Simscape Multibody Research Articles

Dynamic analysis of a five degree of freedom robotic arm using MATLAB-Simulink Simscape

In this paper, a dynamic analysis for a 5 degree of freedom (DOF) robotic arm with serial topology is presented. The dynamic model of the robot is based on importing a tri-dimensional CAD model of the robot into Simulink®-Simscape™-Multibody™. The dynamic model of the robot in Simscape is a necessary and important step in development of the mechanical structure of the robot. The correct choice of the electric motors is made according to the resistant joint torques determined by running the dynamic analysis. One can import complete CAD assemblies, including all masses, inertias, joints, constraints, and tri-dimensional geometries, into the model block. The first step for executing a dynamic analysis is to resolve the Inverse Kinematics (IK) problem for the redundant robot. The proposed method for solving the inverse kinematic problem for this type of structure is based on a geometric approach and validated afterwards using SimScape Multibody. Solving the inverse kinematics problem is a mandatory step in the dynamic analysis of the robot, this is required to drive the robot on certain user-imposed trajectories. The dynamic model of the serial robot is necessary for the simulation of motion, analysis of the robot’s structure and design of optimal control algorithms.

Control of Three-Axis Manipulator Placed on Heavy-Duty Pentapod Robot

Research on the effective use of joint-legged robots continues rapidly in many sectors. However, studies on pentapod robots are rare. In this study, a heavy-duty 5-legged robot on which a manipulator's arm with 3-axis and rotating joints is placed was modeled in a Matlab Simscape Multibody environment. The walking simulations of the robot and the position control of the manipulator arm were carried out. PID control method was used for the control of the joints. In order to minimize the vibrations of the base and the gripper end, a suitable gait sequence for 5 leg structure was formed. The effects of vibrations in the robot's base during the walk on manipulator position control are presented graphically and the results are discussed.

Trajectory-tracking control of a planar parallel robot using generalized predictive control with constraints

This paper presents the generalized predictive control with constraints, implemented to a planar parallel robot in order to calculate and track the desired trajectory of the end-effector of this robot. The manipulator is driven by three brushless direct current motors, and each one has an encoder to measure the velocity and rotation angles of the motors. Three constraints were considered to interact with the control law: control signal, terminal response and the over impulse constraints. The performance of the control law is evaluated in the simulation environment using Matlab/Simulink with the physic model developed through simscape multibody. The angular position and velocity errors for each of the three motors were calculated. Likewise, the output torques for each one were estimated. The results proved that the control law proposed with the constraints imposed for each motors has a good efficiency with a stable response time of the robot in performing the trajectory tracking, contributing to the scientific community a strategy of predictive optimization of control actions with multiple constraints applied on parallel robots.

A state augmented adaptive backstepping control of wheeled mobile robots

The present paper aims to design an integrated kinematic/dynamic-based tracking controller for wheeled mobile robots (WMRs) considering motors’ dynamics. By defining a reference WMR, the role of kinematic controller is to not only minimize the posture error which indicates the difference between the reference and actual WMRs, but also to generate a desired path for the actual WMR. The kinematic tracking control problem of WMRs is so challenging if motors’ dynamics, parametric and nonparametric uncertainties and external disturbances are considered. Thus, proposing a dynamic control law alongside a kinematic control is unavoidable. In this study, we propose a new dynamic controller, namely, a state augmented adaptive backstepping such that the desired path is asymptotically tracked. Several numerical results accompanied by 3D simulations of trajectory tracking control of a WMR in ‘Simscape Multibody’ environment and comparisons with two well-designed controllers in the literature are reported to show the high performance of proposed control structure.

A Lagrangian method for constrained dynamics in tensegrity systems with compressible bars

This paper presents a Lagrangian approach to simulating multibody dynamics in a tensegrity framework with an ability to tackle holonomic constraint violations in an energy-preserving scheme. Governing equations are described using non-minimum coordinates to simplify descriptions of the structure’s kinematics. To minimize constraint drift arising from this redundant system, the direct correction method has been employed in conjunction with a novel energy-correcting scheme that treats the total mechanical energy of the system as a supplementary constraint. The formulation has been extended to allow tensegrity structures with compressible bars, allowing for further discussion on potential choices for softer bar materials. The benchmark example involving a common tensegrity structure demonstrates the superiority of the presented formulation over Simscape Multibody in terms of motion accuracy as well as energy conservation. The effectiveness of the energy correction scheme is found to be increasing with the extent of deformations in the structure.

Quasi-physical modeling of robot IRB 120 using Simscape Multibody for dynamic and control simulation

Quasi-physical modeling of robot IRB 120 using Simscape Multibody for dynamic and control simulation

Teaching forward kinematics in a robotics course using simulations: transfer to a real-world context using LEGO mindstorms™

Previous studies show that traditional teaching methods such as oral explanations and PowerPoint presentations can be complemented with the use of computer simulations in problem-solving sessions to teach robotics. Nevertheless, these previous works rest upon the assumption that the knowledge that is learned in virtual laboratories transfers to its equivalent real task. The main contribution of this work is to validate that the knowledge obtained by students in an undergraduate robotics course using computer simulations of 3D model robots can be applied to its real-world context. The experimental platform used to run the computer simulations was based on the Simscape Multibody library of the MATLAB™ software. Results show a satisfactory knowledge transfer because more than 75% of the students finished a forward kinematics problem using a physical manipulator built with LEGO Mindstorms™. In addition, the observation analysis of the professor reveals that students reinforced their knowledge previously learned, and their problem-solving and critical thinking skills also improved. In this way, this study demonstrates that the proposed methodology not only helps the transfer of knowledge to the real-world context but also helps to develop student competencies. Future work is needed to replicate the findings in other robotics topics, such as the generation of trajectories, the analysis of the dynamics of manipulators, and the design of various controllers for the actuators of the robot.

Preliminary development and technical evaluation of a belt-actuated robotic rehabilitation platform.

BACKGROUND: To provide effective rehabilitation in the early post-injury stage, a novel robotic rehabilitation platform is proposed, which provides full-body arm-leg rehabilitation via belt actuation to severely disabled patients who are restricted to bed rest.OBJECTIVE: To design and technically evaluate the preliminary development of the rehabilitation platform, with focus on the generation of various leg movements.METHODS: Two computer models were developed by importing the components from SolidWorks into Simscape Multibody in MATLAB. This allowed simulation of various stepping movements in supine-lying and side-lying positions. Two belt-actuated test rigs were manufactured and automatic control programs were developed in TIA Portal. Finally, the functionality of the test rigs was technically evaluated. RESULTS: Computer simulation yielded target positions for the generation of various stepping movements in the experimental platforms. The control system enabled the two-drive test rig to provide three modes of stepping in a supine position. In addition, the four-drive test rig produced walking-like stepping in a side-lying position.CONCLUSIONS:This work confirmed the feasibility of the mechanical development and control system of the test rigs, which are deemed applicable for further development of the overall novel robotic rehabilitation platform.

Design and Physical Modelling Series Elastic Actuator for Ankle-Foot Orthosis

This paper describes the development of Physical Modelling of Series Elastic Actuator for Active Ankle-Foot Orthosis by using Simscape Multibody Link. Active Ankle-Foot Orthosis is essential that can be used for the rehabilitation process to the patient. It is useful in medicine to help a patient who loses their walking ability, due to ankle weakness, to regain the walking ability. This project focuses on the design, simulate and physical modelling for Ankle-Foot Orthosis. This project was used Solidworks as a platform to design the Active Ankle-Foot Orthosis and using MatLab/Simulink for simulation by using Simscape Multibody Link tools. The Active Ankle-Foot Orthosis moves in 2 basic movement of ankle that is dorsiflexion and plantar flexion for rehabilitation. So, this project focuses on the physical modelling for the Series Elastic Actuator that drives the ankle movement mimicking the normal gait cycle.

Four-legged hunter (FLH) robot: design and shooting control to moving targets with SMC

The design and control of robotic shooting control systems in defense systems is one of the important research topics in recent years. This study focuses on the design, modeling, and success of the shooting control system of the 14 Degrees of Freedom (DoF) Four Legged Hunter Robot (FLH) system with 2 DoFs gun barrel systems. The three-dimensional dynamic model of the FLH-Robot with gun barrel system was created by the Simscape Multibody toolbox of the MATLAB program. The leg joints of FLH were controlled by the PID control method to perform the motion of the robot. Gun barrel stabilization was performed in order to ensure the orientation of the gun barrel system to the predetermined targets and to enhance the hitting success rate. Mechanical oscillations in the robot body were applied as a disruptive effect on the gun barrel system. The sliding-mode control (SMC) method was applied to 2 DOFs gun barrel system. Ballistic simulations were repeated for situations where the targets were fixed and mobile. While the robot was walking, in the first shooting scenario, the shots made on fixed targets placed in random coordinates were hit with a maximum error of 3.3 cm. In the second shooting scenario, shots were fired on moving targets at a speed of 0.1 to 1 rad / s, and hitting success was achieved with a maximum error of 0.387 m. When hit error rates are analyzed, the usability of FLH-Robot for the defense industry was demonstrated.

Design and Simulation of Under Limb Orthosis for Rehabilitation of Paraplegics

Lower limb orthosis can be used to replace the loss of functioning of lower limb that causes a lot of inconvenience in carrying out day to day activities. However, wheelchair may assist to some extent it might lead to medical issues. Replacing the wheelchair with rehabilitation devices helps in sorting this issue. Various rehabilitation techniques and devices that are developed are reviewed and their specifications and comparisons are mentioned in brief. A lower limb orthosis is designed using solidworks and the design imported into MATLAB using simmechanics is simulated using simscape multibody and the resulting torques for each joint namely hip, ankle and knee joints are obtained.

Design and Simulation of Brain Controlled Electronic Wheelchair for Physically Challenged Person

Improving the quality for the life of elders and disabled person and giving proper care at the right time is one of the most important role to be performed as a responsible citizen in the society. This paper is describing about the integration of hardware, software and sensors with the help of Brain Computer Interface (BCI) to develop best generation wheelchair for physical challenged persons. Electronic wheelchair is one of the easiest way for disabled persons to lead an independent life. This smart wheelchair is totally controlled by brain, and here mechatronics plays an important role in safety recovery. By developing these types of wheelchairs it can reduce the usage of human effort and force to drive the wheels of wheelchair. It also provides a better opportunity for physically handicap person to move from one place to another. One of the best method to record brain activities can be done with the help of electroencephalography (EEG) this is also known as brain waves signal, through these EEG signals the BCI interface encode and decode the signals and transfers to ATMEGA 328 microcontroller. This wheelchair with the support of motor drives the movement is designed in such a way to control the commands like moving forward and backward, stop, turn left and right. Intelligent Wheelchair is designed using solid works and implementing into MATLAB using simmechanics is simulated using simscape multibody and the resulting torque is obtained. The aim of this paper is implement mind controlled movements for disabled persons.Keywords: Orthosis, Paraplegia, Rehabilitation, Simulation, Under limb.

Effect of the payload mass on forces acting from the overhead crane drives during movement in the mode of suppressing uncontrolled oscillations

Using two-point Hermite splines, the reference spatial trajectory of a payload on a non-rigid pendulum suspension of an overhead crane was set as a combination of plane controlled oscillations in two mutually perpendicular movement directions of the bridge and the trolley. Under the absent uncontrolled payload oscillations, payload, suspension point coordinates and the rope deviation angles were calculated. Using the example of a constant spatial trajectory of the payload bypassing a single obstacle in the absence of uncontrolled oscillations, the payload mass effect on the forces acting from the side of the bridge drives and the trolley was investigated. The time dependences for horizontal components of the drive side forces were determined using an overhead crane simulation model developed in the Simscape Multibody Matlab application. Payload of various masses was repeatedly moved along the reference constant trajectory by rigidly setting the bridge and trolley movement trajectories. By virtual sensors, the forces acting from the drives on the bridge and trolley were evaluated. The payload mass effect on the maximum values of drive forces is established to be linear. The results can be used in the design and development of intelligent mechatronic control systems for overhead and gantry cranes.

A validation procedure to identify joint friction, reductor self-locking and gear backlash parameters

The paper presents a new method for the identification of joint friction, reductor self-locking and gear backlash parameters. The method was developed using an existing hexapod robot. During the process, the motor driving currents given by the model and measured on the real device were observed and compared. Initially, the current curves showed specific differences. After the analysis of these deviations, their causes were identified as joint friction, reductor self-locking and gear backlash. The parameters of these phenomena were determined using swarm optimization. As a result of this process, a validated model was obtained. The mentioned mechanical properties were identified using a step-by-step method, in which one property aided in the discovery of another. The robot model was created in a MATLAB/Simulink environment, using the Simscape Multibody Toolbox.

Adaptive control of electrically‐driven nonholonomic wheeled mobile robots: Taylor series‐based approach with guaranteed asymptotic stability

ABSTRACTTaking advantage of an adaptive Taylor series approximator, this research seeks to address a two‐loop robust controller for electrically‐driven differential drive wheeled mobile robots. A fictitious current signal is designed in the outer loop such that the good tracking performance as well as the asymptotic stability of system will be achieved. Also, the error of currents will be minimized by an actual control input in the inner loop. For both inner/outer loops, uncertain nonlinear functions can be approximated by adaptive Taylor series systems. To validate the proposed control algorithm, numerous simulations have been carried out with two different desired trajectories and multiple initial conditions. Also, the proposed controller is compared with a recent well‐designed robust adaptive fuzzy controller. In addition, to simplify the procedure of mathematical modelling of a wheeled mobile robot, the “Simscape Multibody” environment of “MATLAB” is used for 3D simulations.

Control of Eight-Leg Walking Robot Using Fuzzy Technique Based on SimScape Multibody Toolbox

In this article, a simulation platform is used to design and test the proposed controller and to study the performance of the eight legs walking robot based on SimScape Multibody toolbox. We show that, by using the SimScape Multibody toolbox, the intelligent controller can be designed without needing for the mathematical model of the legged robot. This toolbox is used to simulate and visualize the motion of the legged robot with the proposed controller. The fuzzy technique is used for designing a control system for the walking robot. The particle swarm optimization (PSO) algorithm is used to obtain the optimal parameters of output membership function of the proposed fuzzy controller. The effectiveness and robustness of the designed controller are studied by changing the carried load by the walking robot. The obtained results demonstrate efficiently the validity of the proposed controller for guiding the walking robot when the disturbance is applied.

Kinematic and dynamic analysis of a novel parallel kinematic Schönflies motion generator

This paper analyses the kinematics and dynamics of an over-constrained parallel mechanism with four degrees of freedom providing Schönflies motion with infinite tool rotation. Despite its limited motion capability in one translational degree of freedom, the proposed mechanism has several potential uses, such as assembly of electronic components or fabric cutting.Firstly, the instantaneous kinematic problem of the investigated mechanism is presented, which includes formulating the inverse kinematics for the position, velocity and acceleration of the mechanism. Then, singular configurations of the manipulator are studied, based on the obtained Jacobin matrices. Secondly, based on the foregoing kinematic relations and the concept of link Jacobian matrices, the dynamic model is formulated by means of the principle of virtual work. Finally, the correctness of the derived models is verified by comparing the results obtained from the formulated models with those obtained using MATLAB Simscape Multibody.

Quadcopter flight control system simulation in Simulink and Simscape Multibody

Quadcopter flight control system simulation in Simulink and Simscape Multibody

System Level Modeling and Control Design of hTetrakis–A Polyiamond Inspired Self-Reconfigurable Floor Tiling Robot

Fixed morphology cleaning robots mostly face significant challenges in cleaning the narrow spaces in the environment. To overcome this, a new class of self-reconfigurable floor cleaning robot, hTetrakis, made of four triangular blocks, is built. This paper focuses on the modeling and controller design of the locomotion and reconfiguration mechanism of the platform. The locomotion of the platform with respect to the velocity of the wheels is formulated based on the kinematic analysis. By modeling the system in Simscape multibody toolbox of Matlab, the maneuverability of the platform is studied. The reconfiguration of the platform is studied based on the dynamics of individual block about the hinged joint. The control architecture of this platform has two distinct Proportional-Integral-Derivative (PID) controllers to eliminate the position error during reconfiguration, and to maintain the platform’s velocity. The coverage path planning of the platform is based on the classical Travelling Salesman Problem which finds the optimal sequence of waypoints as per the minimal energy consumption. Real time experiments are carried out to validate the effectiveness of the proposed control schemes in terms of eliminating the velocity errors, and maintaining the desired trajectory.

Modeling and Analysis of hHoneycomb—A Polyhex Inspired Reconfigurable Tiling Robot

hHoneycomb, a self-reconfigurable cleaning robot, is designed based on tiling theory, to overcome the significant challenges experienced by the fixed morphology cleaning robot. It consists of four regular hexagonal units and the units are connected by a planar revolute joint which helps in reconfiguration. This platform attains six distinct configurations (bar, bee, arch, wave, worm, and pistol) and these configurations have circular arcs and irregular concave and convex boundary that would help in accessing various obstacles in the cleaning space. This work addresses the mechanical design, system-level modeling, reconfiguration of the platform via hinged joint mechanism, mobility of the platform, polyhex based tiling set, and power consumption during reconfiguration. The strength of the mechanical structure is studied based on the structural analysis of the system using finite element method. Based on the natural frequency and deformation pattern, the proposed design is validated and proven to overcome structural failure and system resonance. The kinematics formulation of the platform during locomotion and dynamics of each block during reconfiguration are derived. The robotic system is modeled in Simscape multibody toolbox of Matlab and the mobility of the platform is studied using the numerical simulation. Based on the real-time current consumption of each joint during reconfiguration, the energy efficient configuration and tiling set are addressed.