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

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

10.1115/1.4032120 ◽

2016 ◽

Vol 8 (5) ◽

Cited By ~ 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 ◽

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.

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

10.1115/1.4049191 ◽

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.

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

10.1115/1.4051132 ◽

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 ◽

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.

A Backdrivable Kinematically Redundant (6+3)-Degree-of-Freedom Hybrid Parallel Robot for Intuitive Sensorless Physical Human–Robot Interaction

IEEE Transactions on Robotics ◽

10.1109/tro.2020.3043723 ◽

2020 ◽

pp. 1-17

Author(s):

Kefei Wen ◽

Tan Sy Nguyen ◽

David Harton ◽

Thierry Laliberte ◽

Clement Gosselin

Keyword(s):

Parallel Robot ◽

Human Robot Interaction ◽

Degree Of Freedom ◽

Robot Interaction

Seven-Position Synthesis of a Spatial Eight-Bar Linkage by Constraining a TRS Serial Chain

Volume 7: 33rd Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2009-87366 ◽

2009 ◽

Cited By ~ 1

Author(s):

Gim Song Soh ◽

J. Michael McCarthy

Keyword(s):

Degree Of Freedom ◽

Upper Arm ◽

End Effector ◽

Serial Chain ◽

Position Synthesis ◽

Two Degree Of Freedom ◽

Puma Robot

In this paper, we use seven-position synthesis to add four TS constraints to a TRS serial chain robot and obtain a two degree-of-freedom spatial eight-bar linkage. The TRS chain is an elbow manipulator, similar to a PUMA robot. We synthesize a TS dyad to connect the base of the robot to its forearm, and then we synthesize three TS dyads that connect the upper arm of the robot to its end-effector. The result is a two degree-of-freedom spatial eight-bar linkage that moves through seven prescribed positions. It consists of a TRST loop supporting a 3TS-RS platform, which we denote as a TS-TRS-3TS spatial linkage. We formulate and solve the design equations for the TS dyads, and analyze the resulting eight-bar linkage. An example demonstrates our results.

Reactionless Two-Degree-of-Freedom Planar Parallel Mechanism With Variable Payload

Volume 7: 33rd Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2009-86700 ◽

2009 ◽

Author(s):

Alexandre Lecours ◽

Cle´ment Gosselin

Keyword(s):

Dynamic Simulation ◽

Parallel Mechanism ◽

Reaction Force ◽

Simulation Software ◽

Degree Of Freedom ◽

Dynamic Balancing ◽

End Effector ◽

Planar Mechanism ◽

Two Degree Of Freedom ◽

Arbitrary Trajectory

A reactionless mechanism is one which does not exert any reaction force or moment on its base at all times, for any arbitrary trajectory of the mechanism. This paper addresses the static and dynamic balancing of a two-degree-of-freedom parallel planar mechanism (five-bar mechanism). A simple and effective adaptive balancing method is presented that allows the mechanism to maintain the reactionless condition for a range of payloads. Important proofs concerning the balancing of five-bar mechanisms are also presented. The design of a real mechanism where parallelogram linkages are used to produce pure translations at the end-effector is also presented. Finally, using dynamic simulation software, it is shown that the mechanism is reactionless for arbitrarily chosen trajectories and for a variety of payloads.

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

Volume 5B: 40th Mechanisms and Robotics Conference ◽

10.1115/detc2016-59205 ◽

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

10.1115/1.4035683 ◽

2017 ◽

Vol 9 (2) ◽

Cited By ~ 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

Multi-connection load compensation and load information calculation for an upper-limb exoskeleton based on a six-axis force/torque sensor

International Journal of Advanced Robotic Systems ◽

10.1177/1729881419863186 ◽

2019 ◽

Vol 16 (4) ◽

pp. 172988141986318 ◽

Cited By ~ 1

Author(s):

Xin Wang ◽

Qiuzhi Song ◽

Shitong Zhou ◽

Jing Tang ◽

Kezhong Chen ◽

...

Keyword(s):

Upper Limb ◽

Interaction Force ◽

Center Of Gravity ◽

Human Robot Interaction ◽

Whole Body ◽

Torque Sensor ◽

Robot Interaction ◽

End Effector ◽

Load Compensation ◽

Upper Limb Exoskeleton

In this article, a method of multi-connection load compensation and load information calculation for an upper-limb exoskeleton is proposed based on a six-axis force/torque sensor installed between the exoskeleton and the end effector. The proposed load compensation method uses a mounted sensor to measure the force and torque between the exoskeleton and load of different connections and adds a compensator to the controller to compensate the component caused by the load in the human–robot interaction force, so that the human–robot interaction force is only used to operate the exoskeleton. Therefore, the operator can manipulate the exoskeleton with the same interaction force to lift loads of different weights with a passive or fixed connection, and the human–robot interaction force is minimized. Moreover, the proposed load information calculation method can calculate the weight of the load and the position of its center of gravity relative to the exoskeleton and end effector accurately, which is necessary for acquiring the upper-limb exoskeleton center of gravity and stability control of whole-body exoskeleton. In order to verify the effectiveness of the proposed method, we performed load handling and operational stability experiments. The experimental results showed that the proposed method realized the expected function.

Volume 1: Adaptive/Intelligent Sys. Control; Driver Assistance/Autonomous Tech.; Control Design Methods; Nonlinear Control; Robotics; Assistive/Rehabilitation Devices; Biomedical/Neural Systems; Building Energy Systems; Connected Vehicle Systems; Control/Estimation of Energy Systems; Control Apps.; Smart Buildings/Microgrids; Education; Human-Robot Systems; Soft Mechatronics/Robotic Components/Systems; Energy/Power Systems; Energy Storage; Estimation/Identification; Vehicle Efficiency/Emissions ◽

Error Dynamics Design via a Repetitive Loop for UDE-Based Robust Control to Reject Periodic Disturbances

10.1115/dscc2020-3221 ◽

2020 ◽

Author(s):

Yeqin Wang ◽

Yiting Dong ◽

Jiguo Dai ◽

Beibei Ren ◽

Qing-Chang Zhong

Keyword(s):

Robust Control ◽

Disturbance Rejection ◽

Degree Of Freedom ◽

Practical Implementation ◽

Reference Tracking ◽

Charging System ◽

Internal Model Principle ◽

Periodic Disturbances ◽

Error Dynamics ◽

Abstract The uncertainty and disturbance estimator (UDE)-based robust control has a two-degree-of-freedom nature through the design of the error dynamics and the design of the UDE filters. In the conventional design to handle periodic disturbances or mixed sinusoidal disturbances, high-order UDE filters incorporated with the internal model principle (IMP) or time-delay filters (TDF) are adopted to achieve the asymptotic reference tracking and the asymptotic disturbance rejection. In this paper, a new error dynamics design combined with a repetitive loop is proposed for the UDE-based robust control to achieve the asymptotic rejection of both step disturbances and periodic disturbances. The disturbance rejection performance is investigated through the two-degree-of-freedom nature, and the practical implementation of the proposed design is illustrated to eliminate the infinite bandwidth of the repetitive loop. The proposed design is validated through the simulation studies of a battery charging system with comparison to different reported designs of the conventional UDE-based robust control.