Motion Control Algorithm Research Articles

Mathematical Model of 3-P Wheel-Legged Mobile Robotic Platform

In this paper the description of the development of three-point wheel-legged robotic platform and its movement was given. The motion control problem was targeted because of sophisticated walking technique with highly different phase timings. Movement algorithm, straight kinematics problem, inverse kinematics problem and dynamics problem solving are shown for the developed 3D-model. The complete algorithm of motion control was implemented for the model. New methods of mathematical modeling and their assistance were shown for design of new robotic device. The advantages of modern technologies of fast prototyping were described based on 3D printing.

Design and analysis of lateral motion control algorithms for an unmanned aerial vehicle with two control surfaces

This paper considers control of an unmanned aerial vehicle with two horizontal aerodynamic control surfaces in the modes of angular stabilization and coordinated turn. We analyze the linear yaw angle control algorithms based on roll angle variation in terms of their performance. In addition, we suggest an algorithm that ensures a required performance of yaw angle control. Some simulation results are given.

Inverse kinematics research using obstacle avoidance geometry method for EAST Articulated Maintenance Arm (EAMA)

This paper proposed a new method for solving inverse kinematics (IK) of a redundant manipulator called EAST Articulated Maintenance Arm (EAMA), which is applied in the fusion reactor EAST (Experimental Advanced Superconducting Tokamak) and used to complete some maintenance tasks in the complex areas. However, it is difficult to realize remote control due to its redundancy, coupling structure and the complex operational environment. The IK research of the robot played a vital role to the manipulator’s motion control algorithm of remote handling (RH) technology. An Obstacle Topology Partition Projection (OTPP) approach integrated with Modified Inverse Depth First Search (MIDFS) method was presented. This is a kind of new geometric algorithm in order to solve the problem of IK for a high-redundancy manipulator. It can also be used to find a solution satisfying collision avoidance with optimal safety distance between the manipulator and obstacles. Simulations and experiments were conducted to demonstrate the efficiency and accuracy of the proposed method.

Improved Stewart platform state estimation using inertial and actuator position measurements

Accurate and reliable estimation of the kinematic state of a six degrees-of-freedom Stewart platform is a problem of interest in various engineering disciplines. Particularly so in the area of flight simulation, where the Stewart platform is in widespread use for the generation of motion similar to that experienced in actual flight. Accurate measurements of Stewart platform kinematic states are crucial for the application of advanced motion control algorithms and are highly valued in quantitative assessments of simulator motion fidelity. In the current work, a novel method for the reconstruction of the kinematic state of a Stewart platform is proposed. This method relies on an Unscented Kalman Filter (UKF) for a tight coupling of on-platform inertial sensors with measurements of the six actuator positions. The proposed algorithm is shown to be superior to conventional iterative methods in two main areas. First, more accurate estimates of motion platform velocity are obtained and, second, the algorithm is robust to inherent measurement uncertainties like noise and bias. The results were validated on the SIMONA Research Simulator (SRS) at TU Delft. To this end, an efficient implementation of the algorithm was driven, in real time, by actual sensor measurements from two representative motion profiles.

Повышение энергетической эффективности локомотивов с накопителями энергии

Objective: The development of hybrid technologies is an aspect that carries serious changes for the railway industry, its design and technological base. These changes provide the scientific and technological breakthroughs to a much greater extent than the implementation of any new projects in traditional forms. Methods: Of great interest is the solution to the problem of hybrid locomotives and related power supply interaction. In addition, there are problems of quality and reliability of the rolling stock. The relationship between the three sets of technology, as well as the problem of support quality of the latter, becomes essential for the successful implementation of hybrid locomotives with a combined power plant. Results: The primary problems of locomotive projects in question are: electric power storage, in-depth modernization of the traction drive, and implementation of an optimal motion control algorithms in different modes. Increasing energy density stored in the traction battery, while reducing vehicle mass, ensures competitive advantages of eco-friendly hybrid locomotives versus traditional. The cost of the traction battery tends to dominate over the relevant economic parameters of other components of the traction drive hybrid locomotives, therefore, projects with a high technological level are relevant, while ensuring lower total weight of the vehicle. However, in the last decade, due to the increasing importance of electronic components in the transportation industry, along with the objectives stated above, problems of management optimization of rolling stock systems and provision of an appropriate level of quality control take center stage. Issues of energy storage application in the hybrid locomotive and their advantages over the currently used energy sources are considered in the article. Practical importance: It is shown that the use of a hybrid energy storage system will significantly increase the efficiency and reliability of the locomotive.

Introduction, mathematical modelling and motion control of the novel pneumatic textile actuator

AbstractThis paper introduces a novel type of pneumatic actuator, namely the pneumatic textile actuator (PTA). Although the operating principle is similar to pneumatic artificial muscles, design, fabrication and properties of PTAs show significant differences. PTAs consist of double-layered textiles, fabricated in one piece using the Jacquard weaving technology. By filling the chamber between the two layers with pressurised air, one obtains a low-weight, high-power pneumatic actuator at very low cost. The paper first describes the design, fabrication and properties of PTAs in general. Then, the characteristics of a specific PTA are determined experimentally. Moreover, we derive a mathematical model of the dynamic behaviour of the PTA. The model forms the basis for a motion control algorithm, combining flatness-based feedforward and linear feedback control. Finally, the performance of the controller is evaluated experimentally. The results indicate that PTAs are well suited for motion control tasks requiri...

Unmanned mobile power unit for agricultural purposes

It is shown that the basis of robotic technologies in plant cultivation is an unmanned mobile power unit for agricultural purposes on wheeled or tracked platform with hybrid power plant, motion control and machine vision equipment. Description of software algorithm and schematic circuit diagram of motion control are given. It is noted that machine vision is an integral part of working organs, because much of the information about the state of plants (growth rate, maturity degree, disease) is received through visual contact, as well as through systems of motion control and precise positioning. This information allows the robotic working organs to find the technological solutions and implement the required operations, and the unmanned mobile power unit to move on process route. Another fundamental function of unmanned mobile power unit is positioning and motion control on required trajectory. A brief analysis of implementation of this function by means of satellite navigation or ground facilities of positioning including machine vision and target indication is given. Satellite navigation systems provide positioning and identification on large areas, but do not work indoors. Network wireless system of local positioning allows to control the location and motion of objects and reliably identify them both outside and inside the premises. Combined application of such systems allows to extend the motion control of vehicles and agricultural machines to areas not directly visible for satellites: covered yards, buildings. That creates additional opportunities for control of local movements of products and personnel in industrial and non-industrial premises of closed and open type.

Distributed Antiflocking Algorithms for Dynamic Coverage of Mobile Sensor Networks

Mobile sensor networks (MSNs) are often used for monitoring large areas of interest (AoI) in remote and hostile environments, which can be highly dynamic in nature. Due to the infrastructure cost, MSNs usually consist of a limited number of sensor nodes. In order to cover large AoI, the mobile nodes have to move in an environment while monitoring the area dynamically. MSNs that are controlled by most of the previously proposed dynamic coverage algorithms either lack adaptability to dynamic environments or display poor coverage performances due to considerable overlapping of sensing coverage. As a new class of emergent motion control algorithms for MSNs, antiflocking control algorithms enable MSNs to self-organize in an environment and provide impressive dynamic coverage performances. The antiflocking algorithms are inspired by the solitary behavior of some animals who try to separate from their species in most of daily activities in order to maximize their own gains. In this paper, we propose two distributed antiflocking algorithms for dynamic coverage of MSNs, one for obstacle-free environments and the other for obstacle-dense environments. Both are based on the sensing history and local interactions among sensor nodes.

Алгоритм формирования траектории группы подвижных объектов в двумерной среде с использованием неустойчивых режимов

Алгоритм формирования траектории группы подвижных объектов в двумерной среде с использованием неустойчивых режимов

Research of Mechanical-Arm Motion Control Algorithm based on Neutral Network

Currently, robots have been widely used in all walks of life, and mechanical arm of robots have always been the focus of research in the aspect of control. This paper first analyzes motions of mechanical arm, and then applied neutral network in the analysis of mechanical arms’ motions, effectively solving the issue that mechanical arms have multiple variables with strong coupling. Finally, it conducts the optimal control over mechanical arms’ motion through genetic algorithm. Simulation experiment shows that this method is effective and can improve effects of mechanical arms’ motions.

Robotic excavator motion control using a nonlinear proportional-integral controller and cross-coupled pre-compensation

Abstract For a robotic excavator, there is no operator in the cab while it is working, so the moving trajectory of the bucket teeth is planned in advance. For such a multi-joint machine, the coordinate motion control algorithm must be properly designed to achieve high tracking precision. However, due to uncertainty of the load and fluctuation of the speed, the multi-actuator system cannot work stably, resulting in tracking errors. To improve tracking performance, a cross-coupled pre-compensation algorithm is put forward in this paper. It is combined with nonlinear proportional-integral controllers to optimize the control parameters of the actuators. Experiments are performed on a 3.5-ton exactor. The results show that the proposed control algorithm is effective for improving the tracking accuracy.

A Smart Ultrasonic Actuator with Multidegree of Freedom for Autonomous Vehicle Guidance Industrial Applications

A piezoelectric ultrasonic actuator with multidegree of freedom for autonomous vehicle guidance industrial applications is presented in this paper. The actuator is aiming to increase the visual spotlight angle of digital visual data capture transducer. It consists of three main parts, the stator, rotor and housing unit. The stator is a piezoelectric ring made from S42 piezoelectric ceramics material, bonded to three electrodes made from a material that has a close Characteristics to the S42. The rotor is a ball made from stainless steel materials. The actuator working principles is based on creating micro elliptical motions of surface points, generated by superposition of longitudinal and bending vibration modes, of oscillating structures. Transferring this motion from flexible ring transducer through the three electrodes, to the attached rotor, create 3D motions. The actuator Design, structures, working principles and finite element analysis are discussed in this paper. A prototype of the actuator was fabricated and its characteristics measured. Experimental tests showed the ability of the developed prototype to provide multidegree of freedom with typical speed of movement equal to 35 rpm, a resolution of less than 5μm and maximum load of 3.5 Newton. These characteristics illustrated the potential of the developed smart actuator, to gear the spotlight angle of digital visual data capture transducers and possible improvement that such micro-actuator technology could bring to the autonomous vehicle guidance and machine vision industrial applications. Furthermore research are still undertaken to develop a universal control prototype, integrate the actuator with an infrared sensor, visual data capture digital transducers and obtain the trajectory of motion control algorithm.

Algorithm for motion control of an exoskeleton during verticalization

This paper considers lower limb exoskeleton that performs sit-to-stand motion. The work is focused on the control system design. An application of a null space projection methods for solving inverse kinematics problem is discussed. An adaptive multi-input multi-output regulator for the system is presented with the motivation for that choice. Results of the simulation for different versions of the regulator are shown.

Technical Note: A novel leaf sequencing optimization algorithm which considers previous underdose and overdose events for MLC tracking radiotherapy.

Multileaf collimator (MLC) tracking radiotherapy is complex as the beam pattern needs to be modified due to the planned intensity modulation as well as the real-time target motion. The target motion cannot be planned; therefore, the modified beam pattern differs from the original plan and the MLC sequence needs to be recomputed online. Current MLC tracking algorithms use a greedy heuristic in that they optimize for a given time, but ignore past errors. To overcome this problem, the authors have developed and improved an algorithm that minimizes large underdose and overdose regions. Additionally, previous underdose and overdose events are taken into account to avoid regions with high quantity of dose events. The authors improved the existing MLC motion control algorithm by introducing a cumulative underdose/overdose map. This map represents the actual projection of the planned tumor shape and logs occurring dose events at each specific regions. These events have an impact on the dose cost calculation and reduce recurrence of dose events at each region. The authors studied the improvement of the new temporal optimization algorithm in terms of the L1-norm minimization of the sum of overdose and underdose compared to not accounting for previous dose events. For evaluation, the authors simulated the delivery of 5 conformal and 14 intensity-modulated radiotherapy (IMRT)-plans with 7 3D patient measured tumor motion traces. Simulations with conformal shapes showed an improvement of L1-norm up to 8.5% after 100 MLC modification steps. Experiments showed comparable improvements with the same type of treatment plans. A novel leaf sequencing optimization algorithm which considers previous dose events for MLC tracking radiotherapy has been developed and investigated. Reductions in underdose/overdose are observed for conformal and IMRT delivery.

New virtual laboratories presenting advanced motion control concepts

The paper deals with development of software framework for rapid generation of remote virtual laboratories. Client-server architecture is chosen in order to employ real-time simulation core which is running on a dedicated server. Ordinary web browser is used as a final renderer to achieve hardware independent solution which can be run on different target platforms including laptops, tablets or mobile phones. The provided toolchain allows automatic generation of the virtual laboratory source code from the configuration file created in the open- source Inkscape graphic editor. Three virtual laboratories presenting advanced motion control algorithms have been developed showing the applicability of the proposed approach.

Control system architecture for the investigation of motion control algorithms on an example of the mobile platform Rex

Abstract This paper presets the specification and implementation of the control system of the mobile platform Rex. The presented system structure and the description of its functioning result from the application of a formal method of designing such systems. This formalism is based on the concept of an embodied agent. The behaviours of its subsystems are specified in terms of transition functions that compute, out of the variables contained in the internal memory and the input buffers, the values that are inserted into the output buffers and the internal memory. The transition functions are the parameters of elementary actions, which in turn are used in behaviour patterns which are the building blocks of the subsystems of the designed control system. Rex is a skid steering platform, with four independently actuated wheels. It is represented by a single agent that implements the locomotion functionality. The agent consists of a control subsystem, a virtual effector and a virtual receptor. Each of those subsystems is discussed in details. Both the data structures and the transition functions defining their behaviours are described. The locomotion agent is a part of the control system of the autonomous exploration and rescue robot developed within the RobREx project.

Experimental implementation of predictive indicators for configuring a real-time hybrid simulation

Real-time hybrid simulation (RTHS) is gaining acceptance as an efficient and cost-effective method for realistic structural evaluation. Advances in real-time computing and control methods have enabled research in the development of this novel methodology to progress rapidly. However, to explore effectiveness and accuracy, and thus build broader confidence in the use of this method as an alternative to shake table testing, there is a need to better understand and address the key features that determine the success of an RTHS. Here we discuss the design and analysis of a SDOF RTHS case study conducted in Purdue University’s Intelligent Infrastructure Systems Lab (IISL). We examine the key factors that determine the success, through configuration of the test using predictive indicators, design of an appropriately effective actuator controller, and a thorough comparison with shake table testing. The reference structure chosen for this case study is a single story, moment resisting frame structure. This particular specimen is of lab scale and well-known component properties, making it a suitable choice for such an investigation. However, noise, control–structure interaction and damping introduce numerous challenges typically faced in establishing an effective RTHS configuration. We investigate two key issues that lead to the design of a successful RTHS, specifically the partitioning between numerical and physical substructure for stability and performance, and the actuator motion control algorithm. Predictive indicators are demonstrated to be particularly helpful for properly configuring an RTHS experiment to meet a researcher’s specified objectives. Furthermore a direct comparison is conducted to examine the ability of RTHS to replicate a shake table test. The results demonstrate that with proper partitioning and actuator control design, successful RTHS can be implemented despite unfavorable transfer system properties.

Aerodrome vehicle integrated control system using computer vision

A concept of designing an advanced surface movement guidance and control system (A---SMGCS) and algorithms for an onboard integrated navigation system are proposed. The main purpose is to enhance the aerodrome capacity and increase the safety of motion of ground vehicles and aircraft in the aerodrome. The structure of the system and its components, mathematical models, and algorithms of the onboard integrated navigation system are described. Simulation results for the basic properties of the system are presented.

Path scheduling for multi-AGV system based on two-staged traffic scheduling scheme and genetic algorithm

An improved two-staged traffic scheduling scheme with Genetic algorithm (GA) are combined in this paper for a multi-AGV (Automated Guided Vehicle) system, containing path planning and conflicts avoidance for multi-AGV, wherein path following for a single AGV and path scheduling with GA for multi-AG V both in off-line and on-line stages. Multiple objectives and constraints are taken into account for on-line GA when some routes in digital map are unable to use due to unavoidable conflicts. A new conflict-free policy is proposed which changes the velocity or routes of the inferior AGV to make their movement harmoniously. Finally, two numerical simulations are used prove the efficacy of traffic scheduling scheme and the adaptability of motion control algorithm respectively.

Developing algorithms of object motion control on the basis of Kalman filtering of bearing-only measurements

Consideration was given to the problem of controlling the motion of an object subject to random disturbances. It was assumed that the bearings to beacons with certain coordinates are open to measurements. The bearing angles are nonlinear functions of the current coordinates. Therefore, the present paper suggested a modified method of pseudomeasurements proving bias-free estimates of the current object coordinates using the algorithm of conditionallyoptimal filtering. These estimates underlie the object control algorithm demonstrating the possibility of high-quality tracing of the given motion trajectory.