Spline Trajectory for Three Wheel Mobile Robot Swerve Drive

摘要

Wheeled mobile robot platform has been widely used in various field. Some mobile platforms support holonomic motion and others only support non-holonomic motion. A mobile platform that supports holonomic motion became more popular recently since it provides more flexibility in omnidirectional motion. Currently, Omni-wheels and mecanum-wheels based mobile robot platforms are the most common holonomic platforms in the market. They are simpler and cheaper to be implemented. But in applications, it needs more traction and higher efficiency, the swerve drive mobile robot platform will become a more viable solution. It has more smooth movement compared to other holonomic mobile robots because this type of mobile robot can rotate the wheel angle independently, so it has very little wheel slip against the floor. However, when the swerve drive mobile robot is run on an angled trajectory at high speed, it will experience steering delay so that the robot will come out of the predetermined track. Therefore, it is necessary to modify the angled trajectory into a curved line trajectory using the Spline method. On the Spline trajectory, swerve drive can run with higher speed and higher accuracy than the angled trajectory. On the bézier spline swerve drive can run with a velocity of up to 3.25 m/s with an average position error decrease of 36 mm on the bézier spline with $\omega=1$, 72 mm on the bézier spline with various $\omega$ values. While on cubic spline it can run with a velocity up to 2.44 m/s with an average position error decrease of 69.25 mm.