not meet the preset communication conditions, and that frequency point is identified as an interference frequency point.

[0075] For the interfering frequency, at least one of the following operations is performed: subcarrier deactivation, transmit power reduction, and communication resource migration. Subcarrier deactivation involves setting the subcarrier corresponding to the interfering frequency to zero and ceasing data transmission using that subcarrier. Transmit power reduction involves lowering the transmit power spectral density of the interfering frequency or its corresponding set of subcarriers. Communication resource migration involves moving the data originally carried by the interfering frequency to other subcarriers with lower noise and communication quality that meets preset communication conditions. For critical data such as joint control commands and fault information, migration to subcarriers with higher communication quality can be prioritized.

[0076] Furthermore, after performing the corresponding operation, the frequency band selection module counts the number of subcarriers or frequency points still available for data transmission within the target communication frequency band to obtain the available spectrum quantity, and adjusts the communication bandwidth according to the available spectrum quantity. For example, when the available spectrum quantity decreases, the communication bandwidth is reduced; when interference disappears and the available spectrum quantity increases, the communication bandwidth is restored or increased, thereby adapting the communication bandwidth to the currently available spectrum.

[0077] By adopting the above implementation, this application avoids prohibited frequency bands corresponding to protected wireless services and frequency bands with strong motor noise before establishing communication, and dynamically disables interfering subcarriers, reduces transmission power, or relocates communication resources based on the communication quality of each frequency point during communication. This can reduce the impact of motor noise and external interference on carrier communication signals, and adjust the communication bandwidth accordingly when the available spectrum changes, thereby improving the anti-interference capability, reliability, and spectrum adaptability of robot powerline communication.

[0078] Optionally, the resource scheduling module includes a superframe generation unit and a resource allocation unit.

[0079] The superframe generation unit is used to divide the communication time into periodic superframes.

[0080] Specifically, each periodic superframe has the same duration and is transmitted repeatedly according to a preset period. Each periodic superframe includes at least one of the following: a synchronization preamble, a training sequence, a frame header or scheduling information, a downlink control window, a guard interval, an uplink status return window, and a retransmission or diagnostic window.

[0081] The synchronization preamble is set at the beginning of the periodic superframe to enable clock calibration and frame boundary alignment for each joint communication node; the training sequence is used for channel measurement; the frame header or scheduling information is used to carry resource allocation relationships; the downlink control window is used by the central controller to send joint control data to each joint communication node; the uplink status feedback window is used by each joint communication node to send joint position, motor current, joint torque, temperature, operating status or fault information to the central controller; the protection interval is set between different communication time windows to reduce signal interference between adjacent communication time windows.

[0082] The resource allocation unit is used to divide the target communication frequency band into multiple mutually orthogonal subcarrier sets, determine multiple communication time windows in the periodic superframe, and allocate corresponding subcarrier sets and communication time windows to each joint communication node according to the node identifier of each joint communication node, so as to use the allocated subcarrier sets and communication time windows as the communication resources of the corresponding joint communication node.

[0083] Specifically, the resource allocation unit divides the target communication frequency band into multiple mutually orthogonal subcarriers, and groups one or more of these subcarriers into a subcarrier set. Different subcarrier sets can be non-overlapping and can be reused in different communication time windows. Furthermore, the resource allocation unit also determines multiple communication time windows in the periodic superframe, such as determining a downlink control window for downlink transmission and an uplink status return window for uplink transmission, and further divides each communication time window into multiple time slices.

[0084] Each joint communication node has a unique node identifier. The node identifier is used to uniquely or distinctively identify a joint communication node in a robot direct-drive power line communication system and can be configured during the joint communication node's manufacturing, robot assembly, or system initialization phases. For example, the joint communication nodes corresponding to the hip, knee, ankle, lumbar joints, and end effectors can each have different node identifiers.

[0085] The resource allocation unit allocates a corresponding set of subcarriers and a communication time window to each joint communication node based on the node identifier of each joint communication node, and uses the combination of the allocated set of subcarriers and the communication time window as the communication resources of the corresponding joint communication node.

[0086] The resource allocation unit establishes the resource allocation relationship between node identifiers and communication resources using either static or semi-static allocation methods. Static allocation refers to ensuring that joint communication nodes continuously use a fixed set of subcarriers and a fixed communication time window across multiple periodic superframes after system initialization. Semi-static allocation refers to maintaining the resource allocation relationship unchanged for a predetermined number of periodic superframes and reallocating communication resources when communication conditions or needs change. For example, for critical joint communication nodes related to hip, knee, ankle, lumbar, or trunk balance, a shorter communication time window or a larger number of subcarriers is allocated; for joint communication nodes with slower data changes, such as temperature monitoring, a longer communication time window or a smaller number of subcarriers is allocated.

[0087] Furthermore, the central controller sends a synchronization preamble and resource allocation information at the beginning of each periodic superframe. Each joint communication node performs clock calibration and frame boundary alignment based on the synchronization preamble, and determines the corresponding subcarrier set and communication time window from the resource allocation information based on its own node identifier. In the downlink direction, each joint communication node demodulates its corresponding subcarrier set within the corresponding communication time window; in the uplink direction, each joint communication node transmits the second data using its corresponding subcarrier set and communication time window.

[0088] By employing the above scheme, communication time is divided into periodic superframes, and each joint communication node is assigned a corresponding subcarrier set and communication time window according to its node identifier. This allows for unified scheduling of communication between multiple joint communication nodes in both the frequency and time domains. Each joint communication node can send or receive data within pre-determined communication resources, eliminating the need to compete for powerline communication channels through carrier sensing, random backoff, or other methods. This helps avoid data collisions and contention-based retransmissions, reduces communication latency and jitter, and improves the real-time performance and determinism of communication between multiple robot joints. Optionally, the uplink signal receiving module includes a channel estimation unit and a data demodulation unit.

[0089] The channel estimation unit is used to determine the channel estimation results and noise statistics results of each communication resource based on the pilot signals corresponding to each joint communication node, determine the signal-to-noise ratio of each communication resource based on the channel estimation results and noise statistics results, and determine the communication quality of each communication resource based on the signal-to-noise ratio.

[0090] The data demodulation unit is used to perform equalization, demodulation and decoding on the corresponding communication resources in the uplink carrier communication signal according to the channel estimation results of each communication resource, so as to obtain the second data sent by each joint communication node.

[0091] Specifically, the channel estimation unit estimates the channel response of each subcarrier in the corresponding communication resource based on the amplitude and phase differences between the received pilot signal and the known pilot signal, and obtains the channel estimation result for the corresponding communication resource. This channel estimation result is used to characterize the amplitude attenuation and phase shift of the uplink carrier communication signal after transmission through the power line. For example, the channel estimation unit performs least squares channel estimation, minimum mean square error channel estimation, interpolation estimation, or time-frequency two-dimensional filtering based on the pilot signal.

[0092] The channel estimation unit also determines the noise power of the corresponding communication resource based on the difference between the received pilot signal and the pilot signal reconstructed according to the channel estimation result, and obtains the noise statistics result. The noise statistics result includes at least one of the following: noise power, noise power spectral density, and noise variation for each communication resource or subcarrier.

[0093] Furthermore, the channel estimation unit determines the received signal power of the corresponding communication resource based on the channel estimation results, and determines the signal-to-noise ratio (SNR) of each communication resource based on the ratio between the received signal power and the noise power represented by the noise statistics. The communication quality of each communication resource is determined by comparing its SNR with one or more preset SNR thresholds. For example, if the SNR of a communication resource is greater than a first preset SNR threshold, the communication quality of that resource is considered high; if the SNR of a communication resource is less than a second preset SNR threshold, the communication quality of that resource is considered low.

[0094] The data demodulation unit determines the subcarrier set and communication time window corresponding to each joint communication node based on the resource allocation relationship. It extracts the received symbols carried by the corresponding communication resources from the uplink carrier communication signal and performs frequency domain equalization on the received symbols based on the channel estimation results of these communication resources to compensate for amplitude attenuation and phase offset caused by the dynamic line channel. The equalized received symbols undergo constellation demapping or soft demodulation to obtain the corresponding coded bits, and forward error correction decoding is performed on the coded bits. The data demodulation unit also performs at least one of deinterleaving and descrambling processes on the decoded bits according to the digital baseband processing method executed by the data transmitter, thereby recovering the second data transmitted by each joint communication node.

[0095] The above scheme utilizes the pilot signals corresponding to each joint communication node to determine the communication quality of each communication resource, and uses the corresponding channel estimation results to perform equalization, demodulation, and decoding on the received symbols carried by each communication resource. This can compensate for the amplitude attenuation and phase shift caused by the power line channel, reduce the impact of channel variations and noise on uplink data reception, and improve the reception reliability of the second data transmitted by each joint communication node.

[0096] Optionally, the uplink signal receiving module further includes a sampling unit and an impulse noise processing unit. The sampling unit is used to sample the uplink carrier communication signal to obtain the time-domain sampled signal; The impulse noise processing unit is used to perform time-domain limiting or time-domain blanking on the time-domain sampled signal when impulse noise is detected in the uplink carrier communication signal, or to perform frequency-domain erasure on the subcarrier affected by impulse noise.

[0097] Specifically, the sampling unit is used to sample the uplink carrier communication signal extracted from the power line by the first signal coupling module to obtain a time-domain sampled signal. For example, the sampling unit employs a high-speed analog-to-digital converter and uses either direct sampling or bandpass sampling to sample the uplink carrier communication signal within the target communication frequency band.

[0098] Furthermore, before the uplink carrier communication signal enters the sampling unit, it can be processed by at least one of DC isolation, surge protection, overvoltage protection, bandpass filtering, and automatic gain control to suppress signal components outside the target communication frequency band and ensure that the amplitude of the uplink carrier communication signal is within the input range of the sampling unit.

[0099] Impulse noise in the power line is typically caused by motor start-stop, inverter switching, load abrupt changes, or power supply ripple, manifesting as abnormal pulses with large amplitude and short duration in the time-domain sampled signal. By comparing the amplitude of the time-domain sampled signal with a preset pulse detection threshold, if the amplitude of one or more sampling points in the time-domain sampled signal exceeds the preset pulse detection threshold, the corresponding sampling location is determined as the location of pulse noise, and the presence of pulse noise is confirmed.

[0100] Furthermore, upon detecting impulse noise, the impulse noise processing unit performs time-domain limiting or time-domain blanking on the time-domain sampled signal. Time-domain limiting refers to restricting sampled values ​​whose amplitude exceeds a preset limiting threshold to a preset amplitude, thereby reducing the amplitude of abnormal impulses. Time-domain blanking refers to setting the sampled value corresponding to the impulse noise location to zero or replacing it with a preset value, thereby eliminating the impact of abnormal impulses on subsequent signal processing.

[0101] The impulse noise processing unit can also convert the time-domain sampled signal to the frequency domain, identify the subcarriers affected by impulse noise, and perform frequency-domain erasure on the corresponding subcarriers. Frequency-domain erasure refers to setting the received symbols corresponding to the subcarriers affected by impulse noise to zero, marking them as invalid, or excluding them from subsequent demodulation and decoding. Time-domain clipping, time-domain blanking, and frequency-domain erasure can be performed individually or in combination depending on the amplitude, duration, and affected frequency range of the impulse noise.

[0102] By employing the above scheme, performing time-domain limiting, time-domain blanking, or frequency-domain erasure on the impulse noise in the uplink carrier communication signal, the impact of impulse noise on uplink data demodulation can be reduced, thereby improving the reliability of receiving the second data.

[0103] Please see Figure 3 Optionally, the central controller may also include an adaptive modulation and coding module.

[0104] The adaptive modulation and coding module is used to determine the modulation and coding methods for the corresponding joint communication nodes based on the communication quality of each communication resource.

[0105] The resource scheduling module is also used to adjust the communication resources allocated to each joint communication node based on the service priority of each joint communication node and the communication quality of each communication resource.

[0106] The adaptive modulation and coding module is also used to update at least one of the corresponding modulation and coding methods according to the communication quality corresponding to the adjusted communication resources.

[0107] Specifically, the adaptive modulation and coding module pre-stores a modulation and coding configuration table, which is generated based on the service priority, data length, channel quality, bit error rate, historical retransmission count, uplink synchronization quality, and EMC risk level of each communication node. The modulation and coding configuration table records the correspondence between different communication qualities and modulation and coding schemes. Optional modulation schemes include at least one of binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), 16th-order quadrature amplitude modulation (QAM), 64th-order QAM, and 256th-order QAM; optional coding schemes include at least one of convolutional codes, low-density parity-check codes, polar codes, BCH codes, and RS codes. The communication quality can be divided according to the signal-to-noise ratio (SNR) determined by the channel estimation unit. For example, multiple SNR intervals can be set, and corresponding modulation and coding schemes can be configured for each SNR interval.

[0108] Furthermore, in addition to the signal-to-noise ratio (SNR), the adaptive modulation and coding module also determines the modulation and coding scheme based on the bit error rate (BER) and historical retransmission count of the corresponding communication resource. For example, when the SNR of the communication resource meets the requirements of the current modulation and coding configuration, but the BER or historical retransmission count of the communication resource is high, the modulation order can be reduced, coding redundancy can be increased, or both of the above operations can be performed simultaneously to improve the reliability of data transmission.

[0109] The resource scheduling module can prioritize allocating subcarrier sets with high signal-to-noise ratios, low noise, or low bit error rates to joint communication nodes with higher service priority, and can allocate a larger number of subcarriers or shorter communication time windows to them. For joint communication nodes with lower service priority, remaining communication resources, a smaller number of subcarriers, or longer communication time windows can be allocated. Service priority can be determined based on the data type transmitted by the joint communication node or the importance of the corresponding joint in the robot control process.

[0110] Furthermore, the resource scheduling module can increase or decrease the number of subcarriers allocated to a joint communication node while keeping the subcarrier set corresponding to that node unchanged; it can also adjust the corresponding communication time window, transmission period, or transmission order. This allows the allocation of communication resources to simultaneously adapt to the service importance of each joint communication node and the real-time changes in the powerline channel.

[0111] After the resource scheduling module adjusts communication resources, the adaptive modulation and coding module updates at least one of the modulation and coding schemes of the corresponding joint communication nodes based on the communication quality corresponding to the adjusted communication resources. For example, when a joint communication node with higher service priority is migrated from a communication resource with lower communication quality to a communication resource with higher communication quality, the adaptive modulation and coding module increases the modulation order to improve the data transmission rate; when a joint communication node is assigned to a communication resource with lower communication quality, the adaptive modulation and coding module decreases the modulation order, increases coding redundancy, or performs the above operations simultaneously to maintain the reliability of data transmission.

[0112] The above scheme adaptively selects modulation and coding methods based on the communication quality of each communication resource, and dynamically adjusts communication resources in conjunction with the service priorities of each communication node. After the communication resources are adjusted, the modulation or coding method is updated based on the adjusted communication quality, so that the allocation of communication resources and the modulation and coding configuration complement each other, thereby ensuring the reliability, real-time performance, and data transmission efficiency of critical data when changes occur in the power line channel and motor noise.

[0113] Please see Figure 4 Optionally, each joint communication node includes: a second signal coupling module, a downlink signal receiving module, and an uplink direct-drive carrier transmission module.

[0114] The second signal coupling module is used to extract the downlink carrier communication signal from the power line and couple the uplink carrier communication signal to the power line. Exemplarily, the second signal coupling module can be a capacitive coupler, a common-mode coupler, a differential-mode coupler, or a combination of both.

[0115] The downlink signal receiving module is used to demodulate the communication resources corresponding to the communication node of the joint to obtain the corresponding first data.

[0116] For example, the downlink signal receiving module includes a high-speed analog-to-digital converter (ADC) and a digital signal processing circuit. The high-speed ADC uses direct sampling or bandpass sampling to sample the downlink carrier communication signal extracted by the second signal coupling module. The digital signal processing circuit performs at least one of the following processing on the sampled digital signal: digital down-conversion, low-pass filtering, timing synchronization, carrier frequency offset estimation, sampling clock deviation estimation, and fast Fourier transform, to obtain the received symbols corresponding to each subcarrier. Channel equalization, constellation demapping or soft demodulation, and forward error correction decoding are then performed on the received symbols to obtain the corresponding first data.

[0117] The uplink direct-drive carrier transmission module is used to map the second data to the communication resources corresponding to the communication node of the joint, so as to generate uplink carrier communication signals in the digital domain.

[0118] Specifically, the uplink direct-drive carrier transmission module generates a bit stream based on the second data, performs digital baseband processing on the bit stream to obtain modulation symbols, and maps the modulation symbols to the subcarrier set and communication time window allocated to the communication node at its respective joint. Subsequently, an orthogonal frequency division multiplexing (OFDM) signal is generated based on the mapped modulation symbols, and the OFDM signal is shifted to the target communication frequency band in the digital domain to generate the uplink carrier communication signal. Furthermore, the uplink direct-drive carrier transmission module directly converts the uplink carrier communication signal generated in the digital domain into an analog signal within the target communication frequency band through a high-speed digital-to-analog converter, without the need for analog up-conversion via an analog mixer and local oscillator.

[0119] Each joint communication node sends uplink carrier communication signals according to the communication time window allocated to it, and uses a set of mutually orthogonal subcarriers to carry its own second data.

[0120] Using the above scheme, each joint communication node utilizes the second signal coupling module to multiplex the power line to receive downlink carrier communication signals and transmit uplink carrier communication signals, eliminating the need for additional independent communication cables. The downlink signal receiving module only demodulates the communication resources corresponding to its own joint communication node; the uplink direct-drive carrier transmission module generates uplink carrier communication signals in the digital domain and transmits the second data using pre-allocated orthogonal communication resources. This application simplifies the transmission link of the joint communication nodes and reduces communication conflicts between multiple joint communication nodes.

[0121] Optionally, the resource scheduling module is also used to periodically configure communication resources for each joint communication node to transmit pilot signals and training sequences.

[0122] For example, the communication resources used to transmit pilot signals and training sequences include a preset communication time window, a preset subcarrier, or a preset orthogonal frequency division multiplexing (OFDM) symbol in a periodic superframe. The configuration period is determined based on the changing speed of the power line channel, the motor operating state, the joint motion state, or the allowable pilot overhead. The training sequence is a pre-agreed sequence of known symbols between the central controller and each joint communication node, used for at least one of the following processes: frame synchronization, carrier frequency offset estimation, sampling clock deviation estimation, and coarse channel estimation. The pilot signal includes multiple known modulation symbols distributed in the corresponding communication resources of each joint communication node, used to estimate the channel response and noise conditions of the corresponding subcarrier.

[0123] Each uplink direct-drive carrier transmission module is also used to insert pilot signals and training sequences into the corresponding uplink carrier communication signals according to the configuration of the resource scheduling module.

[0124] The channel estimation unit is also used to update the channel estimation results and noise statistics of each communication resource based on the periodically received pilot signals and training sequences, and to update the communication quality of each communication resource based on the updated channel estimation results and noise statistics.

[0125] Specifically, the channel estimation unit performs at least one of the following processes based on the periodically received training sequence: frame synchronization, carrier frequency offset estimation, sampling clock deviation estimation, and coarse channel estimation. Based on the pilot signals corresponding to each communication node, it determines the channel response and noise measurement results of the corresponding subcarriers in each communication resource. The channel estimation unit then replaces or corrects the original channel estimation results and noise statistics of each communication resource based on the channel response and noise measurement results of the current period, obtaining updated channel estimation results and noise statistics results. Based on these updated results, the signal-to-noise ratio and corresponding communication quality of each communication resource are updated.

[0126] By adopting the above scheme, even if the motor's operating status, load, or robot posture changes, the central controller can still update the communication quality of each communication resource in a timely manner, providing an accurate basis for subsequent data equalization, demodulation, modulation and coding selection, and communication resource adjustment.

[0127] Optionally, both the first signal coupling module and the second signal coupling module include a passive high-pass coupling network.

[0128] A passive high-pass coupling network is used to couple downlink and uplink carrier communication signals within the target communication frequency band, and to isolate the power supply components, motor PWM signals and their low-frequency harmonics in the power line.

[0129] Specifically, a passive high-pass coupling network refers to a signal coupling network composed of passive components such as capacitors, inductors, and resistors, and possessing a high-pass frequency response. Within the target communication frequency band, the passive high-pass coupling network exhibits low coupling impedance, allowing downlink and uplink communication signals located within the target frequency band to pass through. In the frequency bands containing DC signals, motor PWM signals, and their low-frequency harmonics, it exhibits high impedance, thereby isolating the power supply components in the power line and suppressing low-frequency motor drive noise from entering the communication link.

[0130] For example, the passive high-pass coupling network employs at least one of the following: a series capacitor differential-mode coupling network, a common-mode current injection coupling network, a broadband high-pass coupling network combining capacitors and inductors, an isolation coupling network with impedance matching and protection circuitry, and a high-pass or band-pass filter network for suppressing low-frequency power noise. The first signal coupling module and the second signal coupling module can use the same passive high-pass coupling network, or different passive high-pass coupling networks can be used depending on the interface impedance, communication power, and installation space of the central controller side and the joint communication node side.

[0131] In one specific embodiment, the passive high-pass coupling network employs a series-capacitor differential-mode coupling network, including a series coupling capacitor Cc and a current-limiting resistor Rc. The series coupling capacitor Cc can be selected from 1 pF to 10 nF, and the current-limiting resistor Rc can be selected from 1 Ω to 1 kΩ. The series coupling capacitor Cc isolates the DC power supply component in the power line and utilizes the characteristic that the capacitor impedance decreases with increasing frequency to allow the carrier communication signal within the target communication frequency band to pass through. The current-limiting resistor Rc is used to limit the current flowing through the coupling branch and can work with the series coupling capacitor Cc to adjust the frequency response and interface impedance of the passive high-pass coupling network.

[0132] By employing the above scheme, the passive high-pass coupling network can effectively inject or extract downlink and uplink carrier communication signals within the target communication frequency band while multiplexing power lines to transmit power and communication signals. It also isolates the power supply components, motor PWM signals, and their low-frequency harmonics in the power lines, thereby reducing the impact of low-frequency noise from the power system on the communication receiver. Furthermore, the passive high-pass coupling network eliminates the need for active RF devices, which helps reduce the size, power consumption, and implementation complexity of the coupling circuit.

[0133] Optionally, the central controller also includes an uplink synchronization module, and each joint communication node also includes a timing control module.

[0134] The uplink synchronization module is used to determine the uplink arrival time deviation of each joint communication node based on the training sequence, pilot signal or measurement signal sent by each joint communication node, and to generate the corresponding transmission advance based on the uplink arrival time deviation.

[0135] The timing control module is used to adjust the transmission time of the uplink carrier communication signal according to the corresponding transmission advance, so that the uplink carrier communication signals transmitted by each joint communication node are time-aligned at the central controller.

[0136] Specifically, because the connection positions, transmission path lengths, coupling networks, and interface impedances of each joint communication node in the power line may differ, the arrival times of the uplink carrier communication signals sent by each joint communication node to the central controller may vary. If this deviation exceeds a preset range, it may cause the uplink orthogonal frequency division multiplexing symbols of different joint communication nodes to not fall within the same fast Fourier transform window or cyclic prefix protection range of the central controller, thereby disrupting the orthogonality between different communication resources.

[0137] Based on this, during the robot initialization phase, the uplink synchronization module sends synchronization measurement commands to each joint communication node and configures communication resources for each joint communication node to send training sequences, pilot signals, or measurement signals. The uplink synchronization module detects the actual arrival time of the signals sent by each joint communication node, compares the actual arrival time with the corresponding expected arrival time, obtains the uplink arrival time deviation of each joint communication node, and generates the corresponding transmission advance.

[0138] The central controller sends the transmission advance corresponding to each joint communication node to the corresponding joint communication node via downlink carrier communication signal. The timing control module of each joint communication node receives and stores the corresponding transmission advance, and adjusts the timing of the uplink direct-drive carrier transmission module to send the uplink carrier communication signal according to the transmission advance.

[0139] By adopting the above scheme, the uplink arrival time deviation caused by the different connection positions and signal propagation paths of the communication nodes at different joints is compensated, so that the uplink orthogonal frequency division multiplexing symbols sent by each communication node fall within the same fast Fourier transform window or cyclic prefix protection range of the central controller. This maintains the orthogonality between different communication resources, reduces inter-subcarrier interference, and improves the reliability of uplink data reception of multi-joint communication nodes.

[0140] Optionally, the central controller may also include an attitude-aware electromagnetic compatibility control module.

[0141] The attitude-aware electromagnetic compatibility control module is used to acquire the robot's attitude information and cable layout information. Based on the attitude information and cable layout information, it determines the electromagnetic radiation risk of the robot at the corresponding frequency of each communication resource, and adjusts at least one of the usage status and transmission power of the corresponding communication resource according to the electromagnetic radiation risk control resource scheduling module.

[0142] Specifically, robot limbs, power lines, batteries, motor housings, and metal frames may form an equivalent antenna structure under certain postures. When the frequency corresponding to a certain communication resource satisfies a preset resonance relationship with the equivalent radiation length of the robot limb or power line loop, the carrier communication signal carried by that communication resource may generate strong leakage radiation, affecting the overall electromagnetic compatibility performance of the robot or interfering with external protected wireless services.

[0143] Based on this, the attitude-sensing electromagnetic compatibility control module of this embodiment acquires the robot's attitude information and cable layout information. The attitude information includes at least one of the following: joint angles, joint positions, and attitude data collected by the inertial measurement unit (IMU) for each joint of the robot. The cable layout information includes at least one of the following: the robot limbs through which the power lines pass, the direction of the power lines within each limb, the length of each cable segment, and the loop structure formed by the power lines. The cable layout information is predetermined based on the robot's computer-aided design model, mechanism model, and cable routing model.

[0144] Optionally, the attitude sensing electromagnetic compatibility control module includes: an equivalent length determination module, a risk assessment module, and a radiation suppression module.

[0145] The equivalent length determination module is used to determine the equivalent radiation length of the robot limb or power line loop based on the posture information and cable layout information. The equivalent radiation length characterizes the effective length of the equivalent radiation structure formed by the robot limb, power lines, motor housing, and metal frame, which radiates signals of a specific frequency under the current posture.

[0146] The risk assessment module is used to identify target communication resources with radiation enhancement risks based on the equivalent radiation length and the frequency corresponding to each communication resource.

[0147] The radiation suppression module is used to perform at least one of the following operations on the target communication resource: stop its use, reduce transmission power, relocate the communication resource, or adjust the modulation and coding scheme.

[0148] Specifically, the equivalent length determination module acquires the joint angles output by the joint encoders and the attitude data output by the inertial measurement unit. It then determines the current spatial position and orientation of each limb segment of the robot using a forward kinematics model. Combining this with the direction and length of the power lines within each limb segment, it calculates the equivalent radiation length of the robot limb or power line loop in the current posture. When robot joint rotation causes changes in the relative position between limb segments or the spatial shape of the power line loop, the equivalent length determination module updates the equivalent radiation length accordingly.

[0149] The risk assessment module calculates the corresponding signal wavelength based on the frequency of each communication resource. This signal wavelength can be determined based on the ratio of the electromagnetic wave propagation speed to the corresponding frequency, or it can be determined after correcting for the propagation speed based on the dynamic line medium, dielectric constant, and robot structure.

[0150] When the equivalent radiation length of a robot limb or power line loop is close to one-quarter, one-half, or another preset resonant length of the corresponding signal wavelength, it is determined that the equivalent radiation length and the corresponding frequency satisfy a preset resonant relationship, and the communication resource corresponding to that frequency is identified as a target communication resource with a risk of radiation enhancement. Here, "close to" means that the difference or proportion between the equivalent radiation length and the preset resonant length is less than a preset length threshold.

[0151] The radiation risk model used in the risk assessment module can be established based on the robot's computer-aided design model, cable routing model, and forward kinematics model; it can also obtain radiation risk tables for different robot postures and frequencies through electromagnetic simulation; or it can establish a posture-frequency-radiation risk lookup table through anechoic chamber testing or near-field scanning. In other embodiments, the above assessment model can be updated based on online measurement results, or joint angles, frequencies, transmission power, and cable segment information can be input into a machine learning model to output the risk level or power limit of the corresponding communication resources.

[0152] By adopting the above scheme, communication resources that may generate radiation enhancement under specific postures can be dynamically identified based on the robot's posture and power line layout, and electromagnetic radiation at the corresponding frequencies can be suppressed. This can reduce the electromagnetic radiation risk caused by changes in robot posture, improve the electromagnetic compatibility performance of the robot's direct-drive carrier power line communication system, and reduce interference to external protected wireless services.

[0153] Optionally, the central controller may also include a security degradation and fault protection module.

[0154] The safety degradation and fault protection module is used to perform emergency operations when preset conditions are met; Among them, the preset conditions are determined to be met when at least one of the following occurs: the communication link quality is lower than the preset quality threshold, the uplink synchronization fails, the number of consecutive packet losses of the joint communication node reaches the preset number, and the communication bandwidth corresponding to the available communication resources is less than the preset bandwidth. Emergency operations include at least one of the following: reducing modulation order, increasing coding redundancy, shortening the scheduling cycle of critical communication nodes, suspending non-critical data transmission, switching to backup communication frequency bands, and activating emergency communication mode.

[0155] Specifically, the security degradation and fault protection module obtains the communication quality of each communication resource, the uplink synchronization status and packet loss statistics of each joint communication node, and the communication bandwidth corresponding to the currently available communication resources, and compares them with the corresponding preset conditions.

[0156] By adopting the above scheme, when communication link quality deteriorates, uplink synchronization fails, joint communication nodes experience continuous packet loss, or available communication bandwidth is insufficient, the communication rate is promptly reduced or the communication resources occupied by non-critical data are minimized, prioritizing the transmission of critical joint communication nodes and critical control data. This prevents communication anomalies from directly causing the robot to lose control, improving the robot's communication reliability and operational safety in complex electromagnetic environments or under conditions of limited communication resources.

[0157] Each module in the aforementioned robot direct-drive carrier power line communication system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the corresponding operations of each module.

[0158] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0159] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A robot direct-drive carrier power line communication system, characterized in that, The system includes: a central controller, a power line, and multiple joint communication nodes; The power line is used to supply power to the plurality of joint communication nodes and to form a communication channel between the central controller and the plurality of joint communication nodes; The central controller is used to allocate mutually orthogonal communication resources to the plurality of joint communication nodes, and to map the first data to be sent to each of the joint communication nodes to the corresponding communication resources, so as to generate a downlink carrier communication signal located in the target communication frequency band in the digital domain and couple it to the power line; wherein, the target communication frequency band is determined based on the motor noise spectrum in the power line; Each of the joint communication nodes is used to extract the downlink carrier communication signal from the power line, demodulate the communication resources corresponding to the joint communication node, and obtain the corresponding first data. Furthermore, the second data to be sent to the central controller is mapped to the corresponding communication resources to generate an uplink carrier communication signal in the digital domain located in the target communication frequency band and coupled to the power line, so that the central controller can obtain the second data from the uplink carrier communication signal.

2. The system according to claim 1, characterized in that, The central controller includes: The resource scheduling module is used to allocate mutually orthogonal communication resources to the multiple joint communication nodes and generate the resource allocation relationship between each joint communication node and the corresponding communication resource. The downlink direct-drive carrier transmission module is used to map the first data to be transmitted to each of the joint communication nodes to the corresponding communication resources according to the resource allocation relationship, so as to generate a downlink carrier communication signal located in the target communication frequency band in the digital domain; The first signal coupling module is used to couple the downlink carrier communication signal to the power line and extract the uplink carrier communication signal sent by each of the joint communication nodes from the power line; The uplink signal receiving module is used to demodulate the communication resources corresponding to each of the joint communication nodes in the uplink carrier communication signal according to the resource allocation relationship, so as to obtain the second data sent by each of the joint communication nodes.

3. The system according to claim 2, characterized in that, The downlink direct-drive carrier transmission module includes: A digital baseband unit is used to perform digital baseband processing on the first data to obtain modulation symbols, and to map the modulation symbols to corresponding communication resources according to the resource allocation relationship. An orthogonal frequency division multiplexing modulation unit is used to generate orthogonal frequency division multiplexing signals based on modulation symbols mapped to each of the communication resources; A digital frequency shift unit is used to shift the orthogonal frequency division multiplexed signal to the target communication frequency band; A digital-to-analog converter is used to perform digital-to-analog conversion on orthogonal frequency division multiplexing signals moved to the target communication frequency band, so as to output the downlink carrier communication signal located in the target communication frequency band.

4. The system according to claim 3, characterized in that, The digital baseband unit performs digital baseband processing on the first data to obtain modulation symbols, including: The digital baseband unit generates a bit stream based on the first data, performs at least one of scrambling, forward error correction coding and interleaving on the bit stream, and performs constellation mapping on the processed bit stream to obtain the modulation symbol.

5. The system according to claim 2, characterized in that, The central controller also includes: The frequency band selection module is used to obtain the prohibited frequency bands corresponding to the protected wireless services, and to scan the motor noise spectrum in the power line during robot startup, calibration or operation, determine the frequency bands in the motor noise spectrum whose noise power spectral density is greater than a preset noise threshold, and select the target communication frequency band from outside the prohibited frequency bands and the determined frequency bands.

6. The system according to claim 5, characterized in that: The frequency band selection module is also used to detect the communication quality of each frequency point in the target communication frequency band during the communication process, identify the frequency points whose communication quality does not meet the preset communication conditions as interference frequency points, perform at least one of the following operations on the interference frequency points: subcarrier deactivation, transmission power reduction and communication resource migration, and adjust the communication bandwidth according to the amount of available spectrum after the operation is performed.

7. The system according to claim 2, characterized in that, The resource scheduling module includes: A superframe generation unit is used to divide communication time into periodic superframes; The resource allocation unit is used to divide the target communication frequency band into multiple mutually orthogonal subcarrier sets, determine multiple communication time windows in the periodic superframe, and allocate corresponding subcarrier sets and communication time windows to each joint communication node according to the node identifier of each joint communication node, so as to use the allocated subcarrier sets and communication time windows as the communication resources of the corresponding joint communication node.

8. The system according to claim 2, characterized in that, The uplink signal receiving module includes: The channel estimation unit is used to determine the channel estimation result and noise statistics result of each communication resource based on the pilot signal corresponding to each of the joint communication nodes, determine the signal-to-noise ratio of each communication resource based on the channel estimation result and the noise statistics result, and determine the communication quality of each communication resource based on the signal-to-noise ratio. The data demodulation unit is used to perform equalization, demodulation, and decoding on the corresponding communication resources in the uplink carrier communication signal based on the channel estimation results of each of the communication resources, so as to obtain the second data sent by each of the joint communication nodes.

9. The system according to claim 8, characterized in that, The uplink signal receiving module further includes: A sampling unit is used to sample the uplink carrier communication signal to obtain a time-domain sampled signal; The impulse noise processing unit is used to perform time-domain limiting or time-domain blanking on the time-domain sampled signal when impulse noise is detected in the uplink carrier communication signal, or to perform frequency-domain erasure on the subcarrier affected by the impulse noise.

10. The system according to claim 8, characterized in that, The central controller also includes: An adaptive modulation and coding module is used to determine the modulation and coding methods for the corresponding joint communication nodes based on the communication quality of each of the communication resources. The resource scheduling module is further configured to adjust the communication resources allocated to each of the joint communication nodes based on the service priority of each of the joint communication nodes and the communication quality of each of the communication resources. The adaptive modulation and coding module is further configured to update at least one of the corresponding modulation and coding methods based on the communication quality corresponding to the adjusted communication resources.

11. The system according to claim 8, characterized in that, Each of the aforementioned joint communication nodes includes: The second signal coupling module is used to extract the downlink carrier communication signal from the power line and couple the uplink carrier communication signal to the power line; The downlink signal receiving module is used to demodulate the communication resources corresponding to the communication node of the joint to obtain the corresponding first data; The uplink direct-drive carrier transmission module is used to map the second data to the communication resources corresponding to the communication node of the joint, so as to generate the uplink carrier communication signal in the digital domain.

12. The system according to claim 11, characterized in that: The resource scheduling module is also used to periodically configure communication resources for each of the joint communication nodes to transmit pilot signals and training sequences; Each of the uplink direct-drive carrier transmission modules is further configured to insert the pilot signal and the training sequence into the corresponding uplink carrier communication signal according to the configuration of the resource scheduling module; The channel estimation unit is further configured to update the channel estimation results and noise statistics results of each communication resource based on the periodically received pilot signals and the training sequence, and update the communication quality of each communication resource based on the updated channel estimation results and noise statistics results.

13. The system according to claim 11, characterized in that, Both the first signal coupling module and the second signal coupling module include a passive high-pass coupling network; The passive high-pass coupling network is used to couple the downlink carrier communication signal and the uplink carrier communication signal within the target communication frequency band, and to isolate the power supply component, motor PWM signal and its low-frequency harmonics in the power line.

14. The system according to claim 11, characterized in that, The central controller also includes an uplink synchronization module, and each of the joint communication nodes also includes a timing control module; The uplink synchronization module is used to determine the uplink arrival time deviation of each joint communication node based on the training sequence, pilot signal or measurement signal sent by each joint communication node, and generate a corresponding transmission advance based on the uplink arrival time deviation. The timing control module is used to adjust the transmission time of the uplink carrier communication signal according to the corresponding transmission advance, so that the uplink carrier communication signals transmitted by each joint communication node are time-aligned at the central controller.

15. The system according to claim 2, characterized in that, The central controller also includes: The attitude-aware electromagnetic compatibility control module is used to acquire the robot's attitude information and cable layout information, determine the electromagnetic radiation risk of the robot at the corresponding frequency of each of the communication resources based on the attitude information and the cable layout information, and control the resource scheduling module to adjust at least one of the usage status and transmission power of the corresponding communication resources based on the electromagnetic radiation risk.

16. The system according to claim 15, characterized in that, The attitude-aware electromagnetic compatibility control module includes: An equivalent length determination module is used to determine the equivalent radiation length of a robot limb or power line loop based on the posture information and the cable layout information. The risk assessment module is used to determine the target communication resources with radiation enhancement risk based on the equivalent radiation length and the frequency corresponding to each of the communication resources. The radiation suppression module is used to perform at least one of the following operations on the target communication resource: stop using it, reduce transmission power, relocate the communication resource, or adjust the modulation and coding scheme.

17. The system according to claim 2, characterized in that, The central controller also includes: The safety degradation and fault protection module is used to perform emergency operations when preset conditions are met; The preset condition is determined to be met when at least one of the following occurs: the communication link quality is lower than a preset quality threshold, uplink synchronization fails, the number of consecutive packet losses of the joint communication node reaches a preset number, and the communication bandwidth corresponding to the available communication resources is less than a preset bandwidth. The emergency operations include at least one of the following: reducing the modulation order, increasing coding redundancy, shortening the scheduling cycle of critical communication nodes, suspending non-critical data transmission, switching to a backup communication frequency band, and activating an emergency communication mode.

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