The position-changing robot uses navigation technology to obtain the current location of the robot, combines sensor technology with real-time detection of surrounding external conditions (obstacles, etc.), and plans a feasible route based on the information provided by the surrounding conditions. The path completes the task of reaching the destination. Position-changing robot technology involves sensor technology, navigation technology, computer technology, artificial intelligence and other fields. Therefore, it places high demands on the control part of position-changing robots. In particular, the emergence of visual sensors requires that the control system not only Large storage capacity and fast processing speed. In the past, position-changing robots based on PLC and microcontroller control could not meet the characteristics of real-time and rapidity.
With the emergence and development of ARM processors and the development of embedded systems, the real-time and rapid requirements of position-changing robots can be well satisfied. Now this technology has been effectively used in a variety of fields. This article is based on SAMSUNG’s low-power, high-performance 32-bit processor chip S3C44B0X based on the ARM7TDMI core as the core, and uses the Sunrise 16-bit microcontroller SPCE061A as the auxiliary processor to process the obstacle information detected by the sensor, and uses embedded The advanced real-time multi-task operating system? C/OS-II manages the implementation of the navigation algorithm of the position-changing robot and the execution of multi-tasks. The test results show that the system can achieve obstacle avoidance and navigation functions and successfully reach the destination.
Hardware design of control systemSierra Leoneans Sugardaddy
Control system of position-changing robot It mainly realizes functions such as detection of external obstacles and transmission of information, acquisition of the current position of the robot, path planning, and operation control. Sierra Leoneans Escort divides the system into functional modules. The system can be divided into the following five major modules: surrounding environment detection module; global positioning Modules; program download module, motor drive module and power management module. The relationship between each module is shown in Figure 1. Sierra Leone Sugar
2.1 Surrounding situation detection module
Changing position machineryDuring the process of obstacle avoidance and path planning, the robot must detect information about surrounding obstacles in real time and measure the distance of obstacles. Today Sierra Leoneans Sugardaddy there are infrared, ultrasonic, laser and visual (CDD) sensors. Laser sensors are greatly affected by the surrounding environment and the price Relatively expensive, the vision sensor (CCSierra Leone Sugar DaddyD) requires a chip with large storage capacity and fast processing speed, which is not easy to use. Based on this, this article installs a set of red sensors and ultrasonic sensors on the back, left, and right sides of the position-changing robot to measure the distance of obstacles in three directions. The use of multiple sensors can avoid the measurement of a single sensor. There are blind spots.
The red sensor is composed of a transmitter and a receiver. The 3-way transmitting port of this sensor is connected to the 3-way I/O port of the Sungyang microcontroller SPCE061A, and the 3-way receiver port is connected to the other 3 channels of the microcontroller. When the I/O input of the microcontroller is at high power, the transmitter port emits infrared light. The light wave hits an obstacle and is reflected by the receiver, resulting in a current with relative light intensity that is converted by A/DSierra Leone SugarTransform Sierra Leoneans Escort out of the microcontroller, calculate the size of the obstacle based on the voltage interval. The working principle of the ultrasonic sensor is basically the same as that of the infrared sensor. When the sound wave encounters an obstacle, it is received by the receiver, and the distance to the obstacle is calculated based on the time difference.
The detection module can measure obstacles within a distance of 0~2m with small measurement error. It uses 16-bit Sungyang microcontroller SPCE061A to quickly process the obstacle information. Once an obstacle is detected, it communicates with S3C44B0X through the bus interface and for data transmission.
2.2 Global Positioning Module
It is very important to determine the current position of the robot, providing essential information for robot path planning. The current positioning sensors include Global Positioning System (GPS), rotary potentiometer, and photoelectric encoder , magnetic compass, electronic compass, accelerometer, etc. In view of the situation around the application, this module uses the photoelectric encoder and electronic compass produced by Changchun First Optics Co., Ltd. to determine the current coordinate point of the robot. Photoelectric encoder is photoelectrically convertedSierraLeone Sugar, converts the angular displacement of the shaft into an electrical pulse electronic signal, 6 is input to the counter T1 of S3C44B0X through the amplification circuit, and the pulse collected at a specific time is stored. The pulse electronic signal is associated with the rotation of the wheel. The number of turns is inversely proportional and can therefore be calculated in setting the actual journey of the robot. The electronic compass uses Honeywell’s Sierra Leoneans Escort low-cost HMR3100 three-dimensional electronic compass, SL Escorts There is an HMC1022 two-axis magnetic sensor inside. The angle measurement accuracy can reach 5 degrees. The electronic compass can determine the absolute direction of the robot relative to the North Pole and accurately measure the robot’s movement. The error between the target Sierra Leoneans Sugardaddy and the actual direction, thereby correcting the robot’s trajectory.
2.3 Program download module and motor drive module
The program download module mainly completes the download of startup programs and application programs. This system provides two download methods, serial port download and parallel port download. The serial port download communicates with the PC through RS2Sierra Leoneans Escort32 serial port cable connection board COM1, and the parallel port download uses the parallel port cable and JTAG debugging The interface connection completes the communication between PC and S3C44B0. Sierra Leone Sugar
The accuracy of the motor drive module is critical to the entire bodySL Escorts system accuracy Sierra Leoneans Escort has a great impact. Considering various reasons, this module chooses a basic Sierra Leoneans Escort Integrated driver ISierra Leoneans EscortR2110. The IR2110 driver chip can convert the output logic electronic signal into a low-impedance input driver electronic signal with the same phase, which can drive 2 inputs on the same bridge arm. It has strong driving capability, fast response speed, high operating voltage, and high cost. System accuracy and reliability. The motor adopts an ordinary high-power DC acceleration motor and uses a high-power H-bridge drive circuit. The circuit principle is shown in Figure 2.
In the circuit, IR2110 is used as a pre-driver, and four IRFP250 constitute an H-bridge drive circuit. When ISL Escorts a PWM electronic signal is applied to the N1 end and low power is applied to the IN2 end, usually Q2 and Q5 are turned on, and Q3 and Q4 are turned off. , drives the motor to rotate forward; when a PWM electronic signal is applied to the IN2 end and low power is applied to the IN1 end, usually Q3 and Q4 are turned on, Q2 and Q5 are turned off, and the drive motor is reversed. Adjusting the PWM pulse width can adjust the motor speed. In order to make the motor run stably, the frequency of the PWM electronic signal is not less than 1KHZ.
System software implementation
The implementation of the software department is based on the real-time multi-task operating system C/OS-II transplanted to S3C44B0X. It is a priority-based, preemptive real-time kernel, with source code openness and portability It has the characteristics of good flexibility, tailorability, and multi-tasking. It can handle 64 tasks and the application can handle 56 tasks. It mainly realizes tasks management, time management, electronic signal volume management, memory management and other functions.
The robot mainly completes obstacle avoidance detection and information transmission, location acquisition, path planning, and operation control functions. Therefore, the system has created a total of 4 tasks, Task 1: Obstacle avoidance detection and information transmission, Task 2: Position acquisition, task 3: path planning, task 4: motor drive control. Tasks are prioritized in descending order, and messages are passed between tasks via the tank. After the position-changing robot completes the initialization system, the drive motor performs tasks 4 according to the route ordered by Sierra Leone Sugar Daddy to the destination. At the same time, the sensor task controlled by the single-chip microcomputer SPCE061A, when the sensor detects an obstacle nearby, task 1 enters the standby state. Because task 1 has a high priority, it seizes the use rights of the CPU to complete the processing and transmission of obstacle information. Through the transmission of electronic signalsSierra Leone Sugar Daddy, task 2 enters the standby state, completing the calculation of the current position, and providing a basis for path planning. Task 3 starts the navigation algorithm to plan the route based on the failure information provided by Task 1 and the information location information provided by Task 2. After the new route plan is completed, Task 4 enters the running state, thereby completing SL EscortsUltimate Rules Obligation.
Test results
The test was conducted indoors, with an area of 12m×12m, and a green blanket-like material was attached to the surface of the venue to prevent slipping. The route Sierra Leoneans Sugardaddy is planned to use a grid-based navigation algorithm? The robot shape size is 0.8m×0.8m×0.6mSierra Leoneans Escort, the grid standard is 0.8m×0.8m according to the robot standard, the number of rows and columns of the grid are both 15, the grid Sierra Leone Sugar DaddyThe total number is 15×15=225 squares. Move obstacles with blocks and other mechanical artifacts. The operation trajectory of the position-changing robot is shown in Figure 3. In the picture, the light gray Sierra Leoneans Escort boxes are obstacles, and the dark gray box road is the robot’s trajectory, starting point and destination point. As marked in Figure 4 below. The test results show that the robot can avoid obstacles and reach the target point. After repeated tests, the position error is between 0 and 0.4m, which is feasible.
The author’s innovation point of this article is to use the high-performance ARM chip S3C44B0X as the main control and the single-chip microcomputer SPCE061A as the auxiliary control Sierra Leone Sugar Daddy Control the robot through a combination of computers and computers, and introduce an embedded real-time operating system? C/OS-II to realize the robot navigation algorithm and perform multiple tasks on the robot SierraLeoneans Sugardaddy carries out reasonable planning and adjustment, as well as ensuring the robot’s rapid response to unknown surrounding conditions and ensuring the accuracy of the entire system. The experiment has proven the feasibility of this method.
The control system has abundant hardware resources, and the processing of information obtained by the sensor also uses high-performance microcontroller SPCESierra Leone Sugar061A , which provides the hardware foundation for the future application of Sierra Leone Sugar vision sensor (CCD). The robot also occupies the hardware of the main controller. Relatively few, providing convenience for future system upgrades. You can also use the more advanced Sierra Leone Sugar navigation algorithm to make it more intelligent.
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