scholarly journals Iterative Learning without Reinforcement or Reward for Multijoint Movements: A Revisit of Bernstein's DOF Problem on Dexterity

2010 ◽  
Vol 2010 ◽  
pp. 1-15
Author(s):  
Suguru Arimoto ◽  
Masahiro Sekimoto ◽  
Kenji Tahara
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Joint Space ◽  
Iterative Learning ◽  
Joint Control ◽  
Robot Arm ◽  
Kinematic Redundancy ◽  
History Of ◽  
The Central Nervous System ◽  
Multijoint Movements

A robot designed to mimic a human becomes kinematically redundant and its total degrees of freedom becomes larger than the number of physical variables required for describing a given task. Kinematic redundancy may contribute to enhancement of dexterity and versatility but it incurs a problem of ill-posedness of inverse kinematics from the task space to the joint space. This ill-posedness was originally found by Bernstein, who tried to unveil the secret of the central nervous system and how nicely it coordinates a skeletomotor system with many DOFs interacting in complex ways. In the history of robotics research, such ill-posedness has not yet been resolved directly but circumvented by introducing an artificial performance index and determining uniquely an inverse kinematics solution by minimization. This paper tackles such Bernstein's problem and proposes a new method for resolving the ill-posedness in a natural way without invoking any artificial index. First, given a curve on a horizontal plane for a redundant robot arm whose endpoint is imposed to trace the curve, the existence of a unique ideal joint trajectory is proved. Second, such a uniquely determined motion can be acquired eventually as a joint control signal through iterative learning without reinforcement or reward.

Control of a Handwriting Robot with DOF Redundancy Based on Feedback in Task Coordinates

2004 ◽  
Vol 16 (4) ◽  
pp. 381-387 ◽  
Author(s):  
Hiroe Hashiguchi ◽  
◽  
Suguru Arimoto ◽  
Ryuta Ozawa
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Sensory Feedback ◽  
Closed Loop ◽  
Joint Space ◽  
Hand Dexterity ◽  
Loop Dynamics ◽  
Additional Input ◽  
Ill Posed ◽  
Joint Motions

To enhance robot hand dexterity, it is said that the robot should be designed to have a redundant number of degrees of freedom. In redundant robotic systems, inverse kinematics from task description space to joint space becomes ill-posed, making it difficult to determine joint motions. To avoid this ill-posedness, most proposed methods introduce an additional input term calculated from an intentionally introduced artificial index of performance. We propose a 4 DOF redundant handwriting robot using novel simple control to solve the problem of ill-posedness based on sensory feedback. We demonstrate the effectiveness of proposed control in computer simulation of closed-loop dynamics with the constraint that the robot’s endpoint be always on a two-dimensional plane.

scholarly journals Compliant behaviour of redundant robot arm - experiments with null-space

2015 ◽  
Vol 12 (1) ◽  
pp. 81-98
Author(s):  
Petar Petrovic ◽  
Nikola Lukic ◽  
Ivan Danilov
Keyword(s):  
Stiffness Matrix ◽  
Jacobian Matrix ◽  
Null Space ◽  
Joint Space ◽  
Robot Arm ◽  
Kinematic Redundancy ◽  
Redundant Robot ◽  
Redundant Robots ◽  
Compliant Behavior ◽  
Congruent Transformation

This paper presents theoretical and experimental aspects of Jacobian nullspace use in kinematically redundant robots for achieving kinetostatically consistent control of their compliant behavior. When the stiffness of the robot endpoint is dominantly influenced by the compliance of the robot joints, generalized stiffness matrix can be mapped into joint space using appropriate congruent transformation. Actuation stiffness matrix achieved by this transformation is generally nondiagonal. Off-diagonal elements of the actuation matrix can be generated by redundant actuation only (polyarticular actuators), but such kind of actuation is very difficult to realize practically in technical systems. The approach of solving this problem which is proposed in this paper is based on the use of kinematic redundancy and nullspace of the Jacobian matrix. Evaluation of the developed analytical model was done numerically by a minimal redundant robot with one redundant d.o.f. and experimentally by a 7 d.o.f. Yaskawa SIA 10F robot arm.

Research on Kinematics Analysis and Trajectory Planning of Novel EOD Manipulator

2021 ◽  
Vol 11 (20) ◽  
pp. 9438
Author(s):  
Jianwei Zhao ◽  
Tao Han ◽  
Xiaofei Ma ◽  
Wen Ma ◽  
Chengxiang Liu ◽  
...  
Keyword(s):  
Trajectory Planning ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Random Number ◽  
Polynomial Interpolation ◽  
Interpolation Method ◽  
Joint Space ◽  
Work Requirements ◽  
Multiple Degrees Of Freedom ◽  
Quintic Polynomial

To address the problems of mismatch, poor flexibility and low accuracy of ordinary manipulators in the complex special deflagration work process, this paper proposes a new five-degree-of-freedom (5-DOF) folding deflagration manipulator. Firstly, the overall structure of the explosion-expulsion manipulator is introduced. The redundant degrees of freedom are formed by the parallel joint axes of the shoulder joint, elbow joint and wrist pitching joint, which increase the flexibility of the mechanism. Aiming at a complex system with multiple degrees of freedom and strong coupling of the manipulator, the virtual joint is introduced, the corresponding forward kinematics model is established by D–H method, and the inverse kinematics solution of the manipulator is derived by analytical method. In the MATLAB platform, the workspace of the manipulator is analyzed by Monte Carlo pseudo-random number method. The quintic polynomial interpolation method is used to simulate the deflagration task in joint space. Finally, the actual prototype experiment is carried out using the data obtained by simulation. The trajectory planning using the quintic polynomial interpolation method can ensure the smooth movement of the manipulator and high accuracy of operation. Furthermore, the trajectory is basically consistent with the simulation trajectory, which can realize the work requirements of putting the object into the explosion-proof tank. The new 5-DOF folding deflagration manipulator designed in this paper has stable motion and strong robustness, which can be used for deflagration during the COVID-19 epidemic.

Natural Resolution of Ill-Posed Inverse Kinematics for Redundant Robots: A Challenge to Bernstein’s Degrees-of-Freedom Problem

2006 ◽  
Vol 18 (5) ◽  
pp. 651-660 ◽  
Author(s):  
Suguru Arimoto ◽  
◽  
Masahiro Sekimoto ◽  
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Sensory Feedback ◽  
Joint Space ◽  
Dimensional Manifold ◽  
Reaching Task ◽  
Loop Dynamics ◽  
Ill Posed ◽  
Human Limb ◽  
Joint Velocity

Over half a century ago, A. N. Bernstein observed that “dexterity” in human limb movement emerges from the involvement of multijoint motion with surplus degrees of freedom (DOF). Robotics posits that DOF redundancy in robot may enhance dexterity and versatility. Kinematic redundancy involves the problem of ill-posed inverse kinematics from task-description space to joint space. This problem is conventionally avoided by introducing an artificial performance index and uniquely determining an inverse kinematics solution by minimizing it. Instead of taking this conventional avoidance solution, we propose challenging Bernstein’s DOF problem by introducing two direct novel concepts - stability on a manifold and transferability to a submanifold - in dealing with human multijoint movement in reaching and showing that sensory feedback from task space to joint space together with adequate damping (joint velocity feedback) enables any solution to overall closed-loop dynamics to converge naturally and coordinately to a lower-dimensional manifold describing a set of joint states fulfilling a given motion task. This means that a reaching task is accomplished by sensory feedback with the appropriate choice of a stiffness parameter and damping coefficients without having to consider inverse kinematics. We also show that these concepts cope with the annoying “variability” of redundant joint motion seen typically in skilled human reaching. In conclusion, we propose a virtual spring/damper hypothesis that leads to natural control of skilled movement in redundant multijoint reaching.

scholarly journals Joint Space Redundancy Resolution of Serial Link Manipulator: An Inverse Kinematics and Continuum Structure Numerical Approach

2020 ◽  
Author(s):  
Toshit Jain ◽  
Jinesh Kumar Jain ◽  
Debanik Roy
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Complex Structure ◽  
Initial Approximation ◽  
Joint Space ◽  
Primary Objective ◽  
Target Point ◽  
Redundancy Resolution ◽  
Redundant Manipulator ◽  
Serial Link

Automatic control to any of robot manipulators, some kind of issues are being observed. A numerical method for solution generation to the inverse kinematics problem of redundant robotic manipulators is presented to obtain the smoothest algorithm as possible, leading to a robust iterative method. After the primary objective of the reachability of end-effectors to the target point is achieved, the aim is set to resolve the redundant degrees of freedom of redundant manipulator. This method is numerically stable since it converges to the correct answer with virtually any initial approximation, and it is not sensitive to the singular configurations of the manipulator. In addition, this technique is computationally effective and able to apply for serial manipulators with any DOF applications. A planar 3R-DOF serial link redundant manipulator is considered as exemplar problem for solving. Also, the continuum approach for resolving more complex structure with variable DoF is illustrated here and their brief applicability to support surgeries and adaptive use of artificial linkage moments is also calculated.

Four Degrees of Freedom Robot Arm, Low-Cost Competition in the Design and Development

2013 ◽  
Vol 5 (1) ◽  
pp. 50-65 ◽  
Author(s):  
Liu Hongcong
Keyword(s):  
Inverse Kinematics ◽  
Optical Materials ◽  
Degrees Of Freedom ◽  
Low Cost ◽  
Serial Communication ◽  
Materials Processing ◽  
Robot Arm ◽  
Servo Motor ◽  
Industrial Labor ◽  
Normal Work

The focus of this work is to design, develop and implement enhanced control and competitive robot arm thick and short cost. Design of four degree of freedom and talent of robot arm is to complete the accurate and simple tasks, such as optical materials processing, will be integrated into the mobile platform, as an assistant for the industrial labor force. Between the robot arm equipped with weapons and arm movements associated with the plurality of servo motor. Servo motor, encoder, so as to realize no controller includes. To control the robot, using Lab view, to the computation of the inverse kinematics of serial communication and proper angle, a micro controller, servo motor and drive ability of modify the location, velocity and acceleration. The robot arm was tested and verified, results show that, its normal work.

Exploiting the Kinematic Redundancy of a (6 + 3) Degrees-of-Freedom Parallel Mechanism

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Louis-Thomas Schreiber ◽  
Clément Gosselin
Keyword(s):  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Redundancy ◽  
Spatial Parallel Mechanism ◽  
Compressive Loads ◽  
Moving Platform

This paper presents methods to exploit the redundancy of a kinematically redundant spatial parallel mechanism with three redundant DOFs. The architecture of the mechanism is similar to the well-known Gough–Stewart (GS) platform and it retains its advantages, i.e., the members connecting the base to the moving platform are only subjected to tensile/compressive loads. The kinematic redundancy is exploited to avoid singularities and extend the rotational workspace. The architecture is described and the associated kinematic relationships are presented. Solutions for the inverse kinematics are given, as well as strategies to take into account the limitations of the mechanism such as mechanical interferences and velocity limits of the actuators while controlling the redundant degrees-of-freedom.

scholarly journals Research on kinematic structure of a redundant serial industrial robot arm

2016 ◽  
Vol 19 (3) ◽  
pp. 24-33
Author(s):  
Hung Minh Vu ◽  
Trung Quang Trinh ◽  
Thang Quoc Vo
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Inverse Kinematic ◽  
Kinematic Structure ◽  
Robot Arm ◽  
Revolute Joints ◽  
Prismatic Joints ◽  
Serial Robot ◽  
Inverse Kinematic Analysis

This paper proposes a new kinematic structure of a redundant serial robot arm and presents forward and inverse kinematic analysis. This is a new structure developed based on the robot IRB 2400 of ABB. The new structure consists of six revolute joints and two prismatic joints. The proposed robot arm has only seven degrees of freedom because the structure has a constraint between two revolute joints. Two prismatic joints help to expand workspaces of manipulator from small to very large. The paper describes in details about forward and inverse kinematics. Forward kinematics is derived based on DH Convention while inverse kinematics is calculated based on an objective function to minimize motions of a revolute joint and two prismatic joints. The simulation results on Matlab software indicated that the joint positions and velocities of a redundant serial robot arm matched well the trajectories in Cartesian Space.

Exploiting the Kinematic Redundancy of a 6+3 Dofs Parallel Mechanism

2018 ◽  
Author(s):  
Louis-Thomas Schreiber ◽  
Clément Gosselin
Keyword(s):  
Trajectory Planning ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Stewart Platform ◽  
Kinematic Redundancy ◽  
Compressive Loads ◽  
Planning Methods ◽  
Moving Platform

This paper presents trajectory planning methods for a kinematically redundant parallel mechanism. The architecture of the mechanism is similar to the well-known Gough-Stewart platform and it retains its advantages, i.e., the members connecting the base to the moving platform are only subjected to tensile/compressive loads. The kinematic redundancy is exploited to avoid singularities and extend the rotational workspace. The architecture is described and the associated kinematic relationships are presented. Solutions for the inverse kinematics are given, as well as strategies to take into account the limitations of the mechanism such as mechanical interferences and velocity limits of the actuators while controlling the redundant degrees of freedom.

Enhanced Whole-Arm Robot Teleoperation Using a Semi-Autonomous Control Policy

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Hsien-I Lin ◽  
Chi-Li Chen
Keyword(s):  
Degrees Of Freedom ◽  
Position Control ◽  
Control Policy ◽  
Joint Space ◽  
Autonomous Control ◽  
Robot Arm ◽  
End Effector ◽  
Human Control ◽  
Pose Control ◽  
6 Degrees Of Freedom

Previous work in robot teleoperation focused on the movement of a robot's end-effector by a human operator. However, a lack of pose control in teleoperation resulted in the robot arm frequently colliding with obstacles. Furthermore, even with pose control, it is still difficult for the robot to quickly and accurately move to the target due to mechanical discrepancies between human and robot. This paper proposes a semi-autonomous method to teleoperate the robot arm by integrating whole-arm teleoperation in joint-space control and autonomous end-effector position control. The proposed method is validated through experimental work on a robot arm with 6 degrees of freedom, with results showing significant improvement in human control for reaching for objects safely, quickly, and accurately.

Sign in / Sign up

Export Citation Format

Share Document