Abstract: High slip rate will reduce the efficiency of tractor operation. Therefore, it was of great significance to accurately monitor the slip rate. Aiming at the problem that the method of measuring the slip rate at the minimum wheel speed was fails under steering conditions, a sliding rate measurement method based on the Ackerman steering principle was proposed. By establishing the slip rate measurement model during steering, the relationship between slip rate and the theoretical vehicle speed, the vehicle speed and steering angle of the right front wheel was obtained. Based on the John Deere 4720 tractor, the slip rate measurement system was designed, including the speed measurement device of the right front wheel, the CAN bus analysis module and the slip rate calculation module. The slip rate measurement test was carried out in the straight driving condition of the cement pavement, and the average slip rate in the straight driving condition was 3.0%. The slip rate was measured under the steering condition of cement pavement, and the target theoretical velocities were 05, 0.8, 1.0, 1.2 and 1.5 m/s respectively. The test results showed that the average sliding rate in steering condition was 39%, 3.4%, 3.7%, 3.8%, 2.9%, respectively. The slip rate of the steering condition was in the slip rate range of the straight running condition. Therefore, it was considered that this method was feasible and provided support for the measurement of the slip rate of agricultural machinery in field steering conditions.

Key words: tractor, slip rate, Ackerman steering, minimum wheel speed method

摘要： 拖拉机作业时滑转率过高会降低作业效率，准确监滑转率具有重要意义。针对基于最小轮速的滑转率测量方法在转向工况下失效的问题，提出一种基于阿克曼转向原理的滑转率测量方法。通过建立转向时的滑转率测量模型，得到滑转率与理论车速、右前轮车速、右前轮转向角的关系。基于约翰迪尔4720型拖拉机设计滑转率测量系统，包括右前轮轮速测量装置，CAN总线解析模块和滑转率计算模块。水泥路面直行工况下滑转率测量试验结果表明，直行工况滑转率的平均值为3.0%。在水泥路面转向工况下，进行目标理论速度分别为0.5、0.8、1.0、1.2、1.5 m/s的滑转率测量试验。试验结果表明：转向工况滑转率的平均值分别为3.9%、3.4%、3.7%、3.8%、2.9%，处于直行工况的滑转率区间；因此认为此方法可行，为农机田间转向工况滑转率测量提供支撑。

关键词: 拖拉机, 滑转率, 阿克曼转向, 最小轮速法