Automatic centralized controller design for modular and reconfigurable robot manipulators

Abstract

Abstract-We address the problem of controlling modular robot manipulators. The challenge of modular-robot control is that the overall system dynamics are unknown due to its flexible composition from given modules. Most previous work has faced this problem by designing decentralized controllers. Simple decentralized controllers do not guarantee global asymptotic stability without knowledge of the overall system dynamics and alternative versions involving communication with neighboring modules result in complicated control concepts. Our approach is completely different: we store parameters regarding the dynamics and kinematics of each module and a unique identification number in itself. After finishing the assembly of the modules, the parameters are gathered in a central controller, which also detects the configuration using the identification numbers. Our centralized controller uses this information to synthesize modelbased control laws on-the-fly as if the full system dynamics are known beforehand. We introduce a novel and compact notation to automate this procedure and to generalize the derivation of the kinematic and dynamic model for heterogeneous modules. Finally, a possible application is shown using simulations.

Combined inverse-dynamics/passivity-based control for robots with elastic joints

“…6 where different link-modules have been used. The modular and reconfigurable nature of this set-up allows us to apply a framework for automatically designing model-based controllers of modular robot manipulators [24]. Following that approach, each module is systematically characterized and a compact set of information (module data) is stored within the module or in a database.…”

“…We test the effectiveness of our controller using simulations and experiments. For the experiments, we consider a modular reconfigurable testbed with elastic joint modules and we implement the on-the-fly synthesis of the model-based global tracking controllers under test according to the framework proposed in [24].…”

Cost-optimal composition synthesis for modular robots

“…To implement the task space collision avoidance, task space coordinates of each module are obtained for each time interval. This process is realized by using the transformation matrices of the Denavit and Hartenberg (D-H) frames and an additional translation for the i th link which is defined as n i in [14]. All link modules are modeled as lines, and base module, all joint modules and end effector modules are modeled as points.…”

“…Another technique to automatically generate dynamic models of modular robots based on the theory of Lie algebras is proposed in [13]. In [14], all kinematic and dynamic parameters are stored in each module and the dynamics of the desired composition is generated automatically. In this paper, we use the NewtonEuler method as in [14] to generate the dynamics because of its simplicity.…”

“…In [14], all kinematic and dynamic parameters are stored in each module and the dynamics of the desired composition is generated automatically. In this paper, we use the NewtonEuler method as in [14] to generate the dynamics because of its simplicity.…”