CN101020313A - Motion controller for modular embedded polypod robot - Google Patents

Abstract

The invention discloses a motion controller of a modular embedded multi-legged robot, which comprises a PC module, a fuselage control module and a foot unit control module respectively located on each foot. The PC module is used to identify the environment where the robot is located, determine the next action of the robot and transmit the data to the fuselage control module. The fuselage control module is used to process the data into specific motion data, and then distribute the data to each foot unit control module through the fuselage bus. The invention adopts a layered control mode, which is composed of a data operation layer, a fuselage control layer and a joint control layer. The data operation layer is established on the PC, and the gait data of the robot is calculated according to the forward and reverse kinematics and dynamics of the robot. The fuselage control layer uses the ARM processor as the control core. The fuselage control layer has a large storage space, which can store the gait data of the robot to realize the offline movement of the robot. It also has a seamless connection interface with the PC, and the PC can realize online debugging of the robot.

Description

A Modular Embedded Multi-legged Robot Motion Controller

technical field

The invention belongs to the technical field of robots, and in particular relates to a motion controller of a modular embedded multi-legged robot.

Background technique

The robot controller is the most important and critical part of the robot system. The performance of the robot controller directly determines the motion performance of the robot. Existing robot systems are mostly dedicated systems that can only be adapted to robots with a specific structure. Once the structure of the robot changes, its controller must be redesigned, which limits the ability of the robot to change or expand according to the requirements of the task and working environment. . And the existing controller does not have fault-tolerant function, once some joints of the robot are damaged, the whole robot system falls into a paralyzed state immediately.

Although various open-structure robot controllers currently exist have achieved portability, scalability, etc., most of them use industrial control computers as controllers, and the hardware structure cannot be changed, and the cost is high and the volume is large, so it cannot be embedded. control.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of existing controllers and provide a modular embedded multi-legged robot motion controller. The controller software system is flexible and stable, and it is a reconfigurable and fault-tolerant embedded type controller.

The modular embedded multi-legged robot motion controller provided by the present invention is characterized in that: the controller includes a PC module, a fuselage control module and a foot unit control module respectively located on each foot; wherein,

The PC module includes an operating software module and a first communication module, the operating software module is used to realize the functions of environment recognition, path planning and gait planning, and transmits the calculated data to the first communication module; the first communication module has a processing body The bus data function connects the fuselage control module and the PC module through the USB bus;

The fuselage control module includes a second PC communication module, a status display module and a fuselage controller; the second PC communication module is used to communicate with the first communication module and transmit data to the fuselage controller; the fuselage controller adopts ARM The processor processes the data and then forwards the processed data to each foot unit controller, and the status of the fuselage controller is displayed through the status display module;

The foot unit control module includes a foot unit controller, a hip joint control module, a knee joint control module, an ankle joint control module and a sensor module; the foot unit controller coordinates and controls the coordinated movement of three joints in a foot, and controls The module feeds back the motion state of the entire foot; the hip joint control module, knee joint control module, and ankle joint control module have the same structure, and are all composed of a joint controller and a foot joint motor; the joint controller is based on the motion transmitted by the fuselage control module through CAN_Bus Data, the single-chip computer is used to control the motor of the foot joint to perform a predetermined movement, and the movement is transmitted to the body of the joint mechanism through the transmission chain of the foot joint. The coordinated movement of each joint forms the overall movement of the robot, and then the motion state of the joint is fed back through the sensor module to realize Closed-loop control.

The modular embedded robot controller proposed by the present invention adopts a layered control mode, and is composed of a data operation layer, a fuselage control layer with an ARM microprocessor as the control core, and a joint control layer with a single-chip microcomputer as the control core. The data operation layer is established on the PC to calculate the gait data of the robot. The fuselage control layer uses the ARM processor as the control core, which can store the gait data of the robot and realize the offline movement of the robot. It also has a seamless connection interface with the PC. The single chip microcomputer is the control core. Specifically, the present invention has the following technical effects:

(1) The robot controller proposed by the present invention has reconfigurable ability. When the robot is changed or expanded according to the requirements of the task and working environment, it is only necessary to add the joint controller to the CAN bus network of the fuselage controller or from the It can be deleted from the network.

(2) When the robot is damaged during operation, the fuselage controller will automatically identify and close the joint, and directly jump out of the operation of the joint, which has a certain fault tolerance.

(3) Expand the joints of the fuselage control layer, add other equipment to realize plug and play, and automatically identify the ID number.

(4) The present invention can be used for the control of robots, and can also be used for the control of other motion systems.

Description of drawings

Figure 1 is a diagram of the corresponding relationship between each logical layer and physical realization of a modular reconfigurable robot;

Fig. 2 is the structure schematic diagram of the motion controller of modular embedded multi-legged robot of the present invention;

Figure 3 is a flow chart of the operating software module;

Fig. 4 is a block diagram of the hardware structure of the fuselage controller;

Fig. 5 is a block diagram of the fuselage controller software system;

Fig. 6 is a hardware block diagram of the joint controller;

Figure 7 is the three-layer abstraction of the joint controller software

Fig. 8 is a flow chart of joint controller software;

Fig. 9 is a flow chart of ID identification.

Detailed ways

A modular embedded robot controller proposed by the present invention will be further described in detail below in conjunction with the accompanying drawings and examples.

The modular embedded robot in the present invention can realize walking motion similar to ordinary walking robots, and can provide expanded functions for the robot by adding new modules to the robot platform. Therefore, the controller needs to realize two functions: (1) control the robot to complete basic actions such as walking and turning; Plug and play" function. In order to realize modular functions, it is necessary to realize: (1) Divide the control system into different logical levels, (2) Implement a class of functions in each logical layer, (3) Use standard interfaces between logical layers interact.

After realizing the control system with modular characteristics, by analyzing the robot's motion control strategy, the robot's motion control can be subdivided and divided into the logic layer of the control system according to different functions. As shown in Figure 1, the specific logical layers include: scenario planning layer, stand-alone planning layer, unit module layer and device implementation layer. The scene planning layer recognizes the environment of the robot, plans the path of the robot, and calculates the forward and reverse kinematics of the robot. The scene planning layer mainly identifies the environment where the robot is located, and determines the next action of the robot according to the environment, which is a gait generator in physical implementation. The stand-alone planning layer mainly coordinates and controls multiple joint controllers, and operates the fuselage bus and joint bus, corresponding to the fuselage controller in physical implementation. The unit module layer is mainly responsible for the communication between various modules, processing CAN_Bus data, and physically realizing multiple joint controllers. The device implementation layer is responsible for executing commands, specifically driving the actuator motor to move according to the specified motion parameters. In terms of physical implementation, it is the motor control circuit, actuators and sensors.

As shown in FIG. 2 , according to the above idea, the motion controller of the modular embedded multi-legged robot in the present invention includes a PC module 1 , a body control module 2 and several foot unit control modules 3 . The PC module 1 is used to identify the environment where the robot is located, determine the next action of the robot according to an advanced algorithm and transmit the data to the fuselage control module 2 . The fuselage control module 2 is used to process the data into specific motion data, and then distribute the data to each foot unit control module 3 through the fuselage bus.

1. PC module 1

The PC module 1 is located in the PC, which corresponds to the scenario planning layer in the layered control logic layer, and its software modules include an operating software module 11 and a first communication module 12 . The operating software module 11 is used to realize the functions of environment recognition, path planning and gait planning. As shown in Figure 3, the workflow of the operating software module 11 is:

(1) Obtain work tasks for task planning and generate subtask sequences. And obtain subtask priority and subtask information.

(2) Adjust the subtask with the highest priority as the current task according to the priority of each subtask.

(3) Call in the subtask information, process and generate a motion command sequence, and after the sequence is transmitted to the first communication module 12, continue to call the next subtask until all motion tasks are completed.

(4) After all tasks are completed, the decision-making experience is summarized according to the feedback data of the fuselage control module, and the decision-making library is updated.

The operating software module 11 transmits the calculated data to the first communication module 12, and the first communication module 12 has the function of processing the bus data of the fuselage, and connects the fuselage control module 2 and the PC module 1. The fuselage control module 2 is connected to the PC module 1 through a USB bus.

2. Fuselage control module 2

Airframe control module 2 corresponds to the stand-alone planning layer in the hierarchical control logic layer. The functions of the fuselage control module 2 are as follows: 1) Generate gait during offline motion, and coordinate and control multiple joint controllers to complete the motion. 2) Store and forward the motion data generated by the PC upper-layer software during joint debugging with the PC, and coordinate the operation of each joint controller.

The fuselage control module 2 is composed of a second PC communication module 21 , a status display module 22 and a fuselage controller 23 . The second PC communication module 21 communicates with the first communication module 12 in the PC module 1 and transmits data to the body controller 23 . Airframe controller 23 processes the data and then forwards the processed data to each foot unit controller. The state of the airframe controller 23 is displayed through the state display module 22 to facilitate debugging and error diagnosis.

As shown in FIG. 4 , the body controller 23 includes a USB_Bus control module 231 , a sensor module interface 232 , a serial communication module 233 , an ARM microprocessor 234 and a CAN_Bus driver module 235 . Airframe controller 23 adopts ARM microprocessor 234 as the control core. Compared with industrial control computers, ARM embedded microprocessors have the advantages of small size, light weight, low cost and high reliability. A USB_Bus control module 231 is added on the periphery of the ARM to accept the motion instruction data transmitted from the PC module 1 through the USB_Bus, and return the robot motion state to the PC module 1 . The sensor module interface 232 is used to provide an interface for the sensor 3 in the foot unit module 3 . The serial port communication module 233 transmits and sends data from the PC module 1 through the serial port, and is mainly used in the debugging process. The CAN_Bus driver module 235 is connected to the CAN_Bus network, and provides a physical interface between the CAN controller in the ARM microprocessor 234 and the physical bus.

Due to the large data flow and various tasks in the fuselage control layer, there are multi-layer interrupt nesting, and the real-time requirements are relatively high, so the traditional software structure of the front-end and back-end systems obviously cannot meet the requirements. As shown in Figure 5, the ARM microprocessor 234 can make the airframe control program complete more complex tasks by using advanced functions such as multi-threading and dynamic memory allocation by transplanting the embedded operating system μC/OS-II. The program structure of the ARM microprocessor 234 can be divided into two layers: operating system and application programs. The operating system is the background program that is first executed after the ARM is started, and the application program is the various tasks on the operating system. The operating system performs resource management, message management, task scheduling, and exception handling according to the requirements of each task. μC/OS-II is a real-time multitasking operating system whose source code is open, portable, curable, tailorable, and preemptive. Most of the source code is written in ANSIC, and the parts related to microprocessor hardware are written in assembly language. . Therefore, the operating system includes μC/OS-II kernel, μC/OS-II task setting, and μC/OS-II system transplant code. The μC/OS-II kernel provides all system services. The kernel organically combines the application program with the underlying hardware into a real-time system. The code related to the processor (μC/OS-II porting code) can be regarded as the middle layer between the kernel and the hardware, which realizes that the same kernel is applied to different hardware systems. μC/OS-II task setting is related to the setting of the operating system with the application program.

The application program is composed of multiple tasks, and each task has a unique priority. The real-time operating system dynamically switches each task according to the priority of each task to ensure the real-time requirements. The USB_Bus data processing task has the highest priority and is used to receive motion data from the PC and return various status information of the robot controller. The CAN_Bus data processing task processes the data on the fuselage bus, distributes motion instructions to multiple controllers in the joint control layer, and monitors the status of each joint controller in real time. When there is an error in the joint controller or a new ID is registered, Let the error analysis and processing task or the ID identification record task be in the ready state, and perform task scheduling. The system command processing task is responsible for analyzing, processing, and distributing the data sent by the PC. When offline operation is to be performed, the offline data operation task reads the motion data in the memory to control the operation of the robot. The serial port data processing task and the display module task are all set for the convenience of debugging, and their priority is the lowest, and they only run when there are no other tasks.

3. Foot unit control module 3

A walking robot usually consists of multiple feet, and each foot is provided with a foot unit control module. The foot unit control module corresponds to the unit module layer and the device implementation layer in the layered control logic layer. Foot unit control module 3 among the present invention comprises foot unit controller 30, hip joint control module 31, knee joint control module 32, ankle joint control module 33 and sensor module 34. The hip joint control module 31 is located at the hip joint, the knee joint control module 32 is located at the knee joint, and the ankle joint module is located at the ankle joint.

The foot unit controller 30 is responsible for coordinating and controlling the coordinated movement of the three joints in one foot, and feeding back the movement state of the whole foot to the fuselage control module 2 . Since each foot is structurally and functionally identical, the foot unit controllers are identical on each foot. In order to make full use of the remaining capacity of the joint controller and realize the function of the foot unit controller without increasing the hardware cost, the function of the hip joint controller 31 in each foot can be expanded to enable it to have the foot unit control The function of device 30.

The hardware structures of the hip joint control module 31 , the knee joint control module 32 and the ankle joint control module 33 are also the same, and are all composed of joint controllers and foot joint motors.

The joint controller controls the foot joint motor to perform a predetermined movement according to the motion data transmitted by the fuselage control module 2 through CAN_Bus, and transmits the motion to the joint mechanism body through the foot joint transmission chain, and the coordinated motion of multiple joints forms the overall motion of the robot. The motion state of the joint is fed back through the sensor module 34 to achieve the effect of closed-loop control.

The joint controller is the key in the modular thinking. As shown in FIG. 6 , the joint controller is composed of three modules, namely: a single-chip microcomputer control module 61 , a motor control and driving module 62 and a CAN communication module 63 . The single-chip microcomputer control module 61 is composed of a single-chip microcomputer minimum system 611 , a power monitoring module 612 and a display module 613 . Among them, the minimum system 611 of the single-chip microcomputer ensures that the single-chip microcomputer can complete the simplest functions, the power monitoring module 612 enables the single-chip microcomputer to still operate normally when the external power supply fluctuates, and the display module 613 displays the operating status of the joint controller in real time, which is convenient for debugging.

The motor control and drive module 62 controls the operation of the drive motor according to the motion data received by the CAN communication module 63 , and includes a motor controller 621 and a motor driver 622 . The motor controller 621 uses a dedicated motion control processor. For the main CPU single-chip microcomputer of the joint controller, to control the motion state of the motor, only the relevant parameters such as the position, speed and acceleration of the motor need to be set, which reduces the burden on the CPU. , which simplifies the control method and improves the control efficiency. The motor control part generates signals to control the movement of the motor, and the actual movement of the motor needs to be realized by the drive part. In the present invention, the motor driver 622 is implemented by an integrated power drive circuit, and the motor controller outputs PWM waves to control the motor driver to achieve power amplification. The motor driver 622 is directly connected with the DC motor 623 to complete the motion requirement. Since there is relatively large electromagnetic interference between the motor controller 621 and the motor driver 623 , optocoupler 624 is used for isolation.

The CAN communication module 63 is responsible for the communication between the joint controller and the fuselage controller, receives the motion data sent by the fuselage control module 2, and returns the motion status of the joint in real time. CAN is the only fieldbus with international standards so far. It has the characteristics of strong anti-interference, fast transmission speed and long transmission distance. It only needs to filter the identifier of the message to realize point-to-point, point-to-multipoint and global broadcast. There are several ways to transmit and receive data, so we use the CAN bus as the body bus. The use of the CAN bus can well support a modular structure. The CAN bus communication module is also divided into CAN bus controller 631 and CAN bus driver 632. The CAN bus controller 631 uses a combination of logic circuits on a programmable chip to realize the connection between the data link layer and the physical layer in the network hierarchy. Function. The CAN bus driver 632 provides an interface between the physical bus and the CAN bus controller 631 . Both the CAN bus controller 631 and the CAN bus driver 632 are implemented using dedicated chips. It is programmed and controlled by a single-chip microcomputer.

Joint controller 6 realizes its control by the software programming of single-chip microcomputer minimum system 611, and its architecture includes three layers of abstract software: namely: hardware-related layer (bottom layer), user-defined function layer (middle layer) and application layer (top layer), As shown in Figure 7. Among them, the user-defined function layer and the application layer may also be referred to as hardware-independent layers. There is a one-way call relationship between layers, that is, only the upper layer can call the functions of the lower layer, but the lower layer cannot call the functions of the upper layer. Moreover, calls can only be made between adjacent layers, not cross-layer calls. For example, the application layer cannot skip the custom function layer to call functions in the hardware-related layer. The advantage of using such a three-layer structure design is: when the hardware system changes, only the hardware-related layers need to be changed, while the middle layer and application layer can adapt to the new hardware platform without much change. Such an architecture improves the openness and portability of the software.

Due to the small number of tasks in the joint control layer and the limited storage capacity of the microcontroller in the joint control layer, the overall process of the joint control layer adopts the front-end and back-end methods, and the application program is an infinite loop. The corresponding function is called in the loop to complete the corresponding operation, and the interrupt service routine handles the asynchronous event. Critical operations with strong event dependencies are guaranteed by interrupt service routines. Its specific process is shown in Figure 8. When the system is powered on and reset, the system initialization program initializes the microcontroller, motor controller, CAN bus controller and sets the interrupt mode and priority. Then the ID identification module identifies the ID value of the joint and enumerates it to the fuselage controller. Enter the main loop, query the CAN bus event occurrence flag, the motor in place flag, the motor stall flag, and the CAN network error flag. When a flag is set, the corresponding function is called for processing. When an interrupt comes, it is not processed immediately in the interrupt handler, but the flag is changed, and then processed in the main loop. In this way, it can prevent the time of entering the interrupt from being too long, and correspondingly, the speed of other interrupts will be slowed down, so that the overall interrupt response time of the system will become longer.

ID self-identification is the key point for robots to achieve reconfigurability and fault tolerance. When the robot needs to be reconfigured, as long as the joint ID to be added or changed is changed by means of a code switch, and the specific joint controller is reset, the ID can be automatically updated without operating the body controller, realizing plug and play . The process of ID self-identification is shown in Figure 9. After the joint controller is reset, it first reads the ID number indicated by the DIP switch. The controller first uses 0x00 as the ID number to send an enumeration signal to the fuselage controller, and waits for After the fuselage controls its response, it sends the read ID number to the fuselage controller. The fuselage controller first judges whether the ID number already exists. If it does not exist, it adds the ID number in its joint ID chain list, and Send a confirmation message to the joint controller, and after receiving the confirmation message, the joint controller sets the ID number as the CAN bus ID number for communication. If the ID number already exists in the fuselage controller, it will notify the joint controller that the ID is wrong, and report to the police.

Claims (7)

1. A modular embedded multi-legged robot motion controller is characterized in that: the controller comprises a PC module (1), a machine body control module (2) and foot unit control modules (3) which are respectively positioned on each foot; wherein,

the PC module (1) comprises an operation software module (11) and a first communication module (12), wherein the operation software module (11) is used for realizing the functions of environment recognition, path planning and gait planning and transmitting the calculated data to the first communication module (12); the first communication module (12) has the function of processing the data of the machine body bus, and the machine body control module (2) is connected with the PC module (1) through a USB bus;

the body control module (2) comprises a second PC communication module (21), a state display module (22) and a body controller (23); the second PC communication module (21) is used for communicating with the first communication module (12) and transmitting data to the body controller (23); the body controller (23) adopts an ARM processor to process the data and then forwards the processed data to each foot unit controller, and the state of the body controller (23) is displayed through the state display module (22);

the foot unit control module (3) comprises a foot unit controller (30), a hip joint control module (31), a knee joint control module (32), an ankle joint control module (33) and a sensor module (34); the foot unit controller (30) is used for coordinately controlling the coordinated movement of three joints in one foot and feeding back the movement state of the whole foot to the machine body control module (2); the hip joint control module (31), the knee joint control module (32) and the ankle joint control module (33) have the same structure and are respectively composed of a joint controller and a foot joint motor; the joint controller adopts a single chip microcomputer to control a foot joint motor to perform preset motion according to motion data transmitted by the machine body control module (2) through CAN _ Bus, the motion is transmitted to the joint mechanism body through a foot joint transmission chain, the coordinated motion of each joint forms the overall motion of the robot, and the motion state of the joint is fed back through the sensor module (34) to realize closed-loop control.

2. The modular embedded multi-legged robotic motion controller of claim 1, wherein: the foot unit controller (30) and the hip joint control module (31) are integrated.

3. The modular embedded multi-legged robotic motion controller of claim 1 or 2, wherein: the body controller 23 comprises a USB _ Bus control module (231), a sensor module interface (232), a serial port communication module (233), an ARM microprocessor (234) and a CAN _ Bus drive module (235); wherein,

the ARM microprocessor (234) adopts a transplanted embedded operating system mu C/OS-H to perform resource management, message management, task scheduling and exception handling according to the requirements of each task, and initializes and processes data from the USB _ Bus control module (231), the sensor module interface (232) and the serial port communication module (233) and the CAN _ Bus drive module (235);

the USB _ Bus control module (231) is used for receiving motion instruction data transmitted by the PC module (1) through the USB _ Bus and returning the motion state of the robot to the PC module;

a sensor module interface (232) for interfacing with a sensor module (34) in the foot unit module (3);

the serial port communication module (233) transmits data from the PC module (1) in the debugging process;

the CAN _ Bus driver module (235) is connected to a CAN _ Bus network and provides a physical interface between a CAN controller in the ARM microprocessor (234) and a physical Bus.

4. The modular embedded multi-legged robotic motion controller of claim 3, wherein: the joint controller consists of a single chip microcomputer control module (61), a motor control and drive module (62) and a CAN communication module (63); wherein,

the single chip microcomputer control module (61) is used for controlling the normal work of the single chip microcomputer, receiving bus data of the CAN communication module (63), transmitting the processed data to the motor control driving module (62) to control and drive the motor to move according to instructions; the motor running state data from the motor driving module (62) is received, and the joint motion state data generated after analysis is sent to the bus through the CAN communication module (63);

the motor control and drive module (62) receives the motion instruction data of the singlechip control module (61), controls and drives the motor, and returns the running state of the motor to the singlechip control module (61);

the CAN communication module (63) receives data on the CAN bus, transmits the data to the singlechip control module (61), and transmits the joint state returned by the singlechip control module (61) to the CAN bus.

5. The modular embedded multi-legged robotic motion controller of claim 4, wherein: the single chip microcomputer control module (61) is composed of a single chip microcomputer minimum system (611), a power supply monitoring module (612) and a display module (613);

the single chip microcomputer minimum system (611) is used for the single chip microcomputer to complete the most basic functions, the power supply monitoring module (612) enables the single chip microcomputer to still normally operate when an external power supply fluctuates, and the display module (613) displays the operation state of the joint controller in real time.

6. The modular embedded multi-legged robotic motion controller of claim 4, wherein:

the motor control and drive module (62) comprises a motor controller (621) and a motor driver (622), the motor controller (621) is used for controlling the motor to work, the PWM wave is output to control the motor driver (622) to work, the power amplification effect is achieved, the motor driver (622) is connected with the direct current motor (623) to complete the motion requirement, and the motor controller (621) and the motor driver (623) are isolated by an optical coupler (624).

7. The modular embedded multi-legged robotic motion controller of claim 4, wherein: the CAN bus communication module (63) is composed of a CAN bus controller (631) and a CAN bus driver (632), the CAN bus controller (631) realizes the functions of a data link layer and a physical layer in a network hierarchy, and the CAN bus driver (632) is used for providing an interface between the physical bus and the CAN bus controller (631).

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