# A Construction Method of Lower Limb Rehabilitation Robot with Remote Control System
## 2 Materials and Methods
### Telerehabilitation Interactive System
#### 2.2.2 Hardware of Robot Control System  
The main control module of the rehabilitation robot is located in the top box of the structure. The control module is composed of a core control board, a power acquisition unit, a sensor transmitter unit, and a power distribution unit. Other components are a power switch, an emergency stop button, two limit switches, a 24 V lithium battery, two hub motor drivers, and two BWS motor drivers. The control system of the rehabilitation robot is shown in Figure 5. The system is divided into four sub-modules: force and position information  
Figure 4: The framework of telecrabilitation robot interaction system. sampling module, body panel human-computer interaction input module, data output module, and a communication module with the rehabilitation robot client. Doctors can formulate the rehabilitation programs based on the clinical conditions of the patients' lower limbs and set the rehabilitation parameters of the robot through the operating handle of the robot. The rehabilitation parameters include the BWS value, rehabilitation training time, robot movement speed, etc. Using the operating handle reduces the difficulty of robot operation and simplifies the operation of the rehabilitation robot. The specific value of BWS is fed back by the force sensor on the digital display of the operating handle. The doctor can recognize the change in the BWS value in real-time and make appropriate adjustments according to the patient's lower limb strength. During the patient's exercise rehabilitation process, the robot's force and displacement sensors also collect the patient's lower limb strength change data and body motion state data. The data is transmitted to the control core for processing and displayed on the host computer system interface. Doctors can then analyze the patient's rehabilitation data through the host computer system. Based on this data, the doctor can evaluate the patient's rehabilitation effect and formulate a new round of rehabilitation plans for the patient. The robot control system is composed of three sub-systems: a BWS system, a sensor information feedback system, and a human-machine interaction drive system. The rehabilitation robot control system uses an MCU with Cortex-M7 as the core, with the main frequency of 400 MHz. The hardware framework of the robot system is shown in Figure 6. In the BWS system, the operating handle uses RS-422 to establish two-way data communication with the MCU of the robot control core. The operating handle can be further used to set the BWS value. In the sensing information feedback system, the real-time value of the force sensor in the BWS system is sent to the MCU for processing through the \(A/D\) module and displayed on the operating handle screen through serial communication. The doctor is aware of the specific values of the current adjustment parameters and can make appropriate fine adjustments to the parameters according to the patient's comfort requirements. The control core MCU also receives instructions from the operating handle and transmits the corresponding commands to the BWS system drivers 1 and 2 through the CAN1 bus. The two motors support the patient's weight and adjust the patient's body balance according to instructions. The patient training data collected by the force sensor needs to be sent to the MCU through the A/D module. If the force feedback data is close to the set value and fluctuates in a small range around the set value, it indicates that the patient's lower limb strength is recovering well. If the force feedback data is far from the set value and is in a large fluctuation range, then it indicates that the patient's lower limb strength is insufficient and still depends on the BWS system to maintain the balance of the body. In the human-machine interactive system, the robot's motion modes are divided into manual mode and automatic mode.