Lin Yunhan, Ji Wenlong, He Haowei, Chen Yaojie
College of Computer Science and Technology, Wuhan University of Science and Technology, Wuhan 430000, China.
Hubei Province Key Laboratory of Intelligent Information Processing and Real-time Industrial System, Wuhan 430000, China.
Sensors (Basel). 2021 Apr 12;21(8):2704. doi: 10.3390/s21082704.
In this paper, an intelligent water shooting robot system for situations of carrier shake and target movement is designed, which uses a 2 DOF (degree of freedom) robot as an actuator, a photoelectric camera to detect and track the desired target, and a gyroscope to keep the robot's body stable when it is mounted on the motion carriers. Particularly, for the accurate shooting of the designed system, an online tuning model of the water jet landing point based on the back-propagation algorithm was proposed. The model has two stages. In the first stage, the polyfit function of Matlab is used to fit a model that satisfies the law of jet motion in ideal conditions without interference. In the second stage, the model uses the back-propagation algorithm to update the parameters online according to the visual feedback of the landing point position. The model established by this method can dynamically eliminate the interference of external factors and realize precise on-target shooting. The simulation results show that the model can dynamically adjust the parameters according to the state relationship between the landing point and the desired target, which keeps the predicted pitch angle error within 0.1°. In the test on the actual platform, when the landing point is 0.5 m away from the position of the desired target, the model only needs 0.3 s to adjust the water jet to hit the target. Compared to the state-of-the-art method, GA-BP (genetic algorithm-back-propagation), the proposed method's predicted pitch angle error is within 0.1 degree with 1/4 model parameters, while costing 1/7 forward propagation time and 1/200 back-propagation calculation time.
本文设计了一种用于载体晃动和目标移动情况下的智能喷水射击机器人系统，该系统采用二自由度机器人作为执行器，利用光电摄像机检测和跟踪目标，并使用陀螺仪在机器人安装在运动载体上时保持其机身稳定。特别地，为了实现所设计系统的精确射击，提出了一种基于反向传播算法的水射流落点在线调整模型。该模型有两个阶段。在第一阶段，使用Matlab的polyfit函数拟合一个在无干扰理想条件下满足射流运动规律的模型。在第二阶段，该模型根据落点位置的视觉反馈，利用反向传播算法在线更新参数。通过这种方法建立的模型能够动态消除外部因素的干扰，实现精确命中目标射击。仿真结果表明，该模型能够根据落点与目标之间的状态关系动态调整参数，使预测俯仰角误差保持在0.1°以内。在实际平台测试中，当落点距离目标位置0.5 m时，该模型仅需0.3 s就能调整水射流命中目标。与最先进的遗传算法-反向传播（GA-BP）方法相比，所提方法在模型参数减少至1/4的情况下，预测俯仰角误差仍在0.1度以内，同时前向传播时间减少至1/7，反向传播计算时间减少至1/200。
