A novel control architecture based on behavior trees for an omni-directional mobile robot

Robotic systems are increasingly present in dynamic environments. This paper proposes a hierarchical control structure wherein a behavior tree (BT) is used to improve the flexibility and adaptability of an omni-directional mobile robot for point stabilization. Flexibility and adaptability are crucial at each level of the sense–plan–act loop to implement robust and effective robotic solutions in dynamic environments. The proposed BT combines high-level decision making and continuous execution monitoring while applying non-linear model predictive control (NMPC) for the point stabilization of an omni-directional mobile robot. The proposed control architecture can guide the mobile robot to any configuration within the workspace while satisfying state constraints (e.g., obstacle avoidance) and input constraints (e.g., motor limits). The effectiveness of the controller was validated through a set of realistic simulation scenarios and experiments in a real environment, where an industrial omni-directional mobile robot performed a point stabilization task with obstacle avoidance in a workspace.This work was financed by national funds from the FCT (Foundation for Science and Technology), I.P., through IDMEC under LAETA, project UIDB\50022\2020. The work of Rodrigo Bernardo was supported by the PhD Scholarship BD\6841\2020 from the FCT. This work indirectly received funding from the European Union’s Horizon 2020 programme under StandICT.eu 2026 (Grant Agreement No. 101091933).info:eu-repo/semantics/publishedVersio

Implementation Kinematics Modeling and Odometry of Four Omni Wheel Mobile Robot on The Trajectory Planning and Motion Control Based Microcontroller

The control of kinematic modeling in a four wheel omni-directional robot (FWOR) is very difficult. Because you have to adjust the speed of the four DC motors. The speed of DC motors is controlled so that the FWOR robot can be controlled. This paper will explain the application of kinematic modeling of four wheel omni directional robots as track tracking controllers and microcontroller based movement control. Kinematic is the study of robot motion based on geometric structure analysis of a stationary / moving reference coordinate frame system without considering the force, torque or certain moments that cause movement. By applying kinematic modeling and calculation of the odometric system as feedback, the control of the robot trajectory movement can be controlled with precision in accordance with the path planning that has been made. The robot track control technique is embedded in a 32-bit ARM microcontroller. The path planning system and observing robot movement are carried out using a friendly graphic interface using Processing to facilitate the robot monitoring process. The results of the experiments and tests carried out, the system is able to control the rate of movement of the robot with great precision in accordance with the path planning made

Designing Omni-Directional Mobile Robot Platform for Research

Machines, as a key workforce in manufacturing, mining, construction, are essential for industry, and socially. However, existing mobile robots’ designs do not provide enough mobility and maneuverability. This is one of the major factors that requires an improved design of mobile robot platform. This thesis is focused on designing an improved Omni-directional robot platform that has good mobility and maneuverability. To realize these conditions, a lot of criteria and constraints need to be considered in the design process. The conceptual design flows of this mobile robot are to satisfy the need of a mobile robot platform, establish Omni-directional mobile robot specifications followed by concept generation and concept selection. A full decomposition of Omni-directional mobile robot was done. This was followed by building a morphology chart to gather several ideas for those sub-functions of mobile robot. Combination of different types of sub-functions will generate several new Omni-directional mobile robot concepts. The concepts were drafted by using Three-dimensional (3-D) Computer Aided Designing SOLIDWORKS software. After concept generation, the concepts were evaluated by using weighted decision matrix method. The best concept was generated from 3-D design to get 2-D technical drawing and kinematics analysis. These analysis and results of the robot performance are presented in this thesi

Embedded system for motion control of an omnidirectional mobile robot

In this paper, an embedded system for motion control of omnidirectional mobile robots is presented. An omnidirectional mobile robot is a type of holonomic robots. It can move simultaneously and independently in translation and rotation. The RoboCup small-size league, a robotic soccer competition, is chosen as the research platform in this paper. The first part of this research is to design and implement an embedded system that can communicate with a remote server using a wireless link, and execute received commands. Second, a fuzzy-Tuned proportional-integral (PI) path planner and a related low-level controller are proposed to attain optimal input for driving a linear discrete dynamic model of the omnidirectional mobile robot. To fit the planning requirements and avoid slippage, velocity, and acceleration filters are also employed. In particular, low-level optimal controllers, such as a linear quadratic regulator (LQR) for multiple-input-multiple-output acceleration and deceleration of velocity are investigated, where an LQR controller is running on the robot with feedback from motor encoders or sensors. Simultaneously, a fuzzy adaptive PI is used as a high-level controller for position monitoring, where an appropriate vision system is used as a source of position feedback. A key contribution presented in this research is an improvement in the combined fuzzy-PI LQR controller over a traditional PI controller. Moreover, the efficiency of the proposed approach and PI controller are also discussed. Simulation and experimental evaluations are conducted with and without external disturbance. An optimal result to decrease the variances between the target trajectory and the actual output is delivered by the onboard regulator controller in this paper. The modeling and experimental results confirm the claim that utilizing the new approach in trajectory-planning controllers results in more precise motion of four-wheeled omnidirectional mobile robots. 2018 IEEE.Scopu

Comprehensive Development And Control Of A Path-Trackable Mecanum-Wheeled Robot

This paper presents an intuitively straightforward yet comprehensive approach in developing and controlling a Mecanum-wheeled robot (MWR), with decent path tracking performance by using a simple controller as an end objective. The development starts by implementing two computer ball mice as sensors to realize a simple localization that is immune toward wheel slippage. Then, a linearization method by using open-loop step responses is carried out to linearize the actuations of the robot. Open-loop step response is handy, as it directly portrays the non-linearity of the system, thus achieving effective counteraction. Then, instead of creating a lookup table, polynomial regression is used to generate an equation in which the equation later represents an element of the linearizer. Next, a linear angle-to-gain (LA-G) method is introduced for path tracking control. The method is as easy as just linearly maps the summation of two angles-the angle between immediate and desired positions and the MWR's heading angle, into gains to control the wheels. Unlike the conventional control method which involves inverse kinematics, the LA-G method is directly a displacement-controlled approach and does not require the knowledge of parametric values, such as the robot's dimensions and wheel radius. Finally, all the methods are implemented, and the MWR experimentally demonstrates successfully tracking various paths, by merely using proportional controllers

Design and Control of Robotic Systems for Lower Limb Stroke Rehabilitation

Lower extremity stroke rehabilitation exhausts considerable health care resources, is labor intensive, and provides mostly qualitative metrics of patient recovery. To overcome these issues, robots can assist patients in physically manipulating their affected limb and measure the output motion. The robots that have been currently designed, however, provide assistance over a limited set of training motions, are not portable for in-home and in-clinic use, have high cost and may not provide sufficient safety or performance. This thesis proposes the idea of incorporating a mobile drive base into lower extremity rehabilitation robots to create a portable, inherently safe system that provides assistance over a wide range of training motions. A set of rehabilitative motion tasks were established and a six-degree-of-freedom (DOF) motion and force-sensing system was designed to meet high-power, large workspace, and affordability requirements. An admittance controller was implemented, and the feasibility of using this portable, low-cost system for movement assistance was shown through tests on a healthy individual. An improved version of the robot was then developed that added torque sensing and known joint elasticity for use in future clinical testing with a flexible-joint impedance controller

Trajectory tracking and time delay management of 4-mecanum wheeled mobile robots (4-MWMR)

International audienceNowadays, wheeled mobile robots have a very important role in industrial applications, namely in transportation tasks thanks to their accuracy and rapidity. However, meeting obstacles while executing a mission can cause an important time delay, which is not appreciable in industry where production must be optimal. This paper deals with the time delay management, the trajectory generation and the tracking problem applied on four wheeled omnidirectional mobile robots. A strategy is proposed to minimize or compensate the time delay caused by obstacles. The approach is done by updating the reference trajectory. This update helps to track the trajectory in real time, a new control law based on the feedback linearization control theory is synthesized to track perfectly generated or updated trajectories

3D MODELLING AND DESIGNING OF DEXTO:EKA:

The presented paper is concerned with designing of a low-cost, easy to use, intuitive interface for the control of a slave anthropomorphic teleo- operated robot. Tele-operator “masters”, that operate in real-time with the robot, have ranged from simple motion capture devices, to more complex force reflective exoskeletal masters. Our general design approach has been to begin with the definition of desired objective behaviours, rather than the use of available components with their predefined technical specifications. With the technical specifications of the components necessary to achieve the desired behaviours defined, the components are either acquired, or in most cases, developed and built. The control system, which includes the operation of feedback approaches, acting in collaboration with physical machinery, is then defined and implemented