A reduced actuation mecanum wheel platform for pipe inspection

This paper focuses on the design, development and assessment of a novel, 2 degrees-of-freedom magnetic pipe inspection robot. It consists of 4 mecanum wheels, with the diagonals functionally coupled and the system rotation constrained by the surface geometry, maintaining full translational mobility with reduced control and actuation requirements. The system uses positional encoding that is decoupled from the transmission system to overcome the main sources of positional/positioning errors when using mecanum wheels. The kinematic and dynamic models of the system are derived and integrated within the controller. The prototype robot is then tested and shown to follow a scan path at 20mm/s within ±1.5mm whilst correcting for gravitational drift and slip events

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

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

Unlimited-wokspace teleoperation

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2012Includes bibliographical references (leaves: 100-105)Text in English; Abstract: Turkish and Englishxiv, 109 leavesTeleoperation is, in its brief description, operating a vehicle or a manipulator from a distance. Teleoperation is used to reduce mission cost, protect humans from accidents that can be occurred during the mission, and perform complex missions for tasks that take place in areas which are difficult to reach or dangerous for humans. Teleoperation is divided into two main categories as unilateral and bilateral teleoperation according to information flow. This flow can be configured to be in either one direction (only from master to slave) or two directions (from master to slave and from slave to master). In unlimited-workspace teleoperation, one of the types of bilateral teleoperation, mobile robots are controlled by the operator and environmental information is transferred from the mobile robot to the operator. Teleoperated vehicles can be used in a variety of missions in air, on ground and in water. Therefore, different constructional types of robots can be designed for the different types of missions. This thesis aims to design and develop an unlimited-workspace teleoperation which includes an omnidirectional mobile robot as the slave system to be used in further researches. Initially, an omnidirectional mobile robot was manufactured and robot-operator interaction and efficient data transfer was provided with the established communication line. Wheel velocities were measured in real-time by Hall-effect sensors mounted on robot chassis to be integrated in controllers. A dynamic obstacle detection system, which is suitable for omnidirectional mobility, was developed and two obstacle avoidance algorithms (semi-autonomous and force reflecting) were created and tested. Distance information between the robot and the obstacles was collected by an array of sensors mounted on the robot. In the semi-autonomous teleoperation scenario, distance information is used to avoid obstacles autonomously and in the force-reflecting teleoperation scenario obstacles are informed to the user by sending back the artificially created forces acting on the slave robot. The test results indicate that obstacle avoidance performance of the developed vehicle with two algorithms is acceptable in all test scenarios. In addition, two control models were developed (kinematic and dynamic control) for the local controller of the slave robot. Also, kinematic controller was supported by gyroscope

Development of new intelligent autonomous robotic assistant for hospitals

Continuous technological development in modern societies has increased the quality of life and average life-span of people. This imposes an extra burden on the current healthcare infrastructure, which also creates the opportunity for developing new, autonomous, assistive robots to help alleviate this extra workload. The research question explored the extent to which a prototypical robotic platform can be created and how it may be implemented in a hospital environment with the aim to assist the hospital staff with daily tasks, such as guiding patients and visitors, following patients to ensure safety, and making deliveries to and from rooms and workstations. In terms of major contributions, this thesis outlines five domains of the development of an actual robotic assistant prototype. Firstly, a comprehensive schematic design is presented in which mechanical, electrical, motor control and kinematics solutions have been examined in detail. Next, a new method has been proposed for assessing the intrinsic properties of different flooring-types using machine learning to classify mechanical vibrations. Thirdly, the technical challenge of enabling the robot to simultaneously map and localise itself in a dynamic environment has been addressed, whereby leg detection is introduced to ensure that, whilst mapping, the robot is able to distinguish between people and the background. The fourth contribution is geometric collision prediction into stabilised dynamic navigation methods, thus optimising the navigation ability to update real-time path planning in a dynamic environment. Lastly, the problem of detecting gaze at long distances has been addressed by means of a new eye-tracking hardware solution which combines infra-red eye tracking and depth sensing. The research serves both to provide a template for the development of comprehensive mobile assistive-robot solutions, and to address some of the inherent challenges currently present in introducing autonomous assistive robots in hospital environments.Open Acces

Development of local geometrical planning for omni-directional robot

The goal of this work is the development of an obstacle avoidance algorithm for the mobile platform of the Mobile Anthropomorphic Dual-Arm Robot (MADAR), designed by the Institute of Industrial and Control Engineering (IOC) and Mechanical Engineering Department at the Universidad Politècnica de Catalunya (UPC). The algorithm takes as inputs laser measurements from the front scanner that the robot is equipped, and the vector of the goal to reach. A local geometrical planning is adopted, it is reactive and applied continuously each time that the scanner samples (frequency = 15 Hz). A heuristic is used to choose the direction of motion, which tries to execute the shorter path that the robot needs to cover in order to reach the goal. It is validated the implementation with experimentation on the real robot. In conclusion, the algorithm can be consider a possible solution for obstacle avoidance problems on every omni-directional robots or also, its logic could be reused as a part of other kind of algorithms to improve them

Analysis, design, and control of an omnidirectional mobile robot in rough terrain

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 49-52).An omnidirectional mobile robot is able, kinematically, to move in any direction regardless of current pose. To date, nearly all designs and analyses of omnidirectional mobile robots have considered the case of motion on flat, smooth terrain. In this thesis, an investigation of the suitability of an active split offset caster driven omnidirectional mobile robot for use in rough terrain is presented. Kinematic and geometric properties of the drive mechanism are investigated along with guidelines for designing the robot. An optimization method is implemented to explore the design space. These analyses can be used as design guidelines for development of an omnidirectional mobile robot that can operate in unstructured environments. A simple kinematic controller that considers the effects of terrain unevenness via an estimate of the wheel-terrain contact angles is also presented. It is shown in simulation that under the proposed control method, near-omnidirectional tracking performance is possible even in rough, uneven terrain.by Martin Richard Udengaard.S.M

Modelling of mobility mechanism for Motorized Adjustable Vertical Platform (MAVeP)

During the thermal vacuum, acoustic and vibration test procedure before launching, a satellite needs to be transported from one test area to another area using a mobile platform. To cater the demand, a special platform called Motorized Adjustable Vertical Platform (MAVeP) has been designed and assembled to ensure a smooth transfer operation and to reduce the handling risk that may jeopardize the satellite. This platform is able to move around and equipped with a height adjustable mechanism to elevate the satellite. This paper focuses on the design and modelling of MAVeP mobility. High accuracy and repeatability parking is an important criteria in the mechanical and electrical design. Kinematics and dynamic model of MAVeP mobility is described in this paper and verified experimentally. The result show that the kinematic and dynamic modelling errors are 0.08m respectively and MAVeP is able to move in a confined environment and desired

Calibration of Mobile Robot with Single Wheel Powered Caster

학위논문(석사) -- 서울대학교대학원 : 융합과학기술대학원 지능정보융합학과, 2022. 8. 박재흥.모바일 로봇의 제어와 오도메트리에 큰 영향을 주는 기구학적 파라미터를 보정하는 기구학적 캘리브레이션 방법은 다양한 종류의 모바일 로봇에서 연구되어왔다. 기구학적 캘리브레이션 방법은 모바일 로봇의 종류에 의존적이기 때문에 각 종류에 맞는 기구학적 캘리브레이션 방법이 필요하다. 캐스터 기반 모바일 로봇의 경우 복잡한 기구학적 형상 때문에 기구학적 파라미터가 부정확한 경우 제어 시 응력을 발생시켜 미끄러짐을 유발하기 때문에 정확한 기구학적 파라미터를 아는 것이 중요하다. 캐스터 기반 모바일 로봇을 위한 기구학적 캘리브레이션 방법은 특정 모델인 분할 캐스터에 한하여 연구가 진행되었다. 이전 연구는 캐스터 바퀴를 고정한 경우 바퀴와 바닥 사이에 회전이 일어나면 안 되기 때문에 바닥과 1점 접촉을 하는 단일 바퀴 캐스터에는 적용할 수 없다. 본 논문은 단일 바퀴 캐스터 기반 모바일 로봇의 정확한 기구학적 파라미터를 구하는 기구학적 캘리브레이션 방법을 제안한다. 제안하는 방법은 로봇에 장착된 캐스터 모듈 하나를 고정해 고정된 바퀴를 기준으로 로봇이 회전하는 경우 생기는 기하학적 관계와 로봇의 이동 정보 및 모터 엔코더 정보를 이용해 로봇의 기구학적 파라미터를 구한다. 시뮬레이션과 실제 환경에서 진행된 실험을 통해 제안하는 캘리브레이션 방법을 검증하고 이 방법이 정확한 기구학적 파라미터를 구해 오도메트리 정확도를 향상할 수 있음을 보인다.Kinematic parameters of mobile robot have a great influence on its odometry and control, so many researches were conducted to find accurate kinematic parameters of mobile robot. Since a kinematic calibration method, for finding accurate kinematic parameters, is dependent on the kinematic type of mobile robot, calibration method for certain type is hard to apply for another type. For caster type mobile robots which has complex kinematic model, kinematic parameters are important since inaccurate kinematic parameters cause internal force which results in wheel slippage, a non-systematic error. Previous study on kinematic calibration for caster type mobile robot proposed a method that can only calibrate double-wheeled caster type mobile robot and not single-wheeled caster type mobile robot. This paper proposes a kinematic calibration method for single-wheeled caster type mobile robot. Proposed method uses geometric relationship and movement information of robot and its motor when the robot rotates around its stationary caster wheel. Simulation and hardware experiments conducted in this paper validates the proposed calibration method and shows its performance.제 1 장 서론 1 제 1 절 오도메트리 오차 1 제 2 절 연구 동향 2 제 3 절 연구 기여 5 제 4 절 논문 구성 9 제 2 장 ASOC 기반 모바일 로봇의 캘리브레이션 10 제 1 절 캘리브레이션 방법 10 제 2 절 캘리브레이션 방법의 특징 11 제 3 장 SWPC 기반 모바일 로봇의 캘리브레이션 14 제 1 절 캘리브레이션 방법 14 제 2 절 캘리브레이션 방법의 특징 19 제 4 장 실험 21 제 1 절 시뮬레이션 환경 캘리브레이션 22 제 2 절 실제 환경 캘리브레이션 24 제 3 절 주행 실험 25 제 5 장 결론 33 참고 문헌 35 Abstract 39석