Motion Simulation of a Hybrid Parallel Robot for Ankle Rehabilitation

Author(s):  
Hamid Rakhodaei ◽  
Mozafar Saadat ◽  
Alireza Rastegarpanah

This paper addresses the path planning of a hybrid parallel robot for ankle rehabilitation. The robot contains 3-DOF parallel mechanism that is attached on top of the 6-DOF hexapod. The 6-UPU-3-UPR parallel robot is developed to simulate ankle motions for the rehabilitation of post-stroke patients with an affected ankle. The inverse kinematic of hybrid parallel robot is developed in order to track the end-effector’s position through Matlab software. The calculated stroke size of each actuator is imported to apply the forward kinematic for determining the position of end-effector. The experimental and simulation values of the hexapod are compared with those of the hybrid structure through a number of exercise motion paths. The results reveal that, in general, the simulation values follow well the experimental values, although with different degrees of variation for each of the structures considered.

Author(s):  
Martín Eduardo Rodríguez-Franco ◽  
Ricardo Jara-Ruiz ◽  
Yadira Fabiola López-Álvarez ◽  
Juan Carlos García-Rodríguez

The development and implementation process of a computer interface for the kinematic analysis of a parallel robot, in delta configuration, and its application to a previously formed prototype are exposed. Being identified the associated equations, and deduced the respective geometric parameters. On the other hand, the synthesis of the direct and inverse kinematic models, with the Matlab software, guarantees the calculation of a specific Cartesian position, in the end effector of the robot used, once certain joint values have been assigned to it, or vice versa. Finally, a user-friendly graphical interface is created, whose functions are: data entry, resolution of the models described, issuance of the corresponding results, representation of the robot used and its physical manipulation. The results obtained in the real location of the end effector with respect to the values deduced by the interface, are competitive for both models analyzed, even though the prototype used operates by means of servomotors. An average position error of 0.083 cm per axis and overall of 0.006 cm is observed during the tests developed.


2021 ◽  
Vol 13 (2) ◽  
pp. 125-134
Author(s):  
Fransisko Limanuel ◽  
Calvin Susanto ◽  
Ferry Rippun Gideon Manalu

This paper will discuss the calculation of inverse kinematic which will be used to control the 6-DOF articulated robot. This robot consists of 6 Dynamixel MX-28 smart servo with OpenCM 9.04 microcontroller. The articulated robot has been simplified to 4-DOF because there are no obstacles in the work area and no special movements are required. The calculation method uses the intersection point equation between the ball and the line, so that it can make it easier to determine the point in calculating the kinematic inverse. The experiment is carried out using the desired position as input for the kinematic inverse to produce the angle of each joint. From the angle of each joint obtained, it will be entered into forward kinematic so that the end-effector position will be obtained. The desired position will be compared with the end-effector position, and then how much difference will be calculated. From the experimental results, it was found that the inverse kinematic method which has been inverted by the forward kinematic produces the same final position. Keywords: 6-DOF manipulator, Articulated robot, inverse kinematics and forward kinematics, Dynamixel MX-28, OpenCM 9


Robotica ◽  
2014 ◽  
Vol 34 (1) ◽  
pp. 173-184 ◽  
Author(s):  
Hamid Rakhodaei ◽  
Mozafar Saadat ◽  
Alireza Rastegarpanah ◽  
Che Zulkhairi Abdullah

SUMMARYThis paper presents a new configuration for ankle rehabilitation using a 9-DOF (degree of freedom) hybrid parallel robot. The robot contains nine linear actuators serially connecting two movable platforms and one stationary platform. The optimization is based on the singularity and dynamic analysis of the robot. The obtained data of the ankle motions from a series of experiments were applied to the model in order to investigate the motion of the end-effector and the force required for each actuator in a particular path. The end-effector tracking simulation results validated the proposed theoretical analysis of the required rehabilitation path of the foot.


2014 ◽  
Vol 8 (1) ◽  
pp. 457-461
Author(s):  
Xuewen Rong ◽  
Rui Song ◽  
Hui Chai ◽  
Xiaolin Ma

This paper gives a mechanism design of a six DOF hydraulically actuated manipulator firstly. Then its DH frames and link parameters are given. Next, its forward kinematic equations are derived according to homogeneous transformation method. Fourthly, the analytical solutions of its inverse kinematics are solved by given the position and posture of the end-effector simultaneously. The posture of the end-effector is given with three z-y-z Euler angles for they have obvious geometry meanings and are easy to be measured. In addition, the correctness of the inverse kinematic equations is verified in Simulink by comparing many sets of randomly produced joint variables in workspace and their corresponding inverse solutions.


2017 ◽  
Vol 13 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Hussein M. Al-Khafaji ◽  
Muhsin J. Jweeg

The inverse kinematic equation for a robot is very important to the control robot’s motion and position. The solving of this equation is complex for the rigid robot due to the dependency of this equation on the joint configuration and structure of robot link. In light robot arms, where the flexibility exists, the solving of this problem is more complicated than the rigid link robot because the deformation variables (elongation and bending) are present in the forward kinematic equation. The finding of an inverse kinematic equation needs to obtain the relation between the joint angles and both of the end-effector position and deformations variables. In this work, a neural network has been proposed to solve the problem of inverse kinematic equation. To feed the neural network, experimental data were taken from an elastic robot arm for training the network, these data presented by joint angles, deformation variables and end-effector positions. The results of network training showed a good fit between the output results of the neural network and the targets data. In addition, this method for finding the inverse of kinematic equation proved its effectiveness and validation when applying the results of neural network practically in the robot’s operating software for controlling the real light robot’s position.


2021 ◽  
Vol 1802 (4) ◽  
pp. 042086
Author(s):  
Hongpeng Li ◽  
Chen Xia ◽  
Feilong Li ◽  
Jun Yin ◽  
Xiaoliang Wang ◽  
...  

Author(s):  
DU Hui ◽  
GAO Feng ◽  
PAN Yang

A novel 3-UP3R parallel mechanism with six degree of freedoms is proposed in this paper. One most important advantage of this mechanism is that the three translational and three rotational motions are partially decoupled: the end-effector position is only determined by three inputs, while the rotational angles are relative to all six inputs. The design methodology via GF set theory is brought out, using which the limb type can be determined. The mobility of the end-effector is analyzed. After that, the kinematic and velocity models are formulated. Then, workspace is studied, and since the robot is partially decoupled, the reachable workspace is also the dexterous workspace. In the end, both local and global performances are discussed using conditioning indexes. The experiment of real prototype shows that this mechanism works well and may be applied in many fields.


Author(s):  
Martin Hosek ◽  
Michael Valasek ◽  
Jairo Moura

This paper presents single- and dual-end-effector configurations of a planar three-degree of freedom parallel robot arm designed for automated pick-place operations in vacuum cluster tools for semiconductor and flat-panel-display manufacturing applications. The basic single end-effector configuration of the arm consists of a pivoting base platform, two elbow platforms and a wrist platform, which are connected through two symmetric pairs of parallelogram mechanisms. The wrist platform carries an end-effector, the position and angular orientation of which can be controlled independently by three motors located at the base of the robot. The joints and links of the mechanism are arranged in a unique geometric configuration which provides a sufficient range of motion for typical vacuum cluster tools. The geometric properties of the mechanism are further optimized for a given motion path of the robot. In addition to the basic symmetric single end-effector configuration, an asymmetric costeffective version of the mechanism is derived, and two dual-end-effector alternatives for improved throughput performance are described. In contrast to prior attempts to control angular orientation of the end-effector(s) of the conventional arms employed currently in vacuum cluster tools, all of the motors that drive the arm can be located at the stationary base of the robot with no need for joint actuators carried by the arm or complicated belt arrangements running through the arm. As a result, the motors do not contribute to the mass and inertia properties of the moving parts of the arm, no power and signal wires through the arm are necessary, the reliability and maintenance aspects of operation are improved, and the level of undesirable particle generation is reduced. This is particularly beneficial for high-throughput applications in vacuum and particlesensitive environments.


Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 745
Author(s):  
Marco Carpio ◽  
Roque Saltaren ◽  
Julio Viola ◽  
Cristian Calderon ◽  
Juan Guerra

The design of robot systems controlled by cables can be relatively difficult when it is approached from the mathematical model of the mechanism, considering that its approach involves non-linearities associated with different components, such as cables and pulleys. In this work, a simple and practical decoupled control structure proposal that requires practically no mathematical analysis was developed for the position control of a planar cable-driven parallel robot (CDPR). This structure was implemented using non-linear fuzzy PID and classic PID controllers, allowing performance comparisons to be established. For the development of this research, first the structure of the control system was proposed, based on an analysis of the cables involved in the movement of the end-effector (EE) of the robot when they act independently for each axis. Then a tuning of rules was carried out for fuzzy PID controllers, and Ziegler–Nichols tuning was applied to classic PID controllers. Finally, simulations were performed in MATLAB with the Simulink and Simscape tools. The results obtained allowed us to observe the effectiveness of the proposed structure, with noticeably better performance obtained from the fuzzy PID controllers.


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