371 research outputs found
Challenges and Solutions for Autonomous Robotic Mobile Manipulation for Outdoor Sample Collection
In refinery, petrochemical, and chemical plants, process technicians collect uncontaminated samples to be analyzed in the quality control laboratory all time and all weather. This traditionally manual operation not only exposes the process technicians to hazardous chemicals, but also imposes an economical burden on the management. The recent development in mobile manipulation provides an opportunity to fully automate the operation of sample collection. This paper reviewed the various challenges in sample collection in terms of navigation of the mobile platform and manipulation of the robotic arm from four aspects, namely mobile robot positioning/attitude using global navigation satellite system (GNSS), vision-based navigation and visual servoing, robotic manipulation, mobile robot path planning and control. This paper further proposed solutions to these challenges and pointed the main direction of development in mobile manipulation
Research on a semiautonomous mobile robot for loosely structured environments focused on transporting mail trolleys
In this thesis is presented a novel approach to model, control, and planning the motion of
a nonholonomic wheeled mobile robot that applies stable pushes and pulls to a
nonholonomic cart (York mail trolley) in a loosely structured environment. The method is
based on grasping and ungrasping the nonholonomic cart, as a result, the robot changes its
kinematics properties. In consequence, two robot configurations are produced by the task
of grasping and ungrasping the load, they are: the single-robot configuration and the
robot-trolley configuration. Furthermore, in order to comply with the general planar
motion law of rigid bodies and the kinematic constraints imposed by the robot wheels for
each configuration, the robot has been provided with two motorized steerable wheels in
order to have a flexible platform able to adapt to these restrictions. [Continues.
Task-Space Control of Articulated Mobile Robots With a Soft Gripper for Operations
A task-space method is presented for the control of a head-raising articulated mobile robot, allowing the trajectory tracking of a tip of a gripper located on the head of the robot in various operations, e.g., picking up an object and rotating a valve. If the robot cannot continue moving because it reaches a joint angle limit, the robot moves away from the joint limit and changes posture by switching the allocation of lifted/grounded wheels. An articulated mobile robot with a gripper that can grasp objects using jamming transition was developed, and experiments were conducted to demonstrate the effectiveness of the proposed controller in operations
The State of Lifelong Learning in Service Robots: Current Bottlenecks in Object Perception and Manipulation
Service robots are appearing more and more in our daily life. The development
of service robots combines multiple fields of research, from object perception
to object manipulation. The state-of-the-art continues to improve to make a
proper coupling between object perception and manipulation. This coupling is
necessary for service robots not only to perform various tasks in a reasonable
amount of time but also to continually adapt to new environments and safely
interact with non-expert human users. Nowadays, robots are able to recognize
various objects, and quickly plan a collision-free trajectory to grasp a target
object in predefined settings. Besides, in most of the cases, there is a
reliance on large amounts of training data. Therefore, the knowledge of such
robots is fixed after the training phase, and any changes in the environment
require complicated, time-consuming, and expensive robot re-programming by
human experts. Therefore, these approaches are still too rigid for real-life
applications in unstructured environments, where a significant portion of the
environment is unknown and cannot be directly sensed or controlled. In such
environments, no matter how extensive the training data used for batch
learning, a robot will always face new objects. Therefore, apart from batch
learning, the robot should be able to continually learn about new object
categories and grasp affordances from very few training examples on-site.
Moreover, apart from robot self-learning, non-expert users could interactively
guide the process of experience acquisition by teaching new concepts, or by
correcting insufficient or erroneous concepts. In this way, the robot will
constantly learn how to help humans in everyday tasks by gaining more and more
experiences without the need for re-programming
λͺ¨μ ν리머ν°λΈλ₯Ό μ΄μ©ν 볡μ‘ν λ‘λ΄ μ무 νμ΅ λ° μΌλ°ν κΈ°λ²
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Όλ¬Έ (λ°μ¬) -- μμΈλνκ΅ λνμ : 곡과λν ν곡μ°μ£Όκ³΅νκ³Ό, 2020. 8. κΉνμ§.Learning from demonstrations (LfD) is a promising approach that enables robots to perform a specific movement. As robotic manipulations are substituting a variety of tasks, LfD algorithms are widely used and studied for specifying the robot configurations for the various types of movements.
This dissertation presents an approach based on parametric dynamic movement primitives (PDMP) as a motion representation algorithm which is one of relevant LfD techniques. Unlike existing motion representation algorithms, this work not only represents a prescribed motion but also computes the new behavior through a generalization of multiple demonstrations in the actual environment. The generalization process uses Gaussian process regression (GPR) by representing the nonlinear relationship between the PDMP parameters that determine motion and the corresponding environmental variables. The proposed algorithm shows that it serves as a powerful optimal and real-time motion planner among the existing planning algorithms when optimal demonstrations are provided as dataset.
In this dissertation, the safety of motion is also considered. Here, safety refers to keeping the system away from certain configurations that are unsafe. The safety criterion of the PDMP internal parameters are computed to check the safety. This safety criterion reflects the new behavior computed through the generalization process, as well as the individual motion safety of the demonstration set. The demonstrations causing unsafe movement are identified and removed. Also, the demolished demonstrations are replaced by proven demonstrations upon this criterion.
This work also presents an extension approach reducing the number of required demonstrations for the PDMP framework. This approach is effective where a single mission consists of multiple sub-tasks and requires numerous demonstrations in generalizing them. The whole trajectories in provided demonstrations are segmented into multiple sub-tasks representing unit motions. Then, multiple PDMPs are formed independently for correlated-segments. The phase-decision process determines which sub-task and associated PDMPs to be executed online, allowing multiple PDMPs to be autonomously configured within an integrated framework. GPR formulations are applied to obtain execution time and regional goal configuration for each sub-task.
Finally, the proposed approach and its extension are validated with the actual experiments of mobile manipulators. The first two scenarios regarding cooperative aerial transportation demonstrate the excellence of the proposed technique in terms of quick computation, generation of efficient movement, and safety assurance. The last scenario deals with two mobile manipulations using ground vehicles and shows the effectiveness of the proposed extension in executing complex missions.μμ° νμ΅ κΈ°λ²(Learning from demonstrations, LfD)μ λ‘λ΄μ΄ νΉμ λμμ μνν μ μλλ‘ νλ μ λ§ν λμ μμ± κΈ°λ²μ΄λ€. λ‘λ΄ μ‘°μκΈ°κ° μΈκ° μ¬νμμ λ€μν μ
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ν리머ν°λΈ κΈ°λ°μ λμ μ¬μμ± μκ³ λ¦¬μ¦μΈ Parametric dynamic movement primitives(PDMP)μ κΈ°μ΄ν μκ³ λ¦¬μ¦μ μ μνλ©°, μ΄λ₯Ό ν΅ν΄ λ€μν μ무λ₯Ό μννλ λͺ¨λ°μΌ μ‘°μκΈ°μ κΆ€μ μ μμ±νλ€. κΈ°μ‘΄μ λμ μ¬μμ± μκ³ λ¦¬μ¦κ³Ό λ¬λ¦¬, μ΄ μ°κ΅¬λ μ 곡λ μμ°μμ ννλ λμμ λ¨μν μ¬μμ±νλ κ²μ κ·ΈμΉμ§ μκ³ , μλ‘μ΄ νκ²½μ λ§κ² μΌλ°ν νλ κ³Όμ μ ν¬ν¨νλ€. μ΄ λ
Όλ¬Έμμ μ μνλ μΌλ°ν κ³Όμ μ PDMPsμ λ΄λΆ νλΌλ―Έν° κ°μΈ μ€νμΌ νλΌλ―Έν°μ νκ²½ λ³μ μ¬μ΄μ λΉμ ν κ΄κ³λ₯Ό κ°μ°μ€ νκ· κΈ°λ² (Gaussian process regression, GPR)μ μ΄μ©νμ¬ μμμ μΌλ‘ νννλ€. μ μλ κΈ°λ²μ λν μ΅μ μμ°λ₯Ό νμ΅νλ λ°©μμ ν΅ν΄ κ°λ ₯ν μ΅μ μ€μκ° κ²½λ‘ κ³ν κΈ°λ²μΌλ‘λ μμ©λ μ μλ€.
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μ¦λ μμλ‘ λ체νμ¬ μΌλ°ν μ±λ₯μ μ νμν€μ§ μλλ‘ μμλ₯Ό κ΄λ¦¬νλ€. μ΄λ₯Ό ν΅ν΄ λ€μμ μμ° κ°κ° κ°λ³ λμ μμ μ± λΏ μλλΌ μ¨λΌμΈ λμμ μμ μ±κΉμ§ κ³ λ €ν μ μμΌλ©°, μ€μκ° λ‘λ΄ μ‘°μκΈ° μ΄μ©μ μμ μ±μ΄ ν보λ μ μλ€. μ μλ μμ μ±μ κ³ λ €ν μμ° κ΄λ¦¬ κΈ°μ μ λν νκ²½μ μ μ μ€μ μ΄ λ³κ²½λμ΄ λͺ¨λ μμ°μ κ΅μ²΄ν΄μΌ ν μ μλ μν©μμ μ¬μ©ν μ μλ μμ°λ€μ νλ³νκ³ , ν¨μ¨μ μΌλ‘ μ¬μ¬μ©νλ λ° μμ©ν μ μλ€.
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Όλ¬Έμ 볡μ‘ν μ무μμ μ μ©λ μ μλ PDMPsμ νμ₯ κΈ°λ²μΈ seg-PDMPsλ₯Ό μ μνλ€. μ΄ μ κ·Όλ°©μμ 볡μ‘ν μλ¬΄κ° μΌλ°μ μΌλ‘ 볡μκ°μ κ°λ¨ν νμ μμ
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μ λνλ΄λ μ¬λ¬ κ°μ λ¨μ λμμΌλ‘ λΆν νκ³ , κ° λ¨μλμμ λν΄ μ¬λ¬κ°μ PDMPsλ₯Ό ꡬμ±νλ€. κ° λ¨μ λμ λ³λ‘ μμ±λ PDMPsλ ν΅ν©λ νλ μμν¬λ΄μμ λ¨κ³ κ²°μ νλ‘μΈμ€λ₯Ό ν΅ν΄ μλμ μΌλ‘ νΈμΆλλ€. κ° λ¨κ³ λ³λ‘ λ¨μ λμμ μννκΈ° μν μκ° λ° νμ λͺ©νμ μ κ°μ°μ€ 곡μ νκ·(GPR)λ₯Ό μ΄μ©ν νκ²½λ³μμμμ κ΄κ³μμ ν΅ν΄ μ»λλ€. κ²°κ³Όμ μΌλ‘, μ΄ μ°κ΅¬λ μ 체μ μΌλ‘ μꡬλλ μμ°μ μλ₯Ό ν¨κ³Όμ μΌλ‘ μ€μΌ λΏ μλλΌ, κ° λ¨μλμμ νν μ±λ₯μ κ°μ νλ€.
μ μλ μκ³ λ¦¬μ¦μ νλ λͺ¨λ°μΌ λ‘λ΄ μ‘°μκΈ° μ€νμ ν΅νμ¬ κ²μ¦λλ€. μΈ κ°μ§μ μλ리μ€κ° λ³Έ λ
Όλ¬Έμμ λ€λ£¨μ΄μ§λ©°, ν곡 μ΄μ‘κ³Ό κ΄λ ¨λ 첫 λ κ°μ§ μλ리μ€λ PDMPs κΈ°λ²μ΄ λ‘λ΄ μ‘°μκΈ°μμ λΉ λ₯Έ μ μμ±, μ무 ν¨μ¨μ±κ³Ό μμ μ± λͺ¨λ λ§μ‘±νλ κ²μ μ
μ¦νλ€. λ§μ§λ§ μλ리μ€λ μ§μ μ°¨λμ μ΄μ©ν λ κ°μ λ‘λ΄ μ‘°μκΈ°μ λν μ€νμΌλ‘ 볡μ‘ν μ무 μνμ νκΈ° μν΄ νμ₯λ κΈ°λ²μΈ seg-PDMPsκ° ν¨κ³Όμ μΌλ‘ λ³ννλ νκ²½μμ μΌλ°νλ λμμ μμ±ν¨μ κ²μ¦νλ€.1 Introduction 1
1.1 Motivations 1
1.2 Literature Survey 3
1.2.1 Conventional Motion Planning in Mobile Manipulations 3
1.2.2 Motion Representation Algorithms 5
1.2.3 Safety-guaranteed Motion Representation Algorithms 7
1.3 Research Objectives and Contributions 7
1.3.1 Motion Generalization in Motion Representation Algorithm 9
1.3.2 Motion Generalization with Safety Guarantee 9
1.3.3 Motion Generalization for Complex Missions 10
1.4 Thesis Organization 11
2 Background 12
2.1 DMPs 12
2.2 Mobile Manipulation Systems 13
2.2.1 Single Mobile Manipulation 14
2.2.2 Cooperative Mobile Manipulations 14
2.3 Experimental Setup 17
2.3.1 Test-beds for Aerial Manipulators 17
2.3.2 Test-beds for Robot Manipulators with Ground Vehicles 17
3 Motion Generalization in Motion Representation Algorithm 22
3.1 Parametric Dynamic Movement Primitives 22
3.2 Generalization Process in PDMPs 26
3.2.1 Environmental Parameters 26
3.2.2 Mapping Function 26
3.3 Simulation Results 29
3.3.1 Two-dimensional Hurdling Motion 29
3.3.2 Cooperative Aerial Transportation 30
4 Motion Generalization with Safety Guarantee 36
4.1 Safety Criterion in Style Parameter 36
4.2 Demonstration Management 39
4.3 Simulation Validation 42
4.3.1 Two-dimensional Hurdling Motion 46
4.3.2 Cooperative Aerial Transportation 47
5 Motion Generalization for Complex Missions 51
5.1 Overall Structure of Seg-PDMPs 51
5.2 Motion Segments 53
5.3 Phase-decision Process 54
5.4 Seg-PDMPs for Single Phase 54
5.5 Simulation Results 55
5.5.1 Initial/terminal Offsets 56
5.5.2 Style Generalization 59
5.5.3 Recombination 61
6 Experimental Validation and Results 63
6.1 Cooperative Aerial Transportation 63
6.2 Cooperative Mobile Hang-dry Mission 70
6.2.1 Demonstrations 70
6.2.2 Simulation Validation 72
6.2.3 Experimental Results 78
7 Conclusions 82
Abstract (in Korean) 93Docto
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