Dynamics and Control of Robotic Systems Worn by Humans

1991 ◽  
Vol 113 (3) ◽  
pp. 379-387 ◽  
Author(s):  
H. Kazerooni ◽  
S. L. Mahoney
Keyword(s):  
Material Handling ◽  
Robotic Systems ◽  
Control Technique ◽  
Load Force ◽  
Two Dimensional ◽  
Direct Drive ◽  
Human Arm ◽  
Dynamics And Control ◽  
Physical Interfaces ◽  
And Control

This article describes the dynamics, control, and stability of extenders, robotic systems worn by humans for material handling tasks. Extenders are defined as robot manipulators which extend (i.e., increase) the strength of the human arm in load maneuvering tasks, while the human maintains control of the task. Part of the extender motion is caused by physical power from the human; the rest of the extender motion results from force signals measured at the physical interfaces between the human and the extender, and the load and the extender. Therefore, the human wearing the extender exchanges both power and information signals with the extender. The control technique described here lets the designer define an arbitrary relationship between the human force and the load force. A set of experiments on a two-dimensional non-direct-drive extender were done to verify the control theory.

Design and control of a two-dimensional telerobotic system with a haptic interface

2003 ◽  
Vol 217 (3) ◽  
pp. 169-185
Author(s):  
M-G Her ◽  
M Karkoub ◽  
K-S Hsu
Keyword(s):  
Haptic Interface ◽  
Two Dimensional ◽  
Direct Drive ◽  
Closed Loop System ◽  
Human Arm ◽  
Control Scheme ◽  
Reaction Forces ◽  
And Control ◽  
Theoretical Results ◽  
Good Agreement

A model for a ‘master-slave’ two-dimensional telerobotic dynamic system with a haptic interface device is derived. The telerobotic system consists of a ‘master’ robot, which is a direct-drive robot operated by a human arm, and a ‘slave’ robot, which is an x-y type pallet located at a remote site. When the active handle of the master is moved along an arbitrary trajectory, the remote slave duplicates the motion in a constrained or unconstrained environment. The behaviour of the environment is felt by the operator through the active handle of the master. This is achieved by feeding back the disturbance and reaction forces from the environment and the loads to the active handle. Consequently, the operator gets a feel of the task being performed without being physically at the location of the task. A control scheme is devised for the telerobotic system to establish smooth communication between the master and slave robots. This control scheme integrates the dynamics of the human arm, actuators and the environment in the closed-loop system. It was shown that the experimental and the theoretical results are in good agreement and that the design controller is robust to constrained/unconstrained environments.

Dynamics and Control of a Small-Scale Boom Crane

2011 ◽  
Vol 6 (3) ◽  
Author(s):  
Ehsan Maleki ◽  
William Singhose
Keyword(s):  
Material Handling ◽  
Physical Structure ◽  
Control Technique ◽  
Small Scale ◽  
Command Shaping ◽  
Straight Line ◽  
Theoretical Predictions ◽  
Dynamics And Control ◽  
And Control ◽  
Boom Crane

Cranes are vital to many manufacturing and material-handling processes. However, their physical structure leads to flexible dynamic effects that limit their usefulness. Large payload swings induced by either intentional crane motions or external disturbances decrease positioning accuracy and can create hazardous situations. Boom cranes are one of the most dynamically complicated types of cranes. Boom cranes cannot transfer the payload in a straight line by actuating only one axis of motion because they have rotational joints. This paper presents a nonlinear model of a boom crane. A large range of possible motions is analyzed to investigate the dynamic behavior of the crane when it responds to operator commands. A command-shaping control technique is implemented, and its effectiveness on this nonlinear machine is analyzed. Experimental results verify key theoretical predictions.

Human Extenders

1993 ◽  
Vol 115 (2B) ◽  
pp. 281-290 ◽  
Author(s):  
H. Kazerooni ◽  
Jenhwa Guo
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Mathematical Expression ◽  
Contact Forces ◽  
Degree Of Freedom ◽  
Direct Drive ◽  
Physical Strength ◽  
Dynamics And Control ◽  
And Performance ◽  
And Control

A human’s ability to perform physical tasks is limited by physical strength, not by intelligence. We coined the word “extenders” as a class of robot manipulators worn by humans to augment human mechanical strength, while the wearer’s intellect remains the central control system for manipulating the extender. Our research objective is to determine the ground rules for the control of robotic systems worn by humans through the design, construction, and control of several prototype experimental direct-drive/non-direct-drive multi-degree-of-freedom hydraulic/electric extenders. The design of extenders is different from the design of conventional robots because the extender interfaces with the human on a physical level. The work discussed in this article involves the dynamics and control of a prototype hydraulic six-degree-of-freedom extender. This extender’s architecture is a direct drive system with all revolue joints. Its linkage consists of two identical subsystems, the arm and the hand, each having three degrees of freedom. Two sets of force sensors measure the forces imposed on the extender by the human and by the environment (i.e., the load). The extender’s compliances in response to such contact forces were designed by selecting appropriate force compensators. The stability of the system of human, extender, and object being manipulated was analyzed. A mathematical expression for the extender performance was determined to quantify the force augmentation. Experimental studies on the control and performance of the experimental extender were conducted to verify the theoretical predictions.

scholarly journals Actuation and Control Strategies for Miniature Robotic Surgical Systems

2004 ◽  
Vol 127 (4) ◽  
pp. 537-549 ◽  
Author(s):  
Jason M. Stevens ◽  
Gregory D. Buckner
Keyword(s):  
Minimally Invasive ◽  
Control Strategies ◽  
Three Dimensional ◽  
Robotic Systems ◽  
End Effector ◽  
Cardiac Procedures ◽  
Recovery Times ◽  
Dynamics And Control ◽  
On Line ◽  
And Control

During the past 20years, tremendous advancements have been made in the fields of minimally invasive surgery (MIS) and minimally invasive, robotically assisted (MIRA) cardiac surgery. Benefits from MIS include reduced pain and trauma, reduced risks of post-operative complications, shorter recovery times, and more aesthetically pleasing results. MIRA approaches have extended the capabilities of MIS by introducing three-dimensional vision, eliminating hand tremors, and enabling the precise articulation of smaller instruments. These advancements come with their own drawbacks, however. Robotic systems used in MIRA cardiac procedures are large, costly, and do not offer the miniaturized articulation necessary to facilitate tremendous advancements in MIS. This paper demonstrates that miniature actuation can overcome some of the limitations of current robotic systems by providing accurate, repeatable control of a small end effector. A 10× model of a two link surgical manipulator is developed, using antagonistic shape memory alloy wires as actuators, to simulate motions of a surgical end-effector. Artificial neural networks are used in conjunction with real-time visual feedback to “learn” the inverse system dynamics and control the manipulator endpoint trajectory. Experimental results are presented for indirect, on-line learning and control. Manipulator tip trajectories are shown to be accurate and repeatable to within 0.5mm. These results confirm that SMAs can be effective actuators for miniature surgical robotic systems, and that intelligent control can be used to accurately control the trajectory of these systems.

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