Dynamic Modeling and Control of Pneumatic Artificial Muscles-Driven Multi-Fingered Robots for Circular Object Manipulation

In this research, a nonlinear model predictive controller is designed for the trajectory tracking of spatial cable-suspended parallel robots with four cables. The dynamic model of this robot is derived firstly using the Newton-Euler approach and is subsequently verified using the Simscape environment. Moreover, an identification method based on the Genetic Algorithm is presented to identify the unknown inertial and frictional parameters in the model. It is observed that the Interior-Point optimization method is able to solve the optimization problem resulting from the proposed model predictive controller in real-time. Also, the effectiveness of the designed controller, combined with the presented identification approach, is investigated by assessing the controller performance when the estimated values are used in the model, compared to the cases where the precise values are utilized. Three groups of various inertial and frictional parameter values are considered in these assessments, and it is observed that when the estimated values are utilized in the model, the control of the robot is performed with an average RMSE of 1.1073mm, which is only 0.75716mm more than the average RMSE when the precise values are utilized. The results obtained from the simulations reveal the promising performance of the proposed model predictive controller when combined with the suggested identification method.

This paper presents a dynamic modeling and control studies of mobile robot. The robot is mainly built all around three wheels and platform. A mathematical model of unicycle mobile robot is determined by kinematic and dynamic model. The dynamic modelling equations are based on Lagrangian formulation. The motion control strategy is based on the inverse of dynamic control. This leads to accurate tracking of trajectory. The goal to reach in this paper is to improve the performances of inverse dynamic control of mobile robot. The validity of the proposed controller is demonstrated by the simulation of two wheels mobile robots case.

The effects of flexible joints on the dynamic response and control of robot are studied in this paper. Firstly, the spatial robot model consisting of $n$ flexible joints and $n$ flexible links is built, and the dynamic equations of the robot system are derived via the Lagrangian's equations. The tensile deformation, bending deformation, torsional deformation, and nonlinear coupling deformation of the flexible link are considered. Furthermore, the effects of the flexible joint are also considered in order to provide an important theoretical basis for the research of the vibration suppression and control of robots. The flexible joint is simplified as a linear torsion spring with damping, and the mass effect of the flexible joint is also considered in the model. Secondly, the dynamic simulations of the spatial manipulators are done to explore the effects of the joint stiffness and damping on the dynamic response of the robot system. The results show that as the stiffness coefficient increases, the amplitude of dynamic response of the flexible robot decreases, and the vibration frequency of the system becomes larger. As the damping coefficient increases, the dynamic response of the flexible robot decreases, and the dynamic response decays faster. The vibration of the flexible robot can be suppressed by adjusting the values of the stiffness and damping of the flexible joint. Finally, in order to study the effects of the flexibility of the joint on the control system, the rigid-joint manipulator and flexible-joint manipulator are made to move under the same circular motion. Then the joint torques of the two system are obtained respectively by solving the inverse dynamics equations, and the influence of the flexibility of the joint on the dynamics control is studied. The results show that the actuating torques required in the flexible-joint system are reduced compared to that required in the rigid-joint system.

This paper aims at dynamic modeling and control of a new upper-limb rehabilitation robot which has a parallel structure. Dynamic modeling of parallel robot is a complicated problem, and the dynamics and voluntary force of the patient arm increase the difficulty of dynamic analysis and control in rehabilitation training. The novelties of this study are: (1) dynamics of the robot and the patient are considered together, and this human-robot interaction system is modeled as a redundantly actuated closed-chain system (2 DOFs, 4 active joints); (2) the system dynamics are derived in workspace using a new method based on the dynamics of its three serial open-chain branches, and both kinematic constrains and interaction forces are considered during the derivation. Compared with the other two previous methods reviewed in this paper, the proposed method is easier to derive, more computationally efficient, and it can be used in both redundant and non-redundant cases. Besides, a model based PD-computed torque controller is designed and the simulation of passive training task along a circular path is presented to prove the effectiveness of this method.

Objectives: This paper addresses two key issues in the area of flexible robotics. The issues are dynamic modelling and control of flexible link robots. A brief, yet, significant review is provided that addresses these issues. Methods: The various approaches used by researchers for dynamic modelling and control of flexible robots are presented. Besides that, methods used for achieving optimal control are also discussed. Findings: After a review of 153 research papers from the year 1975 to 2021, it has been found that a good dynamic model of flexible manipulator helps in reducing the control and computational efforts. Recent trends in research in the area of flexible manipulators are towards the use of sliding mode control and vision-based control techniques. Novelty: Inclusion of the effect of torsional vibrations besides lateral vibrations on the positional accuracy of flexible manipulators makes the current research work novel. Keywords: Flexible manipulator; modelling; dynamics; control

Two-wheeled mobile robot is known for advantages on performing better manuever in a confined space. It is a typical mobile robot with some features such as complexity, highly nonlinear, instability, multi-variable and strongly coupling. This research is aimed to design and develop the dynamic model and balance control strategy of the robot. A Gibbs-Appell equation is applied to build the dynamic model of two-wheeled robot in this paper. The virtual prototype model of the robot and the state space model with feedback are obtained. The experiments based on the simulation model and actual model are implemented. They show that the state feedback controller carried on the robot model in the posture and the speed is effective and the dynamical balance process is stable. The nonlinear dynamics model based on non-holonomic constraints and pole placement algorithm on the basis of the dynamic model are effective.

Dynamic models and controllers for compliant framed wheeled modular mobile robots are studied in this paper. This is a new type of wheeled mobile robot using axle and frame modules that can provide both full suspension and enhanced steering capability without additional hardware. In this research modular kinematic and dynamic models of the modules are developed and assembled into a scalable dynamic system model such that a wide variety of configurations could be described. Dynamic control is then achieved by coordinated control of the individual wheel torques as specified by a backstepping controller scaled to the dimension of the system configuration. These results are applied to a two-axle scout case study in order to demonstrate their implementation and performance. Simulation and experimental results illustrate dynamic control of trajectory tracking while path following.

The dynamic modeling and trajectory tracking control of a mobile robot is handled by a hierarchical constraint approach in this study. When the wheeled mobile robot with complex generalized coordinates has structural constraints and motion constraints, the number of constraints is large and the properties of them are different. Therefore, it is difficult to get the dynamic model and trajectory tracking control force of the wheeled mobile robot at the same time. To solve the aforementioned problem, a creative hierarchical constraint approach based on the Udwadia–Kalaba theory is proposed. In this approach, constraints are classified into two levels, structural constraints are the first level and motion constraints are the second level. In the second level constraint, arbitrary initial conditions may cause the trajectory to diverge. Thus, we propose the asymptotic convergence criterion to deal with it. Then, the analytical dynamic equation and trajectory tracking control force of the wheeled mobile robot can be obtained simultaneously. To verify the effectiveness and accuracy of this methodology, a numerical simulation of a three-wheeled mobile robot is carried out.

Modeling of soft robots is typically performed at the static level or at a second-order fully dynamic level. Controllers developed upon these models have several advantages and disadvantages. Static controllers, based on the kinematic relations tend to be the easiest to develop, but by sacrificing accuracy, efficiency and the natural dynamics. Controllers developed using second-order dynamic models tend to be computationally expensive, but allow optimal control. Here we propose that the dynamic model of a soft robot can be reduced to first-order dynamical equation owing to their high damping and low inertial properties, as typically observed in nature, with minimal loss in accuracy. This paper investigates the validity of this assumption and the advantages it provides to the modeling and control of soft robots. Our results demonstrate that this model approximation is a powerful tool for developing closed-loop task-space dynamic controllers for soft robots by simplifying the planning and sensory feedback process with minimal effects on the controller accuracy.

This paper presents techniques for dynamic modeling and control of a Ball robot (Ballbot) with inverse mouse-ball drive that is accomplished by simultaneously activating two independent brushless motors. Under this driving scheme, a completely dynamic model of the robot moving in a flat terrain is established constructed based on Lagrangian mechanics. With the model, a sliding-mode control is proposed based on backstepping to accomplish robust balancing and agile path tracking of the robot with exogenous disturbances. Computer simulations are conducted for illustration of the effectiveness of the proposed modeling and control method.

In this paper, we present the dynamic modeling and model predictive tracking control for a fin-actuated robot with barycentre regulating mechanism in multiple motions. Specifically, a dynamic model for the robot is established firstly. Based on the dynamic model, a model predictive tracking control algorithm is proposed. And simulations of of tracking rectangle trajectory, sine-like trajectory, ascending trajectory, and spiral trajectory are conducted to validate the algorithm. The simulation results demonstrate that the proposed algorithm is able to implement trajectory tracking of the robot with small position error and orientation error. This paper contributes to trajectory tracking for an underwater robot with controllable barycentre in multiple motions, which has been rarely explored.

This article concerns the modeling and motion control of a mobile robot with six independently driven and non-steered wheels. The main research issue is analyzing the influence of the structure of the control system and wheel track on the control accuracy and energy efficiency during robot motion on horizontal paved ground. For this purpose, the kinematic relationships for the robot are discussed and a simplified dynamics model for control applications is developed. The robot’s dynamics model takes into account the most important phenomena of the wheel interaction with the paved ground, including slip. In addition, it is supplemented with a model of the robot’s drive units. Two versions of the control system were adopted for analysis, i.e., with the wheels’ controller only and additionally equipped with a pose controller. Simulation studies were carried out for the developed robot dynamics model and the analyzed versions of the control system in order to investigate the influence of the track width of the wheels and the structure of the control system on motion accuracy and energy efficiency. In order to quantitatively compare the results for the analyzed solutions, quality indices were introduced. The results of the simulation research indicate the influence of the track width of the wheels on the accuracy of motion when using the wheels’ controller, as well as its impact on energy efficiency. Moreover, they show that it is possible to significantly improve the accuracy of motion by using an additional pose controller, which allows limiting the impact of the non-optimal geometric parameters of the robot and the slip of the wheels on trajectory tracking errors. However, the addition of the pose controller does not significantly affect the energy efficiency during the robot’s motion, which may be even worse in this case.

This paper presents the dynamic modeling and control simulation of a novel robot that combines flying motion and on ground motion into an integrated single robot. The ground motion is based on four wheels configuration that provides more stability. The flying motion is depending on the flying mechanism of quadrotor system. Smart transformation mechanism is developed to switch the robot from the ground motion configuration to the flying motion configuration and vice versa without adding any additional actuators. A manipulator with 3 DOF is added to handle an object during the ground motion and it is useful to hold this object during the flying motion. A CAD model is developed using SOLIDWORKS. The dynamic model of this robot is derived to achieve the eccentricity of the payload, the weight of the eccentric manipulator and managing the variation of the payload in the dynamic model. The derived robot dynamics are highly nonlinear. A controller is designed based on feedback linearization technique to stabilize the robot attitude and altitude. Controlling the horizontal movements' nonholonomic constraints is used to generate the desired trajectories of robot attitudes. Another dynamic model and controller have been established for the transformation mechanism. Finally, the simulation results using MATLAB/SIMULINK show that the controller successfully vanish the eccentric effect and stabilize the robot attitude.

The accurate dynamic model of the robot manipulator is essential for better control performance. Dynamic modelling refers to deriving such equations that explicitly describe the relationship between force and motion in a system. There are several methods to solve for the dynamics of the system. The main concern while doing dynamics is to check its reliability and verification. In this paper, Lagrange Euler (L-E) method is used to dynamically model a five-degrees-of-freedom (DOF) robot manipulator and verified through 3D model of robot in Simulink, simscape multibody toolbox. Followed by the implementation of a proportional-integral-derivative (PID) control with a low pass filter ‘N’ (PIDN) on the derived system. The low pass filter enhances the control performance by eliminating the effect of derivative term's fluctuations (noise). Furthermore, Ziegler Nichols's closed-loop tuning method is used to optimally tune the PID control. The derived model and control algorithm simulations have been performed in MATLAB. The simulations results illustrated that the derived model is controllable which indicates the correctness of the derived model.

With the increasing demand for space missions, space robots have become the focus of research and attention. As a typical representative, the free-floating dual-arm space robot has the characteristics of multiple degrees of freedom, a floating base, and dynamic coupling between the manipulator and the base, so its modeling and control are very challenging. To address these challenges, a novel dynamic modeling and control method is proposed for a free-floating dual-arm space robot. First, an explicit dynamic model of a free-floating dual-arm space robot is established based on the explicit canonical multi-rigid-body dynamic modeling theory and combined with the concept of a dynamic equivalent manipulator. The establishment process of this model is not only simple and canonical to avoid the definition and calculation of many intermediate variables, but the symbolic result expression of the model also has the characteristics of iteration, which is convenient for computer automatic modeling. Next, aiming at addressing the problem of trajectory tracking and the base attitude stability of a free-floating dual-arm space robot with parameter perturbation and external disturbance, an improved nonlinear model predictive control method introducing the idea of sliding mode variable structure is proposed. Theoretical analysis shows that the proposed controller has better robustness than the traditional nonlinear model predictive controller. Then, an in-orbit service task is designed to verify the effectiveness of the proposed dynamic modeling and control strategy of the free-floating dual-arm space robot. Finally, the dynamic modeling and control methods proposed are discussed and summarized. The proposed methods can not only realize the tracking of the desired trajectory of the arms of the free-floating space robot, but can also realize the stable control of the base of the free-floating space robot. This paper provides new insights into the difficult problems regarding the dynamics and control of free-floating dual-arm space robots.