A Dual-Stage Planar Cable Robot: Dynamic Modeling and Design of A Robust Controller with Positive Inputs

2004 ◽  
Vol 127 (4) ◽  
pp. 612-620 ◽  
Author(s):  
So-Ryeok Oh ◽  
Kalyan Mankala ◽  
Sunil K. Agrawal ◽  
James S. Albus
Keyword(s):  
Degrees Of Freedom ◽  
Robust Controller ◽  
Two Stage ◽  
End Effector ◽  
Six Degrees Of Freedom ◽  
Cable Robot ◽  
Unknown Disturbances ◽  
Dual Stage ◽  
Loading And Unloading ◽  
Skin To Skin

Cable robots have potential usage for loading and unloading of cargo in shipping industries. A novel six-degrees-of-freedom two-stage cable robot has been proposed by NIST for skin-to-skin transfer of cargo. In this paper, we look at a planar version of this two-stage cable robot. The disturbance motion from the sea is considered while modeling the dynamics of robot. The problem of robust control of the end-effector in the presence of unknown disturbances, along with maintaining positive tensions in the cables, is tackled using redundancy of cables in the system. Simulation results show the effectiveness of the control strategy.

A Dual Stage Planar Cable Robot: Dynamic Modeling and Design of a Robust Controller With Positive Inputs

2004 ◽  
Author(s):  
So-Ryeok Oh ◽  
Kalyan Mankala ◽  
Sunil K. Agrawal ◽  
James S. Albus
Keyword(s):  
Robust Controller ◽  
Two Stage ◽  
End Effector ◽  
Cable Robot ◽  
Unknown Disturbances ◽  
Dual Stage ◽  
Loading And Unloading ◽  
Simulation Results ◽  
Six Degree Of Freedom ◽  
Skin To Skin

Cable robots have been extensively used for loading and unloading of cargo in shipping industries. A novel six-degree of freedom two-stage cable robot has been proposed by NIST for skin-to-skin transfer of cargo. In this paper, we look at a planar version of this two-stage cable robot. The disturbance motion from the sea is considered while modeling the dynamics of robot. The problem of robust control of the end-effector in the presence of unknown disturbances, along with maintaining positive tensions in the cables, is tackled by using the idea of redundancy. Simulation results show the effectiveness of the control strategy.

Robust Control of Dual-Stage Cable Suspended Robots With Input Constraints for Cargo Handling

2004 ◽  
Author(s):  
So-Ryeok Oh ◽  
Kalyan Mankala ◽  
Sunil K. Agrawal ◽  
James S. Albus
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Optimization Techniques ◽  
Input Constraints ◽  
Cargo Handling ◽  
Cable Robot ◽  
Transfer Operation ◽  
Dual Stage ◽  
Positive Input ◽  
Skin To Skin

Skin to skin transfer of cargo is a very challenging task. In a typical skin-to-skin transfer operation, the end-effector and the target are located on different ships and hence subjected to disturbances, which are not in phase. Hence, this transfer operation can be unstable unless the sea condition is properly accounted for. The cable robot should be designed for a versatile motion to track the target. NIST has proposed a dual-stage cable robot, each with six-degrees-of-freedom for this purpose. In this paper, the robust controller of the dual-stage cable robot with positive input constraints is developed which can assure robust tracking of the target in the presence of the disturbance due to the pitch, roll, and yaw motion of a ship, as well as a translation motion. Also, Pointwise optimization techniques are incorporated in order to generate feasible desired trajectories, which satisfy the input constraints. Simulations show the feasiblity of the proposed control method for the control of a dual-stage cable robot.

Experimental results for the flexible joint cable-suspended manipulator of ICaSbot

Robotica ◽  
2013 ◽  
Vol 31 (6) ◽  
pp. 887-904 ◽  
Author(s):  
M. H. Korayem ◽  
M. Bamdad ◽  
H. Tourajizadeh ◽  
A. H. Korayem ◽  
R. M. Zehtab ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Tests ◽  
Parallel Robot ◽  
Joint Space ◽  
End Effector ◽  
Flexible Joint ◽  
Cable Robot ◽  
Six Dof ◽  
And Control ◽  
Computed Torque

SUMMARYIn this paper, design, dynamic, and control of the motors of a spatial cable robot are presented considering flexibility of the joints. End-effector control in order to control all six spatial degrees of freedom (DOFs) of the system and motor control in order to control the joints flexibility are proposed here. Corresponding programing of its operation is done by formulating the kinematics and dynamics and also control of the robot. Considering the existence of gearboxes, flexibility of the joints is modeled in the feed-forward term of its controller to achieve better accuracy. A two sequential closed-loop strategy consisting of proportional derivative (PD) for linear actuators in joint space and computed torque method for nonlinear end-effector in Cartesian space is presented for further accuracy. Flexibility is estimated using modeling and simulation by MATLAB and SimDesigner. A prototype has been built and experimental tests have been done to verify the efficiency of the proposed modeling and controller as well as the effect of flexibility of the joints. The ICaSbot (IUST Cable-Suspended robot) is an under-constrained six-DOF parallel robot actuated by the aid of six suspended cables. An experimental test is conducted for the manufactured flexible joint cable robot of ICaSbot and the outputs of sensors are compared with simulation. The efficiency of the proposed schemes is demonstrated.

Dynamic Modeling and Robust Controller Design of a Two-Stage Parallel Cable Robot

2005 ◽  
Vol 13 (4) ◽  
pp. 385-399 ◽  
Author(s):  
So-Ryeok Oh ◽  
Kalyan K. Mankala ◽  
Sunil K. Agrawal ◽  
James S. Albus
Keyword(s):  
Dynamic Modeling ◽  
Controller Design ◽  
Robust Controller ◽  
Two Stage ◽  
Cable Robot ◽  
Robust Controller Design

Development of a Haptic Device with Wire-Driven Parallel Structure

2017 ◽  
Vol 11 (3) ◽  
pp. 385-395
Author(s):  
Carlo Ferraresi ◽  
◽  
Carlo De Benedictis ◽  
Francesco Pescarmona
Keyword(s):  
Degrees Of Freedom ◽  
Force Feedback ◽  
Parallel Structure ◽  
Control Logic ◽  
End Effector ◽  
Six Degrees Of Freedom ◽  
Force Closure ◽  
Force Reflection ◽  
Definition Of ◽  
Selection Of

This study focuses on the specific problems that may arise in the development of a parallel, cable-driven device designed for teleoperations systems utilizing force-reflection feedback. A redundant six degrees-of-freedom structure, actuated by nine wires, is described as a convenient layout for a haptic master for telemanipulation. A methodology for the kinematic and static analysis and the evaluation of the device workspace is described. The condition of force closure is used to find all available poses of the end-effector, thereby defining the workspace, whose characteristics are assessed by opportunely conceived indexes. Typical characteristics of cable and implementations thereof in the device are considered. Regarding the realization of the device, relevant attention is given to the definition of the control logic, which can be complex for parallel devices. The selection of the actuators, crucial in realizing force feedback, is discussed. In particular, pneumatic actuation is considered, verified as the most appropriate method for implementation and force control of the cylinders.

Design, testing and evaluation of an end-effector for self-relocation

Robotica ◽  
2015 ◽  
Vol 34 (12) ◽  
pp. 2689-2728 ◽  
Author(s):  
Feng Han ◽  
Kui Sun ◽  
Yu Liu ◽  
Hong Liu
Keyword(s):  
Degrees Of Freedom ◽  
Physical Simulation ◽  
Industrial Robot ◽  
Space Environment ◽  
Air Bearing ◽  
End Effector ◽  
Six Degrees Of Freedom ◽  
Soft Capture ◽  
End Effectors ◽  
Prototype Design

SUMMARYTwo identical end-effectors are indispensable for self-relocation of a space manipulator, which is an effective way of extending its servicing capability. The prototype design is intimately linked to the requirements. The significant features and functionality of the end-effector and its grapple fixture are described, including the key analysis efforts. The characteristics of the end-effector and their suitability for self-relocation and payload handling were confirmed by testing, which used two prototype end-effectors, a semi-physical simulation testbed system with two, six degrees of freedom (DOF) industrial robot arms, and an air-bearing testbed system with a seven DOF manipulator. The results demonstrate that the end-effector satisfies the requirements and it can work well in a simulated space environment. With the compliance motion of the manipulator, the end-effector can perform soft capture and the manipulator can securely self-relocate and handle the payload.

scholarly journals Robust Hybrid Control Algorithm for Tuning the Altitude and Attitude of Unmanned Aerial Vehicle

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Bohang Wang ◽  
Daobo Wang
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Hybrid Control ◽  
Pole Placement ◽  
Robust Controller ◽  
State Behavior ◽  
Nonlinear Parameters ◽  
Six Degrees Of Freedom ◽  
Aerial Vehicle

In this article, a new and novel robust hybrid control algorithm is designed for tuning the parameters of unmanned aerial vehicle (UAV). The quadrotor type UAV mathematical model is taken to observe the effectiveness of our designed robust hybrid control algorithm. The robust hybrid control algorithm consists of H∞ based regulation, pole-placement and tracking (RST) controller along with mixed sensitivity function is applied to control the complete model of UAV. The selected rotor craft is under-actuated, nonlinear and multivariable behavior in nature along with six degrees of freedom (DOF). Due to all these aforementioned issues its stabilization is quite difficult as compared to fully actuated systems. For the tuning of nonlinear parameters of the UAV, we designed, robust hybrid control algorithm is used. Moreover, the performance of the designed controller is compared with robust controller. The validity and effectiveness of the designed controllers are simulated in MATLAB and Simulink, in which the designed controller shows better steady state behavior, robustness and converges quickly in specific amount of time as compared to robust controller.

Kinematic model to control the end-effector of a continuum robot for multi-axis processing

Robotica ◽  
2015 ◽  
Vol 35 (1) ◽  
pp. 224-240 ◽  
Author(s):  
Salvador Cobos-Guzman ◽  
David Palmer ◽  
Dragos Axinte
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Euler Angle ◽  
Inverse Kinematic ◽  
End Effector ◽  
Six Degrees Of Freedom ◽  
Hazardous Environments ◽  
Continuum Robot ◽  
Novel Method ◽  
Six Dof

SUMMARYThis paper presents a novel kinematic approach for controlling the end-effector of a continuum robot for in-situ repair/inspection in restricted and hazardous environments. Forward and inverse kinematic (IK) models have been developed to control the last segment of the continuum robot for performing multi-axis processing tasks using the last six Degrees of Freedom (DoF). The forward kinematics (FK) is proposed using a combination of Euler angle representation and homogeneous matrices. Due to the redundancy of the system, different constraints are proposed to solve the IK for different cases; therefore, the IK model is solved for bending and direction angles between (−π/2 to +π/2) radians. In addition, a novel method to calculate the Jacobian matrix is proposed for this type of hyper-redundant kinematics. The error between the results calculated using the proposed Jacobian algorithm and using the partial derivative equations of the FK map (with respect to linear and angular velocity) is evaluated. The error between the two models is found to be insignificant, thus, the Jacobian is validated as a method of calculating the IK for six DoF.

Type Synthesis of a Family of Novel Four, Five, and Six Degrees-of-Freedom Sea Lion Ball Mechanisms With Three Limbs

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
Rongfu Lin ◽  
Weizhong Guo ◽  
Feng Gao
Keyword(s):  
Mathematical Models ◽  
Degrees Of Freedom ◽  
Type Synthesis ◽  
Sea Lion ◽  
End Effector ◽  
Motion Patterns ◽  
Six Degrees Of Freedom ◽  
Rotational Motions ◽  
The Given ◽  
Actuated Joints

A family of novel mechanisms with three limbs called sea lion ball mechanisms (SLBMs) is investigated that looks like a sea lion playing with a ball. The SLBM-type mechanism is composed of an upper part and a lower part connected together by three limbs in parallel, and the translational and rotational motions are fully/partially decoupled. The end-effector position is determined by inputs of the lower part, while the posture is mainly determined by inputs of the upper part. First, two compositional principles are abstracted and the corresponding mathematical models are built for the SLBM-type mechanisms that the commutative feature of the SLBMs is found. Then, two type synthesis procedures containing five steps are proposed correspondingly. Following the procedure, a family of novel four, five, and six degrees-of-freedom (DOF) SLBM-type mechanisms is synthesized systematically. The motion patterns of the limbs are enumerated according to the given desired ones of the mechanisms and the limbs are synthesized correspondingly. Finally, several novel SLBM-type mechanisms are achieved by assembling the obtained limbs and selecting the actuated joints.

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