Task-priority redundancy resolution on acceleration level for underwater vehicle-manipulator system

Abstract

A task-priority redundancy resolution with restoring moments optimized on acceleration level for the underwater vehicle-manipulator system is investigated in this article. Redundant resolution is a key and difficult problem in underwater vehicle-manipulator system's trajectory planning. Firstly, kinematic modeling and dynamic modeling based on Lagrange method are studied. To overcome acceleration's sudden change in traditional task-priority method, a new redundancy resolution method on the acceleration level is proposed. In this approach, a scalar potential function is established and used for reducing the effect of restoring moments by applying gradient projection. Finally, simulation is performed to verify the effectiveness of the proposed approach by comparing with traditional approaches.

Uncalibrated Visual Servoing for Underwater Vehicle Manipulator Systems with an Eye in Hand Configuration Camera

“…Although some previous works utilize the GPM to optimize restoring moments for UVMSs [32][33][34], there are two main differences. One is the Jacobian matrix in [32][33][34] is used to describe the velocity relationship between the configuration space and the Cartesian space (i.e., the Jacobian matrix in (27)), rather than the Jacobian matrix described in (26). The other one is previous works [32][33][34] all depend on the accurate Jacobian matrix, rather than the estimated Jacobian matrix.…”

“…To calculate the reference velocity term in (34) and guarantee the stability of the system, it is necessary to estimate the unknown parameters of the systems (i.e., the constant vectors in (8), (18) and (21)). The adaptive update laws are designed as:…”

“…λ zin , λ zd and λ z are the positive gain matrices, respectively. The novel reference velocity term (34), update laws (39)-(41) and stability analysis in the end of this section is one of the main contributions of this work.…”

“…In vehicle-joint space, the reference velocity term . ζ r is provided by (34), (39)-(41) through estimating J Ω and z.τ d is the estimation term from the disturbance observer in (48).σ is the estimated value of the constant bound σ, and it is updated as the following adaptive law:…”

“…Figure 9 illustrates the two-norm of restoring moments based on (33) and (34), respectively. RMS values of tracking errors based on (33) and (34) can be found in Table 3.…”