A Solution for the Force Distribution Problem in Redundantly Actuated Closed Kinematic Chains

1990 ◽  
Vol 112 (3) ◽  
pp. 523-526 ◽  
Author(s):  
J. F. Gardner ◽  
K. Srinivasan ◽  
K. J. Waldron
Keyword(s):  
System Performance ◽  
Additional Constraint ◽  
Robotic Systems ◽  
Force Distribution ◽  
Distribution Problem ◽  
Walking Machine ◽  
Kinematic Chains ◽  
Constraint Equations ◽  
Redundantly Actuated ◽  
Alternative Solutions

Proper control of robotic systems which incorporate closed kinematic chains is important in many applications. Among these are the multi-robot work cell and legged vehicles. In these no unique solution exists for the force distribution corresponding to a specified trajectory. A framework within which additional constraint equations may be written is presented here, and the force distribution solved in closed form for a walking machine application. These constraints are related to system performance goals of interest, such as improved traction and/or load sharing among the legs. The proposed technique is shown to be computationally simpler than other alternative solutions to the same problem.

Body Vibrations of a Legged Walking Machine

1992 ◽  
Author(s):  
Xiaochun Gao ◽  
Shin-Min Song
Keyword(s):  
The Body ◽  
Robotic Systems ◽  
Force Distribution ◽  
Walking Machine ◽  
Foot Force ◽  
Robot Hands ◽  
Machine Systems ◽  
External Loads ◽  
Wheeled Vehicles ◽  
Quadrupedal Walking

Abstract Unlike in wheeled vehicles, compliance in walking machine systems changes due to the variation of leg geometry, as its body proceeds. This variation in compliance will cause vibration, even if external loads remain constant. A theory is thus developed to predict the body vibrations of a walking machine during walking. On the other hand, dynamic foot forces under body vibrations can be computed by application of the existing numerical methods. As an example, the body vibrations of a quadrupedal walking chair under different walking conditions are simulated in terms of the developed theory. The results show that the influence of body vibrations on the foot force distribution is essential and, in some cases, the walking chair may lose its stability due to its body vibrations, even though it is identified to be stable in a quasi-static analysis. The developed theory can also be extended to other similar multi-limbed robotic systems, such as multi-fingered robot hands.

Grasping, coordination and optimal force distribution in multifingered mechanisms

Robotica ◽  
1994 ◽  
Vol 12 (3) ◽  
pp. 243-251 ◽  
Author(s):  
P. Gorce ◽  
C. Villard ◽  
J. G. Fontaine
Keyword(s):  
Interaction Model ◽  
Force Distribution ◽  
Distribution Problem ◽  
Inverse Dynamic ◽  
Kinematic Chains ◽  
Object Interaction ◽  
Control Command ◽  
Optimal Force ◽  
Gripper Systems ◽  
The Coordinator

SUMMARYIn the field of multifingered mechanisms the control/command problem is mainly a problem o1 coordination. The problem is not only to coordinate joints of a chains but also to coordinate the different chains together.This paper presents a general and efficient method for implementing the control/command of such systems, taking into account the force distribution problem. To solve this problem it is necessary to pay great attention to dynamic effects. To do this, we broke down the Inverse Dynamic Model (I.D.M.) problem into two main levels; One level is devoted to I.D.M. computation; it can be called the Finger Level (F.L.). As we wanted to divide up the work to be done as much as possible, we subdivided the Finger Level according to the number o1 kinematic chains. In addition, we considered a second level, the Coordinator. This level has to control all the chains using the Fingers-to-Object-Interaction Model (F.O.LM.).Next, we will also introduce new grasping systems: Polyvalent Gripper Systems (P.G.S). There are a new solution to multicomponent assembly problems. As they can be equipped with several multifingered mechanisms, they can also use the control/command scheme.

Body Vibration of a Legged Walking Machine

1993 ◽  
Vol 115 (4) ◽  
pp. 856-862
Author(s):  
Xiaochun Gao ◽  
Shin-Min Song
Keyword(s):  
The Body ◽  
Robotic Systems ◽  
Force Distribution ◽  
Walking Machine ◽  
Foot Force ◽  
Robot Hands ◽  
Machine Systems ◽  
External Loads ◽  
Wheeled Vehicles ◽  
Quadrupedal Walking

Unlike wheeled vehicles, compliance in walking machine systems changes due to the variation of leg geometry, as its body proceeds. This variation in compliance will cause vibration, even if external loads remain constant. A theory is thus developed to predict the body vibrations of a walking machine during walking. On the other hand, dynamic foot forces under body vibrations can be computed by application of the existing numerical methods. As an example, the body vibrations of a quadrupedal walking chair under different walking conditions are simulated in terms of the developed theory. The results show that the influence of body vibrations on the foot force distribution is essential and, in some cases, the walking chair may lose its stability due to its body vibrations, even though it is identified to be stable in a quasistatic analysis. The developed theory can also be extended to other similar multilimbed robotic systems, such as multifingered robot hands.

Integrated Kinematic Calibration for All the Parameters of a Planar 2DOF Redundantly Actuated Parallel Manipulator

2009 ◽  
Vol 1 (3) ◽  
Author(s):  
Chunshi Feng ◽  
Shuang Cong ◽  
Weiwei Shang
Keyword(s):  
Parallel Manipulator ◽  
Closed Loop ◽  
Open Loop ◽  
Kinematic Calibration ◽  
Constraint Equations ◽  
Integrated Method ◽  
Uniqueness Of The Solution ◽  
Redundantly Actuated ◽  
Loop Constraint ◽  
Two Degree Of Freedom

In this paper, the kinematic calibration of a planar two-degree-of-freedom redundantly actuated parallel manipulator is studied without any assumption on parameters. A cost function based on closed-loop constraint equations is first formulated. Using plane geometry theory, we analyze the pose transformations that bring infinite solutions and present a kinematic calibration integrated of closed-loop and open-loop methods. In the integrated method, the closed-loop calibration solves all the solutions that fit the constraint equations, and the open-loop calibration guarantees the uniqueness of the solution. In the experiments, differential evolution is applied to compute the solution set, for its advantages in computing multi-optima. Experimental results show that all the parameters involved are calibrated with high accuracy.

Foot force distribution of walking machine with consideration of terrain properties

1992 ◽  
Vol 29 (4-5) ◽  
pp. 497-514 ◽  
Author(s):  
Chun Qi Zheng ◽  
Shin-Min Song ◽  
G.E.O. Widera
Keyword(s):  
Force Distribution ◽  
Walking Machine ◽  
Foot Force

scholarly journals A Recursive Algorithm for the Forward Kinematic Analysis of Robotic Systems Using Euler Angles

Robotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Fernando Gonçalves ◽  
Tiago Ribeiro ◽  
António Fernando Ribeiro ◽  
Gil Lopes ◽  
Paulo Flores
Keyword(s):  
Recursive Algorithm ◽  
Kinematic Chain ◽  
Robotic Systems ◽  
Mobile Manipulator ◽  
Euler Angles ◽  
Joint Angles ◽  
Main Research ◽  
Kinematic Chains ◽  
Research Fields ◽  
Forward Kinematic

Forward kinematics is one of the main research fields in robotics, where the goal is to obtain the position of a robot’s end-effector from its joint parameters. This work presents a method for achieving this using a recursive algorithm that builds a 3D computational model from the configuration of a robotic system. The orientation of the robot’s links is determined from the joint angles using Euler Angles and rotation matrices. Kinematic links are modeled sequentially, the properties of each link are defined by its geometry, the geometry of its predecessor in the kinematic chain, and the configuration of the joint between them. This makes this method ideal for tackling serial kinematic chains. The proposed method is advantageous due to its theoretical increase in computational efficiency, ease of implementation, and simple interpretation of the geometric operations. This method is tested and validated by modeling a human-inspired robotic mobile manipulator (CHARMIE) in Python.

scholarly journals Reconfiguration Analysis of a 3-DOF Parallel Mechanism

Robotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 66
Author(s):  
Maurizio Ruggiu ◽  
Xianwen Kong
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Operation Mode ◽  
Parallel Mechanisms ◽  
Universal Joint ◽  
Kinematic Chains ◽  
Constraint Equations ◽  
The Third ◽  
Equilateral Triangles ◽  
Moving Platform

This paper deals with the reconfiguration analysis of a 3-DOF (degrees-of-freedom) parallel manipulator (PM) which belongs to the cylindrical parallel mechanisms family. The PM is composed of a base and a moving platform shaped as equilateral triangles connected by three serial kinematic chains (legs). Two legs are composed of two universal (U) joints connected by a prismatic (P) joint. The third leg is composed of a revolute (R) joint connected to the base, a prismatic joint and universal joint in sequence. A set of constraint equations of the 1-RPU−2-UPU PM is derived and solved in terms of the Euler parameter quaternion (a.k.a. Euler-Rodrigues quaternion) representing the orientation of the moving platform and of the Cartesian coordinates of the reference point on the moving platform. It is found that the PM may undergo either the 3-DOF PPR or the 3-DOF planar operation mode only when the base and the moving platform are identical. The transition configuration between the operation modes is also identified.

scholarly journals OPTIMAL ENERGY DISTRIBUTION WITH ENERGY PACKET NETWORKS

2019 ◽  
pp. 1-17 ◽  
Author(s):  
Yunxiao Zhang
Keyword(s):  
Energy Distribution ◽  
System Performance ◽  
Renewable Energy Sources ◽  
Packet Networks ◽  
Distribution Problem ◽  
Computer Communication ◽  
Optimal Energy ◽  
Penalty Costs ◽  
Parameter Values ◽  
Special Case

We use the Energy Packet Network (EPN) to investigate an optimal energy distribution problem for the computer-communication system which is powered by intermittent renewable energy sources. The objective is to find an optimal energy distribution to minimize the proposed cost function which computes penalty costs caused by the overall average response time of jobs and the energy loss. In this EPN system, we consider the energy can be lost through storage leakages, or due to empty workstations which will consume energy even no job needs to be processed. Related numerical examples with different sets of parameter values are presented in the paper to evaluate the system performance and to examine the obtained analytical solution. Then a special case is considered to study the optimal system performance when the total energy harvesting rate is sufficiently large.

Force Distribution With Pose-Dependent Force Boundaries for Redundantly Actuated Cable-Driven Parallel Robots

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Han Yuan ◽  
Eric Courteille ◽  
Dominique Deblaise
Keyword(s):  
Energy Consumption ◽  
Lower Boundary ◽  
Parallel Robots ◽  
Force Distribution ◽  
Computational Accuracy ◽  
Boundary Method ◽  
Redundantly Actuated ◽  
Cable Forces ◽  
Reducing Energy

This paper addresses the force distribution of redundantly actuated cable-driven parallel robots (CDPRs). A new and efficient method is proposed for the determination of the lower-boundary of cable forces, including the pose-dependent lower-boundaries. In addition, the effect of cable sag is considered in the calculation of the force distribution to improve the computational accuracy. Simulations are made on a 6DOF CDPR driven by eight cables to demonstrate the validity of the proposed method. Results indicate that the pose-dependent lower-boundary method is more efficient than the fixed lower-boundary method in terms of minimizing the motor size and reducing energy consumption.

Control of Force Distribution in Robotic Mechanisms Containing Closed Kinematic Chains

1981 ◽  
Vol 103 (2) ◽  
pp. 134-141 ◽  
Author(s):  
D. E. Orin ◽  
S. Y. Oh
Keyword(s):  
Linear Programming ◽  
Basic Problem ◽  
Inequality Constraints ◽  
Force Distribution ◽  
Joint Torques ◽  
Kinematic Chains ◽  
System Trajectory ◽  
Reaction Forces ◽  
Tripod Gait ◽  
Weighted Combination

Control of the force distribution in locomotion and manipulation systems containing closed kinematic chains is an important problem since many tasks such as walking or grasping depend upon it. The basic problem is to solve for the input joint torques for a particular system trajectory and is usually underspecified. As such, linear programming has been used to obtain a solution which optimizes a weighted combination of energy consumption and load balancings. Inequality constraints on the maximum actuator torques and reaction forces at the tip of each chain of the system are imposed, in addition to equality constraints which specify movement in a desired system trajectory. An example is given in which the joint torques to drive a hexapod locomotion vehicle in a tripod gait are computed.

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