A multi-configuration kinematic model for active drive/steer four-wheel robot structures

Robotica ◽  
2015 ◽  
Vol 34 (10) ◽  
pp. 2309-2329 ◽  
Author(s):  
Edgar A. Martínez-García ◽  
Erik Lerín-García ◽  
Rafael Torres-Córdoba
Keyword(s):  
Degrees Of Freedom ◽  
Rotation Axis ◽  
Contact Point ◽  
Linear Equations ◽  
Kinematic Model ◽  
Robotic Systems ◽  
Control Law ◽  
Special Design ◽  
Wheel Drive ◽  
Four Wheel Drive

SUMMARYIn this study, a general kinematic control law for automatic multi-configuration of four-wheel active drive/steer robots is proposed. This work presents models of four-wheel drive and steer (4WD4S) robotic systems with all-wheel active drive and steer simultaneously. This kinematic model comprises 12 degrees of freedom (DOFs) in a special design of a mechanical structure for each wheel. The control variables are wheel yaw, wheel roll, and suspension pitch by active/passive damper systems. The pitch angle implies that a wheel's contact point translates its position over time collinear with the robot's lateral sides. The formulation proposed involves the inference of the virtual z-turn axis (robot's body rotation axis) to be used in the control of the robot's posture by at least two acceleration measurements local to the robot's body. The z-turn axis is deduced through a set of linear equations in which the number of equations is equal to the number of acceleration measurements. This research provides two main models for stability conditions. Finally, the results are sustained by different numerical simulations that validate the system with different locomotion configurations.

Robust Trajectory Following Control of Robotic Systems

1985 ◽  
Vol 107 (4) ◽  
pp. 308-315 ◽  
Author(s):  
S. N. Singh ◽  
A. A. Schy
Keyword(s):  
Degrees Of Freedom ◽  
Digital Simulation ◽  
Robotic Systems ◽  
Control Law ◽  
Robot Arm ◽  
Control Laws ◽  
Payload Uncertainty ◽  
Trajectory Following ◽  
And Control ◽  
Three Degrees Of Freedom

Using an inversion approach we derive a control law for trajectory following of robotic systems. A servocompensator is used around the inner decoupled loop for robustness to uncertainty in the system. These results are applied to trajectory control of a three-degrees-of-freedom robot arm and control laws Cθ and CH for joint angle and position trajectory following, respectively, are derived. Digital simulation results are presented to show the rapid trajectory following capability of the controller in spite of payload uncertainty.

Nonlinear numerical and experimental study on the second-order torsional and lateral vibration of driveline system connected by cardan joint

2019 ◽  
Vol 26 (7-8) ◽  
pp. 540-551
Author(s):  
Yuanfeng Xia ◽  
Jian Pang ◽  
Liang Yang ◽  
Qin Zhao ◽  
Xianwu Yang
Keyword(s):  
Degrees Of Freedom ◽  
Second Order ◽  
Nonlinear Dynamic Model ◽  
Vehicle Interior ◽  
Intersection Angle ◽  
Coupling Vibration ◽  
Order Tracking ◽  
Wheel Drive ◽  
Four Wheel Drive ◽  
Cardan Joint

In this article, a nonlinear dynamic model with five degrees-of-freedom for a four-wheel-drive vehicle driveline connected by a cardan joint, including dynamic intersection angle, nonconstant velocity, and additional moment caused by the cardan joint, is established by using the Lagrange method to analyze the driveline coupling vibration in both torsional and lateral directions. High-order Runge–Kutta algorithm is applied to solve the differential equations and to calculate transient responses of the driveline rotors under acceleration condition. The color maps and second-order vibration of the driveline are acquired by frequency spectrum analysis and order tracking analysis, respectively. The second-order vibration and noise of the driveline and vehicle interior caused by the cardan joint is validated by vehicle experimental results and reduced effectively by decreasing intersection angle of the cardan joint under the operational condition. Moreover, application of a flexible coupling instead of the cardan joint significantly reduces the second-order vibration but simultaneously generates low-level third-order vibration.

scholarly journals THE EFFECT OF COLLATERAL LIGAMENT INJURY ON CARTILAGE CONTACT IN KNEE JOINTS MODELED WITH SIX DEGREES OF FREEDOM

2016 ◽  
Vol 16 (03) ◽  
pp. 1650080
Author(s):  
NERIMAN ÖZADA
Keyword(s):  
Knee Joint ◽  
Degrees Of Freedom ◽  
Contact Point ◽  
Kinematic Model ◽  
Surface Geometry ◽  
Collateral Ligament ◽  
Point Distribution ◽  
Six Degrees Of Freedom ◽  
Six Dof ◽  
Intact Knee

The purpose of this study was to create a kinematic model of the knee joint with six degrees of freedom (DOF) and evaluate the effect of medial collateral ligament (MCL) and lateral collateral ligament (LCL) rupture on cartilage contact point distribution on the tibia during flexion. We hypothesized that collateral ligament contributions vary over six DOF of knee joint articulation and affect the cartilage contact point distribution during joint articulation. The ligament contributions and distribution of joint cartilage contact points cannot be fully assessed with simplified joint models or invasive experiments. Therefore, we developed a new model in which the tibia and femur centers of mass were determined from their surface geometry, and the displacement of the moving tibia was determined from the displacements of the attached ligaments. Compared to the intact knee, the tibia with the LCL removed had higher medial translation and lower valgus rotation. The tibia with the MCL removed had higher lateral translation and higher valgus rotation than the intact knee. At 0[Formula: see text], 30[Formula: see text], and 60[Formula: see text], the tibia with the LCL removed had more internal rotation than the intact knee. Understanding six DOF knee joint kinematics with integration of ligament contributions and cartilage contact positions is useful for the diagnosis of ligament injuries and the design of articulating surfaces for total arthroplasty.

scholarly journals Effect of circular arc feet on a control law for a biped

Robotica ◽  
2009 ◽  
Vol 27 (4) ◽  
pp. 621-632 ◽  
Author(s):  
T. Kinugasa ◽  
C. Chevallereau ◽  
Y. Aoustin
Keyword(s):  
Degrees Of Freedom ◽  
Temporal Evolution ◽  
Contact Point ◽  
Basin Of Attraction ◽  
Control Law ◽  
Leg Length ◽  
Circular Arc ◽  
Geometric Evolution ◽  
Cyclic Motion ◽  
The Stability

SUMMARYThe purpose of our research is to study the effects of circular arc feet on the biped walk with a geometric tracking control. The biped studied is planar and is composed of five links and four actuators located at each hip and each knee thus the biped is underactuated in single support phase. A geometric evolution of the biped configuration is controlled, instead of a temporal evolution. The input-output linearization with a PD control law and a feed forward compensation is used for geometric tracking. The controller virtually constrains 4 degrees of freedom (DoF) of the biped, and 1 DoF (the absolute orientation of the biped) remained. The temporal evolution of the remained system with impact events is analyzed using Poincaré map. The map is given by an analytic expression based on the angular momentum about the contact point. The effect of the radii of the circular arc feet on the stability is studied. As a result, the speed of convergence decreases when the radii increases, if the radius is larger than the leg length the cyclic motion is not more stable. Among the stable cyclic motion, larger radius broadens the basin of attraction. Our results agree with those obtained for passive dynamic walking on stability, even if the biped is controlled through the geometric tracking.

scholarly journals Didactic demonstration of 3gdl robot dynamics and partitioned control for trajectory tracking

2020 ◽  
pp. 10-16
Author(s):  
Miguel Ramírez-Aguirre ◽  
José Luis Ortiz-Simón ◽  
Martha Aguilera-Hernández ◽  
Nicolás Cruz-Hernández
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Control Law ◽  
Robot Dynamics ◽  
End Effector ◽  
Christoffel Symbols ◽  
Work Area ◽  
Centers Of Mass ◽  
Three Degrees Of Freedom

The article presents the analysis of a robot with three degrees of freedom to follow trajectories through a partitioned control. Which is made up of two revolute and one prismatic joint where the end effector is located, that allows it to move correctly in its work area. This robot has a different structure from those most studied and analyzed by current literature, therefore it presents an opportunity to be used as a didactic resource, due to the structure, the degrees of freedom and the affinity of the models used by the students. The analysis consists of the use of the DH rule for the assignment of frames and referential axes, centers of mass, dynamic model by Jacobian and Christoffel symbols, inverse kinematic model, variables such as friction, gravitational and friction compensation, ending in a model in "Simulink" capable of following trajectories from the partitioned control law.

scholarly journals Improving the Detection of the Contact Point in Active Sensing Antennae by Processing Combined Static and Dynamic Information

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1808
Author(s):  
Luis Mérida-Calvo ◽  
Daniel Feliu-Talegón ◽  
Vicente Feliu-Batlle
Keyword(s):  
Contact Point ◽  
Load Cell ◽  
Robotic Systems ◽  
Accurate Estimation ◽  
Flexible Beam ◽  
Dynamic Information ◽  
New Developments ◽  
Static Information ◽  
Insect Antennae ◽  
Flexible Antenna

The design and application of sensing antenna devices that mimic insect antennae or mammal whiskers is an active field of research. However, these devices still require new developments if they are to become efficient and reliable components of robotic systems. We, therefore, develop and build a prototype composed of a flexible beam, two servomotors that drive the beam and a load cell sensor that measures the forces and torques at the base of the flexible beam. This work reports new results in the area of the signal processing of these devices. These results will make it possible to estimate the point at which the flexible antenna comes into contact with an object (or obstacle) more accurately than has occurred with previous algorithms. Previous research reported that the estimation of the fundamental natural frequency of vibration of the antenna using dynamic information is not sufficient as regards determining the contact point and that the estimation of the contact point using static information provided by the forces and torques measured by the load cell sensor is not very accurate. We consequently propose an algorithm based on the fusion of the information provided by the two aforementioned strategies that enhances the separate benefits of each one. We demonstrate that the adequate combination of these two pieces of information yields an accurate estimation of the contacted point of the antenna link. This will enhance the precision of the estimation of points on the surface of the object that is being recognized by the antenna. Thorough experimentation is carried out in order to show the features of the proposed algorithm and establish its range of application.

scholarly journals A New Approach of Soft Joint Based on a Cable-Driven Parallel Mechanism for Robotic Applications

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1468
Author(s):  
Luis Nagua ◽  
Carlos Relaño ◽  
Concepción A. Monje ◽  
Carlos Balaguer
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Experimental Tests ◽  
Humanoid Robots ◽  
Inverse Kinematic ◽  
Element Analysis ◽  
New Approach ◽  
Flexible Polymer ◽  
The Mathematical Model

A soft joint has been designed and modeled to perform as a robotic joint with 2 Degrees of Freedom (DOF) (inclination and orientation). The joint actuation is based on a Cable-Driven Parallel Mechanism (CDPM). To study its performance in more detail, a test platform has been developed using components that can be manufactured in a 3D printer using a flexible polymer. The mathematical model of the kinematics of the soft joint is developed, which includes a blocking mechanism and the morphology workspace. The model is validated using Finite Element Analysis (FEA) (CAD software). Experimental tests are performed to validate the inverse kinematic model and to show the potential use of the prototype in robotic platforms such as manipulators and humanoid robots.

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