In this article, the design problem of an adaptive controller for a robotic micromanipulator, including the effects of the applied Van der Waals (VdW) forces is considered. The micro-manipulator’s dynamic model is appropriately modified in order to include the interaction of the attractive VdW-forces. Inhere, every link is decomposed into a series of elementary particles (e.g. spheres), each one interacting with the robot’s neighboring objects during its motion. This interaction induces nonlinear additive terms in the model, attributed to the overall effect of the VdW-forces. The actuation is achieved by a tendon-driven system. At each joint, a pair of tendons is attached and act in an almost passive antagonistic manner. The kinematic and dynamic analysis of the tendon-driven actuation mechanism is offered. Consequently, the microrobot’s model is shown to be linearly parameterizable. Subject to this observation, a globally stabilizable adaptive control scheme is derived, estimating the unknown parameters (masses, generalized VdW-forces) and compensating any variations of those. Simulation studies on a 2-DOF micro-manipulator are offered to highlight the effectiveness of the proposed scheme.
Simple Adaptive Control Synthesis Enhanced by Scaling and Its Application to Positioning Control of Antagonist-Type Pneumatic Actuation Mechanism
