Exploitation of orchard fruit picking locomotive has broad prospects and brings huge economic interests. Meanwhile, China has more complex terrains for orchard distribution, such as plain, hill and terraced hillside, which bring a big security risk for safe and stable driving of orchard locomotive. In order to monitor and prevent tipping, obstacle distance system is particularly important for orchard locomotives in its walking and picking process in the orchard. At present, most pre-alarm system researches are about anti-collision for heavy-duty vehicles or locomotives. There is no system on small vehicles in the orchard, which is working on complex terrain and whose quality is unevenly distributed in the process of moving. This article studies this anti-collision and anti-tipping pre-alarm system of orchard locomotive for further research and improvement. While orchard picker is operating in the orchard, collision and tipping happens easily due to the obstacles and rugged land, which brings danger to the orchard locomotive. In order to give accurate early warning about collision and tipping and ensure to operate orchard picker stably and reliably, this article presents the pre-warning system of anti-rollover collision based on ZigBee wireless transmission. The designed ZigBee wireless network is based on CC2530. The end device collects data from ultrasonic sensor module and spoke type pressure sensors. The design uses a pressure sensor to measure positive pressure between the body and the ground to give rollover warning by comparing with rollover threshold, and uses lateral load transfer ratio (LTR) as an indicator to determine the stability of locomotive tipping. Through the network, the sensor data is sent to the coordinator and then transferred to the computer via RS232 serial port. Alarm is working after the comparison between obtained data and the threshold value. Wireless data transmission test shows that the pre-alarm device realizes the alarm when LTR is 0.9, which prevents tipping effectively;the ultrasonic sensor can detect the obstacles within 2 m, and the error between the measured and real values is not more than 0.01 m, which meets the requirement of anti-collision;the detection data of the pressure sensor conforms to the linear formula 0.3%F·S, which meets the requirement of detection precision of orchard picker wheel pressure. The system uses ZigBee with high reliability, security and low cost, in which wireless transmission mode signals and control signals are detected by the mutual transfer between the sensor and microcontroller to solve the problems such as difficulty and poor scalability of orchard locomotive system wiring, so as to meet the sensor data transmission requirement. The locomotive is a kind of small orchard machinery and the online system is easily installed and with low cost. For the safety in operation of the orchard picker, pre-alarm system for anti-collision and anti-tipping has a significant meaning.%为了准确对果园机车碰撞倾翻进行预警，确保果园机车的安全行驶，该文设计了一套基于ZigBee无线传输方式的防撞防倾翻预报警系统。该系统以CC2530单片机为核心搭建ZigBee网络，终端节点连接超声波传感器模块和轮辐式压力传感器，通过网络将数据发给协调器，协调器通过RS232串口将数据传送至电脑，得到的数据与临界值进行比较后判断是否报警。无线数据传输准确性试验表明，当横向载荷转移率（lateral load transfer ratio, LTR）达到0.9时，报警装置实现报警，有效防止机车倾翻；超声波传感器能检测到2 m以内的障碍物，且测量值与真实值之间的误差不大于0.01 m，满足对避障的要求；压力传感器检测数据为0.03%F·S，符合压力传感器精度范围（±0.05%F·S），精度满足对果园机车车轮压力检测的要求。果园机车防撞防倾翻预警系统的实现，对于果园安全生产有着重大的意义。
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