Intuitive Physical Human-Robot Interaction using an Underactuated Redundant Manipulator with Complete Spatial Rotational Capabilities

2021 ◽  
pp. 1-15
Author(s):  
Julien-Mathieu Audet ◽  
Clement Gosselin
Keyword(s):  
Human Robot Interaction ◽  
Degree Of Freedom ◽  
Static Equilibrium ◽  
Rotational Axis ◽  
Redundant Manipulator ◽  
Equilibrium Equations ◽  
Robot Interaction ◽  
Experimental Validations ◽  
Spatial Rotations ◽  
Two Degree Of Freedom

Abstract In this paper, the concept of underactuated redundancy is presented using a novel spatial two-degree-of-freedom (2-DoF) gravity balanced rotational manipulator, composed of movable counterweights. The proposed kinematic arrangement makes it possible to intuitively manipulate a payload undergoing 3-DoF spatial rotations by adding a third rotational axis oriented in the direction of gravity. The static equilibrium equations of the 2-DoF architecture are first described in order to provide the required configuration of the counterweights for a statically balanced mechanism. A method for calibrating the mechanism, which establishes the coefficients of the static equilibrium equations, is also presented. In order to both translate and rotate the payload during manipulation, the rotational manipulator is mounted on an existing translational manipulator. Experimental validations of both systems are presented to demonstrate the intuitive and responsive behaviour of the manipulators during physical human-robot interactions.

Force Capabilities of Two-Degree-of-Freedom Serial Robots Equipped With Passive Isotropic Force Limiters

2015 ◽  
Author(s):  
Meiying Zhang ◽  
Thierry Laliberté ◽  
Clément Gosselin
Keyword(s):  
Human Robot Interaction ◽  
Contact Forces ◽  
Degree Of Freedom ◽  
Practical Implementation ◽  
Robot Interaction ◽  
End Effector ◽  
Serial Robots ◽  
Serial Robot ◽  
Maximum Contact ◽  
Two Degree Of Freedom

This paper proposes the use of passive force and torque limiting devices to bound the maximum forces that can be applied at the end-effector or along the links of a robot, thereby ensuring the safety of human-robot interaction. Planar isotropic force limiting modules are proposed and used to analyze the force capabilities of a two-degree-of-freedom planar serial robot. The force capabilities at the end-effector are first analyzed. It is shown that, using isotropic force limiting modules, the performance to safety index remains excellent for all configurations of the robot. The maximum contact forces along the links of the robot are then analyzed. Force and torque limiters are distributed along the structure of the robot in order to ensure that the forces applied at any point of contact along the links are bounded. A power analysis is then presented in order to support the results. Finally, examples of mechanical designs of force/torque limiters are shown to illustrate a possible practical implementation of the concept.

Force Capabilities of Two-Degree-of-Freedom Serial Robots Equipped With Passive Isotropic Force Limiters

2016 ◽  
Vol 8 (5) ◽  
Author(s):  
Meiying Zhang ◽  
Thierry Laliberté ◽  
Clément Gosselin
Keyword(s):  
Human Robot Interaction ◽  
Contact Forces ◽  
Degree Of Freedom ◽  
Practical Implementation ◽  
Robot Interaction ◽  
End Effector ◽  
Serial Robots ◽  
Serial Robot ◽  
Maximum Contact ◽  
Two Degree Of Freedom

This paper proposes the use of passive force and torque limiting devices to bound the maximum forces that can be applied at the end-effector or along the links of a robot, thereby ensuring the safety of human–robot interaction. Planar isotropic force limiting modules are proposed and used to analyze the force capabilities of a two-degree-of-freedom (2DOF) planar serial robot. The force capabilities at the end-effector are first analyzed. It is shown that, using isotropic force limiting modules, the performance to safety index remains excellent for all configurations of the robot. The maximum contact forces along the links of the robot are then analyzed. Force and torque limiters are distributed along the structure of the robot in order to ensure that the forces applied at any point of contact along the links are bounded. A power analysis is then presented in order to support the results. Finally, examples of mechanical designs of force/torque limiters are shown to illustrate a possible practical implementation of the concept.

Design and Static Analysis of Elastic Force and Torque Limiting Devices for Safe Physical Human-Robot Interaction

2016 ◽  
Author(s):  
Meiying Zhang ◽  
Thierry Laliberté ◽  
Clément Gosselin
Keyword(s):  
Static Analysis ◽  
Robotic Manipulator ◽  
Numerical Results ◽  
Elastic Force ◽  
Human Robot Interaction ◽  
Degree Of Freedom ◽  
Elastic Component ◽  
Robot Interaction ◽  
Nonlinear Relationships

This paper presents the static analysis of elastic force and torque limiters that aim at limiting the forces that a robotic manipulator can apply on its environment. First, the design of one-degree-of-freedom force and torque limiting mechanisms is presented. It is shown that a single elastic component (spring) can be used to provide a prescribed preload and stiffness in both directions of motion along a given axis. Then, the mechanisms are analyzed in order to determine the nonlinear relationships between the motion of the mechanism and the extension of the spring. These relationships can then be used in the design of the force and torque limiters. Finally, the force capabilities of the mechanisms are investigated and numerical results are provided for example designs.

Design and Static Analysis of Elastic Force and Torque Limiting Devices for Safe Physical Human–Robot Interaction

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Meiying Zhang ◽  
Thierry Laliberté ◽  
Clément Gosselin
Keyword(s):  
Static Analysis ◽  
Robotic Manipulator ◽  
Numerical Results ◽  
Elastic Force ◽  
Human Robot Interaction ◽  
Degree Of Freedom ◽  
Elastic Component ◽  
Robot Interaction ◽  
Nonlinear Relationships

This paper presents the static analysis of elastic force and torque limiters that aim at limiting the forces that a robotic manipulator can apply on its environment. First, the design of one-degree-of-freedom force and torque limiting mechanisms is presented. It is shown that a single elastic component (spring) can be used to provide a prescribed preload and stiffness in both directions of motion along a given axis. Then, the mechanisms are analyzed in order to determine the nonlinear relationships between the motion of the mechanism and the extension of the spring. These relationships can then be used in the design of the force and torque limiters. Finally, the force capabilities of the mechanisms are investigated and numerical results are provided for example designs.

A Coupled Two Degree of Freedom Model for Nano/Micromirrors Under van der Waals Force

2012 ◽  
Author(s):  
Hamid Moeenfard ◽  
Ali Darvishian ◽  
Mohammad Taghi Ahmadian
Keyword(s):  
Coupled Model ◽  
Bending Stiffness ◽  
Degree Of Freedom ◽  
Instability Mode ◽  
Equilibrium Equations ◽  
Bending Mode ◽  
Minimum Potential ◽  
Vdw Force ◽  
Torsion Stiffness ◽  
Two Degree Of Freedom

The current paper presents a two degree of freedom model for the problem of nano/micromirrors under the effect of vdW force. Energy method, the principal of minimum potential energy is employed for finding the equilibrium equations governing the deflection and the rotation of the nano/micromirror. Then using the implicit function theorem, a coupled bending-torsion model is presented for the pull-in characteristics of nano/micromirrors under vdW force and the concept of instability mode is introduced. It is observed that with increasing the ratio of the bending stiffness to the torsion stiffness, the dominant instability mode changes from bending mode to the torsion mode. It is shown that when the bending stiffness of the system is relatively low, the equilibrium point of a one degree of freedom torsion model considerably deviates from that of coupled model. The presented model in this paper can be used for safe and stable design of nano/micromirrors under vdW force.

Rotational Low-Impedance Physical Human–Robot Interaction Using Underactuated Redundancy

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Julien M. Audet ◽  
Clément Gosselin
Keyword(s):  
Experimental Validation ◽  
Human Robot Interaction ◽  
Static Equilibrium ◽  
Robot Interaction ◽  
Equilibrium Conditions ◽  
Passive Joint ◽  
Industrial Assembly

Abstract This paper extends the concept of underactuated redundancy for physical human–robot interaction (pHRI) in a context of industrial assembly by introducing a novel 1-dof gravity balanced rotational manipulator. The proposed architecture consists of a rotational active counterweight with a passive joint equipped with an encoder. The proposed architecture is first described, and the static equilibrium conditions are used to describe the operation of the mechanism. Then, alternative architectures are briefly introduced. Finally, an experimental validation is provided to demonstrate the viability of the concept for rotational low impedance pHRI.

Mechanical Design of a Low-Impedance 6-Degree-of-Freedom Displacement Sensor for Intuitive Physical Human-Robot Interaction

2020 ◽  
pp. 1-15
Author(s):  
Gabriel Boucher ◽  
Thierry Laliberte ◽  
Clement Gosselin
Keyword(s):  
Mechanical Design ◽  
Human Robot Interaction ◽  
Degree Of Freedom ◽  
Displacement Sensor ◽  
Robot Interaction ◽  
Serial Robot ◽  
Kinematic Sensitivity ◽  
Impedance Sensor ◽  
Forward Kinematic ◽  
Six Degree Of Freedom

Abstract This paper presents the mechanical design of a six-degree-of-freedom low-impedance displacement sensor. The sensor is mounted around a link of a serial robot and used as an interface for physical human-robot interaction. The motivation for the use of a low-impedance sensor is first discussed. The mechanical design of each of the elastic components of the sensor is then presented. The kinematic architecture of the mechanism is introduced and the inverse and forward kinematic problems are solved. The kinematic sensitivity is then used to characterize the accuracy of the mechanism. Finally, the design of a prototype is presented and experimental results are provided.

Augmenting an Educational and Research Human Robot Interaction Environment With a Multi-Obstacle Avoidance Algorithm

2015 ◽  
Author(s):  
Christopher E. Ábrego
Keyword(s):  
Path Planning ◽  
Obstacle Avoidance ◽  
Human Robot Interaction ◽  
Robot Interaction ◽  
Current State ◽  
Planning Algorithm ◽  
Holonomic Robot ◽  
Multiple Interaction ◽  
Path Planning Algorithm ◽  
Two Degree Of Freedom

In this manuscript, the development and current state of an inexpensive platform for educational purposes and research in the interaction between humans and robots (human-robot interaction) is described. The platform is based on the ubiquitous LabVIEW programming language and an in-house developed two degree of freedom non-holonomic robot. The platform includes multiple interaction modalities, which will be described, between the robot and the user. The procedures followed for the successful software and hardware implementation are explicated. Furthermore, a demonstration of an obstacle avoidance path planning algorithm for a single obstacle is validated in hardware, as well as simulation demonstration of the multiple obstacle avoidance algorithm. These implementations to the platform further demonstrate the ease of augmenting the existing platform to additional modalities. The algorithm uses a vision acquisition system to identify the location and size of an obstacle, in addition to orientation patterns and calibration points, in the workspace and generate the robot path to reach a desired goal while avoiding the obstacle. The manuscript describes into the current research of path planning in the presence of multiple obstacles. The development of a set of criteria, Generation Succession, Arrival Departure, and Side Consistency, for the algorithm are elucidated in the manuscript. The algorithm has been demonstrated to be successful in simulation by avoiding multiple obstacle in various layouts.

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