Multi-joint Robot Research Articles

2A1-B05 6関節遠隔操作ロボットの手先位置制御における冗長自由度温存による障害物適応(動作計画と制御の新展開)

The paper is concerned with execution of endpoint task in robotic teleoperation in the case that a part of telerobot's body interacts with an obstacle in telerobot's working space. Recently, without any force sensing the simultaneous realization of an endpoint task and adaptation to external forces acting on a part of body of a multi-joint robot has been presented. It is based on preserving redundant degrees of freedom of a robotic system during operation. By applying the idea to a telerobot with six joints, the experimental results demonstrate that thanks to the kinematic redundancy obstacle adaptation is realized and an operator can concentrate on primary tasks without any care for obstacle contact.

The Movement Analysis and Research of 4R Multi-Joint Manipulator for the Loading and Unloading

This paper studies the problem of multi-joint robot with four degrees of freedom that is used in the process of loading and unloading, the method of homogeneous coordinate transformation is used to achieve the exchange between the implementation end of the space coordinate and the joint angle. Providing the theoretical reference and a basis of calculating for the follow-up study, and ultimately meeting the actual needs of production.

Handling Motion Simulation for Multi-joint Stance Robot Based on Repeatedly Direct Kinematics Algorithm

Taking a five-joint stance robot as research subject,a motion generation method based on repeatedly direct kinematics(RDK)algorithm is proposed for multi-joint robots.The handhng motion in daily life is investigated to simulate its handling motion process.Then the desired handling trajectory with which the robot doesn't turn over and all joints suffer the smallest load torque is generated.Finally,the stability of multi-joint stance robot in handling motion is discussed.

Adaptive Fuzzy Immune PID Control for Multi-Joint Robots

To improve the control precision of multi-joint robots, a adaptive fuzzy immune PID control method for multi-joint robots was presented based on the immune feedback mechanism and fuzzy control theory, and the parameters of PID controller was optimized with hybrid algorithm. First, least square algorithm was used for off-line optimization to form immune feedback control system. Then, genetic algorithm was used for on-line optimization to get the optimal performance parameters of immune PID control system and the optimal fuzzy proportional parameters. Simulation results of a 2-joint robot manipulator demonstrated that the control method designed gets tracking effect with high precision and speed.

Research on the Posture Kinematics Model of Multi-Joint Caterpillar Robot and its Motion Control

It is higher superior of the caterpillar mobile robots to others types of robots in unknown complex environment, the advantage is apparently; but the issue is, it is difficulty in exact analyzing the posture of the robot kinematics model. In this paper, the new ideas proposed in the view of this issue, on the solution of posture motion model in the non-structural environment, motion agencies is transformed by the equivalent mechanism transformation, a fixed posture on the ground movement model is established by the screw theory. The posture model of non-holonomic constraints multi-joint caterpillar robot could be transferred into a kinematics model of parallel mechanism posture. Besides, the posture control method on over-obstacle stability is proposed, analyzing with the controlling experiment.

Analysis of Take-Off Performances for a Double-Joint Hopping Leg

The paper is focused on a double-joint hopping leg driven by motors. Using relative coordinates, its kinematics and dynamics between the system and components are established during the launching stage of jumping, and the take-off mechanism is analyzed. Based on mechanics of jump movement and joint trajectory planning method, the impact of the change of the system initial posture and joint trajectories upon the system take-off performances, such as energy efficiency, instantaneous velocity of the system center of mass (CoM), is discussed by using numerical simulation approach with drive constraints. For a hopping robot, good take-off performances can improve its motion ability, so the resulted conclusions here provides a useful and helpful reference for analyzing and designing a multi-joint hopping robot.

A Motion Control Method of Multi-joint Robots Utilizing Stiffness Adaptation for Energy Saving

A Motion Control Method of Multi-joint Robots Utilizing Stiffness Adaptation for Energy Saving

Dynamic surface control-backstepping based impedance control for 5-DOF flexible joint robots

A new impedance controller based on the dynamic surface control-backstepping technique to actualize the anticipant dynamic relationship between the motion of end-effector and the external torques was presented. Comparing with the traditional backstepping method that has “explosion of terms” problem, the new proposed control system is a combination of the dynamic surface control technique and the backstepping. The dynamic surface control (DSC) technique can resolve the “explosion of terms” problem that is caused by differential coefficient calculation in the model, and the problem can bring a complexity that will cause the backstepping method hardly to be applied to the practical application, especially to the multi-joint robot. Finally, the validity of the method was proved in the laboratory environment that was set up on the 5-DOF (degree of freedom) flexible joint robot. Tracking errors of DSC-backstepping impedance control that were 2.0 and 1.5 mm are better than those of backstepping impedance control which were 3.5 and 2.5 mm in directions X, Y in free space, respectively. And the anticipant Cartesian impedance behavior and compliant behavior were achieved successfully as depicted theoretically.

고속 EFEM의 성능평가시스템 개발

본 논문은 반도체 공정에 사용되는 고속 EFEM(Equipment Front End Module) 장치의 새로운 성능평가시스템을 제안한다. 다관절 로봇으로 구성된 EFEM은 실리콘 웨이퍼 또는 포토마스크를 클린 스토리지캐리어와 각종 계측 및 테스팅 시스템 사이를 이동시키는 반도체 자동화의 핵심장치이다.<BR> 성능평가 시스템 개발을 위한 이론과 실험적인 연구가 수행되었고, 그 결과는 고속 EFEM 장치의 성능평가시스템이 적합함을 입증한다. 특히, WTO/TBT(Technical Barriers to Trade) 협정 및 PL(Product Liability)법에 대처하는데 매우 효과적이다.

Design and Control of a Multi-jointed Robot Finger Driven by an Artificial Muscle Actuator

In this paper, we present a robotic actuation system using an artificial muscle actuator based on a dielectric elastomer. A novel linear actuator called a 'multi-stacked actuator' is proposed that can be embedded in the phalanges of a multi-jointed robot finger. This actuator ensures a compact design of the overall system. As an example, a 2-d.o.f. robot finger is developed and its performance under the proposed actuator system is experimentally demonstrated. The application of the proposed system can be extended easily to a multifingered robot hand and even to articulated mechanisms such as legged robots, etc.

Weightlifting Motion Generation for a Stance Robot with Repeatedly Direct Kinematics

This research focuses on how to control the robot easily and how to generate the better trajectories of the robot with multiple joints to implement weightlifting motion. The purpose of this research is to develop a multijoint robot can stand up successfully with an object. This research requires the operations with two items. First, when the object is lifted up slowly, the robot could stand up as easily as possible and does not tumble down. Second, the load applied on each joint should be as small as possible. In this article, a motion control method is proposed to evaluate the variations of the load torque and rotated angle of each joint with the geometrical constraints in the procedure and find the best algorithm to generate the trajectory of a weightlifting motion by a stance robot with repeatedly direct kinematics.

Modeling and Control of 2D Grasping under Rolling Contact Constraints between Arbitrary Shapes: A Riemannian-Geometry Approach

Modeling, control, and stabilization of dynamics of two-dimensional object grasping by using a pair of multijoint robot fingers are investigated under rolling contact constraints and arbitrariness of the geometry of the object and fingertips. First, modeling of rolling motion between 2D rigid bodies with arbitrary shape is treated under the assumption that the two contour curves coincide at the contact point and share the same tangent. The rolling constraints induce the Euler equation of motion that is parameterized by a pair of arclength parameters and constrained onto the kernel space as an orthogonal complement to the image space spanned from all the constraint gradients. Furthermore, it is shown that all the Pfaffian forms of the rolling constraints are integrable in the sense of Frobenius and therefore the rolling contacts are regarded as a holonomic constraint. The Euler-Lagrange equation of motion of the overall fingers/object system is rederived together with a couple of first-order differential equations that express evolution of contact points in terms of quantities of the second fundamental form. A control signal called “blind grasping” is defined and shown to be effective in maintenance or stabilization of grasping without using the details of object shape and parameters or external sensing. An extension of the Dirichlet-Lagrange stability theorem to a system of DOF-redundancy under constraints is discussed by introducing a Morse-Bott function and deriving its Hessian, in a special case that the object to be grasped is a parallelepiped.

A Riemannian-Geometric Approach for Intelligent Control and Fingertip Design of Multi-fingered Hands

Based upon the analysis of modeling and control of two-dimensional (2-D) grasping and manipulation of arbitrary rigid objects under rolling contact constraints, geometrical conditions for the design of desired fingertip shapes of robot fingers are discussed from the Riemannian-geometric standpoint. A required condition is given as an inequality expressed in terms of quantities of the second fundamental form of fingertip contour curves, although the quantities do not enter into the Euler–Lagrange equation of motion of the overall fingers/object system. Satisfaction of the inequality is necessary for stabilization of grasping by using fingers–thumb opposable control signals without use of external sensings or knowledge of an object to be grasped. At the same time, asymptotic convergence of a solution to the closed-loop dynamics of 2-D precision prehension by a pair of multi-joint robot fingers is proved under rolling contact constraints and the existence of redundancy in the system's degrees of freedom. This is regarded as an extension of the Dirichlet–Lagrange stability theorem to a dynamical system with redundancy and geometric constraints.

2P1-B27 Sloshing Suppression by Input Shaping Method for Liquid Container Transfer Using Multi-Joint Robot Arm

2P1-B27 Sloshing Suppression by Input Shaping Method for Liquid Container Transfer Using Multi-Joint Robot Arm

Modeling and Control of 2-D Grasping of an Object with Arbitrary Shape under Rolling Contact

Modeling, control, and stabilization of dynamics of two-dimensional object grasping by using a pair of multi-joint robot fingers are investigated under rolling contact constraints and an arbitrary ...

소형 다관절로봇을 위한 운용 소프트웨어 구현

The small multi-jointed robots for most education are developed with the way of firmware. But the firmware may be very difficult to develop as gradually increasing throughputs and control routines. Due to limit of firmware we try to use on RTOS, but hard to adapt on the small multi-jointed robots. It would be hard to install RTOS into the small multi-jointed robots because of the size capacity of RTOS, and lack of libraries for control of the particular hardware. Moreover, even its RTOS with many functions causes its to make overheads scheduling, TCB (Task Control Block), and task states. Also to keep maintenance of RTOS, it is composed of components for the whole structure of my proposed RTOS. Additionally, We provided with libraries of servo motor and sensor control and developed RMS (Rate Montonic scheduler) to handle tasks on real time and reduce overheads. Therefore, It is possible to work the fixed priority and task preemptive way. We show one example of the multi-jointed robot installed with my proposed RTOS, which shows to obstacle avoidance and climbing up the slope.

Adaptive Tuning of Stiffness and Motion for Multi-Joint Robot

Abstract This paper proposes a new controller that adaptively tunes joint stiffness and motions of multi-joint robots to reduce actuator torque while generating periodic motions. This controller is composed of delayed feedback control, a stiffness adaptation technique, and positive linear state feedback of angular velocity. Advantages of the proposed controller are to work without exact parameter values of the robots nor huge numerical calculations. We analyzed stability of the closed loop systems. Simulation results show that the proposed controller generate energy saving periodic motions. Additionally, we discuss energy saving effect of linear state feedback of the proposed controller.

A Riemannian-Geometry Approach for Modeling and Control of Dynamics of Object Manipulation under Constraints

A Riemannian-geometry approach for modeling and control of dynamics of object manipulation under holonomic or non-holonomic constraints is presented. First, position/force hybrid control of an endeffector of a multijoint redundant (or nonredundant) robot under a holonomic constraint is reinterpreted in terms of “submersion” in Riemannian geometry. A force control signal constructed in the image space of the constraint gradient is regarded as a lifting (or pressing) in the direction orthogonal to the kernel space. By means of the Riemannian distance on the constraint submanifold, stability of position control under holonomic constraints is discussed. Second, modeling and control of two-dimensional object grasping by a pair of multijoint robot fingers are challenged, when the object is of arbitrary shape. It is shown that rolling contact constraints induce the Euler equation of motion, in which constraint forces appear as wrench vectors affecting the object. The Riemannian metric is introduced on a constraint submanifold characterized with arclength parameters. An explicit form of the quotient dynamics is expressed in the kernel space with accompaniment of a pair of first-order differential equations concerning the arclength parameters. An extension of Dirichlet-Lagrange's stability theorem to redundant systems under constraints is suggested by introducing a Morse-Lyapunov function.

Task-Space Iterative Learning for Redundant Robots: Simultaneous Acquirements of Desired Motion and Force Trajectories under Constraints

Abstract This paper focuses on iterative learning control (ILC) for multi-joint robots with redundancy in degrees of freedom (DOFs) when task descriptions are given only in task-space. The specified task is of precise tracking of both endpoint position and force trajectories given on the plane by a five-DOF robot arm whose endpoint contacts with a plane during motion. Even in the case of twice continuously differentiable desired motion and force trajectories given only in task-space, it is possible to construct a learning update law in task-space by using the desired trajectories together with measured data correspond to them. The convergence of trajectory tracking under constraints by the proposed task space ILC is proved theoretically on the basis of nonlinear robot dynamics with DOF-redundancy.

2A1-G03 Experiments on Energy Saving Control Methods for Multi-Joint Robots with Elastic Elements

2A1-G03 Experiments on Energy Saving Control Methods for Multi-Joint Robots with Elastic Elements