International Journal of Modern Research in Electrical and Electronic Engineering

The proposed method models robot motion between maximal and minimal radial mass density values corresponding to minimal and maximal gravitational radii. The nonlinear dynamics of robot motion are transformed into an equivalent linear control problem using the concept of external linearization. The approach introduces a variable step parameter to regulate motion precision in the radial direction. The method is further extended to electromagnetic and gravitational multi-potential fields and illustrated through analytical examples. The results show that maximal radial mass density occurs at the minimal gravitational radius, while minimal radial mass density appears at the maximal gravitational radius. The introduced variable-step control strategy enables precise regulation of robot motion trajectories. The study also derives the energy conservation constant from the ratio of Planck mass and Planck radius and demonstrates its relation to radial mass density behavior. The proposed RRDT-based framework provides a generalized method for controlling robot motion in radial mass density fields. The use of external linearization and variable-step control enables stable and accurate robot motion in electromagnetic and gravitational environments. The proposed control strategy can be applied to nanorobotic systems, particularly in applications requiring highly precise motion control, such as medical microrobots and drug delivery systems.