Certain wheeled mobile robots e.g., electric wheelchairs, can operate through indirect joystick controls from users. Correct steering angle becomes essential when the user should determine the vehicle direction and velocity, in particular for differential wheeled vehicles since the vehicle velocity and direction are controlled with only two actuating wheels. This problem gets more challenging when complex curves should be realized by the user. A novel assistive controller with safety constraints is needed to address these problems. Also, the classic control methods mostly require the desired states beforehand which completely contradicts human's spontaneous decisions on the desired location to go. In this work, we develop a novel assistive control strategy based on differential geometry relying on only joystick inputs and vehicle states where the controller does not require any desired states. We begin with explaining the vehicle kinematics and our designed Darboux frame kinematics on a contact point of a virtual wheel and plane. Next, the geometric controller using the Darboux frame kinematics is designed for having smooth trajectories under certain safety constraints. We experiment our approach with different participants and evaluate its performance in various routes.
翻译:某些轮式移动机器人,例如电轮椅,可以通过用户的间接旋杆控制操作。当用户应该确定车辆的方向和速度时,正确的方向变得至关重要,特别是对于不同的轮式车辆,因为车辆的速度和方向只用两个驱动轮来控制。当用户实现复杂的曲线时,这一问题就更加棘手。需要有一个具有安全限制的新式辅助控制器来解决这些问题。此外,典型的控制方法大多需要事先想要的状态,这与人类对所要到的地点的自发决定完全相矛盾。在这项工作中,我们开发了一种新型的辅助控制战略,其基础是不同的几何测量方法,仅依靠旋杆输入和车辆状态,而控制器并不需要任何预期状态。我们首先在虚拟轮子和飞机的接触点解释车辆的运动学和我们设计的Darboux框架运动学。接下来,使用Darbuux框架的几何体动力学控制器的设计是为了在一定的安全限制下平滑轨。我们与不同的参与者进行了实验,并评估其在各种路径上的性能。