introduction Medically, for lumbar disc herniation, such as lumbar disc herniation, a conservative treatment of physical traction is usually adopted. The traction bed system is a two-stage bed body as a treatment platform, which adopts an embedded processor such as ARM and combines with a computer to realize distributed control of the bed body by degree movement, and implements external force fast and slow traction and bed by DC motor. Rapid and slow rotation of the body at any angle to achieve physical therapy of lumbar spine disease. 1 system function and overall design The traction bed is a two-stage bed for the treatment platform. The bed is divided into two parts, the front and the back, for the patient to lie down. In the front section, a fixed strap is used to fix the upper part of the patient's waist, and the traction belt is used to connect with the movable bed head. The traction motion is the translation of the front and rear direction. The bed head can be pulled forward by a certain distance while the motor is driven, and the patient's waist is fixed, so that the traction belt has a certain force on the lumbar vertebrae. An "S" type tension sensor is installed on the bed to detect the traction. The posterior segment also has a fixed strap to fix the patient's lower back to the tibia, and can be horizontally oscillated, vertically tilted, and rotated to the left and right sides with the waist as the axis at the waist. A total of three degrees of freedom of rotation. The traction speed of the front bed can be adjusted, and the rotation angle and rotation speed of the rear bed can also be arbitrarily set. The traction bed provides the physician with four degrees of freedom to adjust the physical movement, fully meeting the needs of physical therapy for lumbar spondylosis. In the actual treatment, according to the patient's pathological condition, the doctor can play the role of “positive ridge†by rationally using the left and right rotation of the back bed surface combined with the quick-holding function on the slow-drawing basis. The overall design of the traction bed takes a distributed control system, as shown in Figure 1. The computer as the upper computer realizes the control of the bed movement through the RS-485 bus and three embedded controllers (lower machines) to form a distributed bus network. The computer implements the overall operational control interface of the system. The complex control tasks of the system are decomposed into three parts, which are executed in parallel by three embedded controllers in real time. Among them, the detection and control of traction motion and traction force is completed by a STC89C52RD+ single-chip microcomputer; the angle detection and control of three rotary motions are processed by Samsong's 32-bit ARM core RISC processor S3C44B0X; the switch of various limit switches on the bed body The detection and output are implemented by another STC89C52RD+. Figure 1 System overall design block diagram 2 system hardware design 2.1 Traction control based on STC89C52RD+ The fast and slow traction treatment is to drive the bed forward by a DC motor to stretch the fixed strap fixed between the patient's waist, and generate a certain traction force to apply to the lumbar vertebrae. The amount and speed of traction are set by the doctor and kept for a while. During the maintenance period, physical therapy can be performed in conjunction with the rotation of the bed. Traction can be converted to an analog signal by the S-type strain gauge tension sensor at the head. The magnitude of this signal is related to the magnitude of the excitation DC voltage applied to the sensor. The sensor sensitivity is 2mV/V. If the DC excitation voltage is 5V, the sensor output maximum signal is 10mV. If the force sensor has a range of 0-200Kg, the corresponding sensor output analog signal is 0-10mV. The signal is amplified by 500 times and then 0-5V by the AD623 of the instrumentation amplifier. It is filtered by the “Л†type inductor and capacitor passive network and input to the 10-bit A/D converter TLC1549. The traction signal frequency is very low and the processor samples 20 times per second. A dedicated STC89C52RD+ on-chip hardware timer is used to enter the timer interrupt service routine every 50ms to perform A/D conversion through the SPI serial interface, and the converted data is converted by the UART to the 485 signal via the interface chip 74LBC176. To the host computer. After being judged by the host computer, a control command is issued to control the traction motor and the traction process. STC89C52RD+ is an enhanced 51 single-chip microcomputer produced by STC, which has high reliability and strong anti-interference. When the product registration is tested for electromagnetic compatibility of the controller, it is found that the STC89C52RD+ can be easily passed by using the power pulse interference test and the high voltage discharge interference test project that the AT89C52 cannot pass. The reliability of STC microcontrollers is evident. 2.2 Switching quantity detection and control based on STC89C52RD+ The bed body adopts the travel switch to limit the movement strokes, to avoid the system from being out of control and causing excessive traction and pulling the patient, or the rotation and swing angle are too large to cause the patient to pull out of the bed. When there is a situation where the stroke limit switch is touched, the relay control circuit will directly cut off the motor power to stop the motor. The controller STC89C52RD+ detects these signals in real time and quickly transmits this information to the host computer via the 485 serial bus. The system software will stop the process and reset the system. The MCU latches the 23 output switching states of the system into three 74HC377s to ensure reliable output. Each output is isolated by a photocoupler and amplified by ULN2803, and the relay is driven to control the start and stop and combined action of each motor. Set the “Retire†button to press the patient when you feel uncomfortable. The system will quickly release the traction and flatten the bed. When the patient presses the "quick" button, the MCU transmits the message to the host computer via the 485 bus. After the system software receives it, it immediately stops the current traction process and issues a command. The microcontroller then controls the traction motor to reverse the traction. If the bed is in a rotationally tilted state, control the bed to be flattened. These measures greatly improve the safety and reliability of the traction therapy system and must be considered for a medical device. Choose a STC89C52RD+ as a dedicated switching detection and control processor. This makes this part of the control program more concise, pure and easy to implement, ensuring reliable and error-free operation of the system. If this part of the task is merged into other controllers, the programming difficulty of the software will increase, and the process will be more complicated, which will inevitably reduce the reliability and security of the system operation. We are a supplier of high-speed rapier looms and flexible rapier looms. The company specializes in selling second-hand rapier looms and economical rapier looms. Chinese second-hand rapier looms look for Tianchi. Second-Hand Rapier Loom,High-Speed Rapier Loom,Flexible Rapier Loom,Economical Rapier Loom Changzhou Satidi Import and Export Co., Ltd. , https://www.guanjiejt.com