1. Introduction Wheeled mobile robots are an important part of robotics research. They integrate mechanics, electronics, detection technology, and intelligent control, forming a typical intelligent control system. Intelligent robot competitions, combining high technology, entertainment, and competition, have become a widely conducted high-tech competitive activity internationally. This paper designs an intelligent robot control system using an ARM7 processor as the control core, employing wireless communication technology, and porting the embedded real-time operating system μC/OS-II. 2. Hardware Design Based on the functional requirements of the competitive robot, the overall design is modularized, and the hardware block diagram of the control system is shown in Figure 1. The central processing unit adopts a microcontroller structure to control the coordinated operation of peripheral devices. Servo motors control the robot's movement direction; the drive motors use small DC motors with photoelectric encoders on the output shaft to drive the wheel rotation. Electromagnets serve as the actuators for the manipulator's gripping. Two ultrasonic sensors, eight photoelectric detection inputs, and eight switch quantity detection interfaces are set up. The entire robot's operating status and parameters are dynamically displayed on an LCD. 2.1 Microcontroller Selection Robots require numerous actions and functions, necessitating multiple sensors to detect external stimuli and control the robot's position, movements, and operational status in real time. All tasks within the system ultimately run on the real-time operating system μC/OS-II. Therefore, it's crucial to consider not only the microcontroller's internal resources but also its portability and scalability. The LPC2129, a 32-bit ARM7TDMI-S microprocessor manufactured by Philips, features 256 KB of high-speed Flash memory. It employs a three-stage pipeline technology, simultaneously fetching, decoding, and executing instructions, and can process instructions in parallel, enhancing CPU speed. Its small size, extremely low power consumption, and strong anti-interference capabilities make it suitable for various industrial control applications. With two 32-bit timer/counters, six PWM outputs, and 47 general-purpose I/O ports, it is particularly well-suited for industrial control and small intelligent robot systems with low environmental requirements. Therefore, selecting the LPC2129 as the main controller results in a simple and stable intelligent robot control system. 2.2 Wireless Communication Interface Design The system adopts the PTR2000 wireless communication data transceiver module produced by Xuntong Company. The circuit interface is shown in Figure 2. This module is based on the nRF401 radio frequency device produced by NORDIC Company. Its features are: ① Two channels are available, with a working rate of up to 20 Kb/s; ② It combines receiving and transmitting, suitable for full-duplex and simplex communication, thus providing flexible communication methods; ③ It has a small size, requires few external components, and has a simple interface circuit, making it particularly suitable for the miniaturization requirements of robots; ④ It can be directly connected to a microcontroller serial port module, simplifying control; ⑤ It has strong anti-interference capabilities; ⑥ It has low power consumption and stable communication. 2.3 Photoelectric Detection Module Design 2.3.1 Photoelectric Detection Process Design The photoelectric detection module enables the robot to detect the white guide line on the ground. The photoelectric detection circuit mainly includes a transmitting part and a receiving part, the principle of which is shown in Figure 3. The waveform modulation of the transmitting part adopts the frequency modulation method. Since the response speed of the light-emitting diode is fast, its working frequency can reach several megahertz or tens of megahertz, while the modulation frequency of the detection system is in the range of tens to hundreds of kilohertz, thus meeting the requirements. The light source driver is mainly responsible for amplifying the modulated waveform to sufficient power to drive the light source to emit light. The light source uses an infrared LED with a high operating frequency, suitable for emitting modulated light with a square wave waveform. The receiving section uses a photodiode to receive the modulated light and convert the optical signal into an electrical signal. This electrical signal is usually weak and needs to be filtered and amplified before processing. The modulation signal amplification uses AC amplification, which can separate the modulated light signal from the background light signal, facilitating signal processing. The modulation signal processing section identifies the amplified signal and determines the characteristics of the object being detected. Therefore, the essence of this module is to separate the "AC," useful modulated light signal from the "DC," useless background light signal, thereby achieving anti-interference. 2.3.2 Photoelectric Probe A photoelectric probe is installed at the front of the robot chassis, with a total of 5 detection points, as shown in Figure 4. Theoretically, the more and denser the detection points, the higher the accuracy and reliability of the identification. However, the hardware overhead and software complexity also increase accordingly. This line-following system ensures the accuracy of the detection and saves on hardware costs. The modulated light emitted by the LED is reflected by the ground to the photodiode. The photocurrent generated by the photodiode changes linearly with the intensity of the reflected light. Detecting this change allows us to determine whether a detection point is above the white guide line, thus determining the relative position of the robot and the white guide line. 2.4 Design and Implementation of Ultrasonic Ranging Sensor Two ultrasonic sensors are used to control the robot to avoid obstacles and predict the robot's distance to the destination, serving a navigation function. Their receiving part is connected to the capture and timing pins of the microcontroller. The entire ultrasonic detection system consists of ultrasonic transmission, ultrasonic reception, and microcontroller control. The transmission part consists of a high-frequency oscillator, a power amplifier, and an ultrasonic transducer. After amplification by the power amplifier, ultrasonic waves are emitted through the ultrasonic transducer. Figure 5 shows the ultrasonic oscillation circuit composed of digital integrated circuits. The high-frequency voltage signal generated by the oscillator is filtered by capacitor C2 to remove the DC signal and then fed to the ultrasonic transducer MA40S2S. Its working process: U1A and U1B generate a high-frequency voltage signal corresponding to the ultrasonic frequency. This signal is converted into a standard square wave signal by inverter U1C, then amplified by power amplifier, and after DC signal removal by C2, it is applied to the ultrasonic transducer MA40S2S for ultrasonic transmission. If a DC voltage is applied to the ultrasonic transducer for a long time, its characteristics will deteriorate significantly. Therefore, the AC voltage is generally filtered to remove DC. U2A is a 74ALS00 NAND gate, and the control_port pin is the control port. When control_port is high, the ultrasonic transducer transmits an ultrasonic signal. Figure 6 shows the ultrasonic receiving circuit. The ultrasonic receiving transducer uses MA40S2R. The signal received by the transducer is amplified by integrated operational amplifier LM324. After three stages of amplification, the sine wave signal is converted into a TTL pulse signal by voltage comparator LM339. INT_Port is connected to the microcontroller's interrupt pin. When an interrupt signal is received, the microcontroller immediately enters the interrupt and processes and judges the ultrasonic signal. 3. Porting the Real-Time Operating System μC/OS-II μC/OS-II is an embedded real-time operating system kernel that includes basic functions such as task scheduling, task management, time management, memory management, and inter-task communication and synchronization. When μC/OS-II performs task scheduling, it stores the CPU registers of the current task into the task stack, and then restores the original working registers from another task stack to continue running another task. Based on various control functions and the microcontroller's resource structure, tasks are divided into 7 application tasks, as shown in Figure 7. Wireless serial communication uses interrupt reception to ensure real-time data reception. The establishment of a μC/OS-II task includes four parts: defining the task stack, setting task priority, initializing the system hardware required by the task, and implementing the specific control process. Taking Task 1 as an example, the process of establishing an application task is introduced. Developing real-time applications in an embedded real-time operating system environment makes program design and expansion easier, and new functions can be added without major modifications. By dividing the application into several independent task modules, the application design process can be greatly simplified; and it can quickly and reliably handle events with stringent real-time requirements. Effective system services and an embedded real-time operating system enable better utilization of system resources. 4. Debugging and Operation When the robot control system starts, μC/OS-II initializes the stack space, various control registers, and peripheral devices, and sets the initial state of each functional component. In the real-time robot system, after the robot starts normally, the system monitors the robot's operation on the competition field in real time. If an action or function fails, an error message is given. During normal operation, the robot's coordinates and action status on the competition field are displayed in real time, as shown in Figure 8. 5. Conclusion Based on the control requirements of intelligent robots, an embedded robot control system based on wireless communication was designed. The embedded real-time operating system μC/OS-II was ported to the software design. External information was perceived using a photoelectric detection module and an ultrasonic navigation module, realizing the control of the intelligent robot.