A Meso-Scale Rolling-Contact Gripping Mechanism for Robotic Surgery

2015 ◽  
Author(s):  
Clayton L. Grames ◽  
Jordan D. Tanner ◽  
Brian D. Jensen ◽  
Spencer P. Magleby ◽  
John Ryan Steger ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Rolling Contact ◽  
Swept Volumes ◽  
Manufacturing Methods ◽  
Traditional Manufacturing ◽  
Swept Volume ◽  
And Control ◽  
Three Degrees Of Freedom ◽  
Surgical Operations ◽  
Meso Scale

A new, compact 2 degree-of-freedom mechanism 4.1 mm in diameter suitable for robotically controlled surgical operations is presented. Current commercially available robotically controlled instruments achieve high dexterity defined by three degrees of freedom and relatively confined swept volume at just under 1 cm in diameter. Current smaller diameter instruments result in high part count and large swept volumes (less dexterity). A meso-scale rolling contact gripping mechanism is proposed as an alternative. The manufacturing of the parts is made feasible by Metal Laser Sintering, which can produce parts that are difficult to replicate with traditional manufacturing methods. The resulting instrument has only 6 parts and a small swept volume. Instrument actuation and control by a surgical robotic system is demonstrated.

A Compact 2 Degree of Freedom Wrist for Robot-Actuated Surgery and Other Applications

2016 ◽  
Author(s):  
Clayton L. Grames ◽  
Brian D. Jensen ◽  
Spencer P. Magleby ◽  
Larry L. Howell
Keyword(s):  
Degrees Of Freedom ◽  
Rolling Contact ◽  
Degree Of Freedom ◽  
High Part ◽  
Swept Volumes ◽  
Manufacturing Methods ◽  
Traditional Manufacturing ◽  
Swept Volume ◽  
Three Degrees Of Freedom ◽  
Surgical Operations

A new, compact 2 degree-of-freedom wrist mechanism suitable for robotically controlled surgical operations is presented. Current commercially available robotically controlled instruments achieve high dexterity defined by three degrees of freedom and relatively confined swept volume at just under 1 cm in diameter. Current smaller diameter instruments result in high part count and large swept volumes (less dexterity). A mesoscale rolling contact wrist mechanism is proposed as an alternative. The crossed cylinders wrist integrates two half-cylinders whose longitudinal axes are offset by 90°. The surfaces of the half cylinders have been populated with gearing that enables the two halves to roll in two directions while preventing slip. The manufacturing of the parts is demonstrated as feasible by a the layered assembly of Carbon Nanotube (CNT) structures, which can produce parts that are difficult to replicate with traditional manufacturing methods. The resulting wrist has only 2 parts and a small swept volume.

Simulation of Helicopter Powerplant Performance

1978 ◽  
Author(s):  
B. V. Baxendale ◽  
M. E. Inglis
Keyword(s):  
Power Plants ◽  
Degrees Of Freedom ◽  
Vertical Plane ◽  
System Failure ◽  
Flight Data ◽  
Rotor Systems ◽  
Hybrid Computer ◽  
And Control ◽  
Three Degrees Of Freedom ◽  
Proper Account

Programs have been written for a hybrid computer to simulate in real time the dynamic behavior of the engines, airframe, and rotor systems of the Sea King and Lynx helicopters; their purpose is to aid the study of performance and control of helicopter power plants. Since the engines are directly coupled to the lift-producing surface (the rotor), it is important to take proper account of the interactions between the power plant and the rest of the aircraft; however, for this type of work, it is reasonable to limit simulated aircraft maneuvers to three degrees of freedom in a single vertical plane. The method of simulating the major features of the helicopter are discussed, along with their implementation on the hybrid computer. The paper goes on to describe the successful validation of the two models by comparison with specially obtained flight data on a range of rapid maneuvers involving large changes in power demands. Finally, a description is given of an exercise on the Sea King simulation to investigate the effect of an engine or control system failure at a critical flight condition.

Robust Trajectory Following Control of Robotic Systems

1985 ◽  
Vol 107 (4) ◽  
pp. 308-315 ◽  
Author(s):  
S. N. Singh ◽  
A. A. Schy
Keyword(s):  
Degrees Of Freedom ◽  
Digital Simulation ◽  
Robotic Systems ◽  
Control Law ◽  
Robot Arm ◽  
Control Laws ◽  
Payload Uncertainty ◽  
Trajectory Following ◽  
And Control ◽  
Three Degrees Of Freedom

Using an inversion approach we derive a control law for trajectory following of robotic systems. A servocompensator is used around the inner decoupled loop for robustness to uncertainty in the system. These results are applied to trajectory control of a three-degrees-of-freedom robot arm and control laws Cθ and CH for joint angle and position trajectory following, respectively, are derived. Digital simulation results are presented to show the rapid trajectory following capability of the controller in spite of payload uncertainty.

Trajectory Control of an Automated Guided Vehicle Using Feedback Linearization

2006 ◽  
Author(s):  
S. M. Mehdi Ansarey M. ◽  
M. J. Mahjoob
Keyword(s):  
Control System ◽  
Feedback Linearization ◽  
Degrees Of Freedom ◽  
Automated Guided Vehicle ◽  
State Variables ◽  
Discrete Curvatures ◽  
Steering Mechanism ◽  
Dynamics And Control ◽  
And Control ◽  
Three Degrees Of Freedom

In this paper, the dynamics and control of an automated guided vehicle (AGV) is described. The objective is to control the vehicle direction and location with respect to a prescribed trajectory. This is accomplished based on an optimum control strategy using vehicle state variables. A four-wheel vehicle with three degrees of freedom including longitudinal, lateral and yaw motion is considered. The nonlinearity of the tire and steering mechanism is also included. The control system design for circular, straight forward and composite path is presented based on feedback linearization. Some trajectory simulation for discrete curvatures is carried out. The controller was implemented within MATLAB environment. The design was also evaluated using ADAMS full vehicle assembly. The results demonstrated the accuracy of the model and the effectiveness of the developed control system.

Design and analysis of an active gimbal simulator with three degrees-of-freedom for ground testing

2018 ◽  
Vol 233 (7) ◽  
pp. 2552-2562
Author(s):  
Jiao Jia ◽  
Yingmin Jia ◽  
Shihao Sun
Keyword(s):  
Degrees Of Freedom ◽  
Attitude Determination ◽  
Contact Forces ◽  
Design Parameters ◽  
Force Analysis ◽  
Ground Testing ◽  
Neutral Equilibrium ◽  
Main Support ◽  
And Control ◽  
Three Degrees Of Freedom

In this paper, a new active gimbal simulator is developed for testing the attitude determination and control system of satellites. The active gimbal simulator is composed of a rolling joint, a pitching joint, a main support frame, an active yawing joint, and a fixture. The rolling joint enables the active gimbal simulator to be applied to the columnar satellite without the fixture. The contact forces between the rolling joint and the test satellite (or the fixture) can be regulated by the support of the pitching joint. The object attached to the active gimbal simulator is at neutral equilibrium and can maintain balance at an arbitrary attitude. Hence, the object can rotate freely without being affected by its gravity. The active gimbal simulator is an approximately free-to-free suspension or support method. Compared with the traditional gimbals, the active gimbal simulator can be applied to objects of arbitrary shape especially cylinders and the effect of exogenous mass and inertia introduced by the connection mechanism is reduced. The design parameters of the active gimbal simulator are optimized based on the force analysis. A specific prototype was made, and its feasibility was verified by laboratory-based experiments.

scholarly journals Modeling and Control of a Cable-Suspended Sling-Like Parallel Robot for Throwing Operations

2020 ◽  
Vol 10 (24) ◽  
pp. 9067
Author(s):  
Deng Lin ◽  
Giovanni Mottola ◽  
Marco Carricato ◽  
Xiaoling Jiang
Keyword(s):  
Mathematical Models ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Target Point ◽  
Inertial Effects ◽  
End Effector ◽  
Modeling And Control ◽  
And Control ◽  
Three Degrees Of Freedom

Cable-driven parallel robots can provide interesting advantages over conventional robots with rigid links; in particular, robots with a cable-suspended architecture can have very large workspaces. Recent research has shown that dynamic trajectories allow the robot to further increase its workspace by taking advantage of inertial effects. In our work, we consider a three-degrees-of-freedom parallel robot suspended by three cables, with a point-mass end-effector. This model was considered in previous works to analyze the conditions for dynamical feasibility of a trajectory. Here, we enhance the robot’s capabilities by using it as a sling, that is, by throwing a mass at a suitable time. The mass is carried at the end-effector by a gripper, which releases the mass so that it can reach a given target point. Mathematical models are presented that provide guidelines for planning the trajectory. Moreover, results are shown from simulations that include the effect of cable elasticity. Finally, suggestions are offered regarding how such a trajectory can be optimized.

scholarly journals Development and Control of a 5-Axis Reconfigurable Machine Tool

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Z. M. Bi
Keyword(s):  
Control System ◽  
Machine Tool ◽  
Degrees Of Freedom ◽  
Open Architecture ◽  
Constant Length ◽  
Software Reconfiguration ◽  
Parallel Kinematic ◽  
And Control ◽  
Reconfigurable Machine Tool ◽  
Three Degrees Of Freedom

The development of a hybrid reconfigurable machine tool has been introduced. The machine tool consists of a tripod-based parallel kinematic machine (PKM) module with three degrees of freedom (DOF) and a serial linear table with two DOF. The PKM is installed on a gantry system which is capable of reconfiguring its position and orientation. In the design of tripod-based parallel mechanism, a passive link is used to enhance the stiffness and increase the working load. To avoid the buildup of the heat of the extensive actuation, three joints are actuated via the actuators with a constant length. The geometries of the PKM have been optimized for the best and highest accuracy. In this paper, its control system and the prototyping development are focused. An open architecture is applied, the control methodologies are developed and validated, and the corresponding software tools have been implemented for the software reconfiguration of the control system.

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