Different-level algorithms for control of robotic systems.

• The different-level nonlinear system is first investigated. • The zeroing equivalency between different levels is proposed. • The new algorithm is proposed based on the equivalency and a discretization formula. • The problem is solved in a discrete-time manner with the future-instant solution predicted. • The problem of robotic system control with the end-effector orientation and fault tolerance considered simultaneously is solved. In this paper, we consider a special kind of time-dependent nonlinear system that includes different-level subsystems (i.e., a subsystem with respect to time-dependent solution and a subsystem with respect to its time derivative). To solve this kind of time-dependent nonlinear system, an equivalency between different-level subsystems is proposed and termed as zeroing equivalency based on the zeroing neural network method. This kind of time-dependent nonlinear system can be solved in a discrete-time manner with future-instant solution predicted at current instant based on the zeroing equivalency and a discretization formula. Prediction ability can perfectly meet the requirements of real-time computation, which is crucial in engineering fields. In addition, different-level algorithms are further employed to solve the problem of robotic system control considering additional restrictions. The position tracking control and end-effector orientation control are simultaneously achieved with even fault tolerance by utilizing the proposed algorithms. [ABSTRACT FROM AUTHOR]