In this paper, a modification of the classical PID controller scheme for position control is presented. The resulting controller incorporates an exponential trajectory that smoothly guides the system towards the setpoint and a hybrid mechanism to dynamically reset the exponential signal, allowing an adaptive response to discontinuous reference signals. This combination leverages the benefits of exponential trajectories to reduce overshoot and transient oscillations, while the hybrid system ensures robust performance over a wide range of operating scenarios. Among the advantages of the proposed approach, two stand out: (1) significant improvements in energy savings can be achieved in some cases, and (2) closed-loop system performance can be improved even considering poorly tuned PIDs.

The concept of modularity in mobile robots has been aimed to enhance their capabilities, including functionality, adaptability, or robustness. However, modularity often involves the complex design of robotic modules. In this context, this paper introduces the development of a reconfigurable modular mobile robot in differential drive configuration, which main advantage is the generation of an omnidirectional mobile robot when at least two modules are coupled, in consequence, mobility and load capacity are increased. Each robotic module comprises a frame, two Mecanum wheels, a controller, and an active connection mechanism designed to simultaneously perform two functions: 1) locking a module-to-module connection, and 2) automatic reconfiguration of the robot's architecture by lifting a freely rotating spherical wheel. Owing to the integration of Mecanum wheels, the kinematic analysis of differential drive configuration considers the influence of a rollers' angles relative to the robot frame, allowing the model to be extended to a system with n coupled modules. To validate the kinematic models, a multibody simulation was conducted using Simscape Multibody LinktextsuperscriptTM. Finally, a prototype is presented to showcase the modularity capability, including the docking and undocking process, as well as the omnidirectional mobility, even in the presence of backlash.