A Parallel, Four Degree-of-Freedom Robotic Wrist

1995 ◽  
Author(s):  
Robert J. Salerno ◽  
Stephen L. Canfield ◽  
Anthony J. Ganino ◽  
Charles F. Reinholtz
Keyword(s):  
Inverse Kinematics ◽  
Parallel Architecture ◽  
High Strength ◽  
Degree Of Freedom ◽  
Real Time Control ◽  
Time Control ◽  
Robot Wrist ◽  
Forward And Inverse Kinematics ◽  
Three Degree Of Freedom ◽  
Robotic Wrist

Abstract Kinematic considerations are presented for a parallel, four degree-of-freedom robot wrist resembling the Clemens coupling, a constant-velocity joint first described in his 1872 patent. In its new form as a wrist, this device provides general orientational mobility as well as axial displacement through a plunge motion. A possibly more important hybrid of this wrist is identified as an artificially constrained, spherical, three degree-of-freedom pitchyaw-roll wrist that can easily be derived from this new concept. Because of its parallel architecture, the new wrist design displays favorable attributes including high strength-to-weight and stiffness-to-weight ratios, a large workspace, and an open center construction. Closed-form forward and inverse kinematics of the wrist are derived for both the three and four degree-of-freedom configurations, thereby making it a likely candidate for real-time control. Workspace plots are also presented that demonstrate the dexterity of the proposed wrist.

Inverse Dynamics of a 6-DOF Decoupling Manipulator

2014 ◽  
Author(s):  
Taoran Liu ◽  
Feng Gao ◽  
Xianchao Zhao ◽  
Chenkun Qi
Keyword(s):  
Inverse Kinematics ◽  
Inverse Dynamics ◽  
Virtual Work ◽  
Principle Of Virtual Work ◽  
Real Time Control ◽  
Model Accuracy ◽  
Lower Weight ◽  
Time Control ◽  
Speed Reducer ◽  
Forward And Inverse Kinematics

In this paper, the kinematics and inverse dynamics of a 6-dof full decoupling parallel manipulator is presented. The forward and inverse kinematics solution can be easily obtained and simplify the real-time control due to 6 dof motion full decoupling. Three motors are embedded into the moving platform to realize rotational motion, simple kinematics and isotropic configurations due to the motors and speed reducers have a lower weight. An effective inverse dynamics of the manipulator is derived by the principle of virtual work. The existence of speed reducer for motors have advantages of decreasing mechanical couplings between axes and the full varying inertias are not directly onto each motor output shaft. Since the presence of speed reducer and in order to improve dynamic model accuracy, the inertia of motor rotor-reducer should be computed. Finally, numerical simulation of the inverse dynamics provides that the actuating torques created by gravity, velocity, acceleration and decoupling torque, coupling torque have been computed.

Kinematics of a New High-Precision Three-Degree-of-Freedom Parallel Manipulator

2006 ◽  
Vol 129 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Farhad Tahmasebi
Keyword(s):  
Power Dissipation ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degree Of Freedom ◽  
Base Plane ◽  
Degree Polynomial ◽  
Payload Capacity ◽  
Half Angle ◽  
Three Degree Of Freedom ◽  
Direct Kinematics

Closed-form direct and inverse kinematics of a new three-degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three-DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base mounted, higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of the tangent of the half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.

Parametric Design of a Spherical Eight-Bar Linkage Based on a Spherical Parallel Manipulator

2008 ◽  
Vol 1 (1) ◽  
Author(s):  
Gim Song Soh ◽  
J. Michael McCarthy
Keyword(s):  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Parametric Design ◽  
Degree Of Freedom ◽  
Kinematics Analysis ◽  
End Effector ◽  
Arbitrary Base ◽  
Three Degree Of Freedom ◽  
Spherical Parallel Manipulator

This paper presents a procedure that determines the dimensions of two constraining links to be added to a three degree-of-freedom spherical parallel manipulator so that it becomes a one degree-of-freedom spherical (8, 10) eight-bar linkage that guides its end-effector through five task poses. The dimensions of the spherical parallel manipulator are unconstrained, which provides the freedom to specify arbitrary base attachment points as well as the opportunity to shape the overall movement of the linkage. Inverse kinematics analysis of the spherical parallel manipulator provides a set of relative poses between all of the links, which are used to formulate the synthesis equations for spherical RR chains connecting any two of these links. The analysis of the resulting spherical eight-bar linkage verifies the movement of the system.

scholarly journals A singularity handling algorithm based on operational space control for six-degree-of-freedom anthropomorphic manipulators

2019 ◽  
Vol 16 (3) ◽  
pp. 172988141985891
Author(s):  
Zhi-Hao Kang ◽  
Ching-An Cheng ◽  
Han-Pang Huang
Keyword(s):  
Null Space ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Control Input ◽  
Real Time Control ◽  
Time Control ◽  
Operational Space ◽  
Industrial Manipulators ◽  
Space Motion ◽  
Six Degree Of Freedom

In this article, we analyze the singularities of six-degree-of-freedom anthropomorphic manipulators and design a singularity handling algorithm that can smoothly go through singular regions. We show that the boundary singularity and the internal singularity points of six-degree-of-freedom anthropomorphic manipulators can be identified through a singularity analysis, although they do not possess the nice kinematic decoupling property as six-degree-of-freedom industrial manipulators. Based on this discovery, our algorithm adopts a switching strategy to handle these two cases. For boundary singularities, the algorithm modifies the control input to fold the manipulator back from the singular straight posture. For internal singularities, the algorithm controls the manipulator with null space motion. We show that this strategy allows a manipulator to move within singular regions and back to non-singular regions, so the usable workspace is increased compared with conventional approaches. The proposed algorithm is validated in simulations and real-time control experiments.

The Algorithm of Redundant Robotic Kinematics Based on Exponential Product

2011 ◽  
Vol 58-60 ◽  
pp. 1902-1907 ◽  
Author(s):  
Xin Fen Ge ◽  
Jing Tao Jin
Keyword(s):  
Real Time ◽  
Inverse Kinematics ◽  
Screw Theory ◽  
Product Formula ◽  
Real Time Control ◽  
Time Control ◽  
Direct Kinematics ◽  
Product Formulas

The intrinsically redundant series manipulator’s kinematics were studied by the exponential product formula of screw theory, the direct kinematics problem and Inverse kinematics problems were analyzed, and the intrinsically redundant series manipulator’s kinematics solution that based on exponential product formulas were proposed; the intrinsically redundant series manipulator’s kinematics is decomposed into several simple sub-problems, then analyzed sub-problem, and set an example to validate the correctness of the proposed method. Finally, comparing the exponential product formula and the D-H parameters, draw that they are essentially the same in solving the manipulator’s kinematics, so as to the algorithm of the manipulator’s kinematics based on exponential product formulas are correct, and the manipulator’s kinematics process based on exponential product formula is more simple and easier to real-time control of industrial.

Improved Development Cycle of a Compliant Manipulator

2003 ◽  
Author(s):  
Stephen L. Canfield ◽  
Patrick V. Hull ◽  
James W. Beard
Keyword(s):  
Design Process ◽  
Design Methodology ◽  
Low Cost ◽  
Parallel Architecture ◽  
Degree Of Freedom ◽  
Modeling Tools ◽  
Multiple Features ◽  
Positioning Accuracy ◽  
Development Cycle ◽  
Three Degree Of Freedom

Application of the compliant design methodology to manipulators has held the promise of delivering manipulators with many significant advantages, including low cost, small size, low backlash and friction, and high positioning accuracy. This approach has been demonstrated in part by Canfield et. al., [1] to a class of three-degree-of-freedom manipulators based on a specific parallel architecture topology. In [1], the authors’ intent was to develop two compliant manipulators that exhibit several of the features associated with compliant devices. However, upon review of the manipulators resulting from this work it is observed that many of the benefits that were expected were lost at some point in the design process, resulting in manipulators that were large, expensive and suffered significantly from required assembly and inaccuracies in manufacture. This paper will revisit the problem addressed in [1], using the modeling tools demonstrated in that paper but will present several improved development measures that will result in manipulators that exhibit multiple features promised by compliant devices. The resulting manipulators will then be compared against the manipulators from [1] with a summary of the performance and characteristics of each given and evaluated.

Kinematics of a New High Precision Three Degree-of-Freedom Parallel Manipulator

2005 ◽  
Author(s):  
Farhad Tahmasebi
Keyword(s):  
Power Dissipation ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degree Of Freedom ◽  
Base Plane ◽  
Degree Polynomial ◽  
Payload Capacity ◽  
Half Angle ◽  
Three Degree Of Freedom ◽  
Direct Kinematics

Closed-form direct and inverse kinematics of a new three degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base-mounted; higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of tangent of half-angle between one of the limbs and the base plane. Hence, there are at most sixteen assembly configurations for the manipulator. In addition, it is shown that the sixteen solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.

Gesture Based Control of a Simulated Robot Manipulator

2015 ◽  
Author(s):  
Sukhdeep S. Dhami ◽  
Ashutosh Sharma ◽  
Rohit Kumar ◽  
Parveen Kalra
Keyword(s):  
Inverse Kinematics ◽  
Graphical Model ◽  
Robot Manipulator ◽  
Reference Signal ◽  
Human Robot Interaction ◽  
Human Hand ◽  
Hand Gestures ◽  
Matlab Simulink ◽  
Robot Wrist ◽  
Forward And Inverse Kinematics

The number of industrial and household robots is fast increasing. A simpler human-robot interaction is preferred in household robotic applications as well as in hazardous environments. Gesture based control of robots is a step in this direction. In this work, a virtual model of a 3-DOF robotic manipulator is developed using V-Realm Builder in MATLAB and the mathematical models of forward and inverse kinematics of the manipulator are coded in MATLAB/Simulink software. Human hand gestures are captured using a smartphone with accelerometer and orientation sensors. A wireless interface is provided for transferring smartphone sensory data to a laptop running MATLAB/Simulink software. The hand gestures are used as reference signal for moving the wrist of the robot. A user interface shows the instantaneous joint angles of robot manipulator and spatial coordinates of robot wrist. This simple yet effective tool aids in learning a number of aspects of robotics and mechatronics. The animated graphical model of the manipulator provides a better understanding of forward and inverse kinematics of robot manipulator. The robot control using hand gestures generates curiosity in student about interfacing of hardware with computer. It may also stimulate new ideas in students to develop virtual learning tools.

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