Open Control System Research Articles

Adaptive Single-Input Recurrent WCMAC-Based Supervisory Control for De-icing Robot Manipulator

The control of any robotic system always faces many great challenges in theory and practice. Because between theory and reality, there is always a huge difference in the uncertainty components in the system. That leads to the accuracy and stability of the system not being guaranteed with the set requirements. This paper presents a novel adaptive single-input recurrent wavelet differentiable cerebellar model articulation controller (S-RWCMAC)-based supervisory control system for an m-link robot manipulator to achieve precision trajectory tracking. This adaptive S-RWCMAC-based supervisory control system consists of a main adaptive S-RWCMAC, a supervisory controller, and an adaptive robust controller. The S-RWCMAC incorporates the advantages of the wavelet decomposition property with a CMAC fast learning ability, dynamic response, and input space dimension of RWCMAC can be simplified; and it is used to control the plant. The supervisory controller is appended to the adaptive S-RWCMAC to force the system states within a predefined constraint set and the adaptive robust controller is developed to dispel the effect of the approximate error. In this scheme, if the adaptive S-RWCMAC can not maintain the system states within the constraint set. Then, the supervisory controller will work to pull the states back to the constraint set and otherwise is idle. The online tuning laws of S-RWCMAC and the robust controller parameters are derived from the gradient-descent learning method and Lyapunov function so that the stability of the system can be guaranteed. The simulation and experimental results of the novel three-link De-icing robot manipulator are provided to verify the effectiveness of the proposed control methodology. The results indicate that the proposed model has superior accuracy compared to that of the Standalone CMAC Controller. The parameters of the average squared error in the S-RWCMAC -based 3 robot joints are lower than those of the Standalone CMAC Controller by 0.023%, 0.029%, and 0.032%, respectively.

Design and Evaluation of an Intuitive Haptic Teleoperation Control System for 6-DoF Industrial Manipulators

Industrial robots are capable of performing automated tasks repeatedly, reliably and accurately. However, in some scenarios, human-in-the-loop control is required. In this case, having an intuitive system for moving the robot within the working environment is crucial. Additionally, the operator should be aided by sensory feedback to obtain a user-friendly robot control system. Haptic feedback is one way of achieving such a system. This paper designs and assesses an intuitive teleoperation system for controlling an industrial 6-DoF robotic manipulator using a Geomagic Touch haptic interface. The system utilises both virtual environment-induced and physical sensor-induced haptic feedback to provide the user with both a higher amount of environmental awareness and additional safety while manoeuvering the robot within its working area. Different tests show that the system is capable of fully stopping the manipulator without colliding with the environment, and preventing it from entering singularity states with Cartesian end effector velocities of up to 0.25 m/s. Additionally, an operator is capable of executing low-tolerance end effector positioning tasks (∼0.5 mm) with high-frequency control of the robot (∼100 Hz). Fourteen inexperienced volunteers were asked to perform a typical object removal and writing task to gauge the intuitiveness of the system. It was found that when repeating the same test for a second time, the participants performed 22.2% faster on average. The results for the second attempt also became significantly more consistent between participants, as the inter quartile range dropped by 82.7% (from 52 s on the first attempt to 9 s on the second).

MANIPULATOR CONTROL SYSTEMS REVIEW

This review focuses on manipulator control systems, which are systems that control the movement of manipulators, a type of robot programmed to move in specific ways. The control systems send commands to actuators (such as motors or pneumatic cylinders) based on input from sensors (such as position or force sensors) to control the movement of the manipulator's joints. Manipulator control systems have a wide range of applications in industries such as robotics, industrial automation, and medical and surgical robotics. The review covers the different types of manipulator control systems, including open-loop, closed-loop, and hybrid control systems, and their applications. It also discusses control strategies, including Proportional-Integral-Derivative (PID) control, Linear Quadratic Regulator (LQR) control, and Model Predictive Control (MPC). The review also covers sensors and actuators used in manipulator control systems and the challenges and future directions in the field. The review provides a comprehensive understanding of the current state of manipulator control systems and highlights the recent developments and future directions in the field, providing insights for future research and development.

Numerical Analysis of the Kinematic Accuracy of the Hermetic Harmonic Drive in Space Vehicles

The unfriendly-for-humans environment of space causes automatic or remotely controlled vehicles and devices to be used for its research. In robot and manipulator control systems, and also in mechanisms adjusting antennas and photovoltaic panels, the hermetic harmonic drive can be used. A special advantage of this type of gear is the ability to transfer power to an isolated space separated by physical barriers from external influences. Therefore, the purpose was to design gears that will allow achieving the highest kinematic precision for control systems by simultaneously maintaining their hermetics. The article presented an analysis of the kinematic accuracy of harmonic hermetic drives powered by four different types of wave generators. The generators used differed in construction but also caused other deformations of the flexspline. The calculation of angular displacement was prepared in the computer program Abaqus. The simulations were performed on virtual models of a complete harmonic hermetic drive using the finite element method (FEM). The results from the analysis allow the most favorable solution to be applied to the Mars rover drive or spacecraft control system. It was determined for which of the wave generators the kinematic accuracy is the highest and how high the backlash exists for the reversing rotation. Finally, the proposed design will allow one to increase the accuracy of the working movements and control of space vehicles while ensuring a minimal influence of the external ambient.

Calculation of Angular Coordinates for the Control System of a Two-Link Industrial Robot Manipulator

Introduction. One of the tasks of two-link manipulators of industrial robots that move the end-effector along complex trajectories (e.g., robot welder) is associated with the need for careful programming of their movement. For these purposes, manual programming methods or training methods are used. These methods are quite labor-intensive, and they require highly qualified service personnel. A possible solution to the problem of programming the manipulator movements is the simulation of motion with the calculation of angular coordinates. This can help simplify the geometric adaptation of the manipulator in the process of debugging the control program. Therefore, this work aimed at calculating coordinates for programming the control system of a two-link manipulator operating in an angular coordinate system and moving the end-effector along a complex trajectory (e. g., when welding car bodies). Materials and Methods. A two-link robot manipulator designed for cyclically repeating actions in an angular coordinate system was considered. The manipulator consisted of two rotating links: “arm” and “elbow”, which were fixed on the base. The base could rotate, which provided a third degree of freedom. This configuration increased the working area of the manipulator and minimized the area for its placement in production. The movement of the manipulator end-effector could be performed if the kinematics provided its positioning along three Cartesian and three angular coordinates. For software control of robots, including welding robots operating in an angular coordinate system and performing the movement of the end-effector along a complex trajectory, it was required to calculate the angular coordinates of the movement of the end-effector of a two-link articulated manipulator. The robot control system should determine the position of the tool in the angular coordinate system, converting it for user friendliness into x, y and z coordinates of the Cartesian coordinate system. Results. The relations of angular and Cartesian coordinates have been obtained. They can be used for calculating when programming the control system of a two-link manipulator of an industrial robot and organizing the exchange of information between the user and the control system, as well as for checking the accuracy and debugging the movement of the end-effector of an industrial robot through feedback. Discussion and Conclusion. The presented results can be used for software control of a welding robot operating in an angular coordinate system and performing a complex trajectory of the end-effector of a two-link articulated manipulator (gripper). A manipulator operating in an angular coordinate system can be used for contact spot welding when moving the end-effector along a complex trajectory using a positioning or contouring control system. These systems control the movement of the end-effector along a given trajectory with the help of technological commands.

Dynamic correction in manipulator control systems based on intelligent linear motion mechatronic module

Robotic complexes and robotic manipulators are widely used in the management of various objects and processes of control systems; their performance is directly related to the execution element. Electromagnetic actuators of multi-function control systems are structurally created separately for each adjustment body and lead to system complexity. To solve these problems, improve the executive system's weight-gauge indicators, and simplify the structural schemes, implementing intelligent mechatronic modules that perform linear and rotational movements in space coordinates is one of the urgent tasks. In this article, dynamic correction in manipulator control systems built based on an intelligent linear motion mechatronic module is considered. In manipulator control systems, the use of intelligent mechatronic modules in dynamic correction for manual and semi-automatic control manipulation systems that do not have a feedback channel for forces and moments and the relevance of the handle movement and manipulation objects with such a selection of the forces and moments vector m developed by them was seen. The article presents mathematical models for calculating vector components based on the current values of the generalized coordinates of the manipulator, their speed and acceleration, and the selection of the vector of forces and moments m developed by the intelligent mechatronic modules of the manipulator.

Aperture-dynamic properties of the sensor information in mobile object management systems

This article discusses the aperture-dynamic properties of sensor devices used in control systems for unmanned devices, in particular, automatic manipulators operating as part of robotic complexes (RTCS). The effects of interference affecting the software control systems of automatic manipulators using high-speed algorithms with interference-resistant coding under operating conditions in production are considered. It is known that in production conditions, there are sources of network interference, interference of an informational nature through communication channels, wired channels, radio engineering channels in a large radio engineering range, from vibration processes, interference and distortion in optoelectronic networks, interference that violates the safe working conditions of radioelectronic equipment. Examples of implemented algorithms based on aperture operators for controlling automatic manipulators with various program cycles, taking into account the peculiarities of production, are given. A comparative analysis was carried out with analogues having similar technological characteristics. control of automatic manipulators operating as part of robotic complexes.

Trajectory planning algorithm of manipulator based on NURBS

This paper uses the 5Dof manipulator on the YouBot developed by KUKA as a model. Combining quintic polynomial interpolation with quintic non-uniform rational B splines, a novel segmented polynomial interpolation planning technique 5-B-5 is proposed in this study. CoppeliaSim constructs the model, and MATLAB controls the model to acquire the angular displacement, angular velocity, angular acceleration, final trajectory, and joint force for every joint angle. The new optimization algorithm presented in this work is utilized to optimize the manipulator's motion trajectory. Comparing it to the classic 3-5-3 algorithm and the B spline algorithm offers advantages over the higher-order B spline interpolation without increasing the manipulator control system's operational overhead. The experiments prove that the motion trajectory inaccuracy of the manipulator is minimized, the curve is continuous and smooth, and the smoothness is improved, thereby eliminating mechanical shock and other issues.

Research on robotic end positioning based on fuzzy PID control

The existing traditional proportional-integral-derivative (PID) control robot has low-end positioning accuracy, which cannot meet the needs of accurately placing the molding die in the current automatic coal pen production process. To address this problem, this paper proposes a fuzzy strategy PID control method based on fuzzy strategy, aiming to improve the accuracy and robustness of the system when the manipulator grasps the mounding mold. Firstly, a manipulator motor control model is established to derive the parameters of the manipulator control system; secondly, the fuzzy control strategy is applied to adjust the PID control parameters in real time to improve the dynamic stability of the system. Finally, the control system is simulated, and field experiments are conducted to verify the accuracy of robotic end positioning. The experimental results show that the fuzzy PID control system has a shorter response time, better anti-interference ability, and better stability than the traditional PID control and achieves the accuracy requirements of coal pen automation production.

REFINEMENT OF OPTIMAL CONTROL PROBLEM FOR PRACTICAL IMPLEMENTATION OF ITS SOLUTION

The solution of the optimal control problem in the classical formulation is control in the form of a function of time. The implementation of such a solution leads to an open control system and therefore cannot be applied directly in practice. It is believed that solving the classical optimal control problem leads to an optimal control program and program trajectory in state space. To implement the movement of the control object along the program trajectory, it is necessary to build an additional movement stabilization system. The problem of synthesizing a system for stabilizing movement along a program trajectory and the requirements that this system should meet do not arise from the classical setting of the optimal control problem. An updated statement of the optimal control problem is given, which includes an additional requirement for an optimal trajectory, and the solution of which can be directly applied in practice in a real control object.

Magnetically controlled super-wetting surface switching between ultra-low and ultra-high droplet adhesion

Controlled liquid adhesion behaviors on super-wetting surfaces have gained significant attention, however, precise controlling of adhesion behavior is extremely hard to realize due to some inherent limitation in surface chemistry or morphology. Herein, we report a silicone-oil-infused magnetic porous polydimethylsiloxane (SMPP) surface with magnetically tunable super-wetting behaviors. Benefiting from the magnetic-field-responsive structure and interconnected porous characteristics, the SMPP can use magnetic field to control the seepage and absorption of silicone oil in the micropore channels, thereby precisely changing the adhesion of the water droplets on the surface. Compared to conventional super-wetting surfaces, this SMPP surface displays reversible in-situ conversion from ultra-high to ultra-low droplet adhesion with sliding angles ranging from 3° to 180° that hold up well even after severe cutting or abrasion. We also demonstrated that this tunable adhesion behavior can be used not only to enhance droplet manipulation in spatiotemporal but also to design unique microfluidic microreactors and antigravity transport devices. We envision that this proof-in-concept surface can serve as an important component of integrated control systems for intelligent manipulators, biochemical reactions, fluid transport, and biomedical analysis.

Development of a novel parallel soft manipulator with sensing capabilities

It is challenging to equip a soft manipulator with sensors without compromising its mechanical properties. In this paper, we explain the design, analysis, and building of an innovative, low-cost soft parallel manipulator with sensing and actuation capabilities. Innovative bubble artificial muscle actuators serve as the connecting rod and contraction type actuator for the manipulator, as well as an opto-mechanical tactile sensor (TacTip) for objects detection. We propose a simulation method for the key structural design parameters of TacTip, and the influence of TacTip’s pin height, pin diameter, and surrounding pin angle on perceptual sensing has been examined via testing, which can provide a design guideline for the TacTip’s the structure. The impact of the counterweight on the soft parallel manipulator end-ascending effector’s and descending velocity, as well as its vertical and horizontal workspace, has been the topic of dynamic tests using a range of counterweights. The soft parallel manipulator’s workspace has been analyzed. In addition, an innovative, cost-effective, and simple soft-smart parallel robotic manipulator (PSM) control system has been built, and a demonstration of the detection and movement of the soft parallel manipulator is shown. The results demonstrate that the soft parallel manipulator described in this research is capable of detecting motion and collisions. It is anticipated that this soft-smart PSM would expand the employment of optical tactile sensors and artificial muscle actuators in material handling and size/shape sorting assembly lines.

A Discrete Model-Free Scheme for Fault-Tolerant Tracking Control of Redundant Manipulators

Fault tolerance is a critical requirement for robust motion control of redundant robotic manipulators. This article aims to endow the redundant manipulator with the capability to achieve the required path of end-effector in the condition that one or some of its joints’ motion fail. Although many fault-tolerant control algorithms of redundant manipulator have been proposed in recent years. However, few of them are on the basis of the condition that the robotic model is unknown. The complexity of the calculation model limits the efficiency and portability of these algorithms. For the first time, we proposed a discrete model-free fault-tolerant tracking control scheme of redundant manipulator, which takes into account the fault tolerance in the control system of redundant manipulator by formulating it into a quadratic programming (QP) framework. The core of the proposed scheme consists of a discrete kinematic estimator and a discrete QP solver, powered by which the fault-tolerant control problem is transformed into a unified computing problem relaxing the need of knowing the redundant manipulator’s kinematic model. A discrete joint space observer is proposed for the detection of the happening of faulty states. Extensive simulations and experiments based on a redundant manipulator are performed and analyzed to support the verification of the efficiency and effectiveness of the proposed scheme.

Research on flight control system hardware in the loop simulation system based on NI hardware platform for Unmanned Aerial Vehicle

HIL(Hardware in the loop) simulation of UAV(Unmanned Aerial Vehicle) plays an important role in flight control sysrtem development and algorithm verification. Taking the open source flight control system Pixhawk as the research object, this paper establishes a HIL system based on NI(National Instrument) hardware platform. The dynamic model and kinematic model are modeled through Simulink, the online management of simulation model is realized through Veristand, and the online display of model parameters and fault injection are realized through Labview. The simulation system can test the functional performance, reliability and safety of flight control system. The simulation results show that the simulation platform works reliably and has good real-time performance. It can effectively and reliably carry out the HIL of flight control system for UAV.

DESIGN OF AN AUTOMATED CONTROL SYSTEM OF A DELTA MANIPULATOR WITH MICROCONTROLLER BASED MACHINE VISION

The design and implementation of a microcontroller vision-based manipulator control system is described. The control system is divided into high and low-level loops. As high-level devices computers or minicomputers have been used when conducting most research. In this work, a microcontroller board has been used as a high-level device due to its mobility and efficiency. A solution to the inverse kinematics task of a delta manipulator is presented in this work which forms the main part of the low-level device algorithm. Sipeed Maixduino and Arduino Mega dev boards have been used to implement the control system. The objects have been classified by YOLO model for the testing purposes of the control system. This has made it possible to measure the average targeting time for the different objects, which is used to test the implemented control system. The empirical data has shown a suboptimal result. The reason for it has been analyzed and addressed through coding a more optimal solution. Potential improvements to the hardware used in the test setup are suggested to benefit future work.

Design of Optical Tweezers Manipulation Control System Based on Novel Self-Organizing Fuzzy Cerebellar Model Neural Network

Holographic optical tweezers have unique non-physical contact and can manipulate and control single or multiple cells in a non-invasive way. In this paper, the dynamics model of the cells captured by the optical trap is analyzed, and a control system based on a novel self-organizing fuzzy cerebellar model neural network (NSOFCMNN) is proposed and applied to the cell manipulation control of holographic optical tweezers. This control system consists of a main controller using the NSOFCMNN with a new self-organization mechanism, a robust compensation controller, and a higher order sliding mode. It can accurately move the captured cells to the expected position through the optical trap generated by the holographic optical tweezers system. Both the layers and blocks of the proposed NSOFCMNN can be adjusted online according to the new self-organization mechanism. The compensation controller is used to eliminate the approximation errors. The higher order sliding surface can enhance the performance of controllers. The distances between cells are considered in order to further realize multi-cell cooperative control. In addition, the stability and convergence of the proposed NSOFCMNN are proved by the Lyapunov function, and the learning law is updated online by the gradient descent method. The simulation results show that the control system based on the proposed NSOFCMNN can effectively complete the cell manipulation task of optical tweezers and has better control performance than other neural network controllers.

Skill Acquisition and Controller Design of Desktop Robot Manipulator Based on Audio–Visual Information Fusion

The development of AI and robotics has led to an explosion of research and the number of implementations in automated systems. However, whilst commonplace in manufacturing, these approaches have not impacted chemistry due to difficulty in developing robot systems that are dexterous enough for experimental operation. In this paper, a control system for desktop experimental manipulators based on an audio-visual information fusion algorithm was designed. The robot could replace the operator to complete some tedious and dangerous experimental work by teaching it the arm movement skills. The system is divided into two parts: skill acquisition and movement control. For the former, the visual signal was obtained through two algorithms of motion detection, which were realized by an improved two-stream convolutional network; the audio signal was extracted by Voice AI with regular expressions. Then, we combined the audio and visual information to obtain high coincidence motor skills. The accuracy of skill acquisition can reach more than 81%. The latter employed motor control and grasping pose recognition, which achieved precise controlling and grasping. The system can be used for the teaching and control work of chemical experiments with specific processes. It can replace the operator to complete the chemical experiment work while greatly reducing the programming threshold and improving the efficiency.

Autonomous Obstacle Avoidance Path Planning for Grasping Manipulator Based on Elite Smoothing Ant Colony Algorithm

Assembly robots have become the core equipment of high-precision flexible automatic assembly systems with a small working range. Among different fields of robot technology, path planning is one of the most important branches. In the present study, an elite smoothing ant colony algorithm (ESACO) is proposed for spatial obstacle avoidance path planning of the grasping manipulator. In this regard, the state transition probability and pheromone update strategies are improved to enhance the search capability of path planning symmetry and the convergence of the algorithm. Then a segmented B-spline curve is presented to eliminate path folding points and generate a smooth path. Finally, a manipulator control system based on the Arduino Uno microcontroller is designed to drive the manipulator according to the planned trajectory. The experimental results show that the performance of the ESACO algorithm in different scenarios has symmetry advantages, and the manipulator can efficiently complete the simulation trajectory with high accuracy. The proposed algorithm provides a feasible scheme for the efficient planning of manipulators in equipment manufacturing workshops.

Improving the Accuracy of a Robot by Using Neural Networks (Neural Compensators and Nonlinear Dynamics)

The subject of this paper is a programmable con trol system for a robotic manipulator. Considering the complex nonlinear dynamics involved in practical applications of systems and robotic arms, the traditional control method is here replaced by the designed Elma and adaptive radial basis function neural network—thereby improving the system stability and response rate. Related controllers and compensators were developed and trained using MATLAB-related software. The training results of the two neural network controllers for the robot programming trajectories are presented and the dynamic errors of the different types of neural network controllers and two control methods are analyzed.

Study on Impact Test System of Manipulator Based on Six Axis Force Sensor and Intelligent Controller

With the development and application of intelligent nervous system, intelligent control system represented by machine vision has been promoted and used in various fields, including manipulator control system. Mechanical arm is the main actuator of robot and other mechanical components, but the application environment of mechanical arm is extremely complex, and with the development of industrial process, the sensitivity of technology and operating system for its arbitrary posture operation is also steadily improved. Based on the above problems, this paper designs a manipulator control system based on machine vision theory and orthogonal parallel six-dimensional force sensor to meet the working requirements of manipulator in high-precision environment. Systems hardware are consisted by machine vision structure and six dimensions of force sensor. The practical application effect of the model was verified by collision detection experiment. The relevant research can provide theoretical guidance and practical reference for the research of manipulator control field. Dance and practical application reference for the research of manipulator control field.