The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, a novel robust adaptive control scheme is proposed for a lower limb rehabilitation robot designed by our laboratory. The proposed control strategy is based on the radial basis function (RBF) neural networks and the parameters of the system dynamics are unknown. The weights of the RBF neural networks are updated by an adaptive law according to the Lyapunov stability analysis. The robustness...
In this paper, an exoskeleton performing a sit-to-stand motion is studied. A new approach to control system design for this mechanism is proposed. Proposed control system uses information about currents in the motor's armature cores to assess how much the system is loaded and change its behavior accordingly. It also uses ZMP (zero moment point) principle for assessing system's balance. In the paper,...
To the patients with neurological injury or with chronic incomplete spinal cord injury, a gait rehabilitation exoskeleton can reproduce the motion of the user limbs and help to relearn and recover the motion of their limbs. This motion helps in the formation of user new neural path-ways to relearn to walk. In this paper, an exoskeleton type robot-assisted rehabilitation system is studied. A control...
Proportional Integral Derivative (PID) controller is a conventional controller, which is widely used in industrial control system. In this paper, a PID control system is used for path tracking of an autonomous surface vehicle (ASV). The PID controller is selected because it is easy to implement as an embedded controller and practically easy to understand compared to other control methods. However,...
This paper presents adaptive tracking control with a partial regressor for multi-joint robots. The proposed controller can abbreviate the elaborate computations of a regressor matrix, which needs to be wholly calculated in conventional adaptive control. Therefore, this controller can be easily implemented in robotic systems. Even though the proposed controller does not utilize robustification techniques...
The goal in robot motion planning and control is to be able to specify a motion task in a rich, high level language and have the robot(s) automatically convert this specification into a set of low level primitives, such as feedback controllers and communication protocols, to accomplish the task. In most of the existing works, the motion planning problem is simply specified as "go from A to B...
The paper deals with adaptive control system for robotic complex. This system depending on current values of continuously varying parameters of control objects can support the maximum possible speed of the working tools and accessory equipment without reducing a given dynamic accuracy. During performance of various technological operations there are situations when mass-inertial characteristics (parameters)...
In this paper we consider the application problem of a redundant cable-driven parallel robot, tracking a reference trajectory in presence of uncertainties and disturbances. A Super Twisting controller is implemented using a recently proposed gains adaptation law [1], thus not requiring the knowledge of the upper bound of the lumped uncertainties. The controller is extended by a feedforward dynamic...
Teleoperation systems in the medical usage, allows a surgeon to perform a remote distance operation with or without magnification. There is an increasing need to provide telerobots with the ability to interact with unknown and hybrid environments to detect the abnormalities and also performing the diagnostic procedures. In such environments it is challenging to guarantee the whole system stability...
We describe a new approach to the design and real-time implementation of an adaptive controller for robotic manipulator based on digital signal processors in this paper. The Texas Instruments DSPs(TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are...
This paper presents a novel spherical rolling robot and the design procedure of an adaptive sliding mode controller for the proposed robot. Towards containing the uncertainties, the sliding mode controller is utilized and simulation tests represent the effectiveness of this method. However, the chattering phenomenon in the robot operation is the main insufficiency of this controller. Hence, in order...
The main purpose of teleoperation in medical usage is to provide technical means to perform a desired task in patient' body. It is important to haptic feedback of sensitive and delicate environment to the surgeon hand's to improve task performance. The Kelvin-Voigt (KV) model for environment, due to physical contradiction is not suitable, but the Hunt-Crossley (HC) model is chosen because of its accuracy...
Lately a systematic method was presented for the generation of whole families of Fixed Point Transformations that can be used in nonlinear adaptive control of Single Input — Single Output (SISO) as well as Multiple Input — Multiple Output (MIMO) systems as alternatives of Lyapunov's direct method. This transformation was called Sigmoid Generated Fixed Point Transformation (SGFPT). This paper introduces...
Recently a systematic method was presented for the generation of whole families of “Fixed Point Transformations” that can be used in nonlinear adaptive control of “Single Input - Single Output (SISO)” systems as alternatives of Lyapunov's “direct method”. In the present paper further development of this alternative method is considered. It consists in the generalization of the method for “Multiple...
This paper presents an assist-as-needed method for ankle rehabilitation based on adaptive impedance control strategies. First, the dynamic contribution of the patient during the motion is estimated from robot's torque and kinematic information. Then, two robot assistance control strategies (complementary and optimal) are proposed to calculate the stiffness parameter of the impedance controller. In...
A fuzzy controller is established for the wire feeder of the invasive vascular interventional surgery robot in this paper. First of all, the mechanism of the wire feeder is introduced, and the axial motion is analyzed. Second, the dynamic model of the wire feeder is established. Next, the fuzzy PID controller is established to improve the positional accuracy and dynamic performance. At last, the controller...
In this paper, an adaptive control approach is proposed for performance of constrained robot end-effector movements in presence of uncertainty. In real-world scenarios, complex physical phenomena occuring at the place of interaction may introduce nonlinearities in the system dynamics, which have to be taken into account for proper system control. We currently propose an Extremum Seeking (ES) Model...
The soft robotics approach is widely considered to enable robots in the near future to leave their cages and move freely in our modern homes and manufacturing sites. Musculoskeletal robots are such soft robots which feature passively compliant actuation, while leveraging the advantages of tendon-driven systems. Even though these robots have been intensively researched within the last decade, high-performance...
This note deals with the problem of controlling a simple one-degree-of-freedom (1-dof) juggling robot (a system that belongs to the class of nonsmooth hybrid complementary-slackness dynamical systems), when the physical parameters such as the object mass and the restitution coefficient are not exactly known. The proposed adaptive controller is based on so-called dead-beat viable controllers previously...
This paper addresses the stabilization problem of an uncertain intrinsically nonlinear SISO plant containing non-smooth nonlinearities (dead-zone, backlash, hysteresis) in the actuator device. A unified framework for its solution is here proposed, assuming that the parameters of the nonlinearities are uncertain as well. To this purpose, the hysteresis model used in [8] has been modified into an “extended”...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.