Adaptive tracking control for WMRs with skidding and slipping: a double closed-loop strategy

Adaptive ground and water surface control for cross-domain robots based on adaptive finite-time convergence sliding mode observer

“…7−Fig. 9, the controller proposed in this paper converges faster and with less oscillation relative to the algorithm proposed in the literature [20]. The controller is selected with smaller parameters for better control As shown as the green line in Fig.…”

“…The controller is selected with smaller parameters for better control As shown as the green line in Fig. 10, the desired linear velocity when subjected to lateral velocity is about 0.98m/s by the traditional backstepping control and about 0.865m/s by the other three controllers, and the maximum oscillation amplitude of the controller proposed in the literature [20] is about 0.3m/s greater than 0.15m/s for the proposed controller, as shown in the red line and the purple line. The maximum oscillation amplitude of 0.6rad/s for the controller proposed in literature [20] is greater than 0.4rad/s for the proposed control, as shown as the red and purple lines in Fig.…”

“…It should be noted that in the literature [20], the adaptive controllers are designed based on the assumption tan β= tan(α+e 3 ) ≈ tan(α) + tan(e 3 ). This assumption is satisfied only in special cases.…”

“…In the literature [19], a sliding mode observer is designed to estimate the sideslipping coefficient. In the literature [20], the adaptive rate is designed to estimate the side-slipping coefficient based on the Lyapunov function. In fact, the robot is more susceptible to side-slipping by the currents and crosswinds when moving on the water surface.…”

“…Through the discussion of the above literatures, the main contributions of this paper are as follows: 1. Inspired by the literatures [20] and [25], the lateral velocity due to side-slipping, crosswinds, and currents are converted into sideslip rate in the body frame of the robot. Based on the backstepping control theory, a new adaptive position and heading angle controller is proposed to re-plan the linear velocity and angular velocity.…”