Static Walking And Stability Of A Quadruped Weeding Robot

Weeding robot can replace human to control weed effectively, reduce the labor intensity, reduce costs and protect the environment. At present, weeding robot mostly are wheeled or tracked at home and abroad, they have a poor adaptability in complex, irregular farmland arable environment. Aiming at this problem, we put forward the legged walking style, but also static gait is the best one in robot walking gaits. So in this study, weeding robot adopts quadruped static waliking gait in order to obtain better stability. To solve these problems, this paper discusses the static walking and stability problem of quadruped weeding robot in irregular farmland surface, the following several aspects being studied.1. By analyzing the structure and motion mechanism of the quadruped weeding robot, the geometry structure model is established.2. Some basic concepts of static walking such as gait, duty factor, static gait are sketched, several common tetrapod movement gait is introduced, and the timing of various gaits are also analyzed.3. Because of the farmland environment complexity which weeding robot walking on, consecutive slopes are simplified by the limit segmentation method, three coordinate systems which weeding robot walking on the slope have been established, and the feet reachable range, standard position are considered. The common foot position on a slope be recalculated, then the static walking have been studied: selecting a gait based on two static walking patterns, gait transition methods, the swing leg landing location and supporting leg lift position, etc.4. According to the case of robot under interference when the robot walking or working, a triangular pyramid method was proposed, the stability judging criterion of weeding robot - minimum stable angle was deduced, and determined the 13 times fit function error is minimum through comparing minimum error sum of squares of several kinds fitted curve. But also, tilting performance coefficient was used to evaluate the robot’s static and dynamic stability synthetically. By numerical simulation, the effects of ground tilt angle, external load and external torque of irregular farmland surface on the robot’s stability were discussed.5. The quadruped robot experiment platform was constructed and it was used to verified the proposed gait transition method, stability judging method. The experiment platform mainly include control module, power module, drive module and communication module, PC software part. Describing the selection of these modules device, installing and debugging the pc software, it can complete programming, save, download and other functions.This paper completed weeding robot gait planning and transition, realized the robot static walking through to computed some parameters such as reachable range, common foot position when weeding robot walking on irregular land surface; by comparison platform experiment with numerical simulation results, we found that the average relative error is small, the effectiveness of proposed triangular pyramid method which is used to judge the stability is verified; tilting performance coefficient was introduced to evaluate and analyse stability comprehensive, the results show that external force and ground tilt angle influence on the weeding robot stability bigger, the relationship between ground tilt angle and stability is close to linear monotonous.