Human Interaction Dynamics for Its Use in Mobile Robotics:Impedance Control for Leader-follower Formation

A complete characterization of the behavior in human-robot interactions(HRI) includes both: the behavioral dynamics and the control laws that characterize how the behavior is regulated with the perception data. In this way, this work proposes a leader-follower coordinate control based on an impedance control that allows to establish a dynamic relation between social forces and motion error. For this, a scheme is presented to identify the impedance based on fictitious social forces, which are described by distance-based potential fields.As part of the validation procedure, we present an experimental comparison to select the better of two different fictitious force structures. The criteria are determined by two qualities: least impedance errors during the validation procedure and least parameter variance during the recursive estimation procedure.Finally, with the best fictitious force and its identified impedance,an impedance control is designed for a mobile robot Pioneer 3AT,which is programmed to follow a human in a structured scenario.According to results, and under the hypothesis that moving like humans will be acceptable by humans, it is believed that the proposed control improves the social acceptance of the robot for this kind of interaction.

PATH FOLLOWING GPS-BASED CONTROL OF SMALL-SIZE ROBOTIC UNMANNED BLIMP

Robotic unmanned blimps own an enormous potential for applications in low-speed and low-altitude exploration, surveillance, and monitoring, as well as telecommunication relay platforms. To make lighter-than-air platform a robotic blimp with significant levels of autonomy, the decoupled longitude and latitude dynamic model is developed, and the hardware and software of the flight control system are designed and detailed. Flight control and navigation strategy and algorithms for waypoint flight problem are discussed. A result of flight experiment is also presented, which validates that the flight control system is applicable and initial machine intelligence of robotic blimp is achieved.

Adaptive learning tracking control of robotic manipulators with uncertainties

An adaptive learning tracking control scheme is developed for robotic manipulators by a synthesis of adaptive control and learning control approaches. The proposed controller possesses both adaptive and learning properties and thereby is able to handle robotic systems with both time-varying periodic uncertainties and time invariant parameters. Theoretical proofs are established to show that proposed controllers ensure asymptotical tracking performance. The effectiveness of the proposed approaches is validated through extensive numerical simulation results.

Two types of coaxial self-balancing robots

Two types of coaxial self-balancing robots(CSBR)were proposed,one can be used as a mobile robot platform for parts transporting in unmanned factory or as an inspector in dangerous areas,and the other can be used as a personal transporter ridden in cities.Mechanical designing and control structures as well as control strategies were described and compared in order to get a general way to develop such robots.A state feedback controller and a fuzzy controller were designed for the robot using DC servo motors and the robot using torque motors,respectively.The experiments indicate that the robots can realize various desired operations smoothly and agilely at the velocity of 0.6 m/s with an operator of 65 kg.Furthermore,the robustness of the controllers is revealed since these controllers can stabilize the robot even with unknown external disturbances.

OPTIMAL CONTROL OF REDUNDANT ROBOTS WITH LOCAL DEGREES OF FREEDOM

A kinematically redundant robot, with more degrees of freedom than re-quired to complete a desired task, can be usefu1 because of its inherent kinematics flexibili-ty and dynamic performance. lt is very difficu1t, however, to implement optimal redun-dancy control, while simultaneously taking into account hath kinematics and dynamics.To realize dua1-optimization control, a new redundant robot mechanism with local degreesof freedom is introduced, and its kinematics and dynamics features are investigated. Simu-lation results demonstrate the effectiveness of the proPosed method.

APPLICATION OF SPINOR METHOD TO THE DYNAMIC ANALYSIS OF ROBOT

A method known as spinor method is applied to the study of dynamic model of robot.It merges velocity and angular velocity.Force and moments into an organic whole by their internal relation, and mates Newton-Euler method more concise and efficient.A reference system is formed with respect to the mass center of the arms of robot, which simplifies the calculation of inertial lensor and mass center acceleration.And further reduces work load in calculation, and thus ensures a fast real-timecalculation.

Modeling and simulation of percussive impact for robotic riveting system

Riveting is one of the major joining methods used in assembly, and the robotic riveting has been grad- ually introduced into aircraft industry. In this paper, a method is presented for modeling and simulation of per- cussive robotic riveting. In percussive riveting, vibration always exists. When an impact force is employed, a forced vibration will be induced. If it resonates with a robot nat- ural frequency, the vibration will cause damage to the robot. The main content of this paper is divided into three parts. Firstly, a robot dynamic model is established to compute the driving torque for each joint. Secondly, vibration responses under impact are analyzed for the percussive riveting process. Thirdly, the effect of riveting on robot vibration is studied over the robot workspace. The purpose of this paper is to discuss the suitable regions for riveting where the robot vibration is very minimal. It is shown that based on the presented method an appropriate trajectory can be planned for robotic riveting.

Identification of robot dynamic model and joint frictions using a baseplate force sensor

Dynamic models play an important role in robot control and applications.The accurate identification of dynamic models has become crucial to meeting increasing performance requirements.Owing to the inertial forces and the joint frictions coupling,the identification first requires a parametrized friction model.However,the joint frictions are strongly nonlinear and vary with many factors including posture,velocity and temperature.Hence,all friction models have some deviation from the real values,which reduces the identification accuracy.This paper proposes an identification approach using a baseplate force sensor.It identifies the inertial parameters first and then computes the joint friction values by subtracting the inertial torques from the joint torques.This method has the advantage that it does not require a priori friction model.It can choose or construct a proper model to fit the real values and is thus expected to achieve high performance.Experiments on a 6-DoF robot were conducted to verify the proposed method.

Development of Minimalist Bipedal Walking Robot with Flexible Ankle and Split-mass Balancing Systems

This paper presents a novel design of minimalist bipedal walking robot with flexible ankle and split-mass balancing systems.The proposed approach implements a novel strategy to achieve stable bipedal walk by decoupling the walking motion control from the sideway balancing control.This strategy allows the walking controller to execute the walking task independently while the sideway balancing controller continuously maintains the balance of the robot.The hip-mass carry approach and selected stages of walk implemented in the control strategy can minimize the efect of major hip mass of the robot on the stability of its walk.In addition,the developed smooth joint trajectory planning eliminates the impacts of feet during the landing.In this paper,the new design of mechanism for locomotion systems and balancing systems are introduced.An additional degree of freedom introduced at the ankle joint increases the sensitivity of the system and response time to the sideway disturbances.The efectiveness of the proposed strategy is experimentally tested on a bipedal robot prototype.The experimental results provide evidence that the proposed strategy is feasible and advantageous.

Development of Wheel-less Snake Robot with Two Distinct Gaits and Gait Transition Capability

Snake robots are mostly designed based on single mode locomotion. However, single mode gait most likely could not work effectively when the robot is subject to an unstructured working environment with different measures of terrain complexity. As a solution, mixed mode locomotion is proposed in this paper by synchronizing two types of gaits known as serpentine and wriggler gaits used for non-constricted and narrow space environments, respectively, but for straight line locomotion only. A gait transition algorithm is developed to efficiently change the gait from one to another. This study includes the investigation on kinematics analysis followed by dynamics analysis while considering related structural constraints for both gaits. The approach utilizes the speed of the serpentine gait for open area locomotion and exploits the narrow space access capability of the wriggler gait. Hence, it can increase motion flexibility in view of the fact that the robot is able to change its mode of locomotion according to the working environment.

Radial basis function‐based exoskeleton robot controller development

The realisation of a model‐based controller for a robot with a higher degree of freedom requires a substantial amount of computational power.A high‐speed CPU is required to maintain a higher sampling rate.Multicore processors cannot boost the performance or reduce the execution time as the programs are sequentially structured.The neural network is a great tool to convert a sequentially structured program to an equivalent parallel architecture program.In this study,a radial basis function(RBF)neural network is developed for controlling 7 degrees of freedom of the human lower extremity exoskel-eton robot.A realistic friction model is used for modelling joint friction.High trajectory tracking accuracies have been obtained.Evidence of computational efficiency has been observed.The stability analysis of the developed controller is presented.Analysis of variance is used to assess the controller's resilience to parameter variation.To show the effectiveness of the developed controller,a comparative study was performe between the developed RBF network‐based controller and Sliding Mode Controller,Computed Tor-que Controller,Adaptive controller,Linear Quadratic Regulator and Model Reference Computed Torque Controller.