Mobile robotic manipulators can augment the strength and dexterity of human operators in unstructured environments. Here, the control system for a six degree-of-freedom heavy-lift mobile manipulator for lifting and inserting payloads on the deck of a ship is described. The robotic hardware and the application present several control challenges, including structural resonances, high joint fricti...

This paper introduces a new friction compensation strategy which utilizes a rule-based fuzzy logic controller whose parameters are self-tuned according to the previous performance of the controller and a friction model in the lowvelocity range. The proposed controller as well as a conventional fuzzy logic controller and a PID controller were simulated and implemented on a 3-axis milling machine...

Pivot bearing friction and flex cable nonlinearity are the two major torque nonlinearities which lead to performance degradation in hard disk drive (HDD) tracking tasks. Based on a comprehensive model of typical voice-coil-motor (VCM) actuator, which explicitly captures the characteristics of pivot bearing friction and flex cable nonlinearity, this paper presents the design of a parameterized c...

The paper describes the control and friction compensation of a robot with flexible joints (the DLR medical robot), which has strong mechanical couplings within pairs of joints realized with a differential gear-box. In consideration of this coupling, a MIMO state controller is designed for the strongly coupled joints. In addition a disturbance observer is developed to compensate the nonlinear ef...

This paper presents kinematic and dynamic analysis of a holonomic vehicle with continuously-variable transmission. Four ball wheels, independently actuated by DC motors, enable for moving the vehicle in any direction within the plane and rotating it around its center. The angle between the two beams holding the balls can be changed to alter the gear ratio and other dynamic characteristics of th...

In this article, a new method to control a flexible robotic arm using a conventional motor with a gear actuator strongly affected by non-linear friction torque is proposed. This control method does not require friction compensation and hence the estimation of this term because the control scheme is robust with respect to this effect. On the other hand, the only variables to measure are the moto...

In this paper, the dynamic controller design problem of a redundant planar 2-dof parallel manipulator is studied. Using the Euler-Lagrange equation, we formulate the dynamic model of the parallel manipulator in the joint space and propose an augmented PD controller with forward dynamic compensation for the parallel manipulator. By formulating the controller in the joint space, we eliminate the ...

Purpose – Slim and dexterous manipulators with long reaches can perform various exploration and inspection tasks in confined spaces. This paper aims to present the development of such a dexterous continuum manipulator for potential applications in the aviation industry. Design/methodology/approach – Benefiting from a newly conceived dual continuum mechanism and the improved actuation scheme, th...

BACKGROUND National working groups identify the need for return on investment research conducted from the purchaser perspective; however, the field has not developed standardized methods for measuring the basic components of return on investment, including costing out the value of work productivity loss due to illness. Recent literature is divided on whether the most commonly used method undere...