针对除草用四足机器人在不规则农田地面行走稳定性难以评定的问题,在力–角稳定性度量法的基础上,提出了三棱锥法,根据对其角点倾翻角和轴线倾翻角的推导,得到用最小稳定角作稳定性的评判标准。引入倾翻性能系数综合评价四足机器人的静态和动态稳定性,并通过数值模拟,讨论在不规则农田里的地面倾角、外载荷及外力矩对机器人稳定性的影响。使用由舵机驱动的8自由度,尺寸为170 mm×130 mm×140 mm的机器人物理样机在0°~45°的不规则玉米地上进行试验,测量最小稳定角。结果表明:合外力与地面倾角对机器人稳定性影响显著,地面倾角对其影响接近线性单调,试验所测最小稳定角度值与预测结果相比,平均相对误差为9.46%,相关系数为0.979 6。
Aimed at the problem of difficult to assess the stability of quadruped robot for weeding walking on irregular farmland surface, a triangular pyramid method was proposed based on the force-angle stability measurement. According to the relationship of angle point tip-over angle and axis line tip-over angle, the stability judging criterion of minimum stability angle was obtained. Tilting performance coefficient was used to evaluate the robot's static and dynamic stability synthetically. The effects of ground tilt angle, external load and external torque of irregular farmland surface on the robot's stability were discussed by numerical simulation. The prototype robot with size of 170 mm×130 mm×140 mm was used to test the minimum stability on 0°–45° irregular corn land, which was driven by servo and had 8 freedom degree The results showed that external load, ground tilt angle have a significantly influence on the stability, and the ground tilt angle was linearly dependent on the stability. Compared to the results of numerical simulation, the average relative error of minimum stability angle was 9.46% and correlation coefficient of 0.979 6.