Spherical Robot Research Articles

Experimental study on the model-based control of a 2-degree-of-freedom spherical parallel robot camera stabilizer based on multi-thread programming concept

This article aims at proposing a real-time controller for a camera stabilizer using a 2-degree-of-freedom spherical parallel robot with simultaneous display of the control results using multi-threading programming concept. The main contribution of this article can be regarded as employing (a) a 2-degree-of-freedom spherical parallel robot as a camera stabilizer, (b) introducing approximated model and Jacobian model, and (c) using multi-thread programming in order to create equal conditions for comparing accuracy of designed controllers and simultaneous controlling and running of graphical user interface. The experimental setup consists of a 2-degree-of-freedom spherical parallel robot in which a camera is attached to its end-effector plus a 3-degree-of-freedom passive rotational platform, which provide the possibility to apply random perturbations on the base of the foregoing 2-degree-of-freedom spherical parallel robot. At the end-effector of the robot, a 6-degree-of-freedom sensor is installed which sends rotational data to a micro controller, wirelessly. To this end, transceiver boards are constructed to create connection between PC controller and micro-controller. A PC controller is designed in order to ensure that the installed cameras orientation will remain fixed for a prescribed orientation. In this regard, a controller without encoder and a Jacobian-based controller are employed for the under study spherical 2-degree-of-freedom parallel robot. Then, multi-thread programming is used to eliminate complexities of controller structures. Based on the experimental results obtained by implementing both controller, outputs are compared and mean error of each control method and the related RMSE are reported for the sake of proposing the most promising controller.

Adaptive estimation of nonlinear parameters of a nonholonomic spherical robot using a modified fuzzy-based speed gradient algorithm

This paper deals with adaptive estimation of the unknown parameters and states of a pendulum-driven spherical robot (PDSR), which is a nonlinear in parameters (NLP) chaotic system with parametric uncertainties. Firstly, the mathematical model of the robot is deduced by applying the Newton–Euler methodology for a system of rigid bodies. Then, based on the speed gradient (SG) algorithm, the states and unknown parameters of the robot are estimated online for different step length gains and initial conditions. The estimated parameters are updated adaptively according to the error between estimated and true state values. Since the errors of the estimated states and parameters as well as the convergence rates depend significantly on the value of step length gain, this gain should be chosen optimally. Hence, a heuristic fuzzy logic controller is employed to adjust the gain adaptively. Simulation results indicate that the proposed approach is highly encouraging for identification of this NLP chaotic system even if the initial conditions change and the uncertainties increase; therefore, it is reliable to be implemented on a real robot.

A Novel Amphibious Spherical Robot Equipped with Flywheel, Pendulum, and Propeller

The ability of amphibious movement is found widely among small animals such as frogs, tortoises, snakes, and crabs. They can move on land, in water, and even on the water bottom. Inspired by the animals’ moving capability, an amphibious spherical robot with flywheel, pendulum, and propeller has been developed. In this paper, the mechanical structure, motion performance, control architecture, and experimentation of the amphibious spherical robot are presented. The robot can show three outstanding advantages for underwater observation, which distinguish it from the other existing observing robots. First, it can resist great water pressure to protect the internal components that is based on the spherical shell. Second, the robot only requires a single propeller to achieve the flexible movement and control posture in water. Third, the robot can roll on land or on water bottom only through an internal motor that can reduce the energy consumption during the observation process. The robot has a wide range of applications such as underwater observation, search and rescue, sensor networks.

Structure Design and Force Analysis for a Novel Spherical Robot

At present, exploring the vast unknown fields (including space and ocean) has become a hot topic in various agencies. As a moving carrier, the mobile intelligent robot plays an important role, such as communication base stations and observation platform. In order to adapt to a variety of working conditions, a new type of robot was proposed, which can move freely on land or in water with a circular shell, a single propeller and a pair of heavy pendulum. The pendulum inside the robot is used to adjust the attitude, which makes the robot move flexibly, and the circular shell has the excellent compression capability. In order to analyze the kinematics and dynamics characteristics in water, the hydrodynamic forces are studied before the manufacture by CFD simulation. The new type of spherical robot is simplified into spherical finite element model with the pipe. The hydrodynamic force coefficients of robot are calculated by straight shipping, oblique shipping and cantilevered pool simulation. The testing data of robot are obtained in pool for straight shipping by the experiment. Through the above calculation and contrast, the hydrodynamic results can be proved effectively, which can save time for the improved design of robot in the future.

Mimebot: spherical robot visually imitating a rolling sphere

PurposeWhen designing a performance involving people and mobile robots, the required functions and shape of the robot must be considered. However, it can be difficult to account for all of the requirements. The purpose of this paper is to discuss a mobile robot in the shape of a ball that is used in theatrical performances.Design/methodology/approachThe paper proposes a mobile robot that can give the audience the optical illusion of the unique movements of a sphere by mounting a spherical light-emitting diode (LED) display on a high-agility wheeled robot.FindingsIt was found that movements that are difficult to implement with existing mechanisms can nonetheless be visualized through the use of light.Originality/valueThe paper proposes the concept of using pseudo-physical movements in performances with robots. The authors built a robot that visually reproduces the movements of a rolling sphere and is capable of faster movements and easier position estimations in comparison with previous spherical robots.

Brief Analysis of Underwater Movements of Spherical Robot

Underwater robot has become an important tool for people to understand, develop and utilize the ocean. At present, thousands of underwater robots have been developed to satisfy the requirement of underwater tasks and many researchers pay more attention on the underwater robots. This paper uses CFD to simulate the horizontal motion, downward motion and rotary motion of the spherical underwater robot to analyze the influence of spherical robot underwater structure on velocity and pressure, which provides the basic data of underwater motion of the robot and lays the foundation for optimizing the control method of the robot.

Modelling and control of a non‐holonomic pendulum‐driven spherical robot moving on an inclined plane: simulation and experimental results

This study deals with mathematical modelling and motion control of a pendulum-driven spherical robot (PDSR) moving on an inclined plane. Firstly, the model of a PDSR on an inclined plane is developed using a Lagrangian formulation. Afterwards, a PID controller is tuned to stabilise the robot on the inclined plane. A heuristic fuzzy controller and a PID controller are also designed to move the robot upward or downward the inclined plane and approach the target point. A switched control, i.e. a combination of the designed controllers, is finally suggested to control the motion of the robot on the inclined plane. Simulations are conducted to investigate and compare the performance of the proposed controllers. Experiments are also conducted for different cases to validate the simulations and also evaluate the control strategies via image processing.

Mechanics of Combined-Type Spherical Robot

Описываются варианты роботов сферического типа с различными конструкциями механической части, и на их основе предлагается новая компоновочная схема, свободная от ряда ограничений, присущих перечисленным устройствам. Показаны ситуации, в которых новое устройство будет предпочтительнее описанных. Представлены и другие компоновочные схемы, использующие предлагаемый принцип комбинирования их основных движущих частей. Робот предложенной конструкции сможет работать в трех независимых режимах движения, причем как по отдельности, так и в сочетании.

Controlling spherical mobile robot in a two-parametric friction model

The theoretical mechanical model of the spherical robot with the flywheels located in a sphere is considered. The described design is intended for the motion control of a sphere on various trajectories. In the paper, control algorithms of a sphere on basic trajectories are investigated; the movements from rotation on the point and the movements on a straight line piece before the basic movements on curvilinear trajectories are considered. The paper describes dynamical models of a sphere robot, different models of friction, as well as a two-parametrical model as the main model of friction. Technical possibility of realization of a sphere robot with flywheels is proved.

Управление роботом-шаром с помощью маховиков

Управление роботом-шаром с помощью маховиков

Research on Intelligent Flight Software Robot Based on Internet of Things

2010 China Internet of Things Application Promotion Union pointed out that the robot is one of the 100 leading edge technology. 2015, the forefront of the field of robot top10 technology, including Internet of things embedded technology, simulation technology, large data technology, cloud computing robot, robot autonomy technology and so on. The robot uses the sensor technology in the key technology of the Internet of Things. In order to make life better and more convenient, the research of Internet of Things technology and application, focusing on research based on the Internet of intelligent flight spherical monitoring software robot technology. In this paper, you can use mat lab simulation robot and programming algorithm, the use of advanced programming language to develop intelligent flight robots. The research results of intelligent flight monitoring software robot technology can be applied in academia and industry and medical transportation. This paper studies the intelligent flight monitoring software robot under the Internet of Things.

Управление несбалансированным сферическим роботом

Управление несбалансированным сферическим роботом

Исследование устойчивости стационарных движений сфероробота комбинированного типа

Исследование устойчивости стационарных движений сфероробота комбинированного типа

Energy Expenditure Forecasting at Path Generation of Spherical Robots within Multi-Agent System

Background: The present research is relevant due to gathering the experience associated with a practical use of a spherical robot as a chassis for placing the local environmental monitoring equipment and due to the revealed need to use such robots within groups. Therefore, the article is aimed at showing the connections between the parameters of the external environment and kinematic, power and energy characteristics of the spherical robot chassis. Method: The main approaches to the research of the present problem are the methods of the transportation vehicle motion theory which in their turn are based on theoretical mechanics and theoretical physics laws, etc. The methodologies enable to significantly simplify a non-holonomic task associated with a sphere motion and to reach kinetic, power and energy characteristics appropriate for a practical use. Findings: The authors have studied the questions related to the estimation of energy expenditure for the spherical robot motion in an arbitrary path, have offered the concept of energy expenditure chart and shown the principles of using such chart for generation of a path of a spherical robot which operates within a multi-agent system. The approach regarding the generation of energy expenditure chart based on the preliminary area survey using a spherical robot has also been studied in the present article. Improvements: The materials of this article are of a practical value when working on the development of the ground component of multi-component multi-agent systems regardless of the type of the agent chassis.

Controller tuning based on optimization algorithms of a novel spherical rolling robot

This study presents the construction process of a novel spherical rolling robot and control strategies that are used to improve robot locomotion. The proposed robot drive mechanism is constructed based on a combination of the pendulum and wheel drive mechanisms. The control model of the proposed robot is developed, and the state space model is calculated based on the obtained control model. Two control strategies are defined to improve the synchronization performance of the proposed robot motors. The proportional-derivative and proportional-integral-derivative controllers are designed based on the pole placement method. The proportional-integral-derivative controller leads to a better step response than the proportional-derivative controller. The controller parameters are tuned with genetic and differential evaluation algorithms. The proportional-integral-derivative controller which is tuned based on the differential evaluation algorithm leads to a better step response than the proportional-integral-derivative controller that is tuned based on genetic algorithm. Fuzzy logics are used to reduce the robot drive mechanism motors synchronizing process time to the end of achieving a high-performance controller. The experimental implementation results of fuzzy-proportional-integral-derivative on the proposed spherical rolling robot resulted in a desirable synchronizing performance in a short time.

Nonholonomic dynamics and control of a spherical robot with an internal omniwheel platform: Theory and experiments

We present the results of theoretical and experimental investigations of the motion of a spherical robot on a plane. The motion is actuated by a platform with omniwheels placed inside the robot. The control of the spherical robot is based on a dynamic model in the nonholonomic statement expressed as equations of motion in quasivelocities with indeterminate coefficients. A number of experiments have been carried out that confirm the adequacy of the dynamic model proposed.

Design and Analysis of a Four-Pendulum Omnidirectional Spherical Robot

This paper presents the design, analysis, and comparison of a novel four-pendulum spherical robot. The proposed mechanism rolls omnidirectionally via four tetrahedrally-located pendulums that shift the robot's center of mass to create rolling torque. The nine dynamic equations of motion are derived via the Lagrangian and nonholonomic constraint equations, and then simulated numerically; results show successful propulsion with expected behaviors. The mechanism is then compared to existing center-of-mass designs in terms of directionality, drive torque arm, and inertia eccentricity. In these regards, the four-pendulum design is a balance of existing designs: it is omnidirectional with eccentricity and torque capability that are in the middle of the range exhibited by existing designs. In addition, the new four-pendulum mechanism has been built and tested as a successful proof-of-concept prototype.

A roller-skating/walking mode-based amphibious robot

An amphibious spherical robot capable of motion on land as well as underwater is developed to implement the complicated underwater operations in our previous research. In order to improve the speed performance of the spherical robot on a slope or comparatively smooth terrains, we propose a new roller-skating mode for the robot by equipping a passive wheel on each leg to implement the roller-skating motion in this paper. A braking mechanism is designed to transform the state of each passive wheel between free rolling and braking states by compressing and releasing the spring, which is controlled by the vertical servo motor on each leg. Besides, in order to improve the walking stability of the wheeled robot in longitudinal direction, a closed-loop control method is presented to control the stability of the direction of movement while walking. Therefore, we conduct the experiments on smooth terrains and down a slope to evaluate the performance of the roller-skating motion, including gait stability and velocity. Finally, plenty of walking experiments are conducted to evaluate the ability of directional control. We describe a roller-skating/walking mode-based quadruped amphibious robot.The new wheeled robot has two on-land actuating modes: walking and roller-skating.A braking mechanism installed on each leg is proposed to apply brake for the robot.The mechanism is also used as a transformation mechanism for mode switching.We present a closed-loop control method to control the direction of movement.

Modal and fatigue analysis of critical components of an amphibious spherical robot

With continuous improvements being made in science, technology, and production automation, robotics is becoming increasingly popular in the field of automation. Robotics has the potential to improve work efficiency, reduce production cost, protect humans from adverse conditions, and increase production scale. A three-dimensional (3D) printed amphibious spherical robot was designed to operate in various environments with a wide-range of complex conditions over a long period of time. The compact, fully waterproof design has the advantages of a reduced manufacturing time, high efficiency, good mobility, low noise, and reliable stability. This study considers how some of the more critical components of the robot, such as its leg brackets, circular middle plate, and spherical shell, respond to large dynamic stresses, shocks, and vibrations during operation; this can lead to reduced precision of the robot's locomotion and may cause critical components to become damaged or fail. To design the robot with a more rigid structure and improved dynamic characteristics, 3D models of the critical components were constructed with SolidWorks. Using ANSYS WORKBENCH software, these models were incorporated into the robot design to determine the natural frequencies and the associated mode shapes of the first six orders. The procedure and analysis results are described in this paper. The fatigue life of these critical components was examined using the cyclic load spectrum and cyclic stress as a function of number of cycles to failure (S---N curve) of acrylonitrile butadiene styrene plastic, the construction material for the robot. Finite element analysis was used for design optimization relevant to fatigue life, damage, safety, and fatigue sensitivity, and the weak areas in the components were identified. The approach described herein provides a theoretical basis for robotics design optimization.

Planning the Initial Motion of a Free Sliding/Rolling Ball

This paper investigates the motion of a free ball with initial velocity and angular velocity on a horizontal plane under friction. The ball will first slide along a parabolic trajectory (with its contact velocity in constant direction) and then roll along a straight trajectory. Curving of the sliding trajectory can be utilized for obstacle avoidance in path planning. A one-to-one correspondence exists between curved trajectories of the ball from one point to another and pairs of sliding and rolling directions that span a cone at the starting point to contain the ending point in the interior. This leads to a compact 2-D trajectory space, in which obstacles induce monotonic constraint curves. Based on the monotonicity, a plane sweep algorithm is described to find all collision-free trajectories. The work has several distinct features: handling of both sliding and rolling; planning in the configuration space of trajectories not that of the ball; computation of not just one collision-free trajectory but all such trajectories; and, finally, combining dynamics with computational geometry. The application of the work to spherical robots is discussed at the end.