Robotics Laboratory, Universitat de Lleida, Jaume II, 69, 25001 Lleida, Spain.
Sensors (Basel). 2021 Oct 29;21(21):7216. doi: 10.3390/s21217216.
This paper presents the empirical evaluation of the path-tracking accuracy of a three-wheeled omnidirectional mobile robot that is able to move in any direction while simultaneously changing its orientation. The mobile robot assessed in this paper includes a precise onboard LIDAR for obstacle avoidance, self-location and map creation, path-planning and path-tracking. This mobile robot has been used to develop several assistive services, but the accuracy of its path-tracking system has not been specifically evaluated until now. To this end, this paper describes the kinematics and path-planning procedure implemented in the mobile robot and empirically evaluates the accuracy of its path-tracking system that corrects the trajectory. In this paper, the information gathered by the LIDAR is registered to obtain the ground truth trajectory of the mobile robot in order to estimate the path-tracking accuracy of each experiment conducted. Circular and eight-shaped trajectories were assessed with different translational velocities. In general, the accuracy obtained in circular trajectories is within a short range, but the accuracy obtained in eight-shaped trajectories worsens as the velocity increases. In the case of the mobile robot moving at its nominal translational velocity, 0.3 m/s, the root mean square (RMS) displacement error was 0.032 m for the circular trajectory and 0.039 m for the eight-shaped trajectory; the absolute maximum displacement errors were 0.077 m and 0.088 m, with RMS errors in the angular orientation of 6.27° and 7.76°, respectively. Moreover, the external visual perception generated by these error levels is that the trajectory of the mobile robot is smooth, with a constant velocity and without perceiving trajectory corrections.
本文对一款能够在任意方向移动并同时改变其方向的三轮全方位移动机器人的路径跟踪精度进行了实证评估。本文评估的移动机器人配备了精确的机载激光雷达，用于避障、自我定位和地图创建、路径规划和路径跟踪。这款移动机器人已被用于开发多种辅助服务，但直到现在，其路径跟踪系统的准确性还没有得到专门评估。为此，本文描述了移动机器人中实现的运动学和路径规划程序，并实证评估了其轨迹修正的路径跟踪系统的准确性。在本文中，通过注册激光雷达收集的信息，获取移动机器人的真实轨迹，以估计每个实验的路径跟踪精度。本文评估了不同平移速度下的圆形和 8 字形轨迹。总体而言，圆形轨迹的精度在短距离内，但随着速度的增加，8 字形轨迹的精度会变差。对于以标称平移速度 0.3m/s 移动的机器人，圆形轨迹的均方根（RMS）位移误差为 0.032m，8 字形轨迹的误差为 0.039m；最大绝对位移误差分别为 0.077m 和 0.088m，角向位置的 RMS 误差分别为 6.27°和 7.76°。此外，这些误差水平所产生的外部视觉感知是，移动机器人的轨迹是平滑的，具有恒定的速度，并且不会察觉到轨迹修正。
